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Old Jun 11, 2007, 9:24 AM   #1
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Can anyone list the brands of K- mount extension tubes that will transmit data between the lens & the camera??

Are there any that allow full auto capibility with modern Pentax lenses??

Thanks---Bruce
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Old Jun 11, 2007, 10:04 AM   #2
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bruce,
i know kenko makes a set for about $150 but nothing will work in AF..
my set is manual with the aperture lever. it's all i need. doing macros with a manual lens once you take an Ev it's pretty much shoot from there on out. the light just doesn't change that much. until you switch to another shot.
i haven't used mine much for awhile. think i will.

roy
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Old Jun 11, 2007, 10:43 AM   #3
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and if you shoot with flash it's a lot easier. here's my on-camera rig. you can just barely see the difusser. this is 63mm ETs, a M50 @ f11 and the flash. working distance from front of lens to subject is about 1'', 25mm. the hood was almost too long.. that's why i like the distance using a 105mm. i do however really like these on a 200mm.
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Old Jun 11, 2007, 10:43 AM   #4
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and a quickie from the yard.
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Old Jun 11, 2007, 1:03 PM   #5
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I've got Panagor tubes with the lever. They're called auto tubes but I think that name was from a long time ago pre auto focus.
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Old Jun 11, 2007, 1:16 PM   #6
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Hey Roy

Do all those tubes give the approx focal length of a 100mm lens when mounted on the 50mm??

What exactly did you mean about using the tubes on your 200mm lens??



Thanks, Bruce
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Old Jun 11, 2007, 2:37 PM   #7
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extension tubes dont alter focal length, they effectivly reduce the focusing distance of the lens hence increasing magnification.

Total extension used / Focal length used = Magnification
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Old Jun 11, 2007, 3:02 PM   #8
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baltochef920 wrote:
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Hey Roy

Do all those tubes give the approx focal length of a 100mm lens when mounted on the 50mm??

What exactly did you mean about using the tubes on your 200mm lens??



Thanks, Bruce
no, what it does is give you a shot at 1.26:1 magnification.
i like to use them on a 200mm lens because it effectively gives you a 1:3 magnification which is just about right for dragonflies, etc. you also get 30-36'' of working space between the lens and the subject.

roy
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Old Jun 11, 2007, 3:04 PM   #9
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SteveB wrote:
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I've got Panagor tubes with the lever. They're called auto tubes but I think that name was from a long time ago pre auto focus.
mine are just like these but there is no name on them. get on ebay for 15-30bucks..

roy
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Old Jun 11, 2007, 3:42 PM   #10
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Roy - Are you getting good flash coverage with that basic setup?

It seems very small compared to your full blown macro rig, and in fact looks more like my setup.

I am curious, as you have the flash pointed almost vertical.


Darren

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