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I have a 50 - 500 Sigma and have heard that the cheaper 1.4 and 2x Tamron telecoverters work with this lens and still permit AF because they are what is known as dumb converters.

Does anyone know the truth of this?

Oneputt - pinched from a website:

Tamron Teleconverters: Standard vs. SP-Which do I need?


Teleconverters, either 1.4X or 2X, are efficient tools to add focal length to the photographer's arsenal.
However, universal-type teleconverters have certain limitations in performance when used with ultra-telephoto lenses of 200mm or longer as compensation of chromatic aberration alone becomes highly critical in this focal length range. The new PRO-series teleconverters are specifically designed and optimized for use with such ultra-telephoto lenses to deliver maximum resolution, contrast and color rendition without degrading any aspect of the master lens performance.

The 1.4X teleconverter will increase the focal length of the master lens by 1.4X and make the lens one f-stop slower. The 2X doubles the focal length of the master lens and makes the lens two f-stops slower. In addition to increasing focal length, both teleconverters allow greater magnification in macro since the Minimum Object
Distance (MOD) of the master lens does not change when used with the teleconverters.

The 1.4X teleconverter can be used with both AF and MF lenses. AF will be retained if the master lens is F/4.5 or faster. AF will be retained with the 2X teleconverter if the master lens is F/4.0 or faster.

Hope this helps

Chris

Well done and thanks Chris, that answers every thing. Much obliged, looks like I'm off shopping again

so according to the post, the 2x will work with the 70-200 vr with the only detraction being loss of 2 f-stops? Do I read that right?

Andy

atencati wrote:so according to the post, the 2x will work with the 70-200 vr with the only detraction being loss of 2 f-stops? Do I read that right?

And with the 2x some level of sharpness is also lost.

Michael.

sirhc55 wrote:The new PRO-series teleconverters are specifically designed and optimized for use with such ultra-telephoto lenses to deliver maximum resolution, contrast and color rendition without degrading any aspect of the master lens performance.

Chris

I assumed loss of sharpness until I read this line. Where did this review come from or is this tamron speak

Andy

Sounda a whole lot like salesspeak to me, Andy.

Here's a grain of salt to take it with.

I can't imagine a tc that will retain all of the characerisitics of a lens and olny lose 2 f stops. heck, you could buy a 50 1.4 and put a 4x and it would still only be a 5.6 by those standards. not sure where I am going with this, but for < US$200 it might be worth a shot.....

must.......find......test......shots...............<search>

Andy

atencati wrote:I can't imagine a tc that will retain all of the characerisitics of a lens and olny lose 2 f stops. heck, you could buy a 50 1.4 and put a 4x and it would still only be a 5.6 by those standards. not sure where I am going with this, but for < US$200 it might be worth a shot.....

must.......find......test......shots...............<search>

Andy

Hi Andy

Not Nikon but an interesting read

http://www.naturbilder.de/NBenglisch/html/wonders.html

Chris

just found a review stating the Tamron SP 2x and Tokina Pro 2x are one in the same. I can'tseem to confirm nor deny, anyone have an idea???

AHA!!!!! just found this, very useful but must read to understand images! Fairly well done, but shot on FILM (blech) and scanned......PITA!!!!!! I remember those days...

Quick Poll: Raise your hand if you've ever thrown a scanner accross the room.

http://homepages.ihug.com.au/~parsog/Gu ... erter.html

-> hand raised <-


ANdy