100-400 and tcs

Viking

Viking

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Name
John
Edit My Images
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Hi,

I have been revisiting some of the reviews on the 100-400. SLR gear has the following statement, quote

"The lens is fully compatible with full-frame sensors and film bodies, so there are no issues with vignetting. Canon digital SLR cameras with sub-frame sensors have a ''crop factor'' of 1.6x. Thus, for this particular lens, it will exhibit an effective focal length of 160mm to a whopping 640mm. It can also mount 1.4x and 2x extenders, meaning that you could see a potential of 1,280mm, if you're amenable to a maximum aperture of f/11 at that focal length."

My question is about the second part of the quote that makes statements about tcs.

Any views would be appreciated.

John
 
Hi John

A 2x TC will reduce the amount of light getting to the to the sensor by approximately 2 stops, even although the camera says f5.6, the light hitting the sensor will be equivalent to using an aperture of f11. Only problem is, the auto focus wont work unless its a 1D body
 
Well thats no good then with the x2 , because the 1D will only AF up to f8...

Sticking a 1.4x on it is technical possible on a 1D but...
 
Taping the connections or not using a Canon TC?
 
Not using Canon. Saying that I just tried it to see if it would work at the time I got the new camera its a Kenko Pro 300
 
Thanks for the replies.

I tried a 2x with my 70-300 5.6. Took images of the moon. The IQ using the tc was significantly reduced when compared with no tc.

John
 
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