converter

[Dave mac]

I've read hundreds of posts on the subject but I'm still confused (not an uncommon occurrence). I have a Canon 400d and a Canon 100/400 L which is great. I want to buy a 1.4 converter. The question is will any of the available converters work with my camera lens combination. By work I mean, will it autofocus and will the IQ be any better than putting the original image in photoshop and enlarging it by 140%
Cheers

[David Smith]

I will give my twopence (or should that be 2p?) then leave it for the experts to give chapter & verse.
I have the 20D and now the 40D with the 100-400. I have been using the Kenko C-AF 1.4 PRO.
With the weather being so bad/dark I decided to try the lense without the TC. It focused better/quicker but I couldn't see any obvious improvement in IQ.
Not too sure about the 400 but with the 20,30 & 40D you lose af unless you tape the pins (see other threads). With the 20 &30D the af will work fully with taped pins (albeit slower with more hunting in less bright conditions). With the 40D af will still work but with varying success-I 'THINK' it is similar with the 400D but others will confirm (or otherwise).
If you find it will work I would recommend going for it as the extra reach is (imo) valuable and without (again imo) any noticeable lack of IQ.

[Roy C]

Not too sure about the 400 but with the 20,30 & 40D you lose af unless you tape the pins (see other threads). With the 20 &30D the af will work fully with taped pins (albeit slower with more hunting in less bright conditions). With the 40D af will still work but with varying success-I 'THINK' it is similar with the 400D but others will confirm (or otherwise).
.
You would certainly need to tape the pins to achieve AF on the 400D BUT some people have reported a problem with the IS when using a taped tc with the 100-400 on a 400D body. This is a totally different problem to using taped Tc's on the 40D.

[postcardcv]

You would certainly need to tape the pins to achieve AF on the 400D BUT some people have reported a problem with the IS when using a taped tc with the 100-400 on a 400D body. This is a totally different problem to using taped Tc's on the 40D.

The problem wth a taped tc on this lens/camera set up is one that I encountered, the lens will AF but the IS leaps all over the place, so if you switch off the IS it's not an issue. However a friend has the same set up and has no problem at all, I used a Kenko and she used a Sigma. One day we tested this by switching our tc's, mine still went mad and hers still worked, most odd. I can only assume that it is something to do with the age of the lens involved (we both had the same firmware in our 400Ds).

[Dave mac]

Thanks for the info re the autofocus aspects which is encouraging although I did not suspect that there might be a problem with the IS. However, I would be grateful to know if you have any views on the IQ aspects of the converter, ie is using a converter any better than simply enlarging the image in Photoshop
Cheers

[David Smith]

[QUOTE I would be grateful to know if you have any views on the IQ aspects of the converter, ie is using a converter any better than simply enlarging the image in Photoshop
Cheers[/QUOTE]

In my limited experience it is far better. I'm sure people will give you the technical answer but my view is:-
1. With the naked eye for a n0rmal print I cannot see any difference in IQ when using the 1.4TC. I'm sure that there will be some IQ loss that can be seen in lab conditions but you or I won't see them. Niall Benvie is a very respected wild life photographer and in his book on the subject he regularly uses the 1.4 (sometimes a 2.0)
2. If you enlarge on the computer you are immediately cropping and therefor losing pixels-this seems fine on screen but I would think must degrade in real life i.e. prints.
If I'm wrong someone will point it out (gently I hope)