# Tamron Tele Converter Help



## PMphotography (Jun 2, 2009)

i'm sorry if this is on the wrong part of the forum..

i recently received a Tamron AF Tele-converter 2X C-AF 1 BBAR MC7 

i don't really know what it does, i'm not too familiar with teleconverterd.

so the question is, do i really need this thing? or can i sell it on ebay? if so how much is it worth?

i saw one similar on ebay for 160 dollars. and another for 14 dolalrs. which kind of threw me off..


i already have a 70-300 mm lens, and adding thing thing to it makes it extremely long range.

but i'm not too much into bird photography or stuff like that,

what other advantages does this thing have?

thanks


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## Big Mike (Jun 3, 2009)

A 2x Teleconverter doubles the magnification of the lens.  So in a way, it turns your 70-300mm lens into a 140-600mm lens.  This is great if you need the reach of a 600mm lens but don't have (can't afford) one.  

On the other hand, a 2x teleconverter will rob you of two stops of light.  Essentially making your max aperture at '600mm' -- F11.  So unless you are shooting in very bright light, it will be hard to get fast shutter speeds.  Essentially, this isn't a set up you would use hand held.
Also, most cameras need about F5.6 for the AF to work.  So with a TC stealing two stops of light, it's unlikely that your AF would work with this combination.  
Typically, teleconverters are only used with 'fast' lenses.


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## TamiyaGuy (Jun 3, 2009)

Also, to add to what Mike said, generally speaking a 2X teleconverter is fairly harmful to image quality, and as such it is generally booed by the critiques (1.4X converters are normally better in that regard). However, for those situations when you absolutely MUST have that extra reach whatever the cost, they're ideal.

Also, you can attach a teleconverter to a standard lens to make it into a makeshift macro lens (as you are doubling the focal length, but keeping the minimum focus distance the same). So if you're into really close-up still life macro photography, it may be useful.


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## PMphotography (Jun 4, 2009)

Thanks for the great info, 

Im struggling to myself wondering if i really need it. I dont do too much animal photography or macro shots although it might be interesting to try..

How much is this thing worth?

Thanks


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## Big Mike (Jun 4, 2009)

I have one, and I really don't use it all that much.  Because of the loss of image quality, it may be just as good to take the shot without it and crop later.

As for how much it's worth...probably not a whole lot but someone would probably pay you something for it.


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