Teleconverter for 100-400L.

Joemess

Hey folks, does anyone have any examples handy of a teleconverter on a 100-400L? I will be using it on a 7D if that makes any difference.

Opinions or better solutions are welcome

Joemess

Joemess wrote: »

Hey folks, does anyone have any examples handy of a teleconverter on a 100-400L? I will be using it on a 7D if that makes any difference.

Opinions or better solutions are welcome

Mods, if this is better placed in assesories feel free to move it for me.

[Deleted User]

No examples. But you do know it won't autofocus normally don't you.

Joemess

Jim K wrote: »

No examples. But you do know it won't autofocus normally don't you.

Yeah, but that was not the biggest concern that I had. I am just curious as to how much image degradation i will experience.

kdog

What kind of teleconverter? Manual or auto focus? Taped pins, or no? You probably already know that a "reporting" TC like the Canon ones on the 100-400 will not autofocus on Canon bodies with the exception of the pro 1D line. That's because the camera needs a lens of F5.6 or faster to auto focus, and the 100-400 at 400mm with a TC1.4 has an effective max aperture of F8. You can tape up some of the contact pins, or use a non-reporting TC to fool the body into thinking that the combination is F5.6 That has traditionally worked poorly on previous bodies. However, your post got me curious, and I did just get a 7D, and so I tried it. With the reporting TC, the camera won't even try to AF. I didn't tape pins, but I do have a non-reporting Tamron TC1.4 which I tried, and the results were pretty interesting. Between 100 and 300 zoom range, the camera AF'd almost perfectly. However at 400mm, it hunted horribly but did on occasion lock focus. (This makes sense because being variable aperture, the lens is actually faster at the shorter focal lengths.)

You asked for samples, so here you go. Both of these are 100% crops. They've had levels, and some sharpening, as a quick approximation of how I normally process photos. If these were keeper shots, I would have done a better job obviously.

100-400 @ 100mm, + Tamron TC1.4, ISO800, 1/200s, F6.3 (doesn't factor in the 1 stop loss from the TC)

To my eye, this looks really good. It needed almost no sharpening, above and beyond the minimal input sharpening from the raw converter. Although, I did a pinch of output sharpening, just because I always do.

100-400 @ 400mm, + Tamron TC1.4, ISO 800, 1/250, F4.5 (doesn't factor in the 1 stop loss from the TC)

Meh. Exposure is bad (my fault), slow shutter at that focal length probably introduced some motion blur, but there is significant chromatic aberration. The Canon TC would probably do better, but I didn't feel like taping the pins for this experiment. Maybe at some point in the future when I have more time. In general however, you aren't going to get your best optical performance in using zoom lenses with TCs.

Regards,
-joel