bw slides photographed with digital camera

Hello,

 

I have black and white slides of scientific nature (specimens) that I

would like to digitize for grey-scale measurements. I was thinking of

using a digital slr camera (type canon 10D) and a macro lens to take

digital pictures of the slides that I could then manipulate on the

computer. The most important aspects to preserve of the slides are 1)

levels of grey: a feature that is twice as light as another feature on

the original slide should return twice as high a number on the grey

scale; 2) resolution: the smallest features on the slides are about

0.03 mm in size.

 

I would appreciate any advice on whether this is at all possible, what

features to look for in a camera and a macro lens to permit this, and

what errors to avoid.

 

Thank you

 

Jean

Hi Jean, I haven't tried it personally but I have a friend who is a well-respected photographer and he does it all the time and is quite satisfied... but he's not making prints and does it mostly for web posting and viewing on-screen. He's also scanning color slides.

 

I suspect the resolution will not be terribly great with a 10D; however you might be pleasantly surprised if you use a good lens. The EF 50mm f/2.5 Compact Macro is *very* sharp and pretty much distortion-free and might be a good choice.

 

If you can buy, borrow or rent a higher resolution camera then I think that should help. A 5D, an old 1Ds (or new!) would probably get better results than a 6 MP 10D.

 

It'll probably help to be careful with your technique (tripod, mirror-lock, good light, etc.), shoot 16-bit RAW files and "expose to the right" to get as much data as possible.

 

Perhaps someone out there who has tried it will chime in but this sounds like one of those things you'll probably have to just try for yourself to see if the results are good enough for you. Good luck!

The point of working digitally is that you can firstly set up a good camera to produce the level of contrast you require but better is to organise it in editing where you can set up a procedure to batch process a number of files. This batch procedure can be stored and applied to any subsequent file or set of files.

 

You make a test slide to which you apply controls to produce the required result and the editing programme remembers what you did and then applies the process to the rest of the files that you select while you go off and have a cup of coffee etc.

I think you also ought to consider options for scanning. Ask in the Digital Darkroom forum - but say also how your slides are mounted - are they microscope slides, film (what dimensions, what kind of film)? You will find knowledgeable answers about the limitations of both routes there.