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08-18-2009, 04:29 PM   #1
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HELP with Tamron 70-200 DI plus APK 2x tele

Hi,
I have a Tamron 70-200mm DI lens and have just got a used Tele Plus APK 2x teleconverter. It fits perfectly but the only way i can get any image is to use very long exposures.
What am i doing wrong? Camera is a K20d.
Also, I have no idea what apeture it uses...help

08-18-2009, 05:35 PM   #2
Ash
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Do you mean the Kenko MF variety with no electrical contacts?
Normally shouldn't have any problems (other than the camera needing to be in M mode and the lens set manually), but I'm wondering if you've got the lens in A mode on the aperture ring (and you have a non-A TC), causing the lens to stay completely stopped down (ie f/22) and leading to images needing long exposures.

If that's the case, get the lens out of A mode and manually set the aperture you want.
08-18-2009, 06:52 PM   #3
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Umm... If using a TC had no consequences everyone would be using one!

A 200mm f/2.8 with a 2X TC becomes a 400mm f/5.6. 1.4X TC makes aperture move one stop less and 2X TC makes it two stops.
08-18-2009, 06:56 PM   #4
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QuoteOriginally posted by GLXLR Quote
Umm... If using a TC had no consequences everyone would be using one!

A 200mm f/2.8 with a 2X TC becomes a 400mm f/5.6. 1.4X TC makes aperture move one stop less and 2X TC makes it two stops.
I am aware of losing one stop but i think ash is right...i am stuck in f22 or similar....i am talking looong exposures.

08-18-2009, 06:56 PM   #5
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QuoteOriginally posted by Ash Quote
Do you mean the Kenko MF variety with no electrical contacts?
Normally shouldn't have any problems (other than the camera needing to be in M mode and the lens set manually), but I'm wondering if you've got the lens in A mode on the aperture ring (and you have a non-A TC), causing the lens to stay completely stopped down (ie f/22) and leading to images needing long exposures.

If that's the case, get the lens out of A mode and manually set the aperture you want.
ash even in mmanual mode it doesnt let me set aperture
08-20-2009, 12:55 AM   #6
Ash
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I've heard others' reports stating that the aperture lever (or whatever it's called on the inside of the mount, not the aperture ring) gets stuck once in a while, leading to inaccurate exposures, though all those I heard got stuck wide open rather than completely stopped down.

Check it out for yourself, have a *very* gentle play (if you know what you're doing) with the lever that controls the aperture to see if it's free and not caught anywhere. Sad to hear this thing happening more than occasionally on such a great lens.
08-20-2009, 02:44 AM   #7
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QuoteOriginally posted by jackbullet Quote
I am aware of losing one stop but i think ash is right...i am stuck in f22 or similar....i am talking looong exposures.
If you are stuck with a closed-down aperture you should see that clearly by looking into the lens! Otherwise you don't have "one stop" loss, but two stops with your tc, which is very noticeable.

Ben
08-20-2009, 04:03 AM   #8
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QuoteOriginally posted by Ash Quote
I've heard others' reports stating that the aperture lever (or whatever it's called on the inside of the mount, not the aperture ring) gets stuck once in a while, leading to inaccurate exposures, though all those I heard got stuck wide open rather than completely stopped down.

Check it out for yourself, have a *very* gentle play (if you know what you're doing) with the lever that controls the aperture to see if it's free and not caught anywhere. Sad to hear this thing happening more than occasionally on such a great lens.
most of the people are reporting aperture stuck at wide open (that was my case too).
In any case lookingthrough the lens at f22 even without TC would be veeeeeeeeeeeeeeeeeeeeery dark and very noticable. With 2xTC we'd be talking what, f45 as result? You really wouldn't see much through.
Try the lens without the TC, if it works OK on it'sown, then there's problem in lens-TC-body comunication. Checke the levers on the lens and the TC.

BR
Peter

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