HELP! with teleconverter

[atldal]

I purchased a Tamron-F 2x c-af1 BBAR MC7 teleconvertor for my Canon XSI. I have two Canon lenses, an EFS 55-250 and an EFS 18-55. The teleconvertor fits fine on the camera, but neither lens will fit down into the teleconverter. Any help on this is greatly appreciated.


Thanks,
Shane

[DonR]

Sounds like it isn't designed for EF-S lenses. The EF-S lenses extend farther past the lens mount than standard EF lenses, and there are a number of accessories that won't work with them for that reason.

Don

[MT Stringer]

Any help on this is greatly appreciated

Did you browse through the sticky on teleconverters on this forum? There is a lot of good info posted there.

Even if they fit you would have to manually focus the lenses because there isn't enough light coming through the lens to allow the camera to auto focus. Those teleconverters are made for f/2.8 lenses and some f/4's.

Sticky is here.
http://photography-on-the.net/forum/showthread.php?t=41922

[Adrena1in]

I should read that link myself. I purchased a similar teleconverter, mainly to use with my telescopes, and it works fine, but I'd also like to try and get one for my EF-S lens, but I can't find them. There seem to only be the EF versions, which the EF-S lenses don't fit, or the "white" ones, which I've been told only work with the "white" Canon lenses. (Those ones are too expensive for my to justify anyway...why extend my EF-S 18-200mm to 400mm when I've got a 420mm telescope?!)

[hollis_f]

Even if they did fit and you were good at manual focus, your 55-250 f4-f5.6 lens would become a 110-500 f8-f11 lens. Trying to do manual focus at f11 is very difficult because the image is so dark. Trying to do it with anything astronomical, except for the Moon, would be impossible.

[mtbdudex]

Even if they did fit and you were good at manual focus, your 55-250 f4-f5.6 lens would become a 110-500 f8-f11 lens. Trying to do manual focus at f11 is very difficult because the image is so dark. Trying to do it with anything astronomical, except for the Moon, would be impossible.

Thx, so for kit lens forget getting a tele conv because too diff to focus.
I have T1i with recent 55-250, your post saved me some $$ and grief. Well, probably will cause me some $$ cause now I can justify some better glass in near future.....
Yea, I'll read the stickies AND post my Q's before I buy.

[atldal]

Thanks for all the help. I will repost my purchase on EBAY and hope I can get back some of my losses.

[halitime]

Don't fell bad if you have to hang onto it because down the road you will probably have a lens that it will help out.I have the same one and it works fine with my 300mm for man. focus.

[Adrena1in]

Why not keep it? Might come in handy when you want to shoot through a telescope. I've read that teleconverters give a better image than Barlow lenses. (Don't know if that's true though.)

[atldal]

I wish I had read this before I listed it. I do have a telescope and was thinking I should have kept it for that. Well, now I hope it doesn't sell. Not many times i've ever wished my item didn't sell on ebay. Again, thanks for all the help.