Canon 100-400 with 1.4 x still sharp?

[mark_sam]

Just bought the Canon 100-400mm(IS)sold my Sigma Bigma 50-500, just too big

and heavy without a tripod. Question, have any of you used the canon 1.4x

extender with this lens and found the quality to still be good? excellent?

poor?

[nicholas_rowe]

It is still reasonably sharp, but won't autofocus unless you are using a 1-series body.

[chapinstudio]

Eventhough I have not made a formal test, once I can manual focus I have not distinguished any difference in image quality. I have the kenko pro 1.4x teleconverter, for the 100-400, and I am happy with the results.

[robin_sibson1]

I used to use this combination on a 1V, where it gave good but not ideal results, and would AF reasonably satisfactorily. I have used it occasionally on my 20D. I have had very few keepers, but I think that is due more to the difficulty of focusing the lens and (even with IS) keeping it steady enough, than to serious optical problems. I do have one shot taken at 560mm f/13 (true aperture, so 1 1/3 stops down from wide open) which is critically sharp across the frame. I certainly would not recommend the combination for anything other than occasional, and rather speculative, use on 1.6-factor.

[robin_sibson1]

I should make it clear that I am talking specifically about use with the Canon Extender 1.4x.

[mark_chappell]

I've used the combination a few times (on a 1D mk II), but was never happy about the image

quality. From Robin's comment, it sounds like good images are possible, but rare; I certainly

never got any that I wanted to keep.

[m_barbu1]

A bit of a loaded question, I think, since I don't consider the EF 100-400mm f/4.5-5.6L IS USM to be all that sharp, to begin with.

[jim_simon3]

I have used this combination on my 1D MkII. Yes it works and I can get sharp photos. The viewfinder is darker and even though it will autofocus, many of my photos are manually focused and it is difficult to get a critical focus. I'm sure a split prism would darken so that isn't an answer. I have many many more missed auto and manual focus shots than in focus and I'm not sure I can hold the set up steady so I do up the ISO which doesn't help the apparent sharpness. I would rate it acceptable on the hits on single shot. For birds in flight, (servo)so far it hasn't been worth while to me. All in all, I first thought it was a poor quality set up, but I'm now convinced that my problems stem from the small depth of field at 728mm, the darkened viewfinder, and the problems of hand holding 728mm. I hope others have better luck handholding. If all my shots were losers it would be easier for me to abondon, but the few winners keep me using it for shots that would otherwise not be worth while.

 

I used it this past weekend to capture goldfinch in a birch tree. Either the birds would be another set of shots where the bird was the size of the spot meter point or I would use the converter. I used the converter and got 2 usable shots focus and shake wise out of 20. One is a keeper and I'm happy for that. I did set the ISO to 400 and the Av to 11 so movement of the bird and my holding still were problems, but I weighed the factors and decided. Sorry I don't have the picture on line.

[sergey_oboguev]

It is the exact opposite of sharp. But it is a great combination to motivate for buying 600/4.

[bmeister]

I get "acceptable" shots with the 2XII converter. The 1.4x can be useable, but you are losing sharpness, AF speed (or lose AF altogether on a non-1-series body) and are more prone to blur from the longer focal length even with IS. Here's a shot with the 100-400+2X-II wide open on a tripod:

 

http://www.bwbrock.com/gallery/2066309/1/106336602/Large

 

You can click on the image to see the orignal unaltered JPG.