MIXING BRANDS

<p>I have a Canon Rebel XT and I use Sigma lenses. I am wanting to get a teleconverter for my telephoto lens (70-200 f/2.8) for softball games, and I was wondering if a quantaray teleconverter would work with sigma lenses? Would this be a risk of damaging my lens if I hooked them up? I have an opportunity to buy a quantaray teleconverter pretty cheap. Any info would be appreciated.<br>

Thanks!</p>

<p>I can't answer your question specifically, but I would imagine with the Quantaray, you'll get what you pay for!<br />Personally, I once bought an unimportant piece of Quantaray equipment, a small Camera Case to carry one set-up (Body & Lens) I think, I wasn't impressed!</p>

<p>With the electronic's of today's Camera bodies & Lenses, and compatability issues, I would'nt!</p>

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<p>Would this be a risk of damaging my lens if I hooked them up?</p>

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<p>Depends on where you'll buy it. If you buy it at Goodwill or Thriftshop, maybe (not related to brands). Usually if they are all clean, not deformed, and same type (of course if you try to put a Canon lens on a Nikon body, or a Canon FD lens on an EOS body,.. you know what will happen), there won't be any damage. Don't force anything. Quantaray usually has low build quality but the same optics quality as the ones that carry the manufacturer's name; Sigma, Tamron, or Tokina. They usually have better compatibility</p>

<p>I would try it out (if it's clean, if not I'll clean it first). Disclaimer: I'm not responsible for any of your damage</p>

<p>Well, there's a good chance (1 in 3) that the Quantaray converter was made by Sigma. :-)</p>

<p>Having said that, it doesn't make a lot of sense <strong>to me</strong> to put a "pretty cheap" teleconverter on what is presumably a high end f/2.8 APO zoom. YMMV. As Jim so succinctly put it, you do get exactly what you pay for here, particularly when mated to fast zooms like a 70~200/2.8 which are often at their weakest wide open at the long end (right where you would be using a TC). If you want the best possible results, then I think you would be far better off to purchase the <a href="http://www.bhphotovideo.com/c/product/390164-USA/Sigma_824101_1_4x_DG_EX_APO.html">1.4X</a> or <a href="http://www.bhphotovideo.com/c/product/390169-USA/Sigma_876101_2x_EX_DG_APO.html">2X</a> Sigma APO converter that would be <strong>specifically optimized</strong> for this and other similar lenses in the Sigma line.</p>

<p>Jim, I have a medium length Quantaray holster bag that's not too bad. It's very light and opens broadly with a quick pull of two zippers that are lashed together. It makes me the fastest draw in the East.</p>

<p>On-topic, you can probably mix without any difficulties. The only potential problem with teleconverters is that the rear element of the lens will contact the front element of the teleconverter, but you can determine that by examining the two before mounting them together. </p>

<p>Of course... what John said also, including the disclaimer!</p>

<p>It won't hurt anything. I believe Quantaray is (or was) a Ritz camera house brand for Sigma (i.e. they were made by Sigma but not necessarily to the same specifications as Sigma lenses).</p>

<p>You get what you pay for. A cheap TC probably won't give you as good an image as a more expensive TC. I'd get the Sigma if the lens is a Sigma.</p>

<p>Most of Ritz Quantaray lenses, are made by Sigma. Some of the cheapest crap known to man, woman or beast. </p>

<p>Michelle, I don't know how the situation with Canon and Sigma is (I only shoot Nikon lenses on my Canon 5D II. Most of my gear is Nikon) but there's a heck of an incompatibility between Sigma lenses and Nikon or Tokina teleconverters. The lens has to communicate with the teleconverter, because the lens's CPU is responsible for telling the camera that it's now a 100-280mm f4, that it needs to be focused at a different rate because of the DOF change, that the metering compensation is different, etc. Nikon, Tamron, and Tokina lenses and teleconverters communicate just fine in any combination. Sigma lenses do not communicate with Nikon, Tamron, or Tokina converters, nor do Nikon, Tamron, or Tokina lenses communicate with Sigma converters, so you get wrong EXIF info (no biggie), slow focusing and focus errors (major problem) and some metering errors (minor problem).</p>

<p>My gut instinct is that a Sigma lens needs a Sigma converter to work right on a Canon, just like it does on a Nikon.</p>

<p>Bob, Quantaray is the Ritz house brand for whatever Ritz can get their hands on, cheap. I've seen the Quantaray name on Tokina, Tamron, Sigma, and Cosina products.</p>

<p>The thing that scares me most about Quantaray is I know how sourcing agreements work. Barts Camera and Rokona lenses (for example) sit down and negotiate a price. Rokona says "we can give them to you at $125 each in 10,000 lot orders". Bart says "can you get it down to $115?". Rokona says "Sure. Normally, we test each lens to 2% tolerance, and do a full SPC analysis on 1 lens in every 200. If we make it 5% tolerance and 1 lens in 500, we can give them to you for $115".</p>

<p>I bought a Kenko 1.4 teleconverter to use with my Canon 70-300 mm 4-5.6 IS USM lens and I find it works very well. I have since used it with my Canon 70-200mm 4 L IS lens .. I can only comment on the Quantaray filters and I know that some are now made by Hoya. You get what you pay for. I was in the US Camera store in Portland, OR which is owned by Ritz and they have at least two grades of filters. The thin better filter from Quantaray was more than the Hoya filter. This was a 62mm Circ Pol. $98.00 No idea on the teleconverter from Quantaray, but if you are getting it real cheap. "Let the buyer beware." I like Joseph W's comment. </p>

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<p>Having said that, it doesn't make a lot of sense <strong>to me</strong> to put a "pretty cheap" teleconverter on what is presumably a high end f/2.8 APO zoom. YMMV. As Jim so succinctly put it, you do get exactly what you pay for here, particularly when mated to fast zooms like a 70~200/2.8 which are often at their weakest wide open at the long end (right where you would be using a TC). If you want the best possible results, then I think you would be far better off to purchase the <a rel="nofollow" href="http://www.bhphotovideo.com/c/product/390164-USA/Sigma_824101_1_4x_DG_EX_APO.html" target="_blank">1.4X</a> or <a rel="nofollow" href="http://www.bhphotovideo.com/c/product/390169-USA/Sigma_876101_2x_EX_DG_APO.html" target="_blank">2X</a> Sigma APO converter that would be <strong>specifically optimized</strong> for this and other similar lenses in the Sigma line.</p>

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<p>My thoughts exactly. I often heard that Sigma lenses do not behave well with TCs which were not made by Sigma. Last, the 2X TCs I tried (Kenko and Canon, Canon lenses) had too much IQ degradation. That's why my recommendation goes to a Sigma 1.4X TC.</p>

<p>Happy shooting,<br>

Yakim.</p>

<p>It's easy to spend someone elses's money but I'd stick with the Canon tele-extender. I paid under $300 a couple years ago for mine and there doesn't seem to be any degrading of the image. Plus it's waterproof. My philosophy is you can buy a lesser body and survive as they're replaceable, but always opt for good glass as it will outlast the bodies.</p>

<p>Thanks guys for all the advice! I went for the Sigma 2x. I usually shoot in bright sunlight at around f/8-f/11 anyway, so the f/5.6 adjustment wont bother me.</p>