Sounds like you have a good lens. So I was wrong on that. Are your standards really parallel?
C
Sounds like you have a good lens. So I was wrong on that. Are your standards really parallel?
C
For reproducing art work this would not be the lens of choice.Originally Posted by Jim Conaghan
The Schneider Repro and G Clarons are better lenses for this purpose.
One thing you haven't mentioned is how closely you looked at the result. For example, if your allignment was off by 1/2 degree, you took the picture at f/16, and you looked at an 8 x 10 print of your photograph under 2 X magnification, you might easily see it go out of focus toward the corners. Also, a moderate amount of curvature of field might be detectable. But under normal viewing, you shouldn't see any significant loss of sharpness.
You should check everything, you can think of. Check the alignment of the standards by pointing the whole camera down, and adjusting things so the ground glass is perfectly level in all directions, and then doing the same thing for the front standard. When you take the picture, check that both the subject and the camera are plumb. Check that the camera is square by careful examination of the ground glass. You can check this seeing that vertical or horizontal pairs of lines which are parallel in the subject are parallel in the image on the ground glass.
Finally stop down at least to f/22.
JC,
"For those who asked, the lens used was a Nikon Nikkor-W 210mm 5.6, "
a longer lens would help. 300mm or 360mm if you have the room and the bellows, f/22 if you have the light. Moving farther back will decrease the difference from center to the corners and DOF will appear to increase. The extra distance makes lighting easier.
Good luck with it.
Thanks again guys, lots of valuable information here for me to work on. I think I will take your advice and invest in a more suitable lens.
Donald, do you have a specific lenght in mind for the Schneider Repro / G Clarons, as you can see Paul suggests 300 - 360.? Bob - does this agree with your lens of choice.?
Best Regards to ALL who helped,
JC
Not if you have adequate room. If you do then do not use a wide field Process lens. They do not equal the Apo Ronar type lens for copying. The wide field types were designed for vertical copy cameras commonly used in quick print shops. The Apo Ronar type were designed for the larger horizontal process cameras and are a better performer across their field.
"I have been trying to photograph some of my oil paintings, so that I can have the 5x4 transparencies scanned onto digital. I thought that, assuming everything was square and level, if I focused sharply on one part of the image, the rest would also be in sharp focus.? Evidently, this is not the case, - I'm getting scans back where the centre of the image is perfect but other areas, especially out towards the edges, are very blurred."
Jim,
Two observations, either 1) you lens and/or film standards are not parallel to the plane of the artwork, or 2) the lab scanning your transparencies is messing it up.
In your transparencies is the outside edge of the painting parallel to the transparency edges? Are your transparencies sharp when viewed on a light box? If yes to both questions then the scan is bad. If no then there is no way you can get a good scan because your slide isn't done right.
J Koger
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