[jmbradd]

Hey all, are there any teleconverters that would maintain AF and AE @ 300mm on this lens?

Thanks in advance! Its looking like the answer will be no

[Shashinki]

AF on f/5.6 with a TC is pretty doubtful. With a 1.4X it would be f/8 and manual focus seems to be the only option as far as I know.
(edit: If you had a Canon 1D series camera or a camera with a very sensitive AF-sensor, autofocus at f/8 might be possible, but FA lenses do not work well on Canon 1D bodies anyways... )

[clawhammer]

I've thrown a cheap 2.0x on my 100-300 4.5-6.3 (so half a stop slower than your 5.6), and AF was iffy. If the subject contrast was good it found focus, but most of the time it just hunted really, really slow. I wouldn't recommend it, and the quality hit on a consumer-level lens probably wouldn't be worth it.

[jmbradd]

yeah you guys are hitting on what I was thinking...dang, looks like i've got to improve my tactics instead of just getting more length!

[Shashinki]

http://hairyfarmerfamily.files.wordpress.com/2009/12/camouflage.jpg

[jmbradd]

http://hairyfarmerfamily.files.wordpress.com/2009/12/camouflage.jpg

lol!

I'm going to get myself a blind...I'm too fidgety to just sit out in the open. Either a chair blind I can barricade myself in or one that'll hold a friend and I.

thinking about it, when I rented the bigma, the difference between 300 and 500 wasn't all that much, considering the costs of getting to 500.

[SOldBear]

Hey all, are there any teleconverters that would maintain AF and AE @ 300mm on this lens?

Thanks in advance! Its looking like the answer will be no

I bet you a good 1.4X TC (e.g. Tamron) will work. At the long end, you may need to find something contrasty for the focusing sensors to lock on, but it will work.

I tried my Tamron 1.4X TC with the Tamron 18-250 F/3.5-6.3. At 250mm, auto focus indoor is slow and hunting quite a bit. But with sufficient light outdoor, auto focus at 250mm is slow, but bearable.

F/5.6 is almost half a stop faster than F/6.3. So I think auto focus is OK.

[dgaies]

I bet you a good 1.4X TC (e.g. Tamron) will work. At the long end, you may need to find something contrasty for the focusing sensors to lock on, but it will work.

I tried my Tamron 1.4X TC with the Tamron 18-250 F/3.5-6.3. At 250mm, auto focus indoor is slow and hunting quite a bit. But with sufficient light outdoor, auto focus at 250mm is slow, but bearable.

F/5.6 is almost half a stop faster than F/6.3. So I think auto focus is OK.

I can confirm that the Tamron 1.4x with the DA55-300/4.0-5.8 (on a Kx body) works fairly well. Again, indoors at 300mm the AF is a little slow and you need a target with some decent contrast. It's also nice to have the quick-shift of the DA55-300 to get the focus close before using the AF. Outdoors, the AF with the 1.4x is typically much better.