Full frame, crop sensor and focal length?

[Bob Marley]

I'm sorry but I have to ask this, I got very confused.
So, a 24mm EF-S is about 60 degrees wide and is equivalent to a 38mm on a full frame. OK, I got it, but:
Does that mean that a 38mm EF placed on a crop sensor will give the same 60 degrees? Or will it be equivalent to a 38mm EF-S?

 

[Dao]

Please note that the lens focal length is the optical property of the lens, not the recording medium. However, the recording medium size dictate recorded image size.

Let's take an example. EF-S 50mm lens (do not exist, I just make it up) and a EF 50mm lens. Both lenses should yield the same (or similar) result as far as the angle of view or field of view when mounted on a cropped camera body.

In real life, lens manufacturers make lens (i.e. EF-S, DX etc) for cropped camera body so that the image circle cast by the lens is just big enough to cover the recording medium. I could be wrong, but I think the cost of making a DX lens is generally less especially for fast zoom lens (wide aperture) and they are usually less weight when compare to a similar FX lens.

 

[Bob Marley]

Thank you, that cleared it up.

 

[gossamer88]

In the Canon world you would multiply the focal length by 1.6 for cropped sensors. Nikon's 1.4.

So a 38mm (if it existed) on a Canon crop camera would be roughly 61mm.

 

[480sparky]

D80 DOF Lens Page 2 Photography Forum

In the Canon world you would multiply the focal length by 1.6 for cropped sensors. Nikon's 1.4.........

Nikon is 1.5.