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focus stacking workflow

PostPosted: Fri Apr 29, 2011 7:23 pm
by wjh31
The longer the lens the greater the DOF issues, especially with spherical panoramas where just using the hyper focal distance isn't sufficient on longer lenses, and stopping too far down leads to diffraction, so ive been thinking about focus stacking, and trying out this workflow. I wonder if anyone has any thoughts, or comments on their own process.

1:Shoot a sphere multiple times at different focus distances one after the other, to save time compared to a single sphere adjusting the focus at each point multiple times
2:Batch process in combineZM
3:Stitch as normal

So any thoughts before i try it out?

PostPosted: Fri Apr 29, 2011 11:50 pm
by gkaefer
wjh31 wrote:The longer the lens the greater the DOF issues, especially with spherical panoramas where just using the hyper focal distance isn't sufficient on longer lenses, and stopping too far down leads to diffraction, so ive been thinking about focus stacking, and trying out this workflow. I wonder if anyone has any thoughts, or comments on their own process.

1:Shoot a sphere multiple times at different focus distances one after the other, to save time compared to a single sphere adjusting the focus at each point multiple times
2:Batch process in combineZM
3:Stitch as normal

So any thoughts before i try it out?

I would see it diplomaticly... it depends...

1. it works. but if used with longer lens that means an increasing number of images and this means one run takes longer... and in consequence several rund can have whitebalance issues
2. combineZM is free so nothing to say against. if I remember well CombineZM can not handle very well not perfectly alligned images. Commercial products do work here much better: photomatix pro, oloneo can do denpoise & tonemapping by stacking I think focus stacking is not possible (this month in beta free available, in june first stable commercial release...)
3.APG 2.5.x can now handle stacks, but only to enfuse them not to focus stack them. So I think this way is probaply a dead end road...
Alexandre also says that external batching programm can be included in APGs workflow with the new 2.5 plugin engine:
http://www.autopano.net/forum/p71466-2010-10-27-10-10-25#p71466

focus stacking & merlin & papywizard + external software:
http://www.autopano.net/forum/p66634-2010-07-26-16-04-01#p66634

DSLR remote (for Canon and Nikons available) can do focus stacking:
http://www.breezesys.com/DSLRRemotePro/features.htm

Helicon Focus Pro can do focus stacking
http://www.globell.com/Helicon-Focus-Pro_detail_151_55.html

Liebe Gruesse,
Georg

PostPosted: Sat Apr 30, 2011 5:45 am
by tived
isn't the other way around the longer the lens the smaller the DOF, eg. a fisheye has a very large DOF, but a 600mm has a hairline at the same f/stop

Henrik

PostPosted: Sat Apr 30, 2011 5:55 am
by tived
its going to become incredible complicated. i tried to do some pano's with multi-focusing for later stacking, granted i didn't use a robot, but manually, and i didn't succeed, as i did not have enough overlap in my focus using a 200mm lens.

i would like to try this once i get a controller for my merlin, i already have Helicon Focus.

on a different note, i wasn't happy with HF when i tried it shooting outside....too much movement in trees

lets add HDR to the mix while we r at it. :-) the number of images r going to blow your mind, the blending is going to be so complicated - but nothing is impossible :-)

Henrik

PostPosted: Sat Apr 30, 2011 9:42 am
by wjh31
gkaefer wrote:2. combineZM is free so nothing to say against. if I remember well CombineZM can not handle very well not perfectly alligned images. Commercial products do work here much better: photomatix pro, oloneo can do denpoise & tonemapping by stacking I think focus stacking is not possible (this month in beta free available, in june first stable commercial release...)

I was just talking about focus stacking, not exposure stacking aswell. But i shall have a look at helionfocus

PostPosted: Sat Apr 30, 2011 3:42 pm
by wjh31
http://gigapan.org/gigapans/76203/ shows results of following.

After a small test shot, helicon focus seemed much better than combinezm, So i set up the head and shot a 4x3 grid with 50mm on canon crop body at f/8. This was repeated 9 times at different focus setting, batch stacked in helicon focus then stitched in autopano. Image isn't perfectly sharp as exposure was a little long due to being indoors and no MLU. Besides a few stitching errors, i think it's worked well

PostPosted: Sat Apr 30, 2011 4:09 pm
by mediavets
wjh31 wrote:So i set up the head and shot a 4x3 grid with 50mm on canon crop body at f/8. This was repeated 9 times at different focus setting, batch stacked in helicon focus then stitched in autopano. l

Was this using a Merlin mount?

PostPosted: Sat Apr 30, 2011 4:43 pm
by wjh31
mediavets wrote:Was this using a Merlin mount?

Yes. I used mosaic mode to seelct a view which happened to be 4 images across, 3 high in portrait. After selecting the initial focus i ran the mosaic, then adjusted the focus and ran the same mosaic, so the images would align fairly accurately, not too much play in the head, and stiff enough that i didn't knock it much while adjusting the focus, which i did manually in live view with the DOF preview button to ensure overlap was reasonable. Total capture time was about a half hour, and the same again to stack

PostPosted: Fri May 06, 2011 5:50 pm
by Castillonis
1. You should look at Gene Coopers amazing linearly captured macro work at http://www.fourchambers.org/ He uses Autopano Giga to process his focus stacks and stitch.

2. Helicon focus can automate your capture work. You leave the lens in autofocus mode and set the range and step between photographs. You would be able to do this with Papywizard and Merlin, Gigapan head in manual mode, or a Nodal Ninja with a D16 rotator.

3. You can process your image stack using
a. Helicon Focus
http://www.heliconsoft.com/heliconfocus.html
b. Enfuse ( --wContrast=W )
http://wiki.panotools.org/Enfuse
c. Zerene stacker
http://www.zerenesystems.com/
d. combine ZP
http://www.hadleyweb.pwp.blueyonder.co.uk/
e. combine ZM
http://www.hadleyweb.pwp.blueyonder.co.uk/CZM/combinezm.htm

4. Hint: Reduce the range of images so that every image contributes to pixels with better focus. In other words exclude any images at the end of the range that are not necessary.

PostPosted: Sat May 07, 2011 9:57 am
by GURL
wjh31 wrote:The longer the lens the greater the DOF issues, especially with spherical panoramas where just using the hyper focal distance isn't sufficient on longer lenses, and stopping too far down leads to diffraction

Here are two interesting web pages from Cambridge in colour web site, where long lenses DOF and diffraction are discussed:
- Understanding Depth of Field
- Understanding Diffraction: Pixel Size, Aperture and Airy Disks

The DOF page explains why there is not any loss (nor any gain) in depth of field when using a long lens for panoramas: when the "fuzziness" is corresponding for example to 1/10 of an object this is true both for a very short lens and a very long lens: when related to object size DOF depends only on the used aperture.

Not being afraid to use very small apertures like F/22 or F/32 for panoramas when using a long lens makes sense, too, because the DOF is increasing faster than the corresponding diffraction is decreasing image definition.

My own conclusion was to use a long lens at its smallest aperture and rendering the pano at 50% to compensate for diffraction! This could look like an unusual route and there is no doubt this would not work for a single photo but when shooting panos one can get as many pixels as he wants by stitching more photos in a single resulting image: I use this technique when I need it and it works fine...

Anyways and even if one don't want to use such unusual apertures, the Cambridge in colour web pages about DOF and diffraction are worth reading.

PostPosted: Fri Jun 03, 2011 7:35 pm
by Mr Moose
This isn't something I did, but here is a link to a pano that used HDR as well as focus staking, finish size was 50 x 114 inches.
http://www.luminous-landscape.com/forum/index.php?topic=54698.0