Do the Canon I.S. lenses retain stabilization with 3rd party teleconverters ? Specifically the tamron 1.4x . I saw this question asked and answered not too long ago. Unfortunately I can not remember which web page or what the answer was (I have looked) !! Thank you in advance for your responses.

-- Matt Swope (vswope@voyager.net), December 16, 1998

Answers

Matt, why don't you try it yourself if you are REALLY interested. Find a camera store who dares to let you try that. Simple!

-- Hiroshi Shigematsu (pooh02@earthlink.net), December 16, 1998.

Yes.

IS is an internal lens function. It doesn't depend on the body at all, nor what is between the lens and the body.

-- Bob Atkins (bobatkins@hotmail.com), December 16, 1998.

Yes I am REALLY interested since I just put a deposit on the lens used (have not picked it up yet) and I already have the tamron 1.4x . I wanted to know so that when I slap the 3rd party teleconverter on, there will be no excuse for the stabalizer not to work.

Even if I was just curious, this is the camera equipment forum, right ?

Thanks for your response Bob Atkins, I thought that perhaps it was even your web page that I had originally seen the information on.

-- Matt Swope (vswope@voyager.net), December 17, 1998.

Matt, I'm not trying to be rude here, but this kind of question can be easily answered with your little effort. I see many people come up with questions without any effort on their parts, and that bothers me quite a bit; I don't mean you are one of them. I mean if you bothered to go to your local camera store and asked them to let you try out the new 300/4IS on your teleconverter and camera, you would get the most accurate answer to your own question: seeing it with your own eyes. On the second thought, maybe you tried that yourself and couldn't find the lens at your local store. If so, my sincere apologies here.

-- Hiroshi Shigematsu (pooh02@earthlink.net), December 17, 1998.

hiroshi. you must not be thinking too clearly. maybe it's too early in the morning.

some people don't live near camera stores. they order mail order. and some people live near camera stores but most don't have a 300 f4 IS on hand. i live in seattle. a pretty big city. there's 15 camera stores within half an hour drive. i called each and every one of them 6 months ago to "try out" the 300 f4 IS. 14 of them didn't have one, and wouldn't order one unless i paid for it first. the one store that had one didn't want to open the box unless they were sure i was going to buy it. so... no playing with the 300 f4 IS for me.

when people ask unresearched FACTUAL quesitons (ones that have a definate answer as opposed to opinion questions) i like to answer. sharing of knowledge is a GOOD thing. did you go to school? why? why didn't you just "discover" everything first hand? why? because that's a DUMB way to learn. leveraging the knowledge of other people is a MUCH better, faster way to learn.

now... with that said... i don't think OPINION questions are worth answering. "is the 300 IS with tamron tc sharp enough" is an opinion question. there's going to be a different answer for every person. so you HAVE to do it yourself. but "does the IS worh with 3rd party tcs" has a definate answer. YES. so... it's a good question to ask here.

P.S. matt... while IS does work, you get some definite vignetting with the tamron TC especially wide open. you also get some AF hunting. the canon TC fixes both of these problems. is it worth $300 for a new TC? i can't tell you. but i can tell you it is for me.

-- Sean Hester (seanh@ncfweb.net), December 17, 1998.

Sean & Matt, your points well taken ;-)

-- Hiroshi Shigematsu (pooh02@earthlink.net), December 18, 1998.

The camera body do have an influence on the functioning of IS in combination with TC's. For example the IS function work in combination with the 1.4X on my EOS 5 (A2E)and EOS 100 (Elan), but not with the 2X (IS funtion disabled). However, on newer EOS bodies like EOS 1N, Rebel G and Elan II the IS function do work with the 2X TC. I therefore conclude that the IS funtion is not purely an internal funtion of the lens, but that there is definitely some communication between the lens and camera by way of the electronic cantacts. I have unfortunately no experience with 3de party TC's and IS.

-- Nico Smit (nico@anp.co.za), December 18, 1998.

Thanks to all who responded. Sean pretty much sumed up my dilema. Where I live, the camera stores do not carry any "L" glass at all. So to try out any of the equipment, including the Canon tcs, I have to order it, which at the minimum will cost me shipping and handling even if I don't keep it. Thats not always a bad thing though, it does keep one from impulse buying.

Keeping all your advice in mind, if I get a 2x converter I'll get the Canon (I had previously considered the Tamron 2x).

Thanks again.

-- Matt Swope (vswope@voyager.net), December 18, 1998.

about nico's posts about the body making a difference.

he's right to some extent. what's happenning is that the lens get's electric POWER from the body. what do you need power for? autofocus and IS.

now... all eos cameras (except the new eos-3) stop autofocusing at f5.6. so... if you put a 2x an the 300 f4 you're at f8. so you won't get autofocus. older bodies (eos-5, original elan, etc.) that were designed before IS was even thought of cut ALL power to the lenses when they are below f5.6. they figure, "what else do you need power for since you can't AF?". the answer, of course, is IS. newer bodies "fixed" this problem by supplying power for the IS function while cutting it to the AF function if the aperture drops below f5.6.

3rd party tcs don't report the correct aperture to the body and lens. so if you put a tamron 2x on the 300 f4 IS, you'll get IS and AF. the AF will be hunting alot and not work too well, but the lens will try.

-- Sean Hester (seanh@ncfweb.net), December 18, 1998.