300 D AND 20 D efS LENSES

[skskinner]

I AM CONFUSED ABOUT THE DESIGNATION 'S' ON THE NEW LENSES ESPECIALLY MADE FOR OUR REBELS AND 20D'S. In the explainations of the lenses, it states that the 10-20 EFs is equivalent to a 26 - 35 in a 35mm format. Now, I was under the impression that the kit lens, 18-35 is taking pictures with the same angles as an 18-35 on a film camera.
DOES ANYONE KNOW WHAT IS REALLY GOING ON? If I buy the 10-20, will I actually have a 10mm lens or a 16mm? Thanks for any help you can give me on this. Another friend I have also is confused.

[Paul_OH]

skskinner,
Whilst I'm not fully up to speed either I think the following explanation may help. Due to the smaller sensor size of the 300, 10D and 20D (it is the same as that of APS film), which does not utilise the full coverage of a normal 35mm (24mmx36mm) lens. This results in a 1.6x factor, (a crop factor not magnification as a lot of users tend to think). This will result in the 10-22 EF-S as having the same view in 35mm terms as a 16-35mm lens and the 18-55 EF-S kit lens as having the same as a 28-88mm in 35mm terms.

The reason that Canon released these models is that the normal 28-90mm lens sold with film rebels as a good all round zoom length will result in a lens field of view of 45-144mm lens when used with the digital cameras mentioned above. As you can see this doesn't suit those looking for wide angle shots.

On the plus side however a standard 75-300 zoom will result in an equivalent focal length of 120-480mm, great for those looking for long range shots.

I hope i've got this information correct however if someone understands it or can explain it better than myself, please feel free to correct where necessary.

Paul

[skskinner]

Thanks Paul, very much. I think you are right, but why, then, did canon make the special S lenses? Just for lightness and smaller size? Thanks again, Steve

[Paul_OH]

They are designated EF-S as they are slightly different to normal EF lenses. I believe -S stands for short as they have an extension on the back of the lens that protrudes further into the camera body (shorter distance between the lens and the sensor). At this stage they will only fit on the 10D, 20D and 300D as other cameras have a larger mirror that will hit the back of the lens when when releasing the shutter.

Paul

[skskinner]

Thanks again. That settles it for me. Steve