Home > Consumer Reviews > Canon EF 2X II Extender Telephoto Accessory

It should be obvious - this extender really needs to be used with a tripod. That alone will increase your image quality. It's also designed for the higher quality Canon lenses - the EF series. 90% of the complaints about this accessory ignore those two facts. The next biggest complaint - autofocus. Again, Canon is clear that you need a lens with an aperture of 2.8 or faster in order for autofocus to work. Basically, so what! If I'm on a tripod shooting my subject, I'm going to pre-focus . The depth of field is in such a compact area and you're zoomed in so much, autofocus is really not that important. What did people do before autofocus? Skip the photo?

So if you understand what you are purchasing and know how to use it - well, like with any great tool - you'll produce fantastic results. If you don't know how to use it, try and do a hand-held 400mm zoom, or attempt to catch that bird as it swoops past, forget it. This is not a $5,000 lens. It's a $300 add on that extends your current lens.

If you could afford that 10 lb, 800mm telephoto lens - at $12,000 - you would not be looking at this accessory. I'm not trading in my car for a lens any time soon - and this little accessory does the job just fine. I've tried it on action shots freehand - even though I knew better. Forget it. Handheld when it's added on to my 200mm? Almost as bad. On a tripod? Fantastic. Even better if you have the remote trigger.

The bottom line is that if you are looking for an affordable alternative, know how to use it, and are willing to spend the half hour it takes to master this multiplier, you will get great results. If you expect to point and shoot, then buy a point and shoot camera.

This extender is limited to which lenses it will work with, most of them L lenses. The II model features a new seven-element weather-resistant design, and improved anti-reflection internal construction. Auto-focus is possible with any EOS body if an f/2.8 or faster maximum aperture lens is used. Image Stabilization lenses maintain the IS feature when used with current EOS cameras. Using this extender with any lens will eliminate one or two f stops and decrease sharpness to some degree.

I rented this extender to use with the Canon EF 100-400mm f4.5-5.6L IS USM telephoto zoom lens. This lens while sharp and high in quality, is not the sharpest L lens out there. I found adding this extender with the 100-400mm caused the sharpness to suffer too much for my tastes outweighing the benefit of having extra reach. The minimum 7.6 f-stop limits creative abilities with this combination too.

I would imagine that using with an extremely sharp lens like the Canon EF 70-200mm f/2.8L IS USM telephoto zoom lens would be able to handle the reduction in sharpness with minimal effect. I didn't own this lens when I used the extender, so I cannot say for sure.

I would suggest renting or taking your camera and lens to the store and trying this extender out before buying. I can see where certain combinations may benefit the photographer. In my case, it didn't work out for me.

PROS:
Provides extra reach

CONS:
Eliminates one or two f-stops
Decreases sharpness of the lens

If you have the big lenses (400mm f/2.8L IS USM or even the 70-200mm f/2.8L IS USM) this is totally worth the addition. The 2x does NOT kill the autofocus on the f/2.8 and effectively doubles your lens with very little distortion around the edges. Check compatability on Canon's website. You won't be disappointed!

This is a high quality piece of glass, and it's not a coincidence that its color is white, since it is by all means an L series glass and L series only compatible (more on Canon website). A reviewer here underrated this lens for not working as well as he expected on a 100-400 F/4.5, well, I thought it was common knowledge that a 2X extender will remove 2 f/stops and the quality of the final image will somehow suffer, it's called... what you pay for. Otherwise no one would be buying the much more expensive 500mm, 600mm, etc. lenses. I demoed this extender in Yellowstone for a few days with a Canon 70-200 L f/2.8 IS lens and even after I added a polarizer the autofocus was still very fast. All the Canon people I met told me that with a 100-300mm f/4.5 you should use a 1.4X extender and that the 2x is not for that lens. Guess it's useful to do a little bit of homework before investing in expensive technology.
As for the quality of the images taken with the 70-200 above coupled with the 2X I can tell you that you could see it in lab tests but not with a naked eye (Unless you're an eagle maybe).

* Update October 19 2007
I bought the 2X with a Canon 70-200 F/4 non-IS lens and been playing with it for the past 2 weeks. Just as I previously stated the quality remains high; on the f/4 lens the autofocus stops working (as I expected and stated previously) although a friend told me that by blocking one of the pins the autofocus will work although only the central sensor. It's not a big deal to me since I often use manual focus and at the minimum f/8 you get there's still room for error. With my Canon 30D (1.6 crop factor) the image quality is high, surprisingly high, just as I experienced up in Yellowstone at the Canon workshop. So, let's do a bit of math: 70-200 * 1.6 factor makes for a 112-320mm effective range, add the 2X extender and it becomes 224-640 at f/8. So yesterday I took photos of a Bull Moose at 640mm effective with a cheap tripod ($20 BestBuy, horrible, but better than nothing) and the quality of the photos is much better than using my Tamron 70-300 ( effective 112-480) f/3.5 lens which I'm definitely going to get rid of.
This piece of glass definitely deserves 5 stars and not a bit less. Now I can't wait to take it to my trip to Costa Rica's jungle.

This high quality extender is a great addition to my Canon EF 70-200 L f/4 !! With a top-notch build quality and a tough, weather resistant design equal to that of their highly respected line of "L" lenses, Canon has produced a great product for its unbeatable zoom lens !! Although the 2X extender renders the A/F function useless on many Canon cameras, I found this to be a Very small drawback overall ( I prefer to manually focus under many of my shooting conditions). This extender is more suited for a low f/number lens due to the 2-stop change in brightness, but it is still VERY effective with my f/4 in normal lighting. A lightweight and fairly inexpensive way to double your focal length, while maintaining the incredible optical quality of the main lens...My backpack will always contain my 2X and 1.4X extenders !!