I may be going against the grain as to what might generally be advised but you may consider the following.
I am assuming you have the Canon 400f5.6 prime
A 1.4X converter will increase the effective focal length of your lens to 560mm which is quite a bit of power. You will however lose one stop of light. With a 2X converter you will lose two stops of light.
Your camera will not autofocus with a 1.4X converter...though with a dummy converter or taped pins it is hit and miss. However not having auto-focus should not mean it is the end of the game for you. The Canon 400 prime is a sharp lens and you should not lose too much detail if used correctly. An additional 40% more pixels on a bird should easily compensate for the 5% (approx) loss in sharpness. You will however need a good stable support i.e firm tripod with a decent sturdy head and except in the brightest of conditions (which is not always good for bird photography anyway) be prepared to use a cable release or timed shutter release for those birds which are not moving.
Your Canon lens has about equal sharpness to my Sigma Prime 5004.5 EX and I have used both 1.4X And 2X converters successfully by applying manual focus in its various forms i.e using live view but also pre focusing and then putting the lens into manual mode and then attaching the converter. I have also manually focused with the view finder but this is not recommended since it is hard to judge focus through a view finder.
You should find the process easier with your 400 lens than I experience with a 500 lens since as the focal length increases so does the apparent vibration in the lens thus making it more difficult to see if you have achieved critical focus as well as the effect it has on the relative exposure.
You will need to practice your technique but I'm sure in time you will benefit.
If I were using the Canon 400 prime and was not able to autofocus with a 1.4X converter then I'd give the 1.4X a miss and go for the 2X converter...but that's just me. A 2X converter will five you 800mm of focal length.
I have attached links to some images taken using my 500mm lens and 1.4x and 2X converter to give you an idea of what may be achieved
If you get a 1.4x converter the Kenko dgx pro should be adequately sharp at the centre (Art Morris used one on his 800mm lens). If you decide to get a 2X converter then , in my view, you should get a Canon (preferably the MkIII if you can afford it).
If you see me out and about then you are more than welcome to try out my converters.
-- Edited by Adrian Dancy on Sunday 20th of October 2013 05:47:42 AM
I have the Kenko 300dgx pro 1.4 teleconverter which I use with my 70-200 f4 with good results. It will not autofocus reliably with the 400 f5.6 except in liveview, and I am not convinced that the IQ is any better than cropping the bare 400.
Hope this helps
Steve
Thanks for that Steve. I did look at the Kenko but as I've got the 400mm f5.6 it seems that there's no point bothering with one.
I have the Kenko 300dgx pro 1.4 teleconverter which I use with my 70-200 f4 with good results. It will not autofocus reliably with the 400 f5.6 except in liveview, and I am not convinced that the IQ is any better than cropping the bare 400.
You could always come into the light, and change to Nikon where the auto focus works fine with convertors, with my d7100 + 300f4 ,I can use the Nikon tc1.4 which gives me a 420mm f5.7,as you have without convertor more or less, but also I can use a 1.7 and at a push in good light a 2x convertor ,or remain on the dark side like Dennis
Yeah your right. Some people have had sucsess with taping over the first three pins on the left and then tricking autofocus to work though it will be a bit slower and may struggle in poor light. Never tried it myself though you are correct in what youve heard. Just a piece of tape to stop the first 3 pins from contacting. It would be a good test to try. Im sure a hunt on google for taping pins on canon lens to trick auto focus would throw up some more info. It might only work on certain camera models? Good luck
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Did you see it? It was small and brown and flew that way.........................
Cheers for that Dennis and John. I had heard before that there was something about taping up and auto focus not working but I couldn't remember. I think I'll stick to my current set up then as I can't afford one of the f4 lenses.
I use the same lens and as far as im aware a Camera with a converter will work but auto focus will not work unless the lens is under F4 to begin with. I think you lose 2 stops of light with the converter and if this then ends up higher than 5.6 then auto focus wont work. The extra 160mm from the 1.4 would be usefull possibly for static distance birds using manual focus only. Any other opinions please but to my knowledge this is how it works
Cheers Dennis
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Did you see it? It was small and brown and flew that way.........................
I currently shoot with a Canon 50d and a 400mm prime lens.
I'm considering investing in a tele-converter to gain a little extra focal length. There are several makes and models on the market but can someone recommend a particular type, etc.
I am not 100% sure as not Canon, but I think none of the Canon tele-convertors will autofocus with the 400 f5.6 ,canon are strange in that they have set the tele-convertors to only work on the more expensive lenses and cameras that are f4 or less, in fact I don't think without taping one of the pins on the autofocus it will actually fit. I think Kenko pro work, but I would Google it. Dennis has the same kit as you, so he will most likely know the in and outs of it. :)
I currently shoot with a Canon 50d and a 400mm prime lens.
I'm considering investing in a tele-converter to gain a little extra focal length. There are several makes and models on the market but can someone recommend a particular type, etc.