Topic Author
Posts: 223
Joined: Wed Sep 26, 2001 10:13 pm

Teleconverter Question

Sun Jun 23, 2002 6:22 am


I just have a quick question about teleconverters.

I have thought about buying a Sigma 2x APO teleconverter to use mainly with my Sigma 170-500mm APO lens.

I also have a 75-300mm Canon lens, and I was wondering if a Sigma 2x APO converter can be used with this Canon lens?? I ask in my local photoshop and he told me that he was not sure, so does anyone here know??

Thanks in advance

Søren Augustesen
Posts: 1076
Joined: Sun Jun 03, 2001 6:24 am

RE: Teleconverter Question

Sun Jun 23, 2002 8:53 am

The first thing to consider is can you afford to lose 2 stops with the 170-500?
I assume that you want to use it in the 500-1000mm range, which would require extremely fast shutter speed or fast film. I am assuming that you are shooting fast moving aircraft.

I looked up your shots in the database - nice.

Posts: 9973
Joined: Mon Apr 23, 2001 10:12 pm

RE: Teleconverter Question

Sun Jun 23, 2002 4:41 pm

Indeed use at least a monopod and preferably a tripod with that combo!
It's slow, long and heavy which is an open invitation to severely shaken images.

Usually, teleconverters are designed for specific lenses. I believe the Sigma converters are optimised only for certain of their lenses. They may work on other brand lenses, but with less than optimal results.

Teleconverters are also not usually designed for zoomlenses (with exceptions like the Nikon 80-200 f/2.8 AF-S). You'd best check with a reputable dealer about it before making the purchase and ask to try it as the Sigma catalogue and website do NOT list the 170-500 as being compatible with their teleconverters
At best you just loose your autofocus and/or aperture settings, at worst you'll damage one or more of the components of lens, TC or camera when mounting the TC.

You're probably better off getting 2 Canon 2x teleconverters and stacking those (possible, but costs even more light). This would give you a very slow 300-1200mm lens
I wish I were flying

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