Canon 40D, 100-400mm Canon lens and teleconverters

[milalic]

HI there. What would you consider the best non 2X teleconverter that will allow me to AF with this camera lens combo?


thanks

[mike_d]

Doesn't even the 1.4x converter (which costs 1 stop of light) make the autofocus flakey on anything short of a 1D? I have that lens on a 5D and it can still hunt especially at the long end if the light isn't super bright. And that's just the lens, no teleconverters.

[KCMO Al]

Autofocus does not work with the 1.4x although some advocate "pin taping." I was not very pleased with the results of using the 1.4x with this lens. At one of his seminars, George Lepp was asked about using TCs with it and he said he would never do it. I'm afraid I agree.
I had the lens out today at the zoo and even without the TC it was having trouble finding focus. I went to MF a number of times. Admittedly this was in low light (shadow) and low contrast conditions.

[chauncey]

Yeah, you're right...TC's just flat don't work, but...

http://i329.photobucket.com/albums/l383/chauncey43/egrets-merged-2.jpg

I've got numerous examples where they do work.

[Tom Reichner]

Yeah, you're right...TC's just flat don't work, but...

I've got numerous examples where they do work.

Hello, Chauncey!

I have the 100-400, and I have both the 1.4x and 2x extenders. I've tried using the extenders with this lens, and was never satisfied with the results. I used the combo on both my 1D Mk2 and my 5D.

As I said, I was unimpressed with the IQ whenever I used either converter on this lens. I wouldn't say that "it doesn't work", as I suppose you can make it "work", as you have demonstrated. I think what it really comes down to is how much of a hit you're willing to take in image quality. In my opinion, the 100-400 already struggles to produce extremely sharp, clear images. Even with no converter on it and stopping it up to f8 I'm still generally not satisfied with the IQ when compared to Canon's L series primes. So, you can imagine if the 100-400 already struggles to produce strikingly crisp, clear images with no TC at all, how much you are sacrificing by sticking either of the extenders on there?

Yes, I suppose you can get the combo to "work", meaning that the AF will achieve focus. But will the picture even be worth taking with such a compromise to IQ? That depends on the photographer and what they expect in an image. It also depends on the end use of an image. If a photo is going to be posted on the internet at a small or medium size, perhaps the lack of IQ will not be a problem. If it's being printed in a magazine uncropped, and at a small size of 1/4 page or smaller, then it also probably wouldn't matter if it wasn't crystal clear and razor sharp. But if you're printing images out at 20" by 30" or larger to sell on the fine art market, it will matter. It will also matter if you're submitting the image to a publisher or to a stock agency. Imagine trying to submit a pic to Alamy that was taken with a 100-400 plus a 1.4x extender?! At the enormous size they require the files to be upsized to, I'm sure you would have the image rejected, with the reason for rejection being "soft due to size".

I guess what really matters is what you are satisfied with. If you're extremely picky and demanding then you will not think that the 100-400 with an extender "works". If you are more forgiving of your work, and you can get AF to achieve focus, then you will consider the combo to "work" jsut fine.:D

[Picture North Carolina]

In my opinion, the 100-400 already struggles to produce extremely sharp, clear images.

I do not doubt what you say. However, in my experience, and with my copy it is very much to the opposite. Long before this thread, going back to last year I was telling people that I thought that I had the world's best copy of the 100-400. The first shots I looked at when I got it were jaw-dropping sharp. I am astounded at the crispness and contrast of my copy. Almost like a prime. However, I will say it's only been used on the 5D and 5D II bodies. Never used it on a crop body other than on a converted 20D, and the later is not a good test because the IR shots tend to be a little soft. So I guess mileage really does vary.

As to the extender: can't speak against quality because I've never tried it. However, one thing I can say is that I cannot imagine living with the light loss. I shot an assignment this last tuesday largely using the 100-400 in which the native speed (no extender, no filters) was problematic both technically and creatively. On the other hand, to get into the 600 mm FL range in good quality lenses is prohibitively expensive, so there may not be much of a choice other than to use the extender.

[Tom Reichner]

As to the extender: can't speak against quality because I've never tried it. However, one thing I can say is that I cannot imagine living with the light loss.
I've actually found that livign with the light loss is not much of a problem. I always try to shoot at f8, as I have found that to be a 'sweet spot' on my lens (the big 400 f2.8 ) So losing a stop or even two stops really doesn't matter most of the time, as I'm going to be shooting at f8 anyway.

On the other hand, to get into the 600 mm FL range in good quality lenses is prohibitively expensive, so there may not be much of a choice other than to use the extender.
Good point. I put the 1.4 on the 400 2.8 regularly, which gives me a 560 effective focal length. I suffer very, very little loss of IQ with this combination. I will also use the 2x extender on the big 400, but have found that exceptional results only result when there is plenty of direct light - enough light to shoot at f8, ISO 400, and still get shutter speeds of 1/320th or faster.

[Dan-o]

Yeah, you're right...TC's just flat don't work, but...

We all know they work and work well. I have mine on my 300 more then I don't, but the question was directed at a certain lens and camera combo. I have never used the 100-400 but I have never heard anything good about using TCs on it.

[milalic]

any other inputs...?

[PhotosGuy]

On the other hand, to get into the 600 mm FL range in good quality lenses is prohibitively expensive, so there may not be much of a choice other than to use the extender. This is why I got the 2X to go with the 70-200 f/2.8, which works OK in daylight but needs an effective f/11 for reasonable IQ.
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