7D + 400/5.6 + TC?

[RiceCanon]

I'm new to Canon Rumors and so glad I found it because it's been a great source of knowledge for me.  I recently bought a 400/5.6 mainly for birding and wildlife photography.  I chose that particular lens because of its relatively low cost compared to the other super telephotos in Canon's lineup.  I've been thinking about getting a TC to use in combination with my 7D and 400 for the extra reach but am concerned this combination might not work because of an issue with F8 center point AF I've seen mentioned before.  I don't fully understand what this is about but would like to be sure that the TC will work before I spend the money on it.  Any enlightenment on this topic is greatly appreciated as I may be totally off base in my understanding.     

[bseitz234]

Only 1 series bodies (and soon 5d3) can autofocus with a max aperture of f/8. And even then, only with the center point.

Because a 1.4x TC reduces the max aperture by 1 stop (so your 400 f/5.6 becomes an effective 560mm, f/8) it will not be able to autofocus. Manual focus will still work, and you'll be able to take great pictures, but your max aperture is now f/8. Add a 2x TC (instead of a 1.4, not talking stacking here) and you lose 2 f/stops, so your new max is f/11. You're also talking about a much dimmer viewfinder by that point.

Hope that helps!

[viggen61]

I'm new to Canon Rumors and so glad I found it because it's been a great source of knowledge for me.  I recently bought a 400/5.6 mainly for birding and wildlife photography.  I chose that particular lens because of its relatively low cost compared to the other super telephotos in Canon's lineup.  I've been thinking about getting a TC to use in combination with my 7D and 400 for the extra reach but am concerned this combination might not work because of an issue with F8 center point AF I've seen mentioned before.  I don't fully understand what this is about but would like to be sure that the TC will work before I spend the money on it.  Any enlightenment on this topic is greatly appreciated as I may be totally off base in my understanding. 

With that combination, the 7D cannot autofocus using the viewfinder and the 19 AF points. Putting a 1.4x Extender on an f/5.6 lens makes the maximum aperture f/8, and the 7D only will AF down to f/5.6 max aperture.

The 7D can use Live View Autofocus with this combination, however. You mount the extender to the lens and the lens/extender onto the camera (and hopefully to a tripod!). Then turn on Live View with the button on the rear near the viewfinder. You will see the scene with a white box. Put the white box on what you want to focus on, and then engage the AF, and the lens will focus, though very slowly.

You can "zoom in" on the image to assist in the AF process.

I use the 1.4x III Extender with my 100-400 f/4.5-5.6L IS USM, on my gripped 7D, and it works ok. That combination requires a very steady platform (cheap department-store tripods need not apply) to work from.

[RiceCanon]

Thanks bseitz234 and viggen61 for your clarifications.  This doesn't sound like a workable combo for capturing birds in flight. 

[Menace]

I'm new to Canon Rumors and so glad I found it because it's been a great source of knowledge for me.  I recently bought a 400/5.6 mainly for birding and wildlife photography.  I chose that particular lens because of its relatively low cost compared to the other super telephotos in Canon's lineup.  I've been thinking about getting a TC to use in combination with my 7D and 400 for the extra reach but am concerned this combination might not work because of an issue with F8 center point AF I've seen mentioned before.  I don't fully understand what this is about but would like to be sure that the TC will work before I spend the money on it.  Any enlightenment on this topic is greatly appreciated as I may be totally off base in my understanding. 

With that combination, the 7D cannot autofocus using the viewfinder and the 19 AF points. Putting a 1.4x Extender on an f/5.6 lens makes the maximum aperture f/8, and the 7D only will AF down to f/5.6 max aperture.

The 7D can use Live View Autofocus with this combination, however. You mount the extender to the lens and the lens/extender onto the camera (and hopefully to a tripod!). Then turn on Live View with the button on the rear near the viewfinder. You will see the scene with a white box. Put the white box on what you want to focus on, and then engage the AF, and the lens will focus, though very slowly.

You can "zoom in" on the image to assist in the AF process.

I use the 1.4x III Extender with my 100-400 f/4.5-5.6L IS USM, on my gripped 7D, and it works ok. That combination requires a very steady platform (cheap department-store tripods need not apply) to work from.

+1

[degies]

I have a 2xiii tc and the 1.4 on a 7D and 5Diii with no hassle. I only have the 70-200 but I am saving up for a 500. Never had issues with a TC, but you have to learn how your gear works. Well worth the investment.

If you have any doubt of the sharpness you can get with a TC watch what this guy does. http://youtu.be/pas-GiB9jzo
Yes he uses bigger bodies, but I think once you know your gear that you can make many things work

[Mt Spokane Photography]

You will be able to use AF on your 400mm f/5.6L as long as you use a Kenko 1.4X DGX TC. 
 
They are a reporting TC, so you get the full lens information reported, which means correct exposures and focal length in the EXIF, plus they focus faster than tapeing the pins to turn your TC into a non reporting one.
 
The TC Has some issues with certain lenses on the 5D MK III, (100mmL), but on a 7D they all work fine.

[RiceCanon]

Thanks Mt Spokane.  I'll look into the Kenko TC you mentioned.

degies...I watched that Art Morris video a few weeks ago.  His work is amazing.  All of us mere mortals can only dream about the access to equipment that Canon's Masters of Light get!