Dark Edges on Large CCD

[nicholasuniversal]

Hi, I'm new to this forum.

I have the following camera setup:
Prosilica GE4900C
Kodak KAI-16000 CCD sensor
Nikon Nikkor AF 35mm f/2D

I can't figure out why I get dark areas on the edges of my photos. I attached some examples.
I have tried different kinds of F stop settings as well as shutter speed and iso, all that stuff.

Can anyone help me?
Photo 1
Photo 2

 

[Patrice]

No information on aperture provided. Not familiar with that camera or sensor but your words "large CCD" lead me to think the sensor is larger than the image circle that lens was designed to illuminate. Thus, dark edges are vignetting. Try a lens for a larger format camera such as the medium format cameras or even the larger view cameras. All this assumes that the lighting was even across the scene and confirmed by light meter readings.


edit: just did a quick look up on that equipment. Full frame (135 format) with nikon mount. The lens' image circle should illuminate the sensor adequately. Check the lighting.

 

[nicholasuniversal]

Thanks for the response.

Every photo we take with this camera has the dark edges. We have not tried a large format lens before maybe that will work. The photos were taken at F22 but the dark edges are there at all aperture settings.
Here is the spec sheet on our camera, maybe it will help: http://www.1stvision.com/cameras/Prosilica/dataman/GE4900-4900C.pdf

 

[analog.universe]

Is the on camera flash firing? To me these images look like a flash shot at a longer focal length than the lens. The linear instead of circular pattern pretty much means the lens isn't causing it.

edit: whoops, just saw the thing, nevermind :lmao:

 

[nicholasuniversal]

The dark edges are there under all light conditions. We do not have a flash in the sample image we are using halogen lights. The dark edges are there under daylight as well during aerial photography.

 

[Garbz]

Take a shot and remove the lens. If it still comes out the way it does then blame the sensor itself. Otherwise it may just be an interface problem between the lens and sensor such as lens not lined up correctly.

 

[nicholasuniversal]

I took some more test photos today. I took off the lens for a couple of them. Let me know what you guys think.

Inside of camera: photo1
Sky at F/8: photo2
Sky at F/22: photo3
The lens removed indoors (same set up as shown in original post): photo 4
Lens removed outdoors: photo5

Thanks

 

[AUG19]

Lens removed outdoors: photo5

Thanks

This is one I was hoping to see..and it's not showing up in my browser. Is it on the server?

 

[AUG19]

The splash page of your website is kinda weird. I think i'll pass.

 

[nicholasuniversal]

The photo is all white. It doesn't look like it loads on my browser either but its just a white photo.

 

[Garbz]

All white and blown out. Can you do an outside shot with correct exposure? If you can't control the electronic shutterspeed then I suggest taking the photo at dusk or maybe put a polariser on the camera. A blown out photo tells you nothing.

 

[nicholasuniversal]

I'll do anouther outside shot with no lens soon. I bought a new lens yesterday its a Zeiss 50mm f/1.4 ZF. It made a big difference in the shading.
Check out this image, test2
Compare that to the Nikon 35mm, test1

The edge shading is still there. I tried out this one as well, PC-E NIKKOR 24mm f/3.5D ED. The edge shading was not present but that lens does not work for our application. And its over $2000.

The Zeiss lens will work for now but what is a long term solution that will get rid of the shading? I'd like to try a medium format lens or something but I can't find anything in an F mount.

 

[jake337]

have you tried a longer focal length lens? 100mm +

 

[Garbz]

Every CCD camera generates a dark signal that varies with exposure time and chip temperature.

You really didn't look at the source picture did you

 

[nicholasuniversal]

Jake, I did try a Zeiss 85mm f/1.4 and it did not have any shading. This camera is being used for aerial photography and a wider viewing angle is required.

The tilt and shift lens allowed light to cover the whole CCD something like that would be good but the PC-E NIKKOR 24mm was very expensive. Also the tilt and shift feature is not needed.