# Photographing rectangular objects **URL:** \ **Category:** Factual Questions\ **Created:** [August 1, 2015, 4:41pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736 "2015-08-01T16:41:07Z")\ **Posts on this page:** 15\ **Page:** 2
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 2, 2015, 5:12pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/21 "2015-08-02T17:12:19Z")
Any piece of software that can correct a bunch of images to a rectangle can also correct a single image to a rectangle, and much more easily. ---
**Author:** ![Pork\_Rind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pork_rind/32/111_2.png) [@Pork\_Rind](https://boards.straightdope.com/u/Pork_Rind)\ **Post date:** [August 2, 2015, 5:47pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/22 "2015-08-02T17:47:04Z")
> [@Chronos](#): > > Any piece of software that can correct a bunch of images to a rectangle can also correct a single image to a rectangle, and much more easily. It’s not just correcting to a rectangle. There’s non linear barrel or pincushion distortion, wave distortion, all kinds of issues that are not quite as simple as just making the corners all 90 degrees. ---
**Author:** ![Pork\_Rind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pork_rind/32/111_2.png) [@Pork\_Rind](https://boards.straightdope.com/u/Pork_Rind)\ **Post date:** [August 2, 2015, 5:50pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/23 "2015-08-02T17:50:02Z")
> [@Chronos](#): > > Note that this is not due to a defect of the lenses, but to a fundamental aspect of geometry. A field of view is actually spherical, not flat, and so any method of turning it into a flat image is going to involve some form of distortion. It’s the same problem as converting a globe to a map. Barrel and pincushion distortion are separate and independent from that mapping effect though. Some lenses will show little to none of the effect, and others will have a tremendous amount. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 2, 2015, 6:52pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/24 "2015-08-02T18:52:16Z")
> [@](#): > > It’s not just correcting to a rectangle. There’s non linear barrel or pincushion distortion, wave distortion, all kinds of issues that are not quite as simple as just making the corners all 90 degrees. Yes, and all of these issues must be addressed in either case. But the stitched-together method has even more issues to resolve than the single-image method. ---
**Author:** ![scabpicker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scabpicker/32/8268_2.png) [@scabpicker](https://boards.straightdope.com/u/scabpicker)\ **Post date:** [August 3, 2015, 3:11am UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/25 "2015-08-03T03:11:41Z")
> [@LSLGuy](#): > > Said another way, somewhere in that range distortion is closest to zero. So shoot at that zoom setting if possible. Yes. Said another way, lenses in this range are “normal” lenses for the image format. The equivalent would be a 50mm lens on a 35mm film camera. From checking the wiki, a D90’s “normal” length is a 28mm lens. So, either set the zoom to around that for the equivalent of a “normal” focal length, or buy a lens that is around 28mm. I prefer the latter, because generally fixed length lenses have better performance (distort less, absorb less light, etc.). But, then you arrive at the first maxim of photography, which is: If you have more than one lens on your camera, you will inevitably not have the “perfect” lens on it for any given shot. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 3, 2015, 3:27am UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/26 "2015-08-03T03:27:06Z")
Is the second maxim that the perfect lens is always one you don’t have yet, so you always have to buy more? ---
**Author:** ![scabpicker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scabpicker/32/8268_2.png) [@scabpicker](https://boards.straightdope.com/u/scabpicker)\ **Post date:** [August 3, 2015, 4:45pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/27 "2015-08-03T16:45:19Z")
> [@Chronos](#): > > Is the second maxim that the perfect lens is always one you don’t have yet, so you always have to buy more? It’s either about that, or something about having to buy or rent a large format camera (which is really the ideal tool for copy work, but I digress), or maybe it’s the one about how only Ansel Adams _really_ understood the zone system…nah, that’s like number seven… ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [August 3, 2015, 5:09pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/28 "2015-08-03T17:09:15Z")
> [@scabpicker](#): > > It’s either about that, or something about having to buy or rent a large format camera (which is really the ideal tool for copy work, but I digress), or maybe it’s the one about how only Ansel Adams _really_ understood the zone system…nah, that’s like number seven… Related question: Ansel Adams used an 8"x10" format I believe … what is the megapixel equivalent to such? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [August 3, 2015, 5:34pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/29 "2015-08-03T17:34:48Z")
> [@watchwolf49](#): > > Related question: Ansel Adams used an 8"x10" format I believe … what is the megapixel equivalent to such? Megapixels are a hugely overrated measure of quality, but if we assume that something like the 50 megapixel Canon full-frame camera is about as high-resolution as possible, that translates to 33.33 megapixels/square inch, which would make an 8x10 sensor of the same density 2.6666 Giga Pixels. ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [August 3, 2015, 5:35pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/30 "2015-08-03T17:35:59Z")
Are you shooting raw? Because the camera applies some of its own lens distortion correction based on its knowledge of the lens. If you are currently shooting raw, then you might just be seeing the ugly uncorrected source photo. Give JPEG a try and see if you get better results. On the other hand, if you are shooting JPEG then your own corrections might be fighting insufficient corrections already applied by the camera. Give raw a shot and see if that lets PS/LR do a better job of it. ETA: If I were photographing fine art, I would use raw so that I could make fine adjustments to white balance as needed in Adobe Camera Raw or Lightroom–those adjustments are not so easily made with JPEG. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [August 3, 2015, 5:41pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/31 "2015-08-03T17:41:33Z")
> [@watchwolf49](#): > > Related question: Ansel Adams used an 8"x10" format I believe … what is the megapixel equivalent to such? Comparison [here](http://petapixel.com/2014/12/18/comparing-image-quality-film-digital/). ---
**Author:** ![ticker](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@ticker](https://boards.straightdope.com/u/ticker)\ **Post date:** [August 3, 2015, 6:11pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/32 "2015-08-03T18:11:20Z")
> [@scabpicker](#): > > Yes. Said another way, lenses in this range are “normal” lenses for the image format. The equivalent would be a 50mm lens on a 35mm film camera. Radial distortion, of which barrel and pincushion are the inverse forms, is by design usually at a minimum in the centre of the zoom range, thus minimizing the maximum distortion at extremes of the zoom range. If this commonly coincides with a ‘normal’ lens it is because many popular zooms straddle the ‘normal’ range. It is not an inherent property of these focal lengths. Nitpick: the true ‘normal’ focal length for 35mm format is 43mm, notwithstanding the common practice of supplying prime 50mm lenses with SLR cameras before kit zooms became ubiquitous. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [August 3, 2015, 6:19pm UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/33 "2015-08-03T18:19:42Z")
> [@beowulff](#): > > Comparison [here](http://petapixel.com/2014/12/18/comparing-image-quality-film-digital/). Thanx … “… the 10×8 just blows everything out of the water.” ---
**Author:** ![Mr\_Downtown](https://avatars.discourse-cdn.com/v4/letter/m/8e8cbc/32.png) [@Mr\_Downtown](https://boards.straightdope.com/u/Mr_Downtown)\ **Post date:** [August 4, 2015, 3:49am UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/34 "2015-08-04T03:49:23Z")
> [@Pork\_Rind](#): > > Lens profiles are a built in part of LR and Photoshop, so no reason not to take advantage. But they’re only available for DSLRs, right? I can’t get one for my Canon IS800 or even my Olympus C-8080—much less my iPhone. ---
**Author:** ![Pork\_Rind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pork_rind/32/111_2.png) [@Pork\_Rind](https://boards.straightdope.com/u/Pork_Rind)\ **Post date:** [August 4, 2015, 4:21am UTC](https://boards.straightdope.com/t/photographing-rectangular-objects/726736/35 "2015-08-04T04:21:36Z")
> [@Mr\_Downtown](#): > > But they’re only available for DSLRs, right? I can’t get one for my Canon IS800 or even my Olympus C-8080—much less my iPhone. I haven’t looked in ages but I would be surprised to find that profiles didn’t exist for all sorts of non-DSLR cameras. If not, the process of making the profile is easy enough. You print out and shoot the special target and feed it into the profile creator. I did that several times when the tools were released and the pool of available profiles was small. Eta: I see all the iPhone models on the list. Not immediately seeing the Canon or Olympus you mention. [Previous page](https://boards.straightdope.com/t/photographing-rectangular-objects/726736.md?page=1)