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

[bryannemarie]

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? .

[kvbarkley]

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

[ebiggs1]

Believe what you will.  It doesn't.

[ebiggs1]

"... 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. 

[kre84u]

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.

[kvbarkley]

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.

[Tronhard]

Hi again:
To answer your question as simply as I can.  A lens focal length is a physical characteristic of the lens, and as such has nothing to do with the sensor.  So, any EF or EF-S lenses with the same focal lengths, on the same APS-C camera, should produce essentially the same results in terms of Field of View they capture.

To prove that, I did the following experiment.  I used a Canon EOS 80D, which was pointed at a boring fence but gives an easy measure of the field of view by counting the palings.  The camera was firmly mounted on a tripod and, in turn, I attached three lenses to the camera.  All lenses were at 100mm focal length:

All I have done it to use Photoshop to precisely resize the images from the original 6000x4000 resolution, without cropping, to a resolution of 3000x2000 for reduction to <5MB as required for posting

80D with EF 100-400L@100mm80D with EF100mm Macro80D with EF 18-135 IS USM@100mmWhile the first two were easy to set to exactly 100mm, the EF-S 18-135 USM took several attempts to get it at exactly 100mm but to confirm I did, here is the EXIF data from Photoshop.

They are all almost exactly the same Field of View.  I hope this answers your question.

[kvbarkley]

Clear answer to the OP: NO.

[DarbyBo]

To the OP (many years later): I had the same question and this helped me.