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Photography Question 
J. L. White

Zoom Lenses and Aperture

Okay, can someone explain to me in English, what the f-stops on a zoom lens mean? For example, a 28-300 f/3.5-6.3. I understand the 28-300 but I'm not sure what the two numbers mean. I think it means the maximum aperture at 28mm is 3.5, and the maximum aperture at 300mm is 6.3? Is this close? Then how about a zoom with one f-stop number: 28-105/2.8?

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9/17/2003 11:06:31 PM

Jon Close
BetterPhoto Member Since: 5/18/2000
  You've got it. For 28-300 f/3.6-6.3, the maximum aperture at 28mm is f/3.5 and at 300mm it is just f/6.3. There will be intermediate focal lengths where the maximum aperture is f/4 and f/5.6.

A zoom lens spec'd with just a single maximum aperture like the 28-105 f/2.8 or 100-300 f/4 means that maximum aperture is available at all focal lengths.

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9/18/2003 7:11:42 AM

J. L. White   Thank you so much for the info, I'm trying to learn this stuff and sometimes I get myself thoroughly confused;)

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9/18/2003 1:29:05 PM

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