Can PI 12 edit out Vignetting?

blplhp · Post by **blplhp** » Tue Jan 09, 2007 9:17 pm

I am just starting to explore PI 12. Is there an editing function to take care of vignetting? If not, what procedure do most of you use to get rid of vignetting?

heinz-oz · Post by **heinz-oz** » Tue Jan 09, 2007 10:28 pm

Not as far as I know. Can you post a sample of this vignetting? I'm not entirely sure of what you are referring to. If it is the reflections you get from your lens when the sun hits it, that would be difficult to remove and is best to be avoided by using a lens hood.

Post by **Ron P.** » Wed Jan 10, 2007 1:13 am

Heinz, vignetting is the corner cropping that occurs when your focal depth is not matched to the lens. It is where the corners are dark or black.

Brian,
The only way to remove the vignetting, is to crop the photos. Unless it is severe, then it shouldn't affect your image much.

heinz-oz · Post by **heinz-oz** » Wed Jan 10, 2007 1:18 am

Thanks for putting me straight on that one vidoman. Now, how would you get that happening?

I have had a non standard lens hood once on one of my old Minolta's lenses. It kind of showed when going into extreme wide angle. Other than that, how can it happen?

Post by **Ron P.** » Wed Jan 10, 2007 1:56 am

As you've probably read, I have Kodak's P880 digital camera. The lens is a 24mm Wide lens. Now if I put on a Telephoto lens or a Teleconverter, commonly called a TCON that is not matched to the lens on the camera, then the focal length at its widest setting will capture some of the lens itself. This can be extreme, which is a cylindrical vignetting, or most of the time the corners. To avoid this vignetting you have to zoom in slightly so that it captures beyond the TCON itself.

I don't know it that explains it correctly, it is how I understand it. Here is a better explanation, with a photo example...

http://www.vanwalree.com/optics/vignetting.html

heinz-oz · Post by **heinz-oz** » Wed Jan 10, 2007 2:12 am

Thanks vidoman, that explains it. I never use converters, except on my GS 400 to get a better wide angle coverage. My compact digital Canon S45 is only used as is and for my EOS 350D I got the correct lenses. That's why I was not aware of this phenomenon.

blplhp · Post by **blplhp** » Wed Jan 10, 2007 6:37 am

Hello heinz-oz,

Most of my Canon S45 indoor shots with flash at wide angle produces vignetting (darkness in the 4 corners of the frame). My new Canon A630 does the same thing, but not as much as the S45. Is there any way in PI 12 to reduce or eliminate this darkness in the corners.

heinz-oz · Post by **heinz-oz** » Wed Jan 10, 2007 8:04 am

I dont think you can call this vignetting. The flash is not powerful enough to illuminate every corner. I don't use the flash often on the S45 because you get a lot of red eye as well.

I don't think there is anything in PI, or any other software for that matter, which can eliminate that. Except for cropping the picture.

blplhp · Post by **blplhp** » Wed Jan 10, 2007 4:14 pm

heinz-oz,

Thanks for your reply. I didn't think there was any way of getting rid of the dark corners, but I wanted to check with the experts first before resigning to that conclusion.

BTW, here in the U.S., all of the professional digital camera review websites refer to the dark corners as "vignetting". It's not something that I made up.

heinz-oz · Post by **heinz-oz** » Wed Jan 10, 2007 10:52 pm

I didn't say you did either

and it may well be called that too

You could try to mask out the well lit parts of your image, extract as an object and then brighten up the base image to match the brightness of the rest.

This could work because, in your case of vignetting, there is detail in the corners. With vignetting due to the use of a teleconverter for instance, the corners would just be dark because they are formed by the hardware showing in the image. No point to brighten that up.

njdowding · Post by **njdowding** » Wed Jan 10, 2007 11:55 pm

I think Heinz you will find this is vignetting. It comes from as Vidoman described using an adaptor or as you describe not having a strong enough flash. The end result is vignetting. Take a look at your vignette filter in MSP8 to apply this effect to video!

As for the removal in PI well if the data is not there you cant really get it back. You could crop it but you could also apply a mask or a frame to cover it up. An oval mask for example could remove it. If the back ground is fairly consistent you could also use the touch up tools to clone another area of the back ground into the darkened areas.

Nick