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07/26/2004 02:53:47 AM · #1 |
im pretty familiar with photography and terms related to shooting and developing. what i'm not familiar with is hardware. especially lenses.
what the the mm for? 18mm - 70mm? whats all that. and why are different lenses available? i know some are for zooming and other for close up, is that all?
thanks! |
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07/26/2004 03:02:05 AM · #2 |
//www.btinternet.com/~k.trethewey/how_do_lenses_and_prisms_work.htm
try that. Very simple, but gets the point across.
Message edited by author 2004-07-26 03:03:17. |
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07/26/2004 03:19:17 AM · #3 |
That's a great "classroom" definition of how a lens works but doesn't really translate well to buying a quality lens.
What about groups/elements in reference to lenses? It appears to me that the fewer the better. Is that a valid observation? Is there a way to determine the relative clarity of a lens by looking at the specs?
Sorry Reemas, didn't mean to jump in here but I've always wondered how to judge a lens without using the brandname or trusting a salesperson.
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07/26/2004 07:10:31 AM · #4 |
Originally posted by pfellner:
What about groups/elements in reference to lenses? It appears to me that the fewer the better. Is that a valid observation? |
I think it depends on the quality of the glass. For instance, a Canon L range with more elements will generally be better than a cheap zoom with less elements.
Originally posted by pfellner:
Is there a way to determine the relative clarity of a lens by looking at the specs? |
You would need to look at MTF charts, which I believe show sharpness relative to distance from the centre of the lens.
For older lenses I find www.photodo.com very good. Otherwise I will always read www.fredmiranda.com for reviews on focus speed, etc. Also I think www.photozone.de have some lens quality comparison tables. |
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07/26/2004 12:25:04 PM · #5 |
| i checked out that link but i dont think it quite answered my questions. i'm still not sure about different lens sizes and what the the different mm are for. |
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07/26/2004 12:32:34 PM · #6 |
also check out //www.popphoto.com
they have some lens comparisons there to that are pretty in depth. |
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07/26/2004 12:33:53 PM · #7 |
| the smaller the mm is, the more wide angle shot you have, the higher the mm, the more magnified the shot is. so if a lens says "18-55mm" then that means it can be zoomed from a wide angle shot (the 18) to a telephoto (the 55mm) |
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07/26/2004 12:36:42 PM · #8 |
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07/26/2004 12:37:37 PM · #9 |
Good general information at //en.wikipedia.org/wiki/Lens_%28optics%29 and related links.
The short answer, the "mm" in "18mm-70mm" is milimeters, which is the focal length of the lens. The longer the focal length, the more zoom you get; the smaller the wider angle. When a lens gives a range, it means you can zoom it in or out between those values. |
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07/26/2004 12:38:37 PM · #10 |
Originally posted by joebok:
The short answer, the "mm" in "18mm-70mm" is milimeters, which is the focal length of the lens. The longer the focal length, the more zoom you get; the smaller the wider angle. When a lens gives a range, it means you can zoom it in or out between those values. |
i think thats what i said ^_^ |
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07/26/2004 12:40:32 PM · #11 |
Originally posted by longlivenyhc:
i think thats what i said ^_^ |
Sorry - I guess you are a faster typist than I! |
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07/26/2004 01:41:36 PM · #12 |
Reemas, I´m sure you know but just to make sure than your camera has a buildt in lens so you are not able to change lenses on it. You can have some extensions wich can make the lens on your camera work longer (more mm) or wider (less mm) but only SLR or higher format cameras has changable lenses.
Message edited by author 2004-07-26 13:42:14. |
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