Ah, another scientist! [] I may do one better than that, when I have a chance. I've considered setting up a contest here to see if anyone can tell the difference. I checked and I have a wide range of 58mm UV filters--B+W MRC, B+W non-MRC, HMC, Hoya Pro1, Kenko Pro1, Tiffen, and a really cheap Crystal Optics. I can use my 100mm f/2.8 Macro lens--a prime lens would probably be better and that lens, in particular, is exceptionally sharp.
  1. Set up a suitable target (WhiBal carc, Gretag-Maceth Mini Color Checker, some fine detail (magazine clipping?), & something with bright colors on my backyard fence. (No suitable place indoors.)
  2. Shoot on a bright overcast day, if possible, to get flat, consistent lighting with little shadows. (Lots of overcast days here in Eugene, Oregon--at least until mid-June.) Absolutely clear sky would be the other choice, to avoid cloud shadows
  3. Mount the camera on my Feisol tripod & Markins ballhead, locked down tight, with some sort of weight on the tripod's hook.
  4. Use manual exposure at about f5.6-8, "neutral" style, appropriate white balance, but autofocus, in case something moves a bit between shots. (The WhiBal card has a focus target).
  5. Take shots (using mirror lockup and a remote trigger) with each filter and some without a filter. (I'll clean the filters before shooting and brush the lens and filters with a LensPen brush when I change filters.) I'll have to put some number in the shots so that I don't get them mixed up.
  6. Do 100% crops from the RAW images using Digital Photo Professional, but no other processing. (Other option would be use the Trim command in Graphic Converter on the JPEG images.)
  7. Post those on a web page, along with scaled versions of the full shots for reference.



The contest would have two tasks: identify the no-filter shot(s)--I'd probably put in two to lower the probability of getting it right by chance--and identify the shot with the el-cheapo filter.


I'll have some sort of prize--maybe the el-cheapo filter! [:P] (Naw, it will probably be something else.)


It will be a week or two before I can get this done.