I searched on here and I read everything on this page: http://www.geometer.org/beginner/lenses.html

But I still don't understand what's going on with my lenses and how they are labeled. I have a couple of lenses, one is labeled as "3.5-5.6/18-55" and I know that means "F-stops from 3.5 to 5.6 and focal length of 18mm to 55mm" but what I don't understand is I can set the aperture to numbers outside that range, regardless of the focal length. For example I can set the camera (Sony Alpha 65) to F/22 and when I shoot the image, it's obviously F/22.

SO, if the labeled numbers are not a limit, what are they for? What is stated on the web page is not correct, where he says "when you zoom out to 18mm you'll be at F/3.5 and when you go in to 55mm you'll be at F/5.6" - because I can be at whatever F-stop I want, at any point along the zoom range.

OK, after posting I found this in the related posts: How can aperture be f/11 on a lens with an aperture range designation of 3.5-5.6?

That kinda answers my question. So, to be clear, the numbers are the lowest you can go at each zoom extreme?

  • 2
    \$\begingroup\$ Right, I see you've updated your post to link to that too. Yes, the number refer to the most-open possible aperture at each zoom extreme. \$\endgroup\$
    – mattdm
    Commented Jul 25, 2013 at 22:34
  • \$\begingroup\$ It is pretty tricky to search for things like that on here or Google. It's just hard to find the right combination of words. I think the duplicate questions help with that. I've gotten a dupe in my search result many times. \$\endgroup\$
    – Jasmine
    Commented Jul 25, 2013 at 22:38
  • \$\begingroup\$ Yeah, absolutely, and totally not a problem. \$\endgroup\$
    – mattdm
    Commented Jul 25, 2013 at 22:42
  • \$\begingroup\$ I think you have your question answered. :) If you have more, please ask! \$\endgroup\$
    – Joanne C
    Commented Jul 26, 2013 at 0:09
  • 1
    \$\begingroup\$ @Jasmine - no worry about the dupe, it's helpful to have aliases for hard to describe questions to make them easier to find. That's why the system doesn't just delete duplicates, but leaves them pointing to the original question. Some questions have 4 or 5 duplicates that make them easier to find. Honestly, I like your wording better since it is more generic. +1 from me. \$\endgroup\$
    – AJ Henderson
    Commented Jul 26, 2013 at 4:00


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