Canon Teleconverters
Oct 14, 2017 17:27:28 #
chikid68 wrote:
I shoot my rebel xt1 at f8 and beyond frequently and have no problem with autofocus
You are not AFing at f/8, the camera focuses with the lens wide open and then closes down to take the picture at your set f-stop.
We are talking about using lens combos where the fastest f-stop is f/8. Most bodies will only AF a lens with f/5.6 or faster. Some of the higher end ones will AF with lenses that have a max speed of f/8. - 1D series, 5DIII & IV, 6DII, 7DII, 77D, 80D in the Canon brand.
Oct 14, 2017 20:40:04 #
Retired fat guy with a camera
Loc: Colorado
Imagemaster. No, I did not do anything wrong. Set up on a tripod, gimbal head. Wireless shutter control. Ids mark lll and a 300mm L. In focus. More than one shot. The same subject with and without the 1.4, the ones taken without were sharper. So what pray tell did I do wrong. As a master, you must have more knowledge than a lesser photographers like me.
Oct 17, 2017 02:27:35 #
Architect1776 wrote:
The 100-400 is only an L lens and always has been. The 2x will not af with any body on that lens. f8 is the smallest and this becomes f11 with a 2x
I did say " if af was not an issue". I have a medium format system where none of the tc's af, I do ok with it. another point, with an L lens there's defects to magnify at 2x.
Oct 17, 2017 12:41:45 #
imagemeister wrote:
Mainly because there will be no AF with the 2X - because of the 2 f-stop loss of light ......and the image quality will suffer MORE than the 1.4X.
Cropping is your friend - done properly .....
Cropping is your friend - done properly .....
Depending on the lens and body you are using. Some bodies will handle up to effective f8 and maintain AF, some won't.
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