Teleconverters???

therustytracks · Jan 1, 2008

I've been using a canon ef 75-300mm usm lens on my 30d. It's not the best lens in the world but it works pretty good for me. I want to extend my focal length but i don't have the money for a new lens. I've been looking at teleconverters and it seems like it would be the most cost efficient for my needs. I'm not sure what i should go with. I've been looking at some tamron autofocus teleconverters and they seem pretty cheap but also have decent reviews. I was thinking of going with a 2x but i'm not sure. would there be any negative effects? I know i'm going to lose i think one full stop of light or more, but if it's overcast or low light conditions i won't be using the lens/teleconverter any way. I'm starting to get more and more serious about photography it's now become my major. Ultimately i'd love to have the ef 70-200mm f/4L usm lens with a teleconverter. But i'd also like to be able to have a longer reach on my photos immediately and the 70-200mm f/4L is out of the question at the moment. does anyone have any suggestions or more information on teleconverters that could help me make this decision?

soylentgreen · Jan 1, 2008

Best check compatibiltiy on those TC. Dunno if they will work on non-L telephoto lenses. For sure the Canon 1.4X & 2X TC will NOT work on your 75-300.

Sideburns · Jan 1, 2008

check compatibility first....but with a 2x...you're losing 2 stops of light.

Big Mike · Jan 2, 2008

There may be compatibility issues with the Canon brand teleconverters and that lens...funny as it is. The Canon TCs are made to work with a select group of Canon L lenses only.

Another brand TC will probably work, although the quality may not be as good.

I have a Sigma (or is Tamron) 2X TC (Canon mount) and it works with my 75-300 lens.

Yes, you do loose two stops of light...and it's important to mention that you will loose autofocus with this combination.
Most cameras need an aperture of F5.6 for AF to work. This lens already has a maximum aperture of F4-5.6...so when you put the TC on...the effective max is F8-11...which isn't enough.

You can still use the lens and focus it manually, if you can see clearly enough in the tiny viewfinder.

therustytracks · Jan 2, 2008

thanks for clearing everything up for me. I think i might just hold out and save up for the 70-200mm f4L is usm or the ef 300mm f4L is usm they're way more expensive than the tc but i think it will pay off a lot later.