Quick Question...

Does the 100-400mm lens fit the canon 450d? also what about the 70-200mm?

Yes, they both work on the 450D.

If you are refering to Canon EF lenses...Then yes.

rrblint wrote in post #14807754
If you are refering to Canon EF lenses...Then yes.

Ok thanks, what is the difference between EF and EF-S lenses? You can obviously tell i'm an amateur!

EF-S lenses will only work on 1.6x crop bodies (maybe excluding the 10D?), where as EF lenses will work on any Canon dslr including 1.6x, 1.3x and full frame bodies.

Nightdiver13 wrote in post #14807791
EF-S lenses will only work on 1.6x crop bodies (maybe excluding the 10D?), where as EF lenses will work on any Canon dslr including 1.6x, 1.3x and full frame bodies.

^Yes.
CaterhamF1: EF-S lenses have a more-protruding rear, that would hit the mirror of FF and APS-H(1.3x) cameras.

Basically, every EF and EF-S lens will fit your camera.

The 100-400 is an EF lens, so it will fit all EOS cameras. The same goes for the 70-200.
Just keep in mind, with a 450d , the 100-400 will be a 160-640mm lens because of the crop sensor.
The 70-200 will be a 112 - 320 lens

CaterhamF1 wrote in post #14807776
Ok thanks, what is the difference between EF and EF-S lenses? You can obviously tell i'm an amateur!

There is information online.

prustyaditya wrote in post #14808221
Just keep in mind, with a 450d , the 100-400 will be a 160-640mm lens because of the crop sensor.
The 70-200 will be a 112 - 320 lens

The 100-400 will NOT be 160-640, and the 70-200 will NOT be a 112-320. Lens focal length is inherent, and does not alter with body format.

Ignore crop factor entirely unless you are in the very unusual position of having to compare fields of view among different formats. Just get the focal length that you need to do the job on the format you have.

prustyaditya wrote in post #14808221
Just keep in mind, with a 450d , the 100-400 will be a 160-640mm lens because of the crop sensor.
The 70-200 will be a 112 - 320 lens

It does not work that way. 50mm is 50mm on both "cropped" and "full frame" bodies. A 100-400 and 70-200 will still be a 100-400 and 70-200 on a 450D.

prustyaditya wrote in post #14808221
The 100-400 is an EF lens, so it will fit all EOS cameras. The same goes for the 70-200.
Just keep in mind, with a 450d , the 100-400 will be a 160-640mm lens because of the crop sensor.
The 70-200 will be a 112 - 320 lens

Here we go again

Some how we went from will these lenses fit to the focal length debate again.

Yes they will fit. Every EF and EF-S lens will fit, so basically every modern Canon lens, any of them on the Canon website except for the very new EF-M lenses that are for the EOS M mirrorless camera will fit.

prustyaditya wrote in post #14808221
Just keep in mind, with a 450d , the 100-400 will be a 160-640mm lens because of the crop sensor.
The 70-200 will be a 112 - 320 lens

No they won't.

Guess I should have looked at other replies first.