Canon 1Ds Vignetting Problem

[danazoo]

I am a professional photographer, been shooting digital for 2.5 years. Got a 1DS 4 months ago. When I shoot interior, studio, flash, strobe..all is well.

BUT, when I shoot outside, with any of my lenses [all Canon USM ultrasonics]...I keep getting very dark vignetting on the corners/edges of the images. With or without hood/filters/extender etc. I posted a sample at www.danahoff.com/881.jpg & www.danahoff.com/880.jpg (which is cropped some).

How can I stop the vignetting problem? Some please help me before I go insaaaaanneee.

[ilya]

The cos-4th law /geek hat on/

One way is to stop down till it goes away.

Another way is if you own regular Photoshop you can insert a layer with a radial gradient . However, it is usually difficult to match the exact falloff with a custom gradient.

A third way is to get Photoshop CS. The Raw converter has a slider control to fix vignetting. Works pretty well.

Cheers

Ilya

[scotgasch]

Ok here is the deal....

I too have the 1ds and I get the same results. It only gets worse the wider angle lens you use. Here is the reason....

The full frame sensor is made up of pixels right? Right. Now, the sensor is flat and the individual pixels at the edges are receiving light differently than the pixels in the center. The pixels on the edges get light at an angle thus they are less efficient or less able to gather the same amount of light as the ones more in the center. So we get light falloff. The solution would be a non-flat sensor, which would be very expensive to produce...so we live with it for now......


Hope this helps you understand the problem.....

Personally I don't mind it...it gives your shots a nice vignette

[danazoo]

I ponder if a ND filter would help any.....sounds like a test to do

[ChrisNardone]

Ok here is the deal....

I too have the 1ds and I get the same results. It only gets worse the wider angle lens you use. Here is the reason....

The full frame sensor is made up of pixels right? Right. Now, the sensor is flat and the individual pixels at the edges are receiving light differently than the pixels in the center. The pixels on the edges get light at an angle thus they are less efficient or less able to gather the same amount of light as the ones more in the center. So we get light falloff. The solution would be a non-flat sensor, which would be very expensive to produce...so we live with it for now......


Hope this helps you understand the problem.....

Personally I don't mind it...it gives your shots a nice vignette


Good explanation Scot, one question: Why would studio shots not show vignetting?

[scotgasch]

That is a good question.....

I will have to think on that one.....

My shots, even in the studio, display this type of light falloff...

Try the same apeture settings you use outside, inside....

Maybe it hase to do some with the polorizing of the light.....

I will do some checking on that...

[CyberDyneSystems]

This is exactly the issue that Olympus has addresed with its line of lenses for the E1.

I know we knock it,. and I have problems with it too,. but the system is ahaed of it's time.

For a real DSLR to function at it's best it needs purpose built lenses that take the photoreceptors "tunnel vision" into account.

The fact is that the photoreceptors on a CCD/CMOS behave differently than film... film does not seem to mind so much when the light hitting it is coming at a slight angle,. the Photreceptors on the other hand do..

This is why,. some day,. all out\r L lenses WILL be obsolete.. (yes it will be a long time)