EF Vs EF-S and Crop Factor

I just received the latest MacAddict magazine (issue 121 September 2006), and they have a glowing, Five Apple review of the Canon 30D on page 48. However, they make a comment that:

"-when you use any of Canon's EF series of lenses, you will gain a 1.6X multiplier on that len's focal length. You can also use Canon's EF-S series of lenses with no multiplier effect."

Maybe I have not been paying attention all this time, but the EF/EF-S thing has no effect on the crop factor, does it?

Dennis
http://www.pbase.com/d​mwierz45/sports_shots

You are absolutely correct. Focal length is focal length, regardless of the lens design.

While the spacing between the lens mount and the film (sensor) plane is identical for the two lenses, The EF-S lenses have two significant differences in their design, when compared to EF lenses. The first is the size of the projected image. The EF lens design must cover a 35mm film frame while the EF-S lens needs to cover only the APS-C sensor area (a significantly smaller area). The second difference is how far the lens can physically project into the mirror box. Many EF-S lenses would crash into the mirror of cameras they are not designed to fit (at some focal length settings - most EF-S lenses are zooms).

While an EF-S lens covers less "film" space, the size of the items within in the image they do project are identical to that projected by an EF lens of the same focal length. This assumes that you take two photos from the same spot with EF and EF-S lenses mounted to the same body and set to the same focal length.

Additionally, nothing about ANY lens changes based on what camera body format you attach it to. An EF lens does NOT change when you put it on a 20D instead of a 35mm film body, for example.

Further, there is no such thing as a "multiplier" when you put a lens on an APS-C camera. The only thing that occurs is that less of the image will be recorded as compared to using the same lens on a 35mm film camera. It is the field of view that changes when you put different bodies behind a lens, not the focal length, and the change in field of view is totally a function of the body format (size of the film frame or digital sensor).

Um, I think there's an EF-S 60mm macro that isn't.

...Mike

I stand corrected on that point and edited my original post....

Sorry to revive this again but I'm still a little confused.

Will say an EF 60mm lens (or 60mm set on a zoom), therefore have exactly the same angle of view as an EF-S 60mm?

If so, is the only thing going on with them that they're cheaper to make for wide-angle because the back lens is closer to the sensor?

I'm just trying to establish if there is ANY point buying an EF-S lens for a cropped sensor if you don't mind paying more for the EF lens?

KimLeece wrote in post #5812651
Sorry to revive this again but I'm still a little confused.

Will say an EF 60mm lens (or 60mm set on a zoom), therefore have exactly the same angle of view as an EF-S 60mm?

If so, is the only thing going on with them that they're cheaper to make for wide-angle because the back lens is closer to the sensor?

I'm just trying to establish if there is ANY point buying an EF-S lens for a cropped sensor if you don't mind paying more for the EF lens?

Correct, EFS has nothing to do with your FOV. Keep in mind there are a couple very loved and respected EFS lenses (17-55 IS and 10-22). Very good lenses!

Also remember that Since EF lenses are designed to project a larger image, when placed on an APSC body you are using the "sweet spot" of the lens. Most lenses are worse around the edges, but in essence putting an EF lens on a "crop" body trims that edge off, leaving just the middle portion of the lens to project the image.

Also remember this is the same with third party lenses like Sigma and Tamron. The Tamron 28-75 lens is like an EF and will work on a full frame body so when placed on a crop body you are using just the sweet spot (and the lens is great to begin with so I think it is even better on crop bodies). The 17-50 however is like an EFS lens (still a great lens, but it will not work on full frame)

Price plays a factor in your choice of EF vs EFS, but size does also. EFS lenses allow you to have a much smaller, lighter lens.

I believe the deal on the crop is that you can't use a EFS lens on a full frame camera. You can use either on a crop camera.
So if you have a bunch of lens for the 40D and upgrade to a 5D the EFS lens want work. Am I correct here.
Fedxpress

Fedxpress wrote in post #5813209
I believe the deal on the crop is that you can't use a EFS lens on a full frame camera. You can use either on a crop camera.
So if you have a bunch of lens for the 40D and upgrade to a 5D the EFS lens want work. Am I correct here.
Fedxpress

Yes - I know that that's correct. EF-S lenses don't project onto the full size of the sensor, and will hit the mirror physically in some instances because the last element sits much further back in the camera.

nice to see the magazine is doing their research

ninext wrote in post #5813480
nice to see the magazine is doing their research

yes very nice lol

MacAddict magazine is BUSTED!

They are way behind the techno-babble, too. No one refers to it as a "1.6 multiplication factor" anymore - it is most often referred to (properly) as a "crop factor". This guy say anything about the debut of the new Apple G4 chip, too?

fxk wrote in post #5821716
MacAddict magazine is BUSTED!

They are way behind the techno-babble, too. No one refers to it as a "1.6 multiplication factor" anymore - it is most often referred to (properly) as a "crop factor". This guy say anything about the debut of the new Apple G4 chip, too?

Did you check the date of the original post? It's almost 2 years old. And, yes, some uniformed people STILL refer to is as a multiplication factor.