Luminous Landscape Forum
Site & Board Matters => About This Site => Topic started by: ysengrain on October 25, 2010, 03:52:14 am
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Mr Sexton in Digital Tools for Architectural Photography wrote: "My solution for this focal length was to have the excellent photo machinist, S. K. Grimes, custom fabricate a wide-angle body to accommodate a barrel mounted Rodenstock Digitar. I use a Fotoman viewfinder on it and focus with a Canon 40D fitted with a 135mm f/2 using live view and then I dial in that distance on the barrel mount of the Rodenstock. I then stop down to f8, the optimum aperture for this lens. Focus is faster and more accurate with this method than I can achieve using the flexadapter’s groundglass on my Ebony SW45. "
I'm not a profesional photographer, very far from this job. I'm a "very interested amateur". But when I read Mr Sexton's sentence I can't keep saying "Why make it simple as you can make it so complicated".
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The Nikkor 35mm-PC was my workhorse lens back in film days. But with digital, I wonder if there is really an advantage with using these lenses for perspective correction? You can easily correct keystoning, etc in Photoshop (not to mention other lens flaws like barreling and vignetting. I know that this results in some loss of IQ from the pixel interpolation involved, but what I recall with the 35mm PC was that you could notice some image deterioration as you approached full shift, so that seems to be a wash. Not using any PC-lenses these days, I'm curious to know what and how great the advantage of using optical correction as opposed to digital correction actually is (I guess I'm talking about the 35mm FF world, here). Thanks
(I'm not concerned with the advantages of using tilts, a different kettle of fish with no PP counterpart).
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The Nikkor 35mm-PC was my workhorse lens back in film days. But with digital, I wonder if there is really an advantage with using these lenses for perspective correction?
It depends on the actual lens, but I'd say that with the latest lenses, yes there is an advantage. But wait, there's more ...
You can easily correct keystoning, etc in Photoshop (not to mention other lens flaws like barreling and vignetting. I know that this results in some loss of IQ from the pixel interpolation involved, but what I recall with the 35mm PC was that you could notice some image deterioration as you approached full shift, so that seems to be a wash.
Maybe. Part of the complication is with Photoshop, since it's not offering the best resampling quality possible. Depending on the image content, you may find more choices to adapt to image content in some dedicated Pano Stitching applications (they may, besides keystoning correction, also offer geometric distortion correction, and a choice of (higher order) resampling methods), even on a single image. Anyway, software will not solve the need to crop after resampling, which might reduce the resulting number of pixels to output.
Not using any PC-lenses these days, I'm curious to know what and how great the advantage of using optical correction as opposed to digital correction actually is (I guess I'm talking about the 35mm FF world, here).
Not unimportant, lens quality has improved. This raises the stakes for the resampling alternative. Also important, the wider the field of view, the more optical detail counts as an advantage over software/interpolation. Also, the more extreme the shift, the more the optical detail advantage weighs in.
So, it ultimately depends on the actual situation, which lens, how much shift, which focal length. With a good lens, optical quality will probable win, unless the amount of shift gets relatively extreme. When the software alternative is chosen, stitching with a (slightly) longer focal length may offer an even better quality, although it requires more postprocessing time (and some skill/experience).
Cheers,
Bart
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The Nikkor 35mm-PC was my workhorse lens back in film days. But with digital, I wonder if there is really an advantage with using these lenses for perspective correction? You can easily correct keystoning, etc in Photoshop (not to mention other lens flaws like barreling and vignetting. I know that this results in some loss of IQ from the pixel interpolation involved, but what I recall with the 35mm PC was that you could notice some image deterioration as you approached full shift, so that seems to be a wash. Not using any PC-lenses these days, I'm curious to know what and how great the advantage of using optical correction as opposed to digital correction actually is (I guess I'm talking about the 35mm FF world, here). Thanks
(I'm not concerned with the advantages of using tilts, a different kettle of fish with no PP counterpart).
I think that with MFDVC and a serious lens like the Schneider Apo-Digitar 47XL (100 degrees, I have one on my desk, still unmounted) it is a different story
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The Nikkor 35mm-PC was my workhorse lens back in film days. But with digital, I wonder if there is really an advantage with using these lenses for perspective correction? You can easily correct keystoning, etc in Photoshop (not to mention other lens flaws like barreling and vignetting. I know that this results in some loss of IQ from the pixel interpolation involved, but what I recall with the 35mm PC was that you could notice some image deterioration as you approached full shift, so that seems to be a wash. Not using any PC-lenses these days, I'm curious to know what and how great the advantage of using optical correction as opposed to digital correction actually is (I guess I'm talking about the 35mm FF world, here). Thanks
(I'm not concerned with the advantages of using tilts, a different kettle of fish with no PP counterpart).
I am using a Nikon D3x and the three PCE nikkors 24- 45 and 85mm. I do a lot of architecture...
Before this setup i used the perspective correction in photoshop.
( and before that I used a 4x5 inch camera)
There are huge benefits using the PCE lenses
1 Tilt - You can extend the depth of field the way you like it
2 the PCE lenses are about the best Nikon (or Canon) produces- and are a lot better than the old Nikkor 35mm PC- they serve the full 24MP even shifted.
3 In the field you can directly see what you get - and- i do not have to do a lot of photoshopping before i present my clients a selection to choose from.
4 the image quality remains higher because you do not have to stretch and crop
5 Perspective control in photoshop has usually a different outcome than The shift lens. There seems to be not an easy way to do it in photoshop because it all depends on where you are in relation to the subject(- information you do not have when you are back home behind your screen)- By using a Shift lens this problem is solved
6 etc ( this is what came out in a minute - must be more to add)