 Dan C. |
Question: canon lenses and extenders I have two canon lenses I wish to get extenders for, preferrably 2.0x, but will settle for 1.4x or 1.6x. The lenses are: The 70-200 is on the canon brand extender compatibility list, so no problem. However, the one I would really like to extend is the other. I have read that although not on the list, some other canon lenses work with the canon brand extenders. I have also read to other brands, such as tamron, work well with canon lenses and in some cases have increased compatibility. Anybody help here? Obviously, I would like to buy one extender that will work with both. Canon would be preffered (if it will work with the 24-105), but other brands are ok as long as optics are good. Thanks.
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Jon Close |
I'm not following why you want to use a 2x TC on the 24-105. Why would you want a lens that is effectively 48-210 f/8 when you've got a perfectly goo 70-200 f/4 to use? Just for the IS? I don't think it's worthwhile. At f/8 you're going to have a pretty dim viewfinder, AF is going to be hit or miss if it works at all, the contrast and sharpness will be degraded by the 2x, and the IS feature at f/8 gives you basically the same hand-holding capability you have without IS at f/4. But if you want, the usual suspects for very good 3rd party teleconverters that'll work on virtually all lenses are the Tamron SP and Kenko Pro 300 series.
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Christopher A. Vedros |
Dan, I agree with Jon's comments above. If you're still curious about if the TC will work with the 24-105mm lens, try this. This is no guarantee, of course. Look at the mount end of both lenses. Compare them. Look at how much of the rear element, if any, extends beyond the mount. If the geometry of the 24-105mm lens is very similar to the 70-200, then my bet is that it would work. But as Jon said, you would probably be better off using the TC on your longer lens. Chris
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David Earls |
Dan, One other consideration on the power of the teleconverter. Canon's shorter zooms suffer more serious image degradation form the 2x TC than they do from the 1.4x. In other words, the 2x on your shorter zoom will replicate the range of your longer zoom (as Chris pointed out), but the resulting pictures won't be as sharp. Just a thought...
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Dan C. |
Thank you, gentlemen. I appreciate the help. Jon, your reasoning and straightforward talk is appreciated. Yes, you picked my brain - it was to take advantage of the IS in a longer lens. At one time I had thought about trading in the (brand new) 70-200 and trading up to the faster one with IS, but found out it will still cost a thousand. Plus the 200 transformed into a 400 would give me a little better chance at bird and nature photography. Those 400mm and 600mm lenses are AWFULLY expensive. But I have to agree with you all. The tradeoffs in quality, light-gathering power, etc. are just not worth it. Perhaps I can get a decent used 400 if I'm willing to wait. -Dan
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Christopher A. Walrath |
I would avoid the teleextemder if at all posible. I did a series of tests with my Minolta XG-M and lenses and found that fixed focal lengths and zoom lenses had virtually the same exposure at different focal lengths. But when I added a teleconverter into the mix, mind you only 1-2x converter, I lost three stops of light in each test, up to 140mm. If you put a 2x on a 210 zzom, no telling, you could lose 4-5. And your maximum aperture diameter would be halved as indicated above.
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Christopher A. Vedros |
You shouldn't be losing 3, 4, or 5 stops of light with a 2x teleconverter. If so, you have a very poorly made teleconverter. Every teleconverter I've used over the years has performed as advertised: about 1 stop with at 1.4x or 1.6x, and about 2 stops with a 2x. I have a 2x teleconverter that I use sometimes with a 70-200mm f/2.8 zoom. It makes the lens function as a 140-400mm f/5.6 zoom and it works just fine. It loses 2 stops, as expected, not 4 or 5. Chris
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