Question on Canon Teleconveters

[PhotoGimp]

I shoot with a Canon 10D and 100-400 and have been contemplating getting a ef1.4X extender, and am wondering about quality. I know I will loose some, but here is my senario. 2 setups, exactly the same, tripod mount, pointed at an object(say a flower), I take a picture, with aperature of f8-1/500, without the tele, and the same with the extender f8-1/500 . Now I download into adobe, and crop the pic without the extender to the frame size as the one with the extender, and place them side by side. Which one has got better quality, and would you be a ble to tell the difference(without a loupe). I usually only print to 8x10.

[Lionheart]

I shoot with a Canon 10D and 100-400 and have been contemplating getting a ef1.4X extender, and am wondering about quality. I know I will loose some, but here is my senario. 2 setups, exactly the same, tripod mount, pointed at an object(say a flower), I take a picture, with aperature of f8-1/500, without the tele, and the same with the extender f8-1/500 . Now I download into adobe, and crop the pic without the extender to the frame size as the one with the extender, and place them side by side. Which one has got better quality, and would you be a ble to tell the difference(without a loupe). I usually only print to 8x10.

I don't know that works well for comparison. A better comparison would be to shoot at 400 without the 1.4, and shoot at 285mm or so with the 1.4 to get the 400 equivalent framing, that way cropping doesn't skew the actual pixel resolution for accurate comparisons. I've had this lens and have used it with both the 1.4 and 2x TC's. It works, but you're pretty much focusing manually, as the AF struggles with the loss of light from the TC.

[Michael Fanelli]

I shoot with a Canon 10D and 100-400 and have been contemplating getting a ef1.4X extender, and am wondering about quality. I know I will loose some, but here is my senario. 2 setups, exactly the same, tripod mount, pointed at an object(say a flower), I take a picture, with aperature of f8-1/500, without the tele, and the same with the extender f8-1/500 . Now I download into adobe, and crop the pic without the extender to the frame size as the one with the extender, and place them side by side. Which one has got better quality, and would you be a ble to tell the difference(without a loupe). I usually only print to 8x10.

FWIW, George Lepp has shot lots of photos using the 100-400 L and two, count them, two, Canon teleconverters at the same time! The results were excellent. One teleconverter should be better than fine.