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Old Jun 22, 2008, 3:34 AM   #1
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Hi

After reading this im not sure if 1.6 X focal length still applys to EF-S lens's

"Note: since cropped-frame DSLRs aren't using the full area of normal lenses, many manufacturers additionally offer models which are only corrected for this smaller frame. Canon, Nikon, Sony and Pentax refer to these types of lenses as EF-S, DX, DT and DA respectively. These aren't suitable for full-frame DSLRs though, so if you're thinking of upgrading to full-frame in the future, try to avoid these models."

See full artical here
http://www.cameralabs.com/lenses/Can...anEF_55-250_IS

thanks for help
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Old Jun 22, 2008, 5:45 AM   #2
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Yes it does.

The Canon EF-S (and 3rd-party "digital only") lenses simply make a smaller image circle so cannot be used with bigger "FF" sensors or film cameras.
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Old Jun 22, 2008, 6:36 AM   #3
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What they mean by 'corrected' are the digital lens only have the light beam going through the lens striking the sensor at a more perpendicular angle resulting in higher contrast for the smaller frame...

Full frame lenses tend to project the images on the sensor at a more oblique angle hence have a lower contrast especially at the corner hence the lower contrast (i.e. MTF's) and various manufacturers tried to minimize this effect by reducing the internal reflection with anti glare coating.
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Old Jun 22, 2008, 1:10 PM   #4
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great, so the 55-250 EF-S lens im looking at will be equ of about 400mm zoom on a 35mm camera (just comparing it really from my pany fz30's 420mm equivalent) so i know what to expect. ill get a little bit less zoom than the fz30.


cheers.
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Old Jun 26, 2008, 4:19 AM   #5
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decided and bought the canon 70-300 IS USM instead
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Old Jun 26, 2008, 10:23 PM   #6
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New camera and a new lens already, good going. The 70-300 is the next lens on my list to get as well. Seem loads of great pictures taken with the 70-300 and I like the range it give the camera too.
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