Canon 2x Extender

<p>I was wondering if Canon's 2x Extender will technically work on all lenses and focal lengths? how about adapted lenses like a Leica R?</p>

<p>Thanks to anyone who can confirm this =)</p>

<p> </p>

<p>Well, no. Particularly for the Canon lenses, there is only a specific set of lenses that any Canon extender works with. It doesn't matter whether 1.4x or 2x, original, II or III generation.</p>

<p>Part of the reason is there is a bit of the extender optics that protrudes <strong><em>inside</em> </strong>the back of the lens. If the lens isn't built to accommodate this, at best you'll not be able to focus through the full range, and at worst, who knows.</p>

<p>The second part of that is the lenses that accept the converter can tell the camera there is a converter attached, and which one. For example, while the converters can be used on most of the big and white "L" lenses from Canon, they will not work on the 28-300 L nor the 70-300 L. There are a few "black" Canon lenses they are compatible with, but that list is rather small.</p>

<p>Third party converters/extenders may work with more or all lenses, I'm not sure.</p>

<p>Image quality will be degraded somewhat with any extender, even the Canons. Canon's seem to get better the more recent they are, and in general, the third-party converters aren't as good as Canon's.</p>

<p>I'm not sure I would trust the image quality of a high-quality lens like the Leica to any converter, though, much less a third-party converter...</p>

<p>The 2X extender is not compatible with all EF lenses. According to the "EF Lens Work III" Canon manual, the 2xExtender is compatible with single focal length L-series lenses 135mm and up as well as the EF 100-400 f/4.5-5.6 IS USM, and the EF 70-200 zooms. I can't help you with adapted Leica R leses.</p>

<p>The complete list of which Canon Lenses work with the Canon Extenders is in the <a href="http://www.usa.canon.com/cusa/support/consumer/eos_slr_camera_systems/lenses/extender_ef_2x_iii#BrochuresAndManuals">instruction leaflet for the Canon Extenders</a>. Click on the "Extender EF 2X III Instruction Manual" link. (the leaflet covers both the 1.4x and 2x)</p>

<p>Larry you're a sage, thank you. Guess I'll be saving my money =)</p>

<p>Thanks. I only own one extender, a 1.4x III, that I use with my 100-400 f/4.5-5.6 L IS USM. Of course, on my 7D, it's either manual focus or contrast-detect via live view, and I'm still learning how best to use that combination. I chose the 1.4x III over the much cheaper 1.4x II because of the better image quality, even with a 10+ year old design lens like my 100-400. And, I'm ready for future lenses from Canon...</p>

<p>Not included on the list are the 17mm TS-E and 24mm TS-E - both extenders fit these lenses. Of course, both are manual focus to start with. I don't know if the 45 and 90mm TS-E lenses work as well.</p>

<p>With Canon lenses, unless the lens is listed as "extender compatible" even if an extender physically fits on a lens, it will not report its existence, or the combined focal length, to the camera.</p>

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<p>Of course, on my 7D, it's either manual focus or contrast-detect via live view</p>

</blockquote>

<p>Larry, tape the pins and try the off-centre AF points - you might be pleasantly surprised.</p>

<p>It's not a perfect solution, but <a href="http://www.capture-the-moment.co.uk/tp/tfu29/upload/Bridlington_September_2011/carrion_crow_bridlington_1a.jpg">it works pretty well</a>, <a href="http://www.capture-the-moment.co.uk/tp/tfu29/upload/Bridlington_September_2011/knot_bridlington_2.jpg">more often than not</a>.</p>

<p>These are both with the 7D, 100-400mm and 1.4x (might have been my Canon Mk II TC, but thinking back it I reckon it was my cheap and cheerful Kenko 1.5x), handheld at 560mm (600mm if it was the Kenko), and by using off centre AF points, I get useful AF.</p>

<p>If you use a 12mm extension tube between the 1.4 or 2 x extender and the lens, it will work with most lenses, but requires manual focus. You also may or may not be happy with the results.</p>

<p>I guess this will be subjective, but are there any good Universal extenders out there?</p>