White Balance And Exposure Compensation

SuperDave, you may be onto something... If I set WB with a lens directly attached to my D5000, then reassemble the bellows setup, given the same lighting conditions - will this work? Will definitely give this a try tonight...

Using my Canon, Jansjos balance nicely using the Tungsten preset, and the worst I ever have to do is back the Yellow hue off slightly in postprocessing. And Canon is infamous for misinterpreting tungsten in the presets.

So perhaps, even though it looked correct to you, the lighting was not evenly spread over the entire field the camera was seeing. By extending the bellows most fully, you're achieving maximum magnification and therefore the smallest-possible field of view.

OK, as promised some images which should indicate my work-flow progress.

As I was experimenting with Axial lighting, this is White Balance that my camera decided was the closest one based on "auto" setting. Keep in mind - this is not a Gold coin, just a Silver Walker :)



As I mentioned in my earlier posts, I had a really tough time setting a custom "measure" setting for White Balance on my Nikon D5000 with bellows setup. It was throwing an error on each and every attempt. So I thought I would try to attach a stack lens to my camera and attempt to white balance under the same lighting conditions. After a successful attempt, I have reassemble my bellows and snapped this picture:



Still not there... After another half an hour or trial an error, I have set the aperture on my lens (attached to bellows) wide open to f 3.5, cranked up my camera to the highest allowable position on my bellows, and voila - White Balance adjustment worked! Here is the first picture I took at f3.5



Again, the same Axial setup, f4



And f5.6



Now, that I got the White Balance to work, I was not happy with the contrast of the image (coin seems to lost its fire), so I have changed my lighting to two overhead Jansjos, slightly diffused.

This image was taken with 2 diffused Jansjos at high angle, same height as the lens



This image was taken with 2 diffused Jansjos at low angle, about 1/3 of a distance from coin to lens



This image was taken with 2 diffused Jansjos at medium angle, about 3/4 of a distance from coin to lens



This image was taken with 2 diffused Jansjos at medium angle, about 1/2 of a distance from coin to lens



This image was taken with 2 diffused Jansjos at high angle, about 1/3 of a distance from coin to lens



Which of these images has most potential? Any pointers / suggestions for improvement?

I like the medium angle ones.

You can pretty much generalize that "the greater the luster, the higher the angle" will give you best contrast. I rarely go as much as 30 degrees from vertical for any coin.

Guys, thank your for your recommendations and ideas. Here is a modified shot I took last night. I have used an a slightly different diffuser on my two Jansjos (positioned 2 and 10). I have also used Omeragon 75 mm lens (as opposed to Spiratone Flat Field Macro 75mm lens in previous shots)

I think I am settled on as close to 90 degrees as possible shot (thank you SuperDave). Since I am shooting raw coins for now this seems to be the best angle for my set up. I have positioned the lights at the height of the lens.





Ray, I am not sure what Gamma Levels are... I have checked the settings in RAW editor, but when I have tried to change them - I have not noticed any changes on the image.

Your editor probably has a "shadows" adjustment. This is a form of gamma adjustment. Adjust it to brighten the shadows without affecting the highlights.