Wide Angle & Lens Correction in PS

[Thlayle]

Hello,

As an amateur, shooting DSLR for about three years now (and yes with a lifetime of some shooting all the way back to the film days) and now just trying out Lightroom and Photoshop for about 10 months now, I am trying to not only figure out the tools but what steps really matter.

I shoot with a Canon T2i and frequently use a 14mm UWA Rokinon (all manual of course) because I love the lens & how it performs at night, my favorite shooting.

Of course I am seeing some lens distortion, which seems especially distracting when there's much architecture involved.

My question are these:

1)Do you normally worry much about the curved surfaces in your wide angle shots? Or do you disregard it usually or just handle it case by case? If case by case, is it different when considering shots with tall buildings & so forth?

2) In these samples I have generated, I did a lot of correction with Photoshop's Adaptive Wide Angle filter. I like the improvements in geometry but dislike the lost real estate in the image. So my other question is: does the distortion corrected version seem worth it when you look at it, or would you have left it alone?

Feedback appreciated. Also, I realize there are different ways to go about this but using a different lens in not one I am considering at the moment. I have a very limited budget and essentially have just this 14mm and a 50mm 'plastic fantastic' as my only auxiliary lenses. Just shooting kit lenses otherwise & I am seeing lots of issues with those at times, especially with this type of shooting.

Thanks,

Randy

[Manfred M]

In my view the answer is "it depends"; you pretty well have to judge each image on a stand-alone basis; sometimes I correct for distortion and sometimes I don't.

I don't know this when I shoot, so I will provide enough space around the image to ensure I can make corrections in post (I generally worry the most about keystoning) and may take a closer crop as well, because I may like the shot better. I tend to always work the image (take multiple shots changing my PoV), especially on those that may need this correction, so that I have enough material to work with in post.

[FrankMi]

Hi Randy, you bring up several questions that may matter to some folks but not so much to others and may matter more for specific types of image but less to other images so in my view, there is not a definitive right or wrong answer.

Sometimes, the best choice is what you prefer. After all, these are your images being discussed, not someone else's.

From my viewpoint, distortion correction depends very much on the specific image involved and my goal for that image. If this were my image I would correct the perspective distortion because I prefer my images to look like I see them and this scene would not present this level of geometric distortion in real life.

By the same token, if I am shooting an ocean scene from a high altitude, I expect to see the horizon curved so I would not correct that beyond the amount of curve I would see.

For me, there is a place for not being too aggressive in correcting distortion and that is in images that are presented for their artistic or abstract values more than for their reality.

For the loss of real estate image issue, I can see in the viewfinder what will be lost when the perspective correction is applied and shoot wider than the final crop to compensate. Whenever possible, and particularly with a wide angle lens, I try to keep the lens as level and square onto the subject as possible to minimize distortion. For a composition with a wide aspect ratio, I would use a longer lens and do a panoramic set of images. Doing any pano with a wide lens becomes increasingly difficult to stitch together.

Using a wide angle lens provides specific image inclusion and depth benefits but at an increasing distortion cost. Only you can decide where to make the cut on an image by image basis. Hope this helps!

[russellsnr]

Hi, If you have Lightroom then use the upright tool much easier IMO https://www.youtube.com/watch?v=7nQTQPvlg_M
With such a wide angle lens you maybe have to take that little extra in the image to crop out later.
Russ

[rpcrowe]

I have a fetish about the distortions resulting from using a w/a lens at the distances that these lenses are usually shot. However, many photographers don't worry about distortions. In fact some photographers actually like the distortion...

Buildings and other architecture, with strict vertical and horizontal lines show the results of distortion more readily than say landscape views...

One way to minimize distortions in shooting is to keep your sensor perpendicular to the ground, not pointed up or down at an angle...

I also do not like barrel and pincushion distortions. This type of distortion is more prevalent when using certain lenses than with others. Long focal range zoom lenses are most susceptible to barrel and pincushion distortions. These distortions are correctable with software. One way to partially avoid these distortions is to choose a lens that produces these distortions the least...

[Shadowman]

I usually handle the distortion two ways, I have a 10-24mm lens used on a crop sensor camera and if I want to emphasize the UWA effect I'll shoot below 16mm, if I want to control it somewhat I'll shot above 16mm. If there is significant curves afterwards I'll fix during post processing.

[Thlayle]

Manfred & Frank,

Thanks: very helpful comments. It's the framing compensation for geometry corrections later that I might take to the bank, so to speak, and see if that helps. The lens choice for now is 'what it is.' I too prefer to see the image look as much like I remember the actual setting and that's where the wide angle corrections get to be a concern for me, especially with shots including things like tall buildings.

I love this Rokinon lens mainly for night shots of the stars: no coma distortion at all and very inclusive angle of the sky, which is real nice since stitching star shots seems to be more than a little challenging.

I might have to look into another wide angle for some of these types of scenes. The geometry concerns come up a lot more than they might seem to (structures mainly but sometimes natural features).

I gather too that just a longer focal length with stitched images might work really well in this sort of situation. The question, without the benefit of much experience, is what focal length will start to do the work right for me? I see a number of wide angle zooms out there. I am thinking maybe a zoom starting at 24mm at the low end.

[Thlayle]

Hi, If you have Lightroom then use the upright tool much easier IMO https://www.youtube.com/watch?v=7nQTQPvlg_M
With such a wide angle lens you maybe have to take that little extra in the image to crop out later.
Russ

Russ,

Very good suggestion. I just tried it in Lightroom and it worked fairly well -- and very easy! That may suit my purpose for many of these.

For some reason, I never look at the basic tab in the lens correction module. I think it's because I am used to having to do so much manually since this lens profile doesn't get picked up by my camera and thus is not available in Lightroom.

Thanks,

Randy

[Thlayle]

I have a fetish about the distortions resulting from using a w/a lens at the distances that these lenses are usually shot. However, many photographers don't worry about distortions. In fact some photographers actually like the distortion...

Buildings and other architecture, with strict vertical and horizontal lines show the results of distortion more readily than say landscape views...

One way to minimize distortions in shooting is to keep your sensor perpendicular to the ground, not pointed up or down at an angle...

I also do not like barrel and pincushion distortions. This type of distortion is more prevalent when using certain lenses than with others. Long focal range zoom lenses are most susceptible to barrel and pincushion distortions. These distortions are correctable with software. One way to partially avoid these distortions is to choose a lens that produces these distortions the least...

Thanks, Richard. I totally get that and it is why I brought up the question. As noted already, individual preferences enter into this very much. I try to remember that and balance between my preferences, which aren't necessarily static, and what others see in my work. After all, I am trying to convey something to others so it can't be just all about me.

Regards,

Randy

[FrankMi]

I gather too that just a longer focal length with stitched images might work really well in this sort of situation. The question, without the benefit of much experience, is what focal length will start to do the work right for me? I see a number of wide angle zooms out there. I am thinking maybe a zoom starting at 24mm at the low end.

Randy, for wide aspect ratio panoramas, I typically shoot with a zoom lens at about the 50mm focal length. I would start experimenting with your existing 50mm lens and see how it works for you.

Here is a wide aspect ratio panorama (the second image in this post), that also shows the curve of the horizon I mentioned earlier. This would not be as effective in the image you posted as it has closer to a 4:3 than than a 2:1 (or greater) aspect ratio.

[ajohnw]

You can get round the real estate losses by shooting a panorama with your Rokinon. 2 shots rather than one should do it.

I've tried that with the camera in portrait mode, 9mm on m 4/3, 3 shots and stitched them with a very simple application. An application such as Hugin should make an excellent job of it. If you try that one do read the tutorials as the 1st thing that needs to be done is go near the end of the steps and set the correct perspective. This application can also be used to determine a lenses distortion characteristics. I've never used it for that but it should be ok.

John
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[Thlayle]

You can get round the real estate losses by shooting a panorama with your Rokinon. 2 shots rather than one should do it.

I've tried that with the camera in portrait mode, 9mm on m 4/3, 3 shots and stitched them with a very simple application. An application such as Hugin should make an excellent job of it. If you try that one do read the tutorials as the 1st thing that needs to be done is go near the end of the steps and set the correct perspective. This application can also be used to determine a lenses distortion characteristics. I've never used it for that but it should be ok.

John
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Thanks, John. I have had some success with stitching the 14mm shots, but with some mixed results.

I will look into Hugin. Do you recommend that over Photoshop stitching, or just no basis for comparison? Also, prior to Photoshop, I have been using a product called 'DoubleTake.' It works pretty well but since trying out Photoshop I haven't yet done much comparison between the two.

Regards,

Randy

[ajohnw]

I've no idea how good Photoshop is at stitching images. An example of what Hugin can produce is here for instance. 9 shots with a 10mm lens

https://www.flickr.com/photos/gadl/2...n/photostream/

I've also seen example where different focal length lenses have been used.

There are a number of video's on youtube showing it's use.

John
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[Manfred M]

John - Photoshop is excellent in stitiching images. It's usually impossible to find any blending artifacts.

I'd like to add, most of my shots that go into a pano tend to come from medium wide angle to normal shots, not from ultrawide angle shots.

[dje]

Hi Randy

Nice shot. I prefer the corrected version in this case but I would question why you needed to lose so much real estate with this. I quickly ran the un-corrected image through the perspective crop tool in PS and came up with this.

Dave

[travelfinn]

Used Hugin to fix your image. Just a fast way not pefect. Loaded your image then preview and adjusted it and converted it one minute not perfect but nearly. check Hugin
Shooting a lot 14mm full frame and using a manfrotto three way geared head to get the camera absolutly straight. Also using the camranger to frame the picture.
You have a crop sensor so it's 22mm on a full frame so good enough for stitching.http://s8.tinypic.com/2nks6mo_th.jpg

[Polar01]

Randy, I have a 10-20mm I use on my D7000, and a 16-35mm on my D600. I shoot wide angle pans all the time for you shot I would have likely used 3 shots and stitched in Photoshop which does an excellent job by the way. Now I shoot almost all my stuff with the camera set in Portrait mode, now I use a L-bracket so that I can quickly change from landscape mode to portrait in a matter of seconds.

Cheers: Allan

[inkista]

I very rarely correct for pronounced wide-angle barrel distortion (I'll correct more if it's slight or pincushion), but I'm an eccentric when it comes to this kind of thing, as I like fisheyes and often shoot 360x180 panos from fisheye images and do weird remappings, so distortion is a friend to me. I've occasionally defished, but as you note, often it's simply not worth the real estate loss. And I rarely shoot architecture.

When I shoot rectilinear UW with my Oly 9-18 (I'm on four-thirds, so that's only an 18-36 equiv.), I'm generally not correcting at all. I don't mind the leaning verticals.

(9-18 @9mm)


And if I do mine, I can try hoofing it out and zooming in.

(9-18 @18mm instead)

[Shadowman]

I very rarely correct for pronounced wide-angle barrel distortion (I'll correct more if it's slight or pincushion), but I'm an eccentric when it comes to this kind of thing, as I like fisheyes and often shoot 360x180 panos from fisheye images and do weird remappings, so distortion is a friend to me. I've occasionally defished, but as you note, often it's simply not worth the real estate loss. And I rarely shoot architecture.

When I shoot rectilinear UW with my Oly 9-18 (I'm on four-thirds, so that's only an 18-36 equiv.), I'm generally not correcting at all. I don't mind the leaning verticals.

(9-18 @9mm)


And if I do mine, I can try hoofing it out and zooming in.

(9-18 @18mm instead)

Nice spericals in the link, did you use special camera or software? I have one of those Theta360 cameras that provides the software to view.

[Thlayle]

Hi Dave,

I think maybe it's because I chose the Adaptive Wide Angle tool. I know when I tried out the suggestion to apply the 'upright' tool in Lightroom, it worked well for correction & didn't lose so much of the image periphery.

Nice job, by the way, on your rendition of the perspective correction.

-Randy

Hi Randy

Nice shot. I prefer the corrected version in this case but I would question why you needed to lose so much real estate with this. I quickly ran the un-corrected image through the perspective crop tool in PS and came up with this.

Dave