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06-22-2011, 02:12 PM   #1
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DA15/4--How to deal with keystoning?

The DA15 is a recent acquisition. I have not been much of a wide angle shooter in the past. For the most part, I have shot in the normal to short telephoto range. With the DA15, I find myself having to be extra vigilant about what extraneous things manage to sneak into the frame. This is something that I can deal with. But what I find most annoying about wide angle photography is the exaggerated keystone effect that occurs with just slight angulation of the lens. It is not always possible to orient the camera exactly parallel to the subject. How do people manage this? I realize that keystoning can often be corrected in PP, but is this the only solution? Or should I just learn to accept keystoning as part of the wide angle aesthetic?

Rob

06-22-2011, 02:17 PM   #2
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I find the 15mm suffers very little bending, or keystoning, except with verticle objects on the ends of the frame. Keep trees, poles, etc., out of the frame edges and keep the camera level to the scene. Afterall, you should be doing that regardless the FL. Verticle objects toward the center won't look abnormal.
06-22-2011, 02:32 PM   #3
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I think keystoning is just a nature of the beast. Besides handling it in PP, there's not much you can do.

In the last vacation, I let my son handle the GX200 (FL equivalent to 24mm - 72mm). Not used to the wide 24mm FOV, he learned that:

- he had to pay extra attention to keeping the camera level.
- he had to back up to avoid excessive perspective distortion.
- he should not frame too tight, but leave some room for cropping in PP.

In the next vacation, my son will use a K10D and only 1 lens: DA 12-24, to reinforce what he's learned.

Last edited by SOldBear; 06-22-2011 at 06:28 PM.
06-22-2011, 02:34 PM   #4
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Use the lines in the viewfinder to keep vertical / horizontal lines straight.

Then correct the rest in post. It's not too difficult and worth the trouble.

06-22-2011, 03:35 PM   #5
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QuoteOriginally posted by SOldBear Quote
- he should not frame too tight, but leave some room for cropping in PP.

.
That is a biggie that most don't consider. You can correct a lot in PP, but you will lose from the top and from the sides.
06-22-2011, 03:36 PM   #6
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Buy a view camera.
06-22-2011, 03:39 PM   #7
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But yea, I learned the hard way that you must leave room for de-keystoning if you plan to do that PP. DxO has a real easy de-keystoning function, havent played around with it in other programs.
06-22-2011, 04:14 PM   #8
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QuoteOriginally posted by GeneV Quote
That is a biggie that most don't consider. You can correct a lot in PP, but you will lose from the top and from the sides.
Absolutely agree, I found this out the hard way

06-22-2011, 05:07 PM   #9
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QuoteQuote:
...should I just learn to accept keystoning as part of the wide angle aesthetic?
Yes. That is normal perspective. If you "fix" it as others imply, you can make it look unnatural. If you make a tall building perfectly parallel, your mind thinks it is expanding.
06-22-2011, 05:13 PM   #10
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I use PT Lens (PTLens) which also applies barrel and pincushion correction based on the lens in addition to allowing you to correct for key stoning... As stated in this thread, you have to leave yourself the "room" to perform the correction. Consider the following uncorrected and corrected versions of the frame and the amount of crop that this entails. You can see it can really be quite a big "bite." Shot with a DA15mm.

Funny, I am kind of fond of the uncorrected version...




06-22-2011, 05:41 PM   #11
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QuoteOriginally posted by twitch Quote
Absolutely agree, I found this out the hard way
Me, too.
06-22-2011, 05:43 PM   #12
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QuoteOriginally posted by civiletti Quote
Buy a view camera.
I have a camera with movements, but it isn't always handy.
06-22-2011, 05:46 PM   #13
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Woof posted a good example, here's my own one from a picture I took a couple of weeks ago. I like the ferris wheel in the unaltered pic, but far prefer the buildings and poles in the altered one. I think I needed to leave more room to the left of the wheel to avoid the weird effect on where it got stretched during correction.

Unaltered:




Altered:

06-22-2011, 05:50 PM   #14
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QuoteOriginally posted by twitch Quote
Unaltered
I much prefer the unaltered one.
06-22-2011, 06:38 PM   #15
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QuoteOriginally posted by SpecialK Quote
Yes. That is normal perspective. If you "fix" it as others imply, you can make it look unnatural. If you make a tall building perfectly parallel, your mind thinks it is expanding.
This is true. I use Capture One 6 as my raw processor. It has the best and easiest keystone correction tool that I have ever used, and that includes DxO, PTLens and PS. Of note, C1 only corrects converging lines by 80% rather than 100%, as this appears more natural to our eyes.

Regarding leaving room on the edges for cropping, one might as well be using a shorter lens. It does somewhat defeat the purpose of using a wide angle lens.

Rob
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