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I'm fairly amateur, about to buy the Canon 300D Rebel. Want the 75-300mm lens, but don't know the difference (except in price) between the F4.0-5.6 IS-USM lens and the III EF lens. Advice?

Do some checking on the 300D forum at http://www.dpreview.com.

Hi,

I don't have canon brand lenses so I cant answer the difference in IS-USM and other stuff that Canon presents in those lenses. But I can tell you about f/4-5.6. THe f/ is used on all camera and lenses. It is called the aperture. The lower number means how wide the openning is and much light you are letting into the lenses. As you go higher the lens opening decreased, allowing fewer light in. A low aperture such as f/2.8 is an ideal setting for portrait and photographing in low light situations. You can increase the light and blur the background. A higher aperture like f/5.6 is an ideal for landscapes or outdoor shootings of various faraway subjects or if you want every subject in the photo to be in focus. A lens that is lets say 75-300mm zoom and f/4-5.6 means that the aperture is set at f/4 when you are at a 75 mm zoom. THe f/ increases as you zoom in eventually hitting f/5.6 when you reach 300mm.

More expensive lenses have a constant f/2.8 or lower. This is more capable because the aperture will stay at f/2.8 and will only increase if you tell it to by switching into manual or aperture priority.

As for EF, I believe it is the standard name for Canon EOS compatable lenses. Even aftermarket brands of lenses that are made for Canon EOSs have "EF" of the rear lens caps.

Here is the Canon homepage for the lenses they have to offer.

http://www.usa.canon.com/eflenses/


This is all I know for now. I hope it helps. Good luck! Any more questioins, leave a comment on my guestbook, send me an email or a private message.


Hugh

lindy7 wrote:I'm fairly amateur, about to buy the Canon 300D Rebel. Want the 75-300mm lens, but don't know the difference (except in price) between the F4.0-5.6 IS-USM lens and the III EF lens. Advice?

The main difference (and this justifies the cost) is that the IS lens has image stabilization whereas the EF lens does not. The image stabilization is electronic circuitry that automatically "moves" the image to reduce blurring due to camera shake. This is especially critical at the 300mm maximum, which translates to 480mm on the Rebel due to the crop factor of the sensor.

Actually all Canon lenses designed for EOS cameras are part of the EF system, the IS, L, DO etc lenses are subsets of the EF system.