[stevo]

I am thinking about buying a 1.4x teleconverter for my Sigma 135-400mm lens,my question is as the aperture is f5.6 I will lose autofocus so therefore I was considering using the method of taping the contacts on the converter to provide autofocus,how easy is this method? plus should I use any particular type of tape,finally how well does it work?

Regards Steve

[digi-birder]

I haven't tried this with my Sigma 1.4x converter yet, but a friend who has the Canon lenses on his 10D has tried it on my recommendation and says it works well.

I looked at my converter and it doesn't appear to have the same contact configuration as the Canon converter, so I'm a little wary.

[Medlock44]

Originally Posted by stevo

I am thinking about buying a 1.4x teleconverter for my Sigma 135-400mm lens,my question is as the aperture is f5.6 I will lose autofocus so therefore I was considering using the method of taping the contacts on the converter to provide autofocus,how easy is this method? plus should I use any particular type of tape,finally how well does it work?

Regards Steve

Hi Steve, I did not find it too successful with the canon 100/400. It did work, but only in strong light and on subjects that had a lot of contrast detail. I found the auto focus hunting a lot. Others do seem to manage, but it was a no go for me. The same Canon 1.4 mkII works very well with the 200mm f2.8 so I no its ok.

[stevo]

Thanks for your replies.

Regards Steve

[digi-birder]

I should have said above that my friend is using this technique with the Canon 100-400 lens.

[ZeeWire]

I just bought a Sigma 1.4x TC to use with my 50-500, it works great! the only thing is that this Teleconverter has a protuding Lens element and I have to lock the zoom at 100mm. On the other hand this device is supposed to be used with manual focus. But there's a way to easily fool it and make the AF work, just use tape to cover the two left contact pins! It works great, and the sharpness is amazing. I was recommended the 1.4x since the 2x will give me softer pics.

I hope this helps.

ZeeWire

[stevo]

Thanks Zeewire

I thought it was the 3 contact pins though that had to be taped to make the autofocus work.

Regards Steve.

[Doug Greenberg]

Originally Posted by stevo

I am thinking about buying a 1.4x teleconverter for my Sigma 135-400mm lens,my question is as the aperture is f5.6 I will lose autofocus so therefore I was considering using the method of taping the contacts on the converter to provide autofocus,how easy is this method? plus should I use any particular type of tape,finally how well does it work?

Regards Steve

I think you should be SURE that the Sigma 1.4x is fully compatible with your lens before you buy one. The Sigma APO teleconverters are geared for the HSM lenses and may not autofocus with the 135-400mm. model.

I recommend that Kenko Teleplus Pro teleconverters. They are fully compatible with just about all lenses and optically they are terrific. With my Nikon 80-400mm. VR lens the Kenko maintains autofocus (albeit slowly) and VR function (albeit reduced a bit). Optically these teleconverters are quite good, as well

[stevo]

Hi Doug

Thanks for the info I had a look on Sigma`s website earlier today & my lens is not compatible with either 1.4x or the 2x.I am now looking at the Kenko teleconverters.

Regards Steve.

[Andy Bright]

Originally Posted by stevo

Hi Doug

Thanks for the info I had a look on Sigma`s website earlier today & my lens is not compatible with either 1.4x or the 2x.I am now looking at the Kenko teleconverters.

Regards Steve.

Sigma only guarantees full compatabilty with a few of their lenses (I really do mean few!), which is pretty bizarre and not too popular with many Sigma users. I took the safe option and purchased the Kenko Pro t.c (like Doug), despite the name (Kenko have an image problem!) it's top notch Hoya glass inside them and they are very sharp. I seem fortunate with my set-up that i get totally reliable AF with an f4.5 lens + an extra stop of the t.c. Given a reasonably contrasty subject I get reliable AF using a 70-300mm f5.6 lens, so that's AF at f8!
Regards,
Andy

[stevo]

Hi Andy

Thanks for that info.

Regards Steve.

[CJW]

I get full compatibility with my Sigma 1.4x and Sigma 135-400 APO on a 300D

[eospete]

globalphotosite.com/Classroompages/convertors.htm

fredmiranda.com/TipsPage/

Take a peek at these links for how to do it. I am not totally satisfied with the 1.4x on the 100-400 with the D60 for critical sharpness if large prints is your output. I reckon it could be my inability to keep it all still though.

P

[digi-birder]

Those links are fine for the Canon converters, Pete, but when I checked my Sigma converter there aren't three pins to cover up - it's more like a bar and then some pins, but not the same number as on the Canon converter.

[pdackerman]

You are looking at the wrong end of the converter. The Sigma etc must be the same as the Canon to be able to work with their camera.

Originally Posted by digi-birder

Those links are fine for the Canon converters, Pete, but when I checked my Sigma converter there aren't three pins to cover up - it's more like a bar and then some pins, but not the same number as on the Canon converter.

[digi-birder]

Originally Posted by pdackerman

You are looking at the wrong end of the converter.

Doh!! Thanks Phil. I've not had the converter attached for a few weeks and wasn't paying attention to which end went to the lens.

There's really no hope for me.