Yes, Josh. Turn the TC so the end the lens mounts on faces you, and pull the cap off. There is a row of male pins. Rotate the TC so the pins are on top. Tape the three on the left. That should do the trick. The lens will hunt for focus a bit more in low-contrast situations than it did without the TC, but it should operate OK. It also will be a little slower, but not tremendously so.
I've seen quite sharp images with the Canon 2X TC on the 300 f2.8, with a bit more image degradation on the 400 f2.8 and 500 and 600 f4 lenses. I haven't shot these lenses with that TC, just recalling examples I've seen of all of the above. The 1.4, as long as it's Canon or the top model from Sigma, Tamron or Kenko, seems to harm none of image quality of the primes, I've found, unless a person is a true sharpness fanatic. Others may have different experiences.
It'll be interesting to see whether the 300 f4 is as sharp as the 300 f2.8.
Good luck, and have a lot of fun.
Posted by Josh Gahagan on April 24, 2007 at 7:55 PM
Steve, if you saw Jude Hase's last shot of a Tri-colored Heron portriat, it was shot with the 300 f/4 with 2x TC II. It was incredibly sharp and that is what told myself that I need to purchase this accessory once I buy the lens.
Posted by Tom Webster on April 25, 2007 at 12:49 AM
There are some references on the Internet that taping pins can cause AF motors to burn out quicker. Something else you can do, instead, is stack a Canon 1.4x tc and a Kenko 1.4x Teleplus Pro 300 DG teleconverter. You will get nearly the same image mag as a 2x tc and the 20D will still autofocus. Canon cameras only "see" the first teleconverter attached to the lens. This actually yields excellent image quality with my 500mm lens. Check the Avian Gallery for my latest post using stacked 1.4x tc's.
Hi Josh,
the trick does not work with the Canon 2x TC on f4 lenses...I've tried it both with the 300 f4 and with my 600 f4 and it does not work, the AF continues to hunt and it never finds the subject :-/
Juza, it sounds like the 'AF trick' actually did work since autofocus was still enabled even though the true lens aperture (f/8) was outside the acceptable range for your camera. The camera was tricked into thinking that an f/4 lens was attached. I can certainly agree that it led to an undesirable result though.
Josh (and others), I often see people here attempting to make decisions about future equipment purchases (especially lens systems) based on results presented in the galleries. IMO this is a Very Bad Idea unless your only goal is to have images that may only look good on a computer screen after a 5:1 size reduction. I'm not saying the full-size original images are garbage, only that they could be, and the observer is dealing with less than all the facts.
I have only one good example I can give at the moment, though the subject matter might be slightly offensive to a handful of people here. (dead bug body-part) Even after close examination, you would have a difficult time arguing that this photo isn't 100% tack sharp. The original must look perfect too, right? Nope, it's garbage. The original is posted here.
Discussion
6 repliesI've seen quite sharp images with the Canon 2X TC on the 300 f2.8, with a bit more image degradation on the 400 f2.8 and 500 and 600 f4 lenses. I haven't shot these lenses with that TC, just recalling examples I've seen of all of the above. The 1.4, as long as it's Canon or the top model from Sigma, Tamron or Kenko, seems to harm none of image quality of the primes, I've found, unless a person is a true sharpness fanatic. Others may have different experiences.
It'll be interesting to see whether the 300 f4 is as sharp as the 300 f2.8.
Good luck, and have a lot of fun.
the trick does not work with the Canon 2x TC on f4 lenses...I've tried it both with the 300 f4 and with my 600 f4 and it does not work, the AF continues to hunt and it never finds the subject :-/
Josh (and others), I often see people here attempting to make decisions about future equipment purchases (especially lens systems) based on results presented in the galleries. IMO this is a Very Bad Idea unless your only goal is to have images that may only look good on a computer screen after a 5:1 size reduction. I'm not saying the full-size original images are garbage, only that they could be, and the observer is dealing with less than all the facts.
I have only one good example I can give at the moment, though the subject matter might be slightly offensive to a handful of people here. (dead bug body-part) Even after close examination, you would have a difficult time arguing that this photo isn't 100% tack sharp. The original must look perfect too, right? Nope, it's garbage. The original is posted here.