7D + 1.4x + 100-400L IS Focus problem

Ray.Petri wrote in post #15082435
Thanks for all your comments - Taping the contacts is not a very satisfactory solution as there is a lot of hunting when it attempts to focus.

I believe some adaptors operate ok in this combination.

I suppose I'll have to think about spending more money on a wider apperture 400mm. Could always borrow the wife's credit card - I suppose.

I am led to believe that there is an upgrade to the 100-400L rumoured - About time.

All adapters that don't report are going to give you the same hunting behavior, if you are shooting in lower light levels. On a nice sunny day, shooting people milling around on a field, for example, the AF should work just fine with the extender.

There has been a rumor of a 100-400L MKII for about 5 years now, don't hold your breath.

mileslong24 wrote in post #15082492
You could also pick up a Kenko Pro 300 which will AF with that combo. I use one with my 400 5.6L on my T3i and it works, and much better than I anticipated. You will need light though as you are gonna be at f8 constantly.

I use a Kenko PRO300 but you are meaning the newer version? I've heard tell that it manages to fool the body without having to tape any of the pins.

Lowner wrote in post #15082686
I use a Kenko PRO300 but you are meaning the newer version? I've heard tell that it manages to fool the body without having to tape any of the pins.

Yes, but the end result for the AF is the same as with taped pins - it's very slow for static well-lit subjects and useless for anything moving at speed or in dim light.

As for the MkII - I nearly decided not to buy a 100-400 because its replacement was due 'real soon now'. That was in 2006. I'm glad I didn't wait.

So you're trying to get a 560 f/8 lens by combining the 400 f/5.6 and 1.4x. The question is how to get 500+ mm and still have AF.

Canon 500 f/4 is $10,000
Sigma 150-500 is $1,100
Sigma 500 f/4.5 is $5,000

Used 1D IIn body is about $700
Used 1D III body is about $1500

Oh, but if you went to the 1D, you'd lose some crop factor (1.3 vs 1.6) so your 560m setup would act like 455mm putting you just barely ahead of the 7D / 100-400 combo without the converter.

The lowest cost solution here is to use the 7D and 100-400 without the converter. Get closer to your subject and crop when you can't.

n1as wrote in post #15086608
So you're trying to get a 560 f/8 lens by combining the 400 f/5.6 and 1.4x. The question is how to get 500+ mm and still have AF.

Canon 500 f/4 is $10,000
Sigma 150-500 is $1,100
Sigma 500 f/4.5 is $5,000

Used 1D IIn body is about $700
Used 1D III body is about $1500

Oh, but if you went to the 1D, you'd lose some crop factor (1.3 vs 1.6) so your 560m setup would act like 455mm putting you just barely ahead of the 7D / 100-400 combo without the converter.

The lowest cost solution here is to use the 7D and 100-400 without the converter. Get closer to your subject and crop when you can't.

what about the 7d + Sigma 150-500?

The 7D can work fine with the kenko pro 300 DGX 1.4 extender
with the 100-400 lens
but you must choose the 19 point AF from the AF point selection
other AF points will make the focus playing until catch the right focus

I would highly recommend not taking hollis for his word. He states the same thing in every thread I've read about TC's even though countless numbers of us use them without the issues he claims. My Kenko Pro 300 DGX on my 400 5.6L used with my T3i does retain AF. It works perfect on any static subject in any light, and only hunts for BIF and things like that if there isn't very much contrast or very little light. On a sunny day it works fine for anything moving.

TheBB wrote in post #15082406
The 7D can't autofocus if the lens is slower than f/5.6. The 100-400mm has f/4.0-5.6. When you put on the 1.4x extender, the aperture decreases by a stop (the size of the opening doesn't change, but the focal length does), making it effectively f/5.6-8. So if you use a focal length that's too long for the maximal aperture for this lens, it's simply too dark for autofocusing. You should be able to autofocus near the wide end.

This is fine for the 70-200 f/2.8 because the extender only brings it down to f/4, well within tolerances.

Yup. Have to have max aperture of at least f5.6 to AF on 7d

hollis_f wrote in post #15086494
Yes, but the end result for the AF is the same as with taped pins - it's very slow for static well-lit subjects and useless for anything moving at speed or in dim light.

As for the MkII - I nearly decided not to buy a 100-400 because its replacement was due 'real soon now'. That was in 2006. I'm glad I didn't wait.

I agree and also speak from personal experience. It's not that it won't work, but rather, it won't work very well with the 100-400L. If you're used to even mediocre AF performance, you'll probably be disappointed. If you're used to AF performance on par with something like a 70-200 f/2.8L IS II or one of the 2.8/4.0 supertele primes, you'll be downright frustrated and pissed. It's all a matter of what level of AF performance you've become accustomed to and what you deem acceptable.

mileslong24 wrote in post #15087557
I would highly recommend not taking hollis for his word. He states the same thing in every thread I've read about TC's even though countless numbers of us use them without the issues he claims. My Kenko Pro 300 DGX on my 400 5.6L used with my T3i does retain AF. It works perfect on any static subject in any light, and only hunts for BIF and things like that if there isn't very much contrast or very little light. On a sunny day it works fine for anything moving.

my kenko pro 300 DGX 1.4 work fine on my T3i with the lens 70-300L on all the AF points and the focus very fast
but when i use the same lens and the 100-400 with the same kenko extender on my 7D the focus always playing , it can work only on the 19 point AF from the AF point selection
why ? i dont know
that what i see
try your kenko extender on the 7D and see

I've used a 100-400 with a Kenko Pro300 DGX 1.4x and it does AF on a 7D as well as a 550D and a 5D2 cause I've tested it. The IQ is still very good but the AF speed does take a bit of a hit. You can shoot most things and even the occasional BIF but you'd struggle on fast sports and most smaller birds flying. I used it mainly for aviation and wildlife shots such as squirrels and ducks etc.

modchild wrote in post #15087958
I've used a 100-400 with a Kenko Pro300 DGX 1.4x and it does AF on a 7D as well as a 550D and a 5D2 cause I've tested it. The IQ is still very good but the AF speed does take a bit of a hit. You can shoot most things and even the occasional BIF but you'd struggle on fast sports and most smaller birds flying. I used it mainly for aviation and wildlife shots such as squirrels and ducks etc.

that what i meant about the kenko extender
with the T3i the focus very fast
but with the 7D not fast
only fast when i choose the 19 point

Kenko Pro300 and 100-400 is an awesome combo. I use it constantly. No pin taping.

mileslong24 wrote in post #15087557
I would highly recommend not taking hollis for his word. He states the same thing in every thread I've read about TC's even though countless numbers of us use them without the issues he claims. My Kenko Pro 300 DGX on my 400 5.6L used with my T3i does retain AF. It works perfect on any static subject in any light, and only hunts for BIF and things like that if there isn't very much contrast or very little light. On a sunny day it works fine for anything moving.

Cool. Let's see your BiF shots.

mileslong24 wrote in post #15087557
I would highly recommend not taking hollis for his word. He states the same thing in every thread I've read about TC's even though countless numbers of us use them without the issues he claims. My Kenko Pro 300 DGX on my 400 5.6L used with my T3i does retain AF. It works perfect on any static subject in any light, and only hunts for BIF and things like that if there isn't very much contrast or very little light. On a sunny day it works fine for anything moving.

Its works perfectly well on my 5DII as well, no slowing of AF of any kind. Thats why I object to Canon placing these idiotic restrictions in the camera.