AF with Sigma 500mm f/4.5 and tele-converter?

[Lthlwpn1979]

I am looking at picking up a Sigma 500mm f/4.5 lens next year. I would be using it mostly to film (yes, FILM) bears in woodland/mountain settings using only natural light. My question is would the lens have auto-focus available while using a 1.4x teleconverter on a Canon Elan 7E? The material on Sigma's website reads that AF is possible only when certain cameras are used (EOS 3 and one other) because they switch to the center focus point when a converter is attached. Would it be possible to switch to the center AF point on the Elan and have it work? This is a serious investment and I wish to get as much info as possible before unloading $3300.

[mjs1973]

I have a Sigma 170-500mm and I use it with a 2x TC. Granted it's not the same lens that you are looking at, but it does work, sort of... When I use my Sigma with a TC, I switch to manual focus. The auto focus does work, but it's very very slow, and has to hunt a lot, and if I'm lucky, it will focus in on the right spot. More times then not tho, it doesn't so manual focus is the way to go. The TC I'm using is a cheap Quantary, so that could have something to do with it too... It looks like the lens you are talking about has the Hyper Sonic Motor for focusing, so you might be alright.

If I were about to drop that much cash on a lens, I would make a trip to a dealer with my camera and TC, and give that lens a test driver before I made the purchase. Also, did you check the reviews on this site? Someone else with that lens may mention using it with a TC in their review.

Good luck.

[Lthlwpn1979]

MJS, I have that lens. It works well and has produced good results. I have had no luck getting autofocus with a converter, mostly because I am shooting into a shaded woodland areas. My main point of asking that Q was because I already have a good doubler, but if AF won't work with a 1.4x converter I will not purchase one and save a tiny bit of money (compared to cost of lens). I film wildlife on the move and if I can get extra range on the lens and still have AF I'll make the investment.

I have checked the 7 reviews for the lens and none mention using it with an Elan.

I appreciate your input and welcome any answers.

[mjs1973]

I just took a peak at the reviews too, and I see someone mentioned using it with the EOS 3, but also said that it doesn't work with the EOS 10. I'm thinking that it's not going to work for you, but if you have dealer close by, it wouldn't hurt to try it out.

[Lthlwpn1979]

Yes, that would be a good idea. However, there are only a few good camera stores in the Des Moines (central Iowa) area and I don't imagine any would order one just so I could try it. I'll call around and see.