Vignetting – rule clarification

[whammawhamma]

Hey, farktography guys! I’ve been a long time lurker and would like to start entering some pics in some contests.

One question though – I’m using a mismatched lens for my DSLR’s camera body, and it causes a slight (but noticeable and sometimes distracting in bright scenes) vignetting at the corners of each shot. I try to zoom out enough that I can crop it out completely, but sometimes it’s unavoidable.

Photoshop CS3’s RAW image importer has a slider to correct for lens vignetting. Can I correct this without violating the rules? While it’s not really “applied to the whole image”, I’m also not spot correcting – it kinda does it’s thing without me having to select regions or anything. It’s just tweaking a slider before bringing the raw image into photoshop.

Fair? Unfair? Fair only if nobody can tell I did it? 🙂

Would it help if I posted a before/after example of what I’m talking about?

[millera9]

I’d like to see an example if that’s not too much trouble…

[Curious]

it sounds ok but like millera9 said an example would help.

[Analogy]

I imagine it looks pretty similar to what my software does:

Before
After

Except in my case the software is precisely correcting the vignetting based on lab measurements made by DxO Labs, no slider tweaking is involved here.

I don’t think it should be completely taboo, it’s not so much adding an effect to the image as removing an effect that was imposed by an imperfection in the lens design.

[Elsinore]

BibblePro will also remove lens vignetting, similarly to what Analogy mentioned, and probably similar to what whammawhamma is talking about as well. Now, in BibblePro, there is a slider to control the strength of the vignette correction. They use a base correction based on your specific lens (they either tested lens distortion vignetting themselves, or they licensed DxO’s–can’t remember), but if that doesn’t quite do it, you can increase or decrease the effect. I’d lean more on the side of it not being a spot treatment. Now *adding* a vignette (which is also possible under Bibble, btw), would seem more a violation of the spirit of the rules, but correcting it doesn’t seem like that big a deal to me.

[Analogy]

It looks like Bibble creates their own lens profiles by having people send in test shots they took themselves. I’m not sure how much I trust that methodology. DxO doesn’t support as many lenses, but at least I know that the corrections will be perfect.

[Elsinore]

lol didn’t realize Bibble’s correction was that “scientific” lol Explains a lot, actually. While I’ve found the vignette correction to be pretty good, I haven’t been as impressed with its distortion correction. Not to mention that it keeps thinking my Tokina 12-24 is a Sigma 12-24 even though the exif clearly shows Tokina. I can override the lens it pulls from, but it’s still kind of a pain. Overall I use ufraw/gimp more anyway, but they don’t have much in the way of distortion correction, though I did find some chromatic aberration correction. Think Bibble might do a better job on the CA stuff, though.

[whammawhamma]

Example before/after pic <-- clicky! That’s probably not the best example, but it shows the problem and the “fix”. I know it kinda looks like an uneven flash in that pic, but it’s happening even in non-flash pics, so pretend it’s a bright sunny scene! 🙂

[Klahanie]

Example before/after pic <-- clicky! That’s probably not the best example, but it shows the problem and the “fix”. I know it kinda looks like an uneven flash in that pic, but it’s happening even in non-flash pics, so pretend it’s a bright sunny scene! 🙂

Ooh, what a cute widdle puppy wuppy. And no, I don’t see a problem with that.

[schnee]

Example before/after pic <-- clicky!

Heck, I do more than that on every shot I enter.

Wait, did I type that out loud?

I mean: “that’s fine”. But, thanks for asking. Seriously. Thanks. And welcome to Farktography!

[millera9]

Agreed, it’s absolutely fine. We’re on the honor system around here so just self-regulate and don’t get too overzealous with it. And welcome to the wide world of farktography. Please send your entry fees for each week’s contest to:

Miller
PO Box 666
Petaluma, CA 69696

😈

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