While testing the capability of an old set of close up filters I noticed certain things happenin gto the image quality. The filters are simply marked as Plano Close Up numbers 1 - 3. I took a couple of photos for comparasion purposes and saw that a strange fogging was taking place. I cleaned the filters and the lens used and saw no obvious abnormalities. It wasnt my breath or the heat of my hand causing this fogging and I am still clueless as to what is the cause of the problem.
I realise that image degradation will take place when we put extra bits of glass in front of our lenses but this seems to be reasonably extreme. I used a Canon 350D with EF 55 - 200 mm 1: 4,5 - 5,6 II with the three close up filters. All shown shots are taken at 1/80 sec with either f5 (first shot) or 5,6 other shots. Flash was used as a constant light source and yes it is boring direct light but I wasnt looking for a masterpiece - just answers.
The depth of field is very narrow and it was difficult to focus accurately but most of the shots indicate that the main problem is fogging and not being out of focus. The fogging is clearly visible when zooming in and I held my breath several time thinking that I was fogging up the eyepiece. Only later - and out of breath did I discover that the problem was in the close up filters. I did various other tests with fewer filters and the effect was less as was the magnification.
What is happening? Is this flare within the filters or is it a standard occuring feature? Also what are the pros and cons of using close up filters?
P.S. The Fujifilm canister was exposed about 2 years ago and has been sitting on my desk since. Shows how digital is marching ahead.
