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Old Jul 22, 2005, 9:09 AM   #1
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Canon EF-S 18-55/3.5-5.6
I'm new to DSLR and a digi cam user.

What is 3.5-5.6 marked in the lens models? Is it the aperture value? If so I've seen pictures taken at f/8.0 with the same lens. Is it true?

How is this 18-55 compared to digital camera's measurment (eg: 3x, 12X etc)?



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Old Jul 22, 2005, 9:15 AM   #2
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Yes, the 3.5-5.6 is the maximum aperature available at 18 and 55, respectively. The minimum aperature is something like 22 or perhaps even smaller.

So, at 18mm, you can take pics from f/3.5 all the way to f/22 (or whatever the minimum is on that lens). And, at 55mm, you can take pics from f/5.6 to f/22...
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Old Jul 22, 2005, 9:27 AM   #3
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Thanks for the quick reply. I'm clear now about the aperture number.

Any idea about the my second question?
Is 55mm equal to 8X zoom or what 'X' number?
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Old Jul 22, 2005, 9:50 AM   #4
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Hi
that 8x or whatever number, is a useless marketing number used mostly for selling point and shoots.
It is derived by taking the maximum focal length and dividing it by the minimum focal length.

So a 100mm-300mm zoom lens is a 3x zoom and a 28mm-105mm is a 3.75x zoom, bigger number but much smaller actual lens.
(the 18-55 is a 3.05x zoom :blah: )

A lens with a single focal length like the 55mm example
would have a X number of 1
so would a 35mm or 85mm or 400mm lens

Just another impressive marketing term used to sell cameras.
Much like the mega-pixel race. Ever increasing big sounding numbers but very low actual increases in imaging resolution.

In DSLR, you are more interested in the focal length, which along with the crop factor for a particular camera translates to a field of view( FOV).
:-) clear as mud ? :-)



Glass wrote:
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Thanks for the quick reply. I'm clear now about the aperture number.

Any idea about the my second question?
Is 55mm equal to 8X zoom or what 'X' number?
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