Canon 400mm f5.6L ?'s

dragon300zx · April 6, 2007

I was just wondering if I were to buy one of these (seeing as I didn't try to do this when I was at MI 4 and could have) can I throw a TC on it and have the autofocus still work?

Andy · April 6, 2007

dragon300zx wrote:

I was just wondering if I were to buy one of these (seeing as I didn't try to do this when I was at MI 4 and could have) can I throw a TC on it and have the autofocus still work?

Yep - use the Tammy 1.4 w/ Tape on the pins IIRC.

Terrence · April 6, 2007

The Canon 1.4 works too. Confirmed on an XT and 30D with a 100-400.

kdog · April 6, 2007

Terrence wrote:

The Canon 1.4 works too. Confirmed on an XT and 30D with a 100-400.

That combo doesn't work with my 20D. I've spent a lot of time researching TCs and have found that not everyone gets the same results, even with the same combination of components.

I have a 20D, 100-400, and 400 F5.6, Kenko Pro DG 1.4x and Canon 1.4x. Both TCs are taped. Here's what works and what doesn't work for me.

100-400 + Canon 1.4x = Hunts
100-400 + Kenko 1.4x = Works
400 F5.6 + Canon 1.4x = Hunts
400 F5.6 + Kenko 1.4x = Hunts

I'm about to buy the cheap Tamron TC and try that as well as I've heard it AF's the most reliably. Note this is the CHEAP Tamon, which goes for between $109 and $124 depending on where you get it. Don't get the PRO version. Note that the cheap Tamron doesn't need taping because it doesn't report itself to the camera anyway. It also has the worst optical performance of any TC, but evidently isn't all that bad.

The bottom line is that AF using either lens with a TC on the non-pro bodies isn't supported by Canon, and for good reason. The AF system is right on the hairy-edge of being able to focus, and it's pretty much a crap shoot which side you'll fall on. Very slight differences in the implementation or the copy of the lens, TC and camera body might make a difference whether it works for you or not. One fellow on another forum claims to have exchanged several lenses and bodies before he got combination of copies that worked. So shop with this in mind.

I also suspect that it may bad for the lens to hunt, as it's kind of beating the snot out of the focus motor and actuators. I'm always careful not to allow the lens to spend a lot of time hunting. It's not unheard of people to blow the AF in their lens.

Regards,
-joel

lowbone · April 7, 2007

The cheap Tamron works best. If you have really good light it will lock focus pretty fast, otherwise it tends to hunt. No matter how good the light this combination will not be fast enough for birds in flight.

Jekyll & Hyde · April 8, 2007

J: Yup, the cheap Tamron will AF pretty well in good light (with adequate contrast). Better than the Canon 1.4x in my testing (hunts).

H: It's certainly slower to focus, but seems to be spot on.

J: IQ is down a bit, though not too terrible (even wide open).

H: I was out at sunset shooting birds (thus the ISO800) when I looked up and spotted the moon.

30D, Handheld, Autofocused, 400/5.6 wide open with the cheapo Tamron...
(Cropped, run through Noise Reduction, processed, sharpened, yada yada)

J: YMMV.

H: I need to get out some time with a tripod to reshoot (with appropriate settings). I haven't put this lens on a tripod yet. Been having a blast.

J&H

pathfinder · April 8, 2007

Nice moon J&H!!

gluwater · April 8, 2007

Gary I use the Non-DG Tamron TC and as other have stated it is hit or miss. I have gotten birds in flight with the 400 f/5.6, tamron TC and 20D but it is not easy and you will have a lot of OOF shots. Or if there are branches between you and your subject that will also make AF almost impossible. But overall I'm happy with the combo. For stationary shots on a tripod sometimes I'll put it in MF just because it can be faster and easier.

J&H - Good to see you posting again, your stuff is always nice to see. Hope you stick around for a while.

Canon 400mm f5.6L ?'s

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