AF possible with TCX2?


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IvT

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May 9, 2005
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#1
Hi, anyone manage to still do AF using TC with 2X multiplication? I'm using Sigma 70-200 f2.8 with Kenko 2X MC7 DG Teleplus Autofocus Teleconverter for Nikon AF, but it doesn't seem to be able to AF even in good lighting condition.

Pls enlighten me. Thanks a lot!
 

Aug 16, 2005
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#6
IvT said:
Hi, anyone manage to still do AF using TC with 2X multiplication? I'm using Sigma 70-200 f2.8 with Kenko 2X MC7 DG Teleplus Autofocus Teleconverter for Nikon AF, but it doesn't seem to be able to AF even in good lighting condition.

Pls enlighten me. Thanks a lot!
use a Sigma 2xTC lor...
 

DeSwitch

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Oct 28, 2005
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#7
I tried using Kenko pro 1.4x with my lousy 75-300 sigma. cannot focus lock, keep hunting. buy if focusing on bright subject, it works.

1.4x losses 1 stop of light while 2x losses 2 stops. Minimun for AF to work is f4 according to the TC manual.
 

Aug 16, 2005
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#8
DeSwitch said:
I tried using Kenko pro 1.4x with my lousy 75-300 sigma. cannot focus lock, keep hunting. buy if focusing on bright subject, it works.

1.4x losses 1 stop of light while 2x losses 2 stops. Minimun for AF to work is f4 according to the TC manual.
Can cheat by taping the pins....
But ppl normally use TC with big apperture lenses...
 

Horsba85

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Nov 10, 2005
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#9
what happens when you tape the pins?

for 2x tc, isnt it probable that it'll only be for MF?
 

IvT

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May 9, 2005
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#10
Del_CtrlnoAlt said:
u mean it doesn't AF, or the AF cannot lock on the subject?
Ya the AF cannot lock on the subject even at f/2.8. Keeps hunting. Was wondering is it a problem with the TC or is it normally the case.

DeSwitch: Ya i know but it doesn't seem to work even at the widest aperture (i.e 2.8) was wondering maybe other brands of TC can work. I don't mind using MF when using TC but if its able to lock during AF it helps in taking for example bird in flight...no?
 

IvT

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May 9, 2005
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#11
roti_prata said:
good point, but either way theres nth he can do abt it.
actually I just want to find out whether Autofocus function is disabled once you coupled a TC or that if you use an expensive one like Nikon Teleconverter TC-20E II/20E autofocus is still possible.

Thanks for dropping by in this thread anywayz.
 

Del_CtrlnoAlt

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#12
IvT said:
Ya the AF cannot lock on the subject even at f/2.8. Keeps hunting. Was wondering is it a problem with the TC or is it normally the case.

DeSwitch: Ya i know but it doesn't seem to work even at the widest aperture (i.e 2.8) was wondering maybe other brands of TC can work. I don't mind using MF when using TC but if its able to lock during AF it helps in taking for example bird in flight...no?
technically a 2x converter makes the f2.8 lens become a 5.6 lens...

so if your camera cannot focus with a f5.6, den its the body, not the lens... your focusing system lousy... :bsmilie:
 

IvT

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May 9, 2005
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#13
Del_CtrlnoAlt said:
technically a 2x converter makes the f2.8 lens become a 5.6 lens...

so if your camera cannot focus with a f5.6, den its the body, not the lens... your focusing system lousy... :bsmilie:
Oh i see...i'm using D70s currently. Thanks man!!! ;)
 

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