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09-15-2010, 12:44 PM   #1
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sigma teleconvertor advice.

Thinking of buying a sigma ex dg apo 1.4x or 2x teleconvertor. will this fit my Kx body and my DA L 55-300mm lense. Any help would be grateful

09-15-2010, 01:42 PM   #2
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You will generally get better results w/o a TC on that lens and just cropping the pic the size you want. Of course, I had to try it myself rather than just take the word of a couple dozen posts in the forum. Its true.
09-15-2010, 01:52 PM   #3
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Thanks, will maybe try it or might buy the sigma 150-500mm lense i have been looking at
09-15-2010, 01:55 PM   #4
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I doubt it will actually fit - only some Sigma lenses will accept these TCs. Yes, they will fit your camera, but they may not fit the lens. If you really want to use a TC (noting Lee's comment above) try one of the Kenko ones that are for sale in the Marketplace. I use the Kenko TCs with both Sigma and Pentax lenses. Also, I found the Sigma TCs a little weak structurally and electrically - case breaks and pins drop out. So I don't use them any more.

09-15-2010, 03:00 PM   #5
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Sigma is not fully compatible with anything. Especially the TC's. Pentax TC won't work correctly with Sigma lens and sigma TC woun't work correctly with Pentax lens. Just avoid Sigma, problem solved.
09-15-2010, 06:44 PM   #6
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First of all the sigma TC won't fit. They require that the rear of the lens you are mounting has a 35mm diameter 12 mm deep opening in the rear of the lens to accept the front element of the TC. Second your lens is too slow at the 300 mm focal length to AF correctly with the added stop of the TC. The total maximum aperture needs to be F6.7 or faster and even with a 1.4x you are at F8
09-16-2010, 12:48 AM   #7
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Thanks all for advice. will defo stay away from the sigma TC.
09-16-2010, 06:59 AM   #8
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QuoteOriginally posted by chopper70 Quote
Thanks all for advice. will defo stay away from the sigma TC.
You still have the issue that the lens is simply too slow for the AF to work regardless of what brand of TC.

You will be left with Manual focus only.

09-16-2010, 07:09 AM   #9
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Here is the chart for the 1.4x. Hope this helps.

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