Fisheye and entrance pupil  

In the panorama field, hardware is also part of the success. You can discuss here about it: camera, computer, pano head, anything
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Phil Howard
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Fisheye and entrance pupil

by Phil Howard » Sun Jan 11, 2009 2:07 am

Described near the end of this page:

http://www.johnhpanos.com/epcalib.htm

a fisheye lens varies the entrance pupil offset forward as the viewing angle increases. The suggestion is to adjust the head so the lens rotates around the entrance pupil as offset for the angle where shots will meet (and where they get stitched). In a mathematical sense, a theoretical fisheye lens would not make such a change in offset. But that would be a rather uncorrected lens. So I'm assuming common corrections are causing this offset.

I'm still trying to decide on what lens to go with to move beyond the kit lens of a Canon 450D (XSi in USA). I was thinking of a fisheye because it would be a more uniform pixel density once projected into a wide panorama, and give a uniform sharpness. But now I'm concerned and looking to favor a rectilinear lens of some reasonable width (preferring a fixed focal length) so I can easily work with a pano head when I get one (contemplating the NN5 if I can find a trustable retailer that sells it).

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GURL
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by GURL » Mon Jan 12, 2009 5:49 pm

Phil Howard wrote:I'm still trying to decide on what lens to go with to move beyond the kit lens of a Canon 450D (XSi in USA). I was thinking of a fisheye because it would be a more uniform pixel density once projected into a wide panorama, and give a uniform sharpness. But now I'm concerned and looking to favor a rectilinear lens of some reasonable width (preferring a fixed focal length) so I can easily work with a pano head when I get one (contemplating the NN5 if I can find a trustable retailer that sells it).

Jhonh (http://www.johnhpanos.com/epcalib.htm) often uses fisheyes to produce very sharp spherical panos and certainly would not advise against using one.

Using a Tokina 10-17 mm, Autopano Pro V1.4.2 at highest detection quality and distortion correction settings I often get a lower than 2 RMS from automatic stitching. When problems related to a slighty inacurate location of the NPP arise they are more than often located on the ground at a short distance of the tripod where in my opinion small errors don't really matter (bad RMS is often caused by wrong control points which depend on the photographed subject, not the lens.)

An in-depth comparison between a very wide rectilinear lens and a fisheye would be very interesting but alas, as far as I know, none is available.

BTW, a very large number of peoples who bought Nodal Ninja directly from its manufacturer (Fanotec - http://www.nodalninja.com) reported it's a very trustable store.
Georges

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mediavets
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by mediavets » Mon Jan 12, 2009 6:55 pm

Phil Howard wrote:I'm still trying to decide on what lens to go with to move beyond the kit lens of a Canon 450D (XSi in USA). I was thinking of a fisheye because it would be a more uniform pixel density once projected into a wide panorama, and give a uniform sharpness. But now I'm concerned and looking to favor a rectilinear lens of some reasonable width (preferring a fixed focal length) so I can easily work with a pano head when I get one (contemplating the NN5 if I can find a trustable retailer that sells it).

Phil,

If you are wishing to shoot sphericals for display on the Web then choose a fisheye - you will need far fewer shots and the resolution of the stitched pano will be quite sufficient to produce a FlashVR of good quality capable of fullscreen display on the Web. The Tokina 10-17mm zoom FE is a popular choice for Canon 1.6x crop bodies.

If you want to shoot partial panos with a pano FOV of less than 360x180 then consider a rectilinear lens. If you want a lens of shorter focal length that you kit lens then the Sigma 10-20mm WA is considered to offer very good value. Your kit lens should do fine for higher res. partial panos. In fact you can shoot sphericals with your kits lens (or any lens) - it just takes many more shots than using a FE.

If you are based in the US then buy your Nodal Ninja head from nodalninja.com. Bill Bailey offers outstanding customer service.
Last edited by mediavets on Mon Jan 12, 2009 6:57 pm, edited 1 time in total.
Andrew Stephens
Many different Nodal Ninja and Agnos pano heads. Merlin/Panogear mount with Papywizard on Nokia Internet tablets.
Nikon D5100 and D40, Sigma 8mm f3.5 FE, Nikon 10.5mm FE, 35mm, 50mm, 18-55mm, 70-210mm. Promote control.

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Phil Howard
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by Phil Howard » Tue Jan 13, 2009 7:55 pm

mediavets wrote:If you are wishing to shoot sphericals for display on the Web then choose a fisheye - you will need far fewer shots and the resolution of the stitched pano will be quite sufficient to produce a FlashVR of good quality capable of fullscreen display on the Web. The Tokina 10-17mm zoom FE is a popular choice for Canon 1.6x crop bodies.

Spericals isn't my big interest (though if I try some, who knows, maybe I'd become interested). What I was considering the FE for is so the density of pixels was consistent across the range of projection, rather than going between more and less dense as the point in the pano moves from edges to center to edges of where the original images came in.

mediavets wrote:If you want to shoot partial panos with a pano FOV of less than 360x180 then consider a rectilinear lens. If you want a lens of shorter focal length that you kit lens then the Sigma 10-20mm WA is considered to offer very good value. Your kit lens should do fine for higher res. partial panos. In fact you can shoot sphericals with your kits lens (or any lens) - it just takes many more shots than using a FE.

My interest is in full 360 horizontally (viewable as infinitely rotating horizontally) but not all the way to 180 vertically. The kit lens is 18-55mm. 18mm is not quite wide enough in some cases, so I would look for something a bit wider. 18mm in 1.6x cropped sensor is about a 28.8mm in 36x24mm full frame. Something around 20mm in full frame, which would be 12.5mm in 1.6x crop, would be about right for rectilinear for what I want.

This kit lens is not that sharp, and has some chroma aberration in it. So I'd much prefer a fixed focal length. But there's nothing in WA fixed focal length specifically for cropped sensor. A lens with that focal length for full format would be overkill for a croppy like the 450D. I'm kinda waiting to see if maybe I'll move up to a 5DMK2 or something (plus re-invest in CF cards I can't use in other cameras).

Else I'll need to do multi-row panos using a less that very wide lens.

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by hankkarl » Wed Jan 14, 2009 4:10 pm

There are the Sigma 4.5mm FE and 10mm FE -- about the same as an 8mm and 16mm FE on a 1.6 crop camera

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by mediavets » Wed Jan 14, 2009 4:43 pm

Phil Howard wrote:Else I'll need to do multi-row panos using a less that very wide lens.

Phil,
So....what's the problem with that approach?

I think your ponderings about pixel density and so on WRT FE vs. Rectilinear, and issues with kit lens performance are entirely 'academic' as far as producing panos for display on-line are concerned.

If I was you - given your stated objectives - I'd buy a decent pano head (one of the Nodal Ninja series - http://www.panoguide.com/forums/classifieds/5695/) and shoot multi-row with your kit lens. If your kit lens is the Canon EF-S 18-55mm f/3.5-5.6 IS then DXO should sort your perceived sharpness and CA issues.

If you have money burning a hole in your pocket get a Sigma 10mm FE and a 360Precision Atome pano head, or a Tokina 10-17mm Zoom FE (using a Nodal Ninja pano head) and shoot single row. Either should give you more than enough VFOV and resolution for what you say you want to do. Personally I'd opt for a Nodal Ninja pano head for the FE because then you could also do multi-row sphericals, and multi-row partial panos using the kit lens.
Last edited by mediavets on Wed Jan 14, 2009 5:07 pm, edited 1 time in total.
Andrew Stephens
Many different Nodal Ninja and Agnos pano heads. Merlin/Panogear mount with Papywizard on Nokia Internet tablets.
Nikon D5100 and D40, Sigma 8mm f3.5 FE, Nikon 10.5mm FE, 35mm, 50mm, 18-55mm, 70-210mm. Promote control.


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