Exposure Bracketing - how it works  

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Destiny
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by Destiny » Sun May 15, 2011 5:33 am

Hi Andrew.... I only did one pan with the camera angle set to 0... so their shouldn't have been any creep... I know what you mean though.. I will check out all these links you have provided...

For my next trick I put the pano layer images back into apg in the hope that I could merge them some how.. but nop.. cannot to that.. as far as I know.. that’s a real shame.. Out of curiosity I put the same pano layers into PTGui... I pressed Aline and it did its thing.. I them ran it trough optimiser.. Well.. I have had when stitching... "good"... "very good" and even "excellent".. but PTGui said.. "This is to good to be true" which made me laugh.. actually, apg must take credit for that since I used the images stitched from this.. Unfortunately, there is still misalignment.. So this time I put the exposure set into PTGui and stitched each of the three sets of panos.. I dropped the images into Photoshop and had only to do a little bit of alignment and then put the layers on opacity until I liked the results.. I then zoomerfyed the results at this link..

http://www.destinyvirtualtours.com/DPS/ZoomStuff/3-panos-from-PTGui.html

I really do not know why when I put the stacked images into apg or as individual panos that they do not line up as good a PTGui when processed as pano images… Perhaps I am still doing something wrong.. I have found that sometimes if I turn it off or reboot the results can be different each time…

D…

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by Destiny » Sun May 15, 2011 5:35 am

Hi John.. sorry, I took your post over a bit.. I am playing with what you are trying to do.. I will see what I come up with...

D...;)

irpano wrote:George.Destiny and mediavets, Thanks for your responses. I have had similar results to Destiny and have learnt to make sure the overlap is not excessive. I use the T&C controller on the merlin and then load into APG using the inmport function. On single exposed images i dont have any problem at All APG reports excellent RMS.
However with any multiple exposed image (Bracket at each position), APG has trouble and is not even consistent even after loading a number of times. Now to the point of my original question - HOW to control the Fusion process on Bracketed images. IE how do you control the Final exposure, contrast and tones for each individual "Tile ' created. The Fusion control in rendering will alter these settings on the final pano but I sometimes ned to control each 'Tile' settings. Can it be done.
Why I use tufuse pro (Tawbaware) is that it gives me this control for each individual tile, and as the images are aligned , fuse very well.
So from a 90 image set (10X3X3) I will get 30 tiles each having good tone,exposure and contrast. APG then stitches the 30 TILES excellently.
So can I achieve this with APG and do away with the need to proccess brackets manually in tufuse pro.
John

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by Destiny » Sun May 15, 2011 7:35 am

Hi Andrew... I just looked at your links.. I bought that 1.8 lens a few months go...!! I have only just bought a soft focus filter for it to take portraits, I haven't had time to try it out yet.. I love this lens.. Its cheap and just fantastic.. I had no idea I could use it for panos... I will try it out really soon... I always read Ken Rockwell comments.. he is the best for sure... straight to the point and easy to understand... I bought my 10.5 fisheye lens after reading his comments on it... if I bought the D700 I would have bought the 16mm fisheye... Thank you for the info for taking a 360X180... to-date I have not taken a full pano with my fisheye..

When I was a lot younger, my dad bought me my first digital camera, a Canon G3 with an el cheap'o surveyors tripod.. He made me up a piece of wood to clamp in the jaws where the spirit level would normally sit.. I then screwed that to my camera. This was my very first setup for taking a panos... Just one straight row of images in landscape... I soon wanted to put the camera to portrait but the results with the software I was using was not good so I just thought it was how it was meant to be.. until I read an article about kolor sotware... only last year I picked it all up again and I just love it all.... so many people like you just willing so show and tell... I am always learning new things.. Soon my car VRs will be awesome.... You can put that down to my stubbornness to get it right... wow.. i love this 1.8.. it takes really beautiful images.. never thought of using it for panos.... So, what would the setup in using this lens.. same as the 18-105 or different...

I did not use a remote since I my remote is just a little thing and will not take bracketed shots. But soon my wireless controller will arrive.. much better I think... Someone told me about it on the Nodal Ninja forum... I am almost set to take a great car pano... but I am still worried that apg cannot do it... I cannot understand why the images do not line up.. I will try again... and then put the separate panos with different light setting into Photoshop to see how well they line up... PTGui does a very good job but I do not like using it... I really love apg so I need to learn how to do it better.. there must be something I am missing.... My images have been taken a the same time.. in brackets.. so there is no reason why the 3 panos should be different.... like I say, I will give it another try.... with my 1.8....:lol:

Thank you Andrew...

D..




mediavets wrote:Using your 18-105mm lens at 18mm the following pattenn could be used for a 360x180:

Minimum (1.5x): N, 10 images every 36° at -45° pitch, 10 images every 36° at 0° pitch, 10 images every 36° at +45° pitch, Z

http://www.vrwave.com/panoramic-lens-database/

Are you using a remote control to trigger the shutter?

Are you getting zoom creep or focus creep with that 'kit' zoom?

My 18-55mm 'kit' zoom lens creeps at high/low pitch angles on my Merlin mount. That's why I got a Nikkor 50mm f/1.8 D prime for higher res panos, small, light, realtively inexpensive and very little distortion:
http://www.photozone.de/nikon--nikkor-aps-c-lens-tests/217-nikkor-af-50mm-f18-d-review--test-report

http://www.kenrockwell.com/nikon/5018daf.htm

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by mediavets » Sun May 15, 2011 8:57 am

I've only used the 50mm on my Merlin motorised mount with Papywizard.

When shooting partial panos - panos with a FOV of less than 360x180 - the Papywizard software computes the yaw and pitch intervals in the grid/matrix shooting pattern automatically to achieve the desired overlap.

I don't have a shooting pattern for 360x180 with a 50mm on a DX body with a manual pano head.

Start experimenting with a (much) smaller pano FOV and determine the shooting intervals that give you about 25-50% overlap using LiveView. Or download and play with Papywizard in simulation mode to see what shooting pattern it computes/suggests, if you want to try this choose the latest development version:
http://www.papywizard.org/wiki/Download#Developementversions

Then if you feeling bold extrapolate to a 360x180 bearing in mind that you will need fewer images per row as you approach the zenith and nadir.

But shooting with a 50mm lens on a DX body using a manual pano head will probably drive you completely crazy because the much smaller FOV of the 50mm means you will be much more likely to get 'featureless' images - plain blue sky, plain white wall, and so on - that APG cannot link with automatic CP detection. This is where the special Import wizards for supported robotic pano heads come into their own with APG; they use a knowledge of the shooting pattern (in the case of Gigapan heads), or recorded shooting position data (in the case of Merlin/Papywizard, Panogear and others) to place 'featureless' images that would otherwise be left out of the stitch and remain 'orphaned'.

Kolor has promised to develop a 'Generic matrix' Import wizard - a variant of that developed for the Gigapan heads - which will offer assistance in placing 'featureless' images when shooting regular grid/matrix pattern partial panos with a manual pano head, with the camera in either portrait or landscape orientation, and longer focal length lenses.
Last edited by mediavets on Sun May 15, 2011 9:05 am, edited 1 time in total.
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by Destiny » Sun May 15, 2011 9:05 am

Hi John.. apg's main function is to stitch and it does that very well, but when it comes to bracketed shots you have to do a lot more than just stitch your images... I am going to try to take a new set of images tomorrow using my wonderful little 1.8D.. to give me a new set to play with since I have had some real issues with this lot I have.. but I have also leant heaps by doing the wrong things....

Anyway.... I have done so many test over these past few days on fusion and bracketed shots my brain is throbbing.. When I get it right I will be writing it all down... well... after you put your images into apg, bracket them into groups making sure you set the middle image No... I can only take 3 bracketed images with my D90 so I set my groups to 2. I always put my stitching to high.. but leave the level as is... On the Render you can set your render to Exposure Fusion. You can fiddle with this, some people might like to use Anti-Ghost.. Try Anti-Ghost too, see what you get.. Also, try Diamond Weighting.. I read somewhere in apg that it can help with the ghosting/double images blur...

Now render your images.. This will create a layered pano of your exposures. Now, on the right panel, go to 'Edit'... I often get a RMS of less than 2 which is Excellent.. but I don't bother taking any notice of that many more since I have had a RMS of 1.2 but the quality was ####... The other day something was going way wrong so I turned my Mac off and rebooted it.. I was sure something was amiss with the new apg update..

Anyway... In Edit.. go to the forth icon from the right.. its got 3 little images on it.. Exposure Fusion Settings... i have made mention to this that it should have some kind of increments so you can write it down and keep a record of what settings you used.. Better still, it should be able to save this as YOUR settings... Not to worry.. from here you can see live preview of the results.. its really nice tool for sure..

From this editor panel, you can change your 'Channel Levels' too, now this is Really nice tool.. and again, live preview.. Much better than PTGui.. I took just three bracketed groups and played with them and oh wow.. really nice.. There is also a colour anchor but I have never played with that... not sure I want to yet... Now.. There is a Colour Correction icon that is set to Auto.. At this icon you will find the HDR setting.. I have had real issues with my current set of images which show yucky lines where they have stitched so not sure what is happening.. I am sure it is my images.. Anyway.. give the HDR a play.. Edit the setting to something that looks ok since it has live view and then go back to your channels and colour correction to edit the images again... apg can create some really nice looks.. but your images have to be stitched right firstly.. or it will look ####..

Remember this.. apg firstly sitches bracketed shots into layered panos.. From there you can edit just about every element of the pano.. Most importatly, if the images are not working for you.. dump them and try again with a new set.. or you will fry your brain like mine.. :lol:

I hope all this helps and I haven't showed you have to suck an egg.. :lol:

Destiny...


irpano wrote:George.Destiny and mediavets, Thanks for your responses. I have had similar results to Destiny and have learnt to make sure the overlap is not excessive. I use the T&C controller on the merlin and then load into APG using the inmport function. On single exposed images i dont have any problem at All APG reports excellent RMS.
However with any multiple exposed image (Bracket at each position), APG has trouble and is not even consistent even after loading a number of times. Now to the point of my original question - HOW to control the Fusion process on Bracketed images. IE how do you control the Final exposure, contrast and tones for each individual "Tile ' created. The Fusion control in rendering will alter these settings on the final pano but I sometimes ned to control each 'Tile' settings. Can it be done.
Why I use tufuse pro (Tawbaware) is that it gives me this control for each individual tile, and as the images are aligned , fuse very well.
So from a 90 image set (10X3X3) I will get 30 tiles each having good tone,exposure and contrast. APG then stitches the 30 TILES excellently.
So can I achieve this with APG and do away with the need to proccess brackets manually in tufuse pro.
John
Last edited by Destiny on Sun May 15, 2011 9:36 am, edited 1 time in total.

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by Destiny » Sun May 15, 2011 1:30 pm

hey... after painfully adding control points for moving trees.. oh man.. on bracketed shots!!!.. I had a thought... What if you could marque an area like a bunch of ghosted trees and dump a heap of extra control points in a controlled single area... I will will call this.. "A controlled area point dump".. :)

D....

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by tived » Mon May 16, 2011 3:12 am

I have some difficulties with this too in APG.

Ideally when you drop in bracket sets, the program should recognise the sets and gruop/stack them. When it renders it should aim to align these with the same excellence as the program does with a regular pano (is there such a thing?) I think currently you can get the program to make up each exposue plane which can then later be brought into another application of your choice to deal with it.

The HDR function in APG atm does not seem to function properly which I think it public knowledge, but is coming in future versions or maybe this is the future version ?

Any how, it would be really great if we could get a HDR tone-mapper within AGP with some options to tweak it.

Please correct me if I have gotten it wrong, thanks because I am finding this confusing too and end up resorting to PTGui which does a stella job, but also have room for improvements, but it is atleast able to product usable tone-mapped pano's. I am in no doubt that this isn't all that easy to just go and program for, so I would rather you guys get it right (Kolor) then rush it.

There are some cases where, you just got to do to the HDR part outside the Pano program, where neither program will cope with the tast, so it is good to know and have a backup solution. Programs like Enfuse and Tufuse have been mentioned, but almost any of the HDR programs that can run batches are useful, just choose the one that suits you the best. I often find that different HDR apps, suits different type of images, there is to me no app that fits them all.

Regarding the movements that Destiny is talking about, IMHO you shouldn't see huge shifts in trees unless you are shooting in a mad storm, which I doubt that picnic scene was. I thing it has more to do with the bracket images have not been linked (Stacked) properly by the program. Usually the ghosting should be able to deal with light wind movements in the trees, or at least if you know that there is a lot of wind, you might want to render the scene in different planes for later retouching. Its a tricky area the whole movement thing. Sometimes the ghosting comes up with something that is worse then the original, but I am still amazed by how someone have been able to program this to get it to work in the first place. And it is only getting better!

I think we are currently pushing technology, and perhaps we need to slow down a bit and do things in more steps, but one of my concerns is that as we add more steps to the process we are also adding more risk of deterioating the image quality, by pulling and pushing the pixels around, unless we can work in a fully 32-bit workflow which isn't yet available to my knowledge.

Food for thoughs

Henrik

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by Destiny » Mon May 16, 2011 7:17 am

Hi Henrik... some thoughtful comments you made.... Personally I love using apg but sometimes I get very disappointed with its results.. I have had PTGui for a while but have only just started to use it... I use it to test if my shots are ok or its apg not doing what I want or expect.. PTGui seems to cope with movement of trees much better so something needs to be improved on in apg.. The movement was just the results of a very light breeze.. To begin to add control points to this is just too painful.... better off taking new shots if you can....

What has to be remembered with apg, its main function is to stitch.. a program like Photomatix is a dedicated HDR program, it doesn't stitch.. apg has some HDR functionality but it coups much better with Exposure Fusion which is your LDR, for bracketed exposures.. Exposure Fusion is not a kind of HDR. HDR is High Dynamic Rang where Exposure Fusion is LDR.

If you can do without HDR effects then apg is just fine for your normal LDR, so better off leaving the full effects of HDR to Photomatix etc.. I find if I process my images using Photomatix as HDR and then put them in apg you have to be really careful of the HDR output or you get problems with stitching and blending.. I have never used the batch process in Photomatix so I do not know how quick it would process a bunch of bracketed shots.. and if you want to do some fine tuning in apg your images can be greatly effected by HDR images processed by using a different application to apg...

Its a much better option if you really want HDR effects is to process your pano using bracketed images, use the Exposure Fusion tools in apg and when you like the results save the pano and then put the entire pano into Photoshop.. Change the exposure 2+ and 2- or what ever you like and then or add even more exposure settings if you want and save them not as jpg's but as psd files.. This will retain a lot more of the original data so the HDR will process much quicker and the results will be much better.. You will not have blending issues either... and because you have made copies of the same pano, you will not get any ghosting at all... well.. you will but thats from apg not fixing it the first place.. like moving trees.. so put it this way.. you will not get ANYMORE ghosting.. I tried it using up to five exposure setting and the results were awesome...

Edited.. In bold....to make it clearer..

D..... Well thats my $300 worth.. or more.. but never less.. :)

A Destiny message for the day...
If anyone has a nice Nikon 3DX sitting on their shelf gathering dust... I will look after it for you and dust it every day....
Last edited by Destiny on Mon May 16, 2011 11:03 am, edited 1 time in total.

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by irpano » Tue May 17, 2011 2:23 am

Destiny and Hendrik, I read what you have both posted and have experienced the same set of results. To beter understand the process of EXPOSURE FUSION I am atempting to go back to the basics of the technique. Its my understanding that by BRACKETING a scene You are trying to get exposures (Say 3 for this exercise) that will get detail in the dark shadows, Detail in the bright shadows and detail in the midtones. That being said a fusion application (enfuse , Tufuse, etc) would analysize each pixel location and select the one with the best exposure. The resulting image would be like one merged in Photoshop where sections of the image are made up from one of the 3 different exposures. Assuming That I have this right in my thinking process I try to envisage how this is done when using APG to stitch the pano. (I appreciate that APG is good at stitching, but it also has options for fusion in the rendering process). So if for example you had 3 exposures -2, 0, +2 with 0 at calculated neutral, would it not be safe to assume that you should get a fused exposure a bit on either side of 0, depending on the dominant influence of eithr the Shadows or the highlights. (EG the more shadows in the scene the more the final exposure would be towards the -2 side of neutral)
To try and develope a workflow for bracketed pano's its possible to
1 expect APG to do the lot.
2 Fuse bracketed shots in another application first and then stitch in APG
3 Stitch into layers grouped by exposure and then fuse each layer in a another application.
Analysing each option
1 APG is good at stitching but you accept what the application is doing to create the fused images
Is there any control over the empahsis towards -2 or +2 exposure or is it just what APG does within the fusion algorithm.
2 Assuming the fusion application is good at its job you can push the final exposure towards +2 or -2
This is done manually and is time consuming on large panos. Impossible I would think on 360 X 180 panos
3 Test to date seem to indicate that APG rendering take a extra long time ( 3 hours for a 90 image set . 3 layers of 30 images)
ANY thoughts on the above on how toget a good result (THIS IS NOT HDR but LDR as I know it)

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by Destiny » Sun Jun 12, 2011 8:24 am

Hi.. well I am at it again.. experimenting until I get what i want...

I have tried so many settings I don't know what I am doing anymore... I need to start from scratch I think....

Anyway.. I did some intensive testing today... using many methods and software.. Here are my results...

http://www.destinyvirtualtours.com/BKTtesing/BracketedImageTesting.html

Destiny....
Last edited by Destiny on Sun Jun 12, 2011 8:24 am, edited 1 time in total.

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by Destiny » Sun Jun 12, 2011 10:46 am

Hi irpano.. Sorry, I missed your last comments... I think you have it just about right...
Georg has has the right idea I think.. Use software like FusionGUI to fuse your images since this would be the quickest way and after my testing I think probably much better than apg can do.. sad to day... I just stitched my bracketed images splitting them into two groups to test.. I put the darkest and the lightest together and then the mid and the light and the RMS were way different 3.78 to 4.21 but the results are not good since one is too light and the other is too dark... I tried putting the two panos into apg but I was pushing my luck with that one.. Its needs the 3 to work... but apg cannot do it... I have tried so many settings it becoming painful.. I should be able to put the images in and and apg should be able to put something together which is passable and then it would come down to fine tuning .. but its not to be... If the images remained alined then it would work but they don't.. and far too much editing to make it worth the effort....

D....

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by klausesser » Sun Jun 12, 2011 12:03 pm

A major difference between fusioning and HDR is that

1) HDR generates a 32bit/ch floating point file. This can´t be displayed because of it´s nature.
For displaying or using such a file in a usual application it has to be tonemapped - which means it´s reduced from 32bit/ch fp data to 8 or 16 bit/ch integer TIFF or to jpg files.
The point is: for tone-mapping you can select from a practically more or less infinite range of tones to match your demands.
The best way to use it - in my eyes - to shoot a series of -2/0/+2 EV. That can be done as RAW (best) or even as JPG.
2) Fusioning doesn´t generate something as HDR first but mixes three or more shots of different density to one shot containing the density of all of them.
That comes close to HDR - but there´s a difference.

In my eyes and from my experience only "true" HDR can give you the variety of choices you need for really exquisite and natural looking results - if you handle it well. If not you´ll get overexagerated results which look rather artificial - kind of photoclub-taste . . :P:cool:

Handled in the right way HDR can give you the impression of what your eyes see without a camera - becauses it adapts very fast from bright light to dark.
HDR shows it all in once - and let YOU select how this should happen.

Imagine a sunset szene on a beach: the sun "sits" on the horizon, very bright but fading. The water and sand in front of you where some little rocks or something is visible - very low light already.
To have the full foreground and the direct sunlight youl´d need some 12 EV stops to cover all oft it. HDR can do it - take 12 shots with 1EV step in between.
Fusioning can do it also - not as smooth as tonmapping . . . but it can cover the range.

In the end it surely is a matter of taste - both ways are preferable over a single shot.

best, Klaus
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by irpano » Mon Jun 13, 2011 1:21 am

Destiny, Read your post and can confirm that I had almost the exact results using similar software. (Tufuse , Enfuse, Photomatix). My observations were that fusion ( as explained by Klaus) is a blending of the 3 exposed images (-1,0,+1) into a single flat image containing the BEST ? elements from each of the 3 original images. The resulting exposure value seems dependant on the influence of either the -1 or + 1. So if 0 exposure is set for the mid tones and you want to darken the shadows more your bracket setting would be -2, 0, + 1. This is not possible on my camera and the way I have found to get something similar is to estimate ( practice , practice, practice) the range of stops within the scene (Light meter helps) and then select the bracket width on the camera to match the scene. (On my camera if the bracket width is outside 5 stops, i'm up the creek) . Once I get a range that will cover the shadows, midtones and highlights, trying never to blow the highlights, I shift the bracket exposure towards the shadow or highlight end. ( if the bracket width is -1,0,+1 and i want more shadow detail i compensate1 or 1.5 stops toward the highlight end or vice versa)
After capturing the brackets i run the brackets through photomatix because it has an aligning feature (even though I always use a tripod). I found that the other software for fusion sometimes do no align the images before fusion. Now I say fusion because I find fusion is sufficient, Rather than HDR, and as APG is very good at stitching single images from a known grid, I generally get a good result (Around 2 RMS , for what thats worth). Colour wise I havent had too many instances of bad blending from within APG using the fused brackets. ( Any problems have bee dealt with by usings photoshop before stitching), (Note also that I am a Black and white person so colour is not that important to me).
Unfortunately APG doesnt seem to be able to handle bracketed sets all to well and I cant find out WHAT APG is doing with the bracketed sets when it displays all of the images in the edit window. So my best results from all of my test has been achieved using what I have described above. Its a shame that APG hasnt yet got the ability we are after and this manual method is not AUTOMATIC as is APG's aim, and I imagine for a big 360 X 180 pano this process must be daunting.
So for now it seems thatas KLAUS has said on many occassions that we should fuse or HDR each set of barckets before stitching and as I have found pay particular attention to the exposure-compensation process.
Hope I have made myself clear and keep posting your results.

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by irpano » Mon Jun 13, 2011 1:38 am

Destiny, A Image that didnt get the exposure correct in the highlights, Shot with IR camera and FUSED through photomatix. Stiched in APG. ( Pano images - 2 rows or 10 with 3 exposures at each position 2 X 10 X 3 = 60 images)
Fused images = 20 flat Images
APG stitch using defaults.
Thought I might explain a bit better about fusion etc.
John


Last edited by irpano on Mon Jun 13, 2011 1:41 am, edited 1 time in total.

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by tived » Mon Jun 13, 2011 1:54 am

Destiny wrote:Hi.. well I am at it again.. experimenting until I get what i want...

I have tried so many settings I don't know what I am doing anymore... I need to start from scratch I think....

Anyway.. I did some intensive testing today... using many methods and software.. Here are my results...

http://www.destinyvirtualtours.com/BKTtesing/BracketedImageTesting.html

Destiny....

Thanks for doing all this work Destiny, excellent effort.

Henrik

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by tived » Mon Jun 13, 2011 2:00 am

Destiny wrote:Hi irpano.. Sorry, I missed your last comments... I think you have it just about right...
Georg has has the right idea I think.. Use software like FusionGUI to fuse your images since this would be the quickest way and after my testing I think probably much better than apg can do.. sad to day... I just stitched my bracketed images splitting them into two groups to test.. I put the darkest and the lightest together and then the mid and the light and the RMS were way different 3.78 to 4.21 but the results are not good since one is too light and the other is too dark... I tried putting the two panos into apg but I was pushing my luck with that one.. Its needs the 3 to work... but apg cannot do it... I have tried so many settings it becoming painful.. I should be able to put the images in and and apg should be able to put something together which is passable and then it would come down to fine tuning .. but its not to be... If the images remained alined then it would work but they don't.. and far too much editing to make it worth the effort....

D....

I find APG really picky about if the images are part of a bracketing set or not, and most often (this could very well be a user issue - ME ;-) ) I am not getting good results in the blending. However I find that I can take selected exposure sets into PTGui and it will deal with them, as long as each complete pano (layer if you wish) is of the same exposure. I can use 2 of 3 or sometimes I might use 5 or 7 bracket shots but only pick out the sets that I think will give me the best exposure - this is sometimes a bit of experiementing.

Henrik

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by tived » Mon Jun 13, 2011 2:12 am

klausesser wrote:A major difference between fusioning and HDR is that

1) HDR generates a 32bit/ch floating point file. This can´t be displayed because of it´s nature.
For displaying or using such a file in a usual application it has to be tonemapped - which means it´s reduced from 32bit/ch fp data to 8 or 16 bit/ch integer TIFF or to jpg files.
The point is: for tone-mapping you can select from a practically more or less infinite range of tones to match your demands.
The best way to use it - in my eyes - to shoot a series of -2/0/+2 EV. That can be done as RAW (best) or even as JPG.
2) Fusioning doesn´t generate something as HDR first but mixes three or more shots of different density to one shot containing the density of all of them.
That comes close to HDR - but there´s a difference.

In my eyes and from my experience only "true" HDR can give you the variety of choices you need for really exquisite and natural looking results - if you handle it well. If not you´ll get overexagerated results which look rather artificial - kind of photoclub-taste . . :P:cool:

Handled in the right way HDR can give you the impression of what your eyes see without a camera - becauses it adapts very fast from bright light to dark.
HDR shows it all in once - and let YOU select how this should happen.

Imagine a sunset szene on a beach: the sun "sits" on the horizon, very bright but fading. The water and sand in front of you where some little rocks or something is visible - very low light already.
To have the full foreground and the direct sunlight youl´d need some 12 EV stops to cover all oft it. HDR can do it - take 12 shots with 1EV step in between.
Fusioning can do it also - not as smooth as tonmapping . . . but it can cover the range.

In the end it surely is a matter of taste - both ways are preferable over a single shot.

best, Klaus
.

Totally agree with you here Klaus,

To me it is very much about re-creating what the eye sees and not to create some Salvador Dali Impression :-) No matter how cool he was :-)

Only thing I would avoid using is - JPEG files for HDR...I am not saying it can't be done, but if you think about it, JPEG is 8-bit files, however, combining 3 8-bit files will not give you enough true color information, and given that almost all of this is approximations. I think using your RAW files or RAW files converted to 16-bit tiff files would be a bitter starting point to avoid color clipping. At least 16-bit will give you a bit more headroom to push/pull the files e.g. 256 colers (8-bit) vs 65536 colors (16-bit)

One question though, getting the 12 EV stops, you suggest using 12 shots at 1 EV, I haven't done the test myself, but have you tried using 2 EV per shots? using only 6 shots? given there is a fair bit of overlap between each file
I am suspecting that 12x 1 EV would maybe give a smoother graduation... hmmm, I might have to go out and test this later today if time permits

thanks for sharing your great insight, Klaus

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by tived » Mon Jun 13, 2011 3:32 am

irpano wrote:Destiny, Read your post and can confirm that I had almost the exact results using similar software. (Tufuse , Enfuse, Photomatix). My observations were that fusion ( as explained by Klaus) is a blending of the 3 exposed images (-1,0,+1) into a single flat image containing the BEST ? elements from each of the 3 original images. The resulting exposure value seems Dependant on the influence of either the -1 or + 1. So if 0 exposure is set for the mid tones and you want to darken the shadows more your bracket setting would be -2, 0, + 1. This is not possible on my camera and the way I have found to get something similar is to estimate ( practice , practice, practice) the range of stops within the scene (Light meter helps) and then select the bracket width on the camera to match the scene. (On my camera if the bracket width is outside 5 stops, I'm up the creek) . Once I get a range that will cover the shadows, mid-tones and highlights, trying never to blow the highlights, I shift the bracket exposure toward the shadow or highlight end. ( if the bracket width is -1,0,+1 and i want more shadow detail i compensate1 or 1.5 stops toward the highlight end or vice versa)
After capturing the brackets i run the brackets through photomatix because it has an aligning feature (even though I always use a tripod). I found that the other software for fusion sometimes do no align the images before fusion. Now I say fusion because I find fusion is sufficient, Rather than HDR, and as APG is very good at stitching single images from a known grid, I generally get a good result (Around 2 RMS , for what thats worth). Colour wise Ihaven'tt had too many instances of bad blending from within APG using the fused brackets. ( Any problems have bee dealt with byusings photoshop before stitching), (Note also that I am a Black and white person so colour is not that important to me).
Unfortunately APdoesn'tnt seem to be able to handle bracketed sets all to well and I cant find out WHAT APG is doing with the bracketed sets when it displays all of the images in the edit window. So my best results from all of my test has been achieved using what I have described above. Its a shame that APhasn'tnt yet got the ability we are after and this manual method is not AUTOMATIC as is APG's aim, and I imagine for a big 360 X 180 pano this process must be daunting.
So for now it seethat'stas KLAUS has said on maoccasionsons that we should fuse or HDR each set bracketsets before stitching and as I have found pay particular attention to the exposure-compensation process.
Hope I have made myself clear and keep posting your results.

Hi John,

A couple of things and not aimed at you personally - but HDR is not a way of getting around not properly exposing the scene, but capturing all the dynamic range in the scene in multiple shots that a single shot can't, at least not ylight-meterightmeter or the Histogram is certainly a useful tool here. I would take readings of the extremes and the "Correct Exposure" and examen these as well as time permits ;-) ...the amount of times that I haven't done this and pulled my hair outin-fronte infront of the computer because i did not get enough coverage (Clipping) @#$%@#$%!!!

I don't recall what camera you use, John?

I use a Canon 1D Mk IV but I also teach someone using a Nikon D3s, there two beasts are very different in how you are able to do your bracketing, and unless you have a Promote or similar external solution we are bound to use what tools are within the camera itself. Point here is that if you are limited to only 3 shots in your auto exposure bracketing, youexpanded to expeand your EV spread from 1 to 2 or greater, or do two sets per position but this can get complicated as in you might miss shots if you forget where you are at. The difference between these two cameras are that the Nikon D3s can do 9 shots in a AEB series but only at max 1 EV per shot and it can be setup to shoot with a bias to highlights or shadows. The Canon 1D-series can only do max 7 shots, but with a max of 3 EV which means theoritically 21 EV, but will it give us a smooth graduation when we tone-map or fuse the combined image later?

If you get a good exposure and a good spread in your multiple exposures I think you can get a reasonable good result using PTGui, its basic tone-mapper is aimed at a natural looking image vs the more cartoon like that some HDR programs will produce.

However, a dedicated HDR application will be able to give you more control over the process, but it also requires that you become familiar with using it and not just through the files at it and cross your fingers and hope that the AUTO function will do a nice job.

Also as you add more exposures in outdoor shots you increase the chance of ghosting, movement between shots, and though some of the HDR applications are getting better at dealing with it, it is still not ideal.

In The Image attached I actually only used two shot Exposure bracketing, but one at 10sec and one at 2.5 sec @ f/32 using a Canon EF-135 f/2L though in this shot I wanted the water to look flowing but though there was no wind where I was standing there was plenty of wind a bit further up the valley as can be seen in the crop. I tried my very best to avoid any ghosting...but I ain't perfect ;-)

I guess what I am trying to get at with all this is that there isn't a one fits all workflow for adding multi-exposures to pano's, but with we have to use the strength of each tool and technique that we have available to us and use them within their limitations. I have to admit that Klaus produce some really nice tone-mapped pano's and seem to have a really good workflow, but that is also backed up by extensive knowledge of each process and tool. Something we all strive to archive.

So getting to John's conundrum here,

There is a workflow for shooting the pano, adding to that the multi-exposure, which isn't much different to shooting a normal pano (archiving Correct Exposure), but getting the right amount of Dynamic Range (DR) is the big issue and its important to get this right.

Then there is the post production part of it, which is where we are having the biggest issue but less so if the above is done properly. If you only use Autopano for the stitching, I would do the HDR/Fusion process first, which application to use for this opens up a whole new box of worms, I personally like the more naturally looking process of these over the more cartoon/surrealistic looking ones. So here I would suggest to find the application that suits your style, but given that you are shooting a lot IR pano's I would say that you too would most likely be leaning towards the natural looking process too.

THis guy here has done quite a few reviews of the different softwares and most have a 30-days trail http://rf-photography.ca/reviews/
and this (haven't spend much time here) http://www.everydayhdr.com/?cat=278

and http://www.hdrlabs.com/ which is a really good source for HDR and his book is really good too!

there is also the Fusion ones which i think you have had a look at, I think Georg is using EnFuseGUI which makes very nice and pleasant outputs and its very fast too... it will use all the CPU processing you got (in my case 24-cores)

I hope this is of some help

Henrik
Last edited by tived on Mon Jun 13, 2011 3:48 am, edited 1 time in total.

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by tived » Mon Jun 13, 2011 3:49 am

hmm. my image is not showing up ?? @#$%^

:-)

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by Destiny » Mon Jun 13, 2011 8:38 am

hi guys.. really interesting comments.. it has me thinking so much... my D90 is great but it has limitations... but... there is software where I can achieve many more bracketed shots.. I have yet to try it out... Now.. RAW images.. this is what I really needed to try.. The bitmap TIF formate is just wonderful in many ways... although mostly used for the print industry for its retention of data and therefore providing a much better print result than a jpg... I love it for the alpha channel.. I have used it for making great hight quality sequenced animates from Maya or SoftImage and even 3D Studio Max.. but I neglected to link the tif format to a pano image...

I started again with a new pano and set the camera to RAW and then processed the images to the tif format.. I put the images into PTGui Pro but again, I get huge areas of blurriness... I have tried just about every setting there is... but I still get this horrible blurriness patches.. The stitching is good but the pano's final results is not good...

I then put the tif images into apg and stacked them, set the setting so fusion and stiched.. The results were much better than PTGui, without the blurring but the stitching was not great.. Not sure what is going on with that... So then I put the images into EnfuseGUI and the colour is really quit nice.... I tried stitching in PTGui but oh yuck.... apg is much better again... apg seem to like the tif formate much better than jpg's...

I set the stitching to the highness in apg but again not good.. I need to take a single row and test my setting again.. it was perfect so I do not know what going on... The colour and blending from apg is really nice... very natural... well.. i like it... It might need a bit brighter but thats easily fixed... Its the darn stitching that is a pain... At least since these image are not stacked images i should be able to edit the stitching easier...

It might be a fisheye lens issue.. I normally get a RMS of about 3 to low 4 using a fish eye.. I get RMS of a bout 1 to 2 with a normal lens... I think fusion using a normal lens is a lot easier than using a fish eye lens on just 3 bracketed shots...

I need to make sure my nadir is set right.. oh hum... back to the beginning.... again!

Destiny....
Last edited by Destiny on Mon Jun 13, 2011 8:42 am, edited 1 time in total.

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by tived » Mon Jun 13, 2011 9:03 am

Destiny,

Just a quick note, Great to see that you are picking up on the Tiff file format for your image.

A Quick Primer in Image Quality

Always Shoot RAW
Choose the biggest Color Space - usually AdobeRGB - that your camera has.
Edit your images in at least 16-bit and keep them in 16-bit for as long as possible in your workflow.
File format - Tiff is a bit more universial the Adobe's PSD/PSB, but I like to keep my own WIP files in PSD, because I am most likely to deliver my files to the client in TIFF or JPEG, therefore I know that if there is a PSD/PSB file in a Client folder he/she is getting more then what they are asking for ;-)

- I strongly would suggest that if you are in Melbourne that you look up any courses with Les Walkling - an Amazing guy and educator (The Numoro Uno in Australia!!! in Digital Imaging).

Anyway I would suggest that you set your camera up to shoot RAW and if you insist on JPEG. Set it for RAW+JPEG. I don't have a D90 to look at but I am pretty sure you can pick several different sizes if you are worried about running out of space.
2ndly - Make sure your color space on your camera is set to Adobe RGB as oppose to sRGB, you can always go down, but you can;t always go up or add.

I know, or assume given your interest in multi-media, that you more often will have your work destined for monitors (sRGB color space) however, if you are wanting to print, I think you will find that AdobeRGB will give you a better result (if you insist on having the biggest color space ProPhotoRGB is even bigger, but that is a different kettle of fish and can be a beast to tame).

Use 16bit vs 8 bit when ever you can, you will retain more color information this way.

Now for your stitching...colorspace and fileformat is almost always irrelevent, so I am not sure what may have gone wrong there

The blurred patches can be from too much overlap - this is more or less an issue on some applications then others but no fixed rule to. I know how you feel on this one here, its a PITA :-) I sometimes as you mentioned do one row at the time and then I drop each row into Photoshops PhotoMerge and it does a really nice job.

Just some food for thought :-)

Henrik
Last edited by tived on Mon Jun 13, 2011 9:08 am, edited 1 time in total.

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by Destiny » Mon Jun 13, 2011 11:05 am

hi Henrik... yes my D90 is set to RAW+JPG fine and the largest image... I have 2 X 16 GB ScanDisk memory cards so I should be ok with those... My camera is set for AdobeRGB so thats ok too... So.. looks like I have it all ok.. I opened my raw images in the adobe editor and it turned them all into tifs very easily..

Interesting what you say about too much overlap.. That might be something I need to look at.. I am currently taking 6 down at 30 degrees and 6 up at 30 degrees.. I have been doing ok until the last few days so I think that its all becoming a PITA for sure... I try to sooo hard but take one step forward and three back.... Just when I am getting somewhere I am put back... good job I am not relying on this for a living... but I sure want to get out of teaching to do my VR work.. if I ever get any paid work...

I will try taking less images and see what happens.. The problem with a D90, its not full frame so I think 6 images is about right... I do not really like using PTGui but often I use it to test my images after they fail in apg... i have had so many issues with this bracketing thing... Its easy to do with a normal lens and for just a normal wide pano.. but its the fisheye lens that is the issue... real real pain... The light now is yuck so I have to wait until tomorrow....

I had a thought that my bracketed images are not as clear as a single image.. I wonder if the focus changes between the 3 shots....

I need a break from it all but I am too stubborn.. I need to get this right and I will not give up until I work it all out...

Thank you for all the advice.. It looks like I my camera was set to your specs... One thing I have neglected to try is Photoshop.. good idea.. I normally don't since it can take a very long time... I will let you know how I go...

Destiny...

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by klausesser » Mon Jun 13, 2011 1:42 pm

tived wrote:Only thing I would avoid using is - JPEG files for HDR...

Right! But: there are "scenes" which might look a bit better when you take JPGs. Sometimes using RAW might be too ;) good, too smooth . . ;) That´s like some newspaper-printing makes some kind of photographs looking more "special" than exellent magazine-printing.

tived wrote:I am suspecting that 12x 1 EV would maybe give a smoother graduation... hmmm. . .
thanks for sharing your great insight, Klaus

Exactly - graduations are smoother . . depends on the scene you shoot. Some scenes have a profit of it and others don´t. I saw panos for CGI from a Spehron using about 21 f-stops - overwelming with sunsets as example.
But: molto expensive . . ;) You also can do it using a 5D2 and PromoteControl, as an example - and save about 45000.-$ :cool:
You´re welcome! :cool:

best, Klaus
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by klausesser » Mon Jun 13, 2011 2:07 pm

Destiny wrote:hi Henrik... yes my D90 is set to RAW+JPG fine and the largest image... I have 2 X 16 GB ScanDisk memory cards so I should be ok with those... My camera is set for AdobeRGB so thats ok too... So.. looks like I have it all ok.. I opened my raw images in the adobe editor and it turned them all into tifs very easily..

Interesting what you say about too much overlap.. That might be something I need to look at.. I am currently taking 6 down at 30 degrees and 6 up at 30 degrees.. I have been doing ok until the last few days so I think that its all becoming a PITA for sure... I try to sooo hard but take one step forward and three back.... Just when I am getting somewhere I am put back... good job I am not relying on this for a living... but I sure want to get out of teaching to do my VR work.. if I ever get any paid work...

I will try taking less images and see what happens.. The problem with a D90, its not full frame so I think 6 images is about right... I do not really like using PTGui but often I use it to test my images after they fail in apg... i have had so many issues with this bracketing thing... Its easy to do with a normal lens and for just a normal wide pano.. but its the fisheye lens that is the issue... real real pain... The light now is yuck so I have to wait until tomorrow....

I had a thought that my bracketed images are not as clear as a single image.. I wonder if the focus changes between the 3 shots....

I need a break from it all but I am too stubborn.. I need to get this right and I will not give up until I work it all out...

Thank you for all the advice.. It looks like I my camera was set to your specs... One thing I have neglected to try is Photoshop.. good idea.. I normally don't since it can take a very long time... I will let you know how I go...

Destiny...

Destiny - let me drop in here, of course without patronizing you :P:cool::
6 shots horizontal and one Zenith is the configuration most of the pano-buffs use. I used it when working with the 20D and 10,5mm Nikon lens and i use it now with my 5D2 and 15mm Canon lens (fisheye). It definitely works fine and you definitely don´t need more! This way you have an overlap of around 20-25% - and that´s plenty enough. More most likely is counterproductive - you may get blurred zones (at least it was with smartblend).
If you can shoot a Nadir too: fine. If not: set the camera tilted down about 10-12° for the horizontal row and shoot a Zenith as usual. Your Nadir-hole will be remarkably smaller and very easy to retouch. Zenith is ok too - the 10,5´s fov is big enough.

best, Klaus

P.S.: here´s an example using only 5 shots horizontal at - 12° and one Zenith at +90° as usual. I need only 5 shots because Josef´s head is very precise and 20% overlap are sufficient. To shoot a full sphere this way takes about 45 seconds - of course more when using bracketing, like i did here:
http://s341703522.online.de/Kneipzimmer.html - as you can see: 5+1 shots did it all. Your Nikon with 10,5mm fe and my Canon with 15mm fe have a comparable fov at f8/11.
Last edited by klausesser on Mon Jun 13, 2011 2:15 pm, edited 1 time in total.
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by hermer-blr » Mon Jun 13, 2011 2:33 pm

I am interested by what Tived wrote regarding color spaces.

I also shoot raw (nikon D60) and use and sRGB color space for the raw image storage. My question is:

As the files are in raw format, does that make any difference between selecting an RGB or an sRGB color space for image storage ? If there is a difference, the RGB stored files should be in theory a little bigger...

Interested to know the answer and/or have some links to explanations regarding that. The camera documentation are in general very sparse on the topic...
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