What lens my Canon 20D?

[labdogs42]

I have the 20D with the kit lens and I also bought a Tamron 18-200 lens. I am not thrilled with the performance of the Tamron lens. Sometimes, it just doesn't want to autofocus! It is really annoying. It is much more finicky than the kit lens and I'm not sure why. I'm reluctant to take this lens on our upcoming Disney trip because of its unreliable behavior. I'm also thinking maybe a different lens would suit me better. I want something with some zoom and a wide enough angle to use every day. That's why I chose 18-200 instead of 28-200. Or maybe for Disney, I wouldn't need such a wide angle? I also know that I can crop and zoom on the computer so maybe I don't even need as much zoom as I have! Maybe something with IS would suit me better? Any suggestions or ideas? Thanks!

 

[boBQuincy]

I'll take a shot at this one, the aperture at 200mm on Tamron's 18-200 does not fall within Canon's f/5.6 range for auto focus. There are tricks the lens manufacturers can use to get around the Canon limitation but sometimes (especially in low light or low contrast) the lens will hunt, focus inaccurately, or not focus at all.

The 18-55 kit lens has a minimum aperture of f/5.6 and should focus reliably, if not quickly. For more reliable focus performance a lens that stays within the f/5.6 aperture at it's longest focal length would be a better choice.

 

[deletedpenguin]

If you're not wanting to spend the money on Canon lenses, check out Sigma lenses. Keep in mind that no manufacturer makes a perfect lens everytime either, so it may be worth sending it to Tamron to have them recalibrate it for you. It could be you just got a bad copy, as I've heard some good stuff about some of Tamron lenses (not your model specifically, but I haven't heard bad things either.).

 

[jann1033]

i have seen a few reviews that are not that great for that lens, mostly softness though rather than hunting...really i am starting to feel like with almost any lens you can get a dud lens...i had the same problem with sigma lens with my old canon , it drove me nuts cause i missed so many shots while it tried to figure out where it wanted to focus...not any expert but i would imagine since any 3rd party lens is reversed engineered for canon you could conceivably have a problem with it....of course i have a canon 28-135 i've been less than thrilled with so that accounts for sentence #2. i'd either ship it back for a check up or sell it and start over although i think the sigma 18-200 was pretty much disliked across the board...this site has lots of lens and ratings http://www.fredmiranda.com/reviews/
and
http://www.photodo.com/products.html
as far as disney goes, i haven't been yet with my dslr but it seems a lot use the 50mm range but like a wider aperture. ak naturally would make you drool for zzoomm
not as much range but i really love my 70-200 f4 canon, it's sharp the color is good, i have no complaints ( rare for me) and now that i figured out how to focus my 50mmf1.8 i like that as well. have a 3rd party macro 100 prime i like for the prime as a walk around type lens.( phoenix which is usually pretty bad but this one was rated decent...looks like a toy but didn't cost a bunch either although i had to send it in since it started sounding like a tank running over another tank for some reason)

 

[labdogs42]

I'll take a shot at this one, the aperture at 200mm on Tamron's 18-200 does not fall within Canon's f/5.6 range for auto focus. There are tricks the lens manufacturers can use to get around the Canon limitation but sometimes (especially in low light or low contrast) the lens will hunt, focus inaccurately, or not focus at all.

The 18-55 kit lens has a minimum aperture of f/5.6 and should focus reliably, if not quickly. For more reliable focus performance a lens that stays within the f/5.6 aperture at it's longest focal length would be a better choice.

That makes sense. It definitely has trouble focusing at the longer focal lengths a lot of times. I didn't realize that it fell outside of the camera's aperture range. Thanks!

I will also try taking it to the camera shop where I purchased the camera and see if they can tell me anything. Thanks!