Auto focus with teleconverter.

why don't you try just using the 100-400 for a bit before getting a TC...see how it even works out for you before deciding you need more reach before even getting the lens

Whatever you decide, with the 7D remember that 400mm x1.6=640 x1.4=896 or x2=1280

While IS will work, the longer you get the less effective it will be. You can for all practical purposes not handhold at all and will need a steady tripod and head. The longer you get out there, the greater skill and experience you will need.

I have gotten some amazing shots with TCs, even stacking the 1.4 and the 2x on the 100-400@400mm = 1120mm on FF, 1792mm on crop. Live View, MLU, remote release, sandbags, etc are a must. It's fun, but forget any moving subject, have no expectations and don't be disappointed if you only manage one halfway decent shot out of _________.

I sometimes use the Canon 1.4X converter with my 100-400. I am lucky in that, with the pins taped, autofocus on my 50D works surprisingly well. The same cannot be said for the 2X converter, though.

Julius

I recently purchased a Kenko 1.4x Teleplus Pro 300 DGX to use with my 100-400. The pins do not need to be taped to retain autofocus and it reports the focal length/aperature accurately to the camera. I have only done a few initial tests with it on my 60D, but it seems to do pretty well. Focus searches quite a bit in low contrast or low light conditions. With fair to good light/contrast it focuses quickly and picture quality doesn't appear to suffer very much. If I can ever get a decent day off with good light I plan to test it a bit more. I have also tried a non reporting 2x and could not get autofocus to operate at all with this combination.

DreDaze wrote in post #13965500
why don't you try just using the 100-400 for a bit before getting a TC...see how it even works out for you before deciding you need more reach before even getting the lens

That's what I was planning on doing, but I would really like to get some moon shots as well.

That combo (7D+100-400) is perfectly capable of decent moon shots in its own

Can some of those who say that AF 'works' with a 100-400 at 400mm or a 400 f5.6, with TC, please post some examples of birds in flight taken with that combination.

Ha-ha, man make joke. I take MIF for OP.

I just went out and took some moon shots with the 7D + 100-400L

- @400mm
- @400mm + 1.4 TC = 560mm (890mm with crop factor)
- @400mm + 2.0 TC = 800mm (1280mm with crop factor)
- @400mm + 1.4 TC + 2.0 TC + 1120mm (1792mm with crop factor)

Funnily enough, I will only post the last because though the last has the most pixels, they effectively all look the same.

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pol024 wrote in post #13960584
on a 7d yes

canon 1.4 x didn't work on my 7D and 100-400.


No AF at all

John_T wrote in post #13970275
Ha-ha, man make joke. I take MIF for OP.

I just went out and took some moon shots with the 7D + 100-400L

- @400mm
- @400mm + 1.4 TC = 560mm (890mm with crop factor)
- @400mm + 2.0 TC = 800mm (1280mm with crop factor)
- @400mm + 1.4 TC + 2.0 TC + 1120mm (1792mm with crop factor)

Funnily enough, I will only post the last because though the last has the most pixels, they effectively all look the same.

looks pretty good for 1,120mm

...well, a little less atmosphere, little colder, tiny adjustments, weight the tripod, beanbag the lens, refine the settings, stop breathing, none of which I did, would have been a little sharper. Focus was with Live View. Point is, the difference between 400mm and 1120mm is pixels, no more detail.

...now I'm a little startled. This morning I took out the same 7D+100-400+1.4TC+2.0TC as I used in the moon shot last night, and just on a lark shot this Magpie about 50 meters distant in the top of a tree, far away and tiny.

That's 1120mm (1792mm), you aren't supposed to be able to get shots like this with that...

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watt100 wrote in post #13960516
Do a search, the Kenko Pro 300 DGX 1.4x teleconverter works on the 100-400 with autofocus and IS

I've got one of these TC's and I can confirm that the 100-400 L does indeed retain AF and IS without having to tape any pins at all. It works very well in good light and will slow down as the light dissipates, but mine still does AF at dusk.