2X Tamron Extender | Shutterbug

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Submitted By: smilydyno

Joined: Aug 30 2005

Posts:

2X Tamron Extender

Posted: August 30, 2005 - 4:15pm

I have a TAMRON AF Aspherical XR LD (IF) 28-300mm 1:3.5-6.3 MACRO lens and a
TAMRON SP AF Tele-converter 300F-CA 2X. When I combine the two lenses at any
zoom above 75mm, the zoom lens constantly searches for focus and never fins
it in AF mode. In manual focus mode it will work. Can you tell me why this
happens and maybe give me some suggestions on what to do? Thanks.

Submitted By: Larry Berman

Location: Pittsburgh

Joined: Mar 7 2005

Posts:

Re: 2X Tamron Extender

Posted: August 30, 2005 - 4:25pm

One of two reasons or both. Either there is not enough light because of the variable aperture combined with the exposure compensation of the teleconverter, or the subject isn't contrasty enough for the lens to lock focus.