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Does an EF-S lens' focal length have the 1.6 crop factor calculated?

bryannemarie
Apprentice
For example, the kits lens that is often 18-55mm purchased with a canon rebel, since it is specifically made for crop-sensored camera, is it a 'true' 18mm focal length, just as an 18mm EF lens would be on a full frame camera (other than smaller field of view)? Or to get the 18mm focal length effect, would you still need to purchase something closer to a 10mm EF or EF-S lens? In other words, say you had two 50mm lenses, one EF, one EF-S and used them on a APS-C camera (ex. Canon Rebel T4i), would they both come up with the same image or would the EF be closer to an 80mm, while the EF-S provides a 50mm image, since the lens is created with the crop factor in mind? .
35 REPLIES 35

My Rebel certainly does "throw away" the part of the FF image circle that does not fit onto the smaller sensor.

Believe what you will.  It doesn't.

EB
EOS 1DX and 1D Mk IV and less lenses then before!

"... the part of the FF image circle that does not fit ..."

 

OK, if your Rebel throws away anything so does your FF.  Lenses produce a circular image which is projected on a rectangular sensor.  Some light is ignored because one is round ant the other ain't. 

EB
EOS 1DX and 1D Mk IV and less lenses then before!

The question I asked did not relate to differences between APS-C vs FF cameras. It was about EF-S vs EF lenses with the same focal length dialed in and on the same APS-C camera, identically placed, seeing the exact same subject. Are the resulting images different?

 

Sorry if I appear to be obtuse. This entire discussion has gone off into the technical weeds on bunny trails several times, where the essential question is simple.

And the answer is no, a 70 mm lens is a 70mm lens. It will provide the exact same magnification. It only makes a difference when you are talking about the size of the format.

Clear answer to the OP: NO.

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