Reptile & Amphibian Forums

Looking through lenses, I see fixed focal length lenses and then zoom lenses. The zoom lenses, obviously, are attractive because you get multiple focal lengths in one lens, but my question is are there disadvantages to such a lens? Does photo quality drop at the maximum zoom?

Yes, there is a loss in image quality with zooms generally. The problem is that a fixed lens is optimized to provide the sharpest focus at a particular focal length. A zoom lens can't do that and therefore has to compromise somewhat.

The wider the zoom range, the bigger the compromise. So an 18-200 zoom is going to be less sharp than a 70-200 zoom. There are exceptions - Sigma's 50-500 zoom is surprisingly sharp.

That said, there are some very good zoom lenses around and many of them are very sharp. They usually are sharpest at intermediate focal lengths but a few good ones are sharp at the long focal lengths as well. You get what you pay for however. A $1200 70-210 lens is going to be a very different beast than the 70-210 zoom that you can get for $89.95.

So for optimal quality, a good prime is always best. But a good zoom can take excellent pictures.
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Chris Harrison
San Antonio, Texas

I've heard that the quality of sharpness is improving in newer zoom lenses, but another downfall is with many variable focal length lenses comes a variable aperture versus a fixed aperture. Pain in the butt!
Some zooms have fixed apertures. I have an 80-200 2.8... but they tend to be $$$ because it isn't exactly a multipurpose consumer lens; more special purpose, like sports/nature photography.

~Tiff
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"Were the diver to think upon the jaws of the shark, he would never lay hands on the precious pearl."

Haha, I just saw the date on the 2 posts before mine, I'm retarded. Annnnd the last pony finishes the race; sorry for adding my 2 cents super late.
~Tiff
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"Were the diver to think upon the jaws of the shark, he would never lay hands on the precious pearl."