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oldtimer56's picture
Submitted By: oldtimer56
Location: Germany
Joined: May 15 2007
Posts:
Teleconverter
Posted: June 5, 2007 - 2:45am

I am finding it hard to get an answer to this question.
I have a Sony Alpha 100 camera, using a tamron AF 28-300mm F/3.5-6.3 XR DI LD aspherical lens. and want to buy the Kenko PRO 300 DG AF 3x Teleconverter. I would like to know if I will still have Auto focus?

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DaveBelew's picture
Submitted By: DaveBelew
Joined: Mar 16 2005
Posts:
#1
Re: Teleconverter
Posted: June 5, 2007 - 8:34am

Hi,
Your 3 X teleconverter will not allow auto focus with the lens you are using since the effective maximum apertures will range from about F 14 on upwards. (F3.5 X 3 stops)

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Larry Berman's picture
Submitted By: Larry Berman
Location: Pittsburgh
Joined: Mar 7 2005
Posts:
#2
Re: Teleconverter
Posted: June 5, 2007 - 6:45pm

Hi Dave, Actually three stops from f3.5 would be between f8 and f11. And if the camera was actually able to auto focus, it would be so slow that it would be worthless.

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