telephoto lenses

[asm]

I have a EF 55-200 f/4.5-5.6 II and I need more power. Am I right in thinking I cannot use a 2x or 1.4x extender with this lens? If I am wrong, and an extender wil provide me with all the power I need, why would I buy a 100-400 lens? I am actually considering the 100-400mm f/4.5-5.6L IS USM. I know the advantages of the IS bit so it is really advice on the simle issue of telephoto I seek.

Thanks.

Adrian

[PacAce]

I have a EF 55-200 f/4.5-5.6 II and I need more power. Am I right in thinking I cannot use a 2x or 1.4x extender with this lens? If I am wrong, and an extender wil provide me with all the power I need, why would I buy a 100-400 lens? I am actually considering the 100-400mm f/4.5-5.6L IS USM. I know the advantages of the IS bit so it is really advice on the simle issue of telephoto I seek.

Thanks.

Adrian

If you are talking about the Canon 1.4x and 2x TCs, then they won't work with your lens. 3rd paty vendor TCs might. The 2nd thing is that if you could get a TC that fits your lens, you may lose AF or, at best, AF would be very slow and very erratic, especially with the 2X TC. And thirdly, there's a good chance that image quality will suffer, too, and again, especially with the 2X TC.

[asm]

Thanks Leo. I knew there would be some good reasons but did not know what they were.

[jaypie77]

asm, are you familiar with the other reasons why the 100-400 would be better than your lens? I'm not sure how familiar you are with the technical details, but the 55-200 wouldn't be very good with a teleconverter anyway, even if it did work. I actually own that lens myself, but I just recently bought a 200mm f/2.8 and plan on picking up, among other things, a 1.4x TC. This combo will work, 2x might also work, but I'll do tests before I buy.

[danphoto1]

I use the Is Canon100-400 and love it I also sometimes use it with a 1.4 tc. It's great for outdoor sports.