Last summer Canon announced a new matched pair of extenders. They updated the Canon EF 1.4X III Telephoto Extenderand Canon EF 2.0X III Telephoto Extender. The new models feature an integrated processor which ensures all focusing, metering and ID information when paired with the right lenses. Canon claims that when combined with premium Canon L-series lenses, these extenders enable higher AF accuracy compared to previous generations.

In the past, I’ve been reluctant to recommend extenders for the simplest of reasons – I’ve never used one with satisfactory results.

Well that’s changed. On my recent trip to Alaska to photograph eagles, I tried both the EF Extender 1.4x III and EF Extender 2x III. They were both extremely well-built. Solid as a rock comes to mind.

They are easy to mount and dismount. The optics are of the highest quality – which is a good thing considering these devices cost as much as some lenses. They use Canon’s Super Spectra coating which does seem to reduce flare. They also feature a fluorine coating which is designed to make them easier to clean. They are dust and water resistant – note – they are not waterproof.

I got very good results using both these extenders on Canon’s latest 70-200 F/2.8 IS L series II models. I did not try stacking them, although I know at least one person who does and who still gets good results.

At F/8 the 2X shows almost no vignetting (a common problem with extenders.) The images were sharp and crisp and autofocus when matched to an IS “L” lens and a Canon 1DMKIV was superb. At F/6.3 (Electronic FStop) you see minimal distortion. At F/5.6 results are acceptable but noticeably impacted.

The real question is how much better are the version III compared to the version II extenders? The answer is – I don’t know. I can see a very slight improvement atF/6.3 and better at  f/8. I didn’t do a scientific test. That’s not how I do things. I simply work based on my impressions. And my impressions are that if you already have the Model II extenders and are happy with them, you probably don’t need to upgrade. If you don’t have the version II extenders, you may want to consider these. I bought the pair after these tests. I was able to get consistently good results with both version III extenders and I can’t say that about  the version II extenders.

The two of these extenders combined cost an amazing $1100 plus. But if you have been putting off buying extenders, I believe the quality, the optics and the performance in the new models justify the purchase.

I’m very happy with the few images I made using the extenders and I’ll do some longer-term, more exhaustive testing with other Canon lenses and post my results here at

Highly recommended.


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