Hi to everybody.
I post the attached image, because I want to know what makes the background that "fuzzy"?
It happens sometimes with some images and I want to know the reason. Might it be the converter?
I think, I used a 1.7 "Soligor" Converter. The image is a crop (may be it is 2/3 of the Original image). I did not use the Canon 1.4 because the birds were too far away and not the 2.0 because I did not want to use the centered AF.
I am not sure, if this happens with the Canon converter too. There are some backgrounds where I had that kind of problem: brown fields are one of them.
The image is taken with the Canon Mark IV, 500mm f 4, 1/400 sek, f 8, ISO 1000
I am happy to get some answers from you!
Rose
Based on what I see in your image (the "fuzzy" look increasing with distance behind the birds) and my somewhat limited use of a long lens (200-400mm zoom) with a 2X converter, I think it's all about depth of field. It would probably make sense that the effect is more apparent with different backgrounds and perspectives. Backgrounds that are fairly level with small features are likely to look worse even though the depth of field is, of course, no different. In addition, a teleconverter will exaggerate any aberrations of the lens you're using it with.
I found an online site for calculating depth of field. Because I didn't know how far from the birds you were, I used two distances. Even if neither is close to your distance, it will give you an idea. Using your camera and a focal length of 800mm (the drop-down list didn't have 850, which is what your 1.7X converter and 500mm lens would be), here are the results I got.
distance from subject 50m, distance in focus in front of and behind the subject -- 0.7m
distance from subject 10m, distance in focus in front of and behind the subject -- 0.1m
With 850mm, the in-focus-distances would be somewhat less.
Why that?
