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can someone explain this numbers please?, what means equivalent?
Focal Length 4.25-42.5mm, 35mm equivalent 30.4-305mm
thanks for your help

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This may be better migrating to Photography –  Dr Mayhem Mar 4 '13 at 7:58
    
Here's a relevant question at photo.stackexchange.com about focal length and angle of view: photo.stackexchange.com/questions/5917/… –  Bart Arondson Mar 4 '13 at 8:06
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closed as off topic by Dr Mayhem, JoshP, Travis Dtfsu Crum, Bart Arondson, Eugene S Jun 11 '13 at 7:01

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1 Answer

From the wikipedia entry on focal length:

Due to the popularity of the 35 mm standard, camera–lens combinations are often described in terms of their 35 mm equivalent focal length, that is, the focal length of a lens that would have the same angle of view, or field of view, if used on a full-frame 35 mm camera. Use of a 35 mm-equivalent focal length is particularly common with digital cameras, which often use sensors smaller than 35 mm film, and so require correspondingly shorter focal lengths to achieve a given angle of view, by a factor known as the crop factor.

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good explanation,thanks. I my camera says 4.25-42.5, that means that my wider angle would be 4.25mm? that seems too wide, I am sure I am getting something wrong –  user17252 Mar 4 '13 at 4:19
    
Well, yes. The wide angle on your camera is 4.25mm. But since your sensor is smaller than that of a 35mm camera, this is equivalent to a 30.4mm lens on a 35mm camera. Alternatively, when your lens is fully zoomed in, it's focal distance is 42.5mm, which is equivalent to 305mm on a 35mm camera. –  Jason Conrad Mar 4 '13 at 6:19
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