Recently, I came across an opportunity to borrow an old Sigma 500mm F5.6 lens. I have never shot with anything that long, my previous max was only 400, and I normally shoot with a 200 or my wife’s 300. It really is a different world when shooting. The first day, I was too busy, but my wife could not wait to try it out and snapped this shot of a gator at the Viera Wetlands:
She was disappointed with the shot because it did not seem as sharp and in focus as she was expecting. (Personally, I really like this shot, the shallow depth of field and composition really hit me.) She told me that she was only 15-20 ft away from the gator when she took the shot from her car. Plugging this information into the DOF Calculator, I found out that the acceptable sharpness distance is only 3/4″! This is a big difference from the normal +/-1′ or more that we are used to with our more plebian lenses. Armed with this knowledge, we took the lense out again.
The results were mixed. It appears that the lense still needs a shutter speed of around 1500-2000 or faster. Also, subjects that were far away with large areas of uniform back drops (water, sky, etc.) had a speckle to them. I believe the lense has a bit of fungus in it from being stored so long. With a good servicing, this lense may be useful, but it may not be financially wise.