Check my Maths

troutfisher

troutfisher

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Name
Chris
Edit My Images
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Hi
Can someone please confirm or otherwise if I am correct in my thinking that a canon 40D with a Canon 100/400 puts more pixels on target than a Canon 5Dc with a 100/400+1.4 TC

Cheers

Chris
 
The 40D is 10.1, the 5d is 12.8 that doesn't change because you're using a TC?

The 40d will have a slightly smaller FOV as it's a 1.6 crop vs 1.4 magnification.
 
troutfisher said:
It does on my 5Dc with the pins taped,hence the question
Click to expand...

As Chris said, using a TC wont affect the resolution of the sensor. But using the 1.4TC you will get a focal length of 560mm, the 40D will give you a FOV equivalent to 640mm on the 5D.

To crop to the same FOV will mean cropping the 5D image by 12.5% so 12.8*0.875=11.2Mp - the 5D wins. But this wont take into account the loss of IQ from using the TC - I suppose you'll either need to find some test shots or do some yourself to work out which combination will give the better IQ. I suspect the full frame sensor might not make up for the loss of IQ, and thats not considering the loss of AF
 
J.D. said:
As Chris said, using a TC wont affect the resolution of the sensor. But using the 1.4TC you will get a focal length of 560mm, the 40D will give you a FOV equivalent to 640mm on the 5D.

To crop to the same FOV will mean cropping the 5D image by 12.5% so 12.8*0.875=11.2Mp - the 5D wins. But this wont take into account the loss of IQ from using the TC - I suppose you'll either need to find some test shots or do some yourself to work out which combination will give the better IQ. I suspect the full frame sensor might not make up for the loss of IQ, and thats not considering the loss of AF
Click to expand...

Thanks thats what I wanted to confirm,using the TC costs me a stop f5.6-f8 so on balance I am better off with the 40D as any small gain in mp on the 5D is offset by the loss of light and associated AF speed.
 
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