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04-05-2008, 06:14 PM   #1
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K20D and Teleconverters

Maybe this has been answered already - Does the K20D have some method where the user can input a focal length multiplier for when a teleconverter is in use?

One small thing that frustrates me is how SR capability of my K10D is degraded with a teleconverter - The camera thinks a 300mm lens is attached (Tamron 70-300 at the far end) when it's actually a shade under 450mm (1.4x TC). I have yet to find a way to override lens FL for lenses that report a FL to the camera - and it would be much easier to just have the camera calculate it automatically.

04-05-2008, 06:20 PM   #2
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No. A solution is to use an "A" teleconverter, which doesn't transmit the focal length to the camera. In this case you can dial in the FL yourself. Which, of course, is quite inconvenient when using a zoom.

Hopefully the announced Pentax SDM teleconverter will multiply the focal length.
04-06-2008, 10:01 AM   #3
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Too bad they didn't solve it with a firmware update.
04-06-2008, 03:17 PM   #4
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QuoteOriginally posted by Matjazz Quote
Too bad they didn't solve it with a firmware update.
Which is very easy to do. Clearly, they have no interest in helping us out here.

04-06-2008, 03:59 PM   #5
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QuoteOriginally posted by Matjazz Quote
Too bad they didn't solve it with a firmware update.
this has been an soustanding and Known issue for over a year now on K10D and K100D, and there is no excuse on pantax's part.
04-07-2008, 04:02 AM   #6
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QuoteOriginally posted by Lowell Goudge Quote
this has been an soustanding and Known issue for over a year now on K10D and K100D, and there is no excuse on pantax's part.
Perhaps there is: Pentax (Hoya) wants you to buy new tele converters!

04-07-2008, 05:49 PM   #7
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QuoteOriginally posted by Matjazz Quote
Perhaps there is: Pentax (Hoya) wants you to buy new tele converters!

Unfortunately it is an undefined function in the KAF and KAF2 mounts.

Since it is undefined, they could simply address it, in the same way they could address the K10D Metering issue for Manual apature lenses, the solutions are easy nad only software.

What really gets me is they go our of their way to advertize that the camera will function with every lens they ever made, and yet there are fundamental errors, where it does not function as it should. The teleconverter issue is one, the exposure for K10D and manual lenses is another.

They need to make the cameras work in a reasonable manner, otherwise they will loose credibility as a maker
04-07-2008, 08:05 PM   #8
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How exactly does the lens transfer focal length data to the camera? Is it a digital code of some sort, or an analog signal? I would think that either could be intercepted by a properly equipped TC and either recoded (if digital) or multiplied (if analog) somehow.

04-07-2008, 08:36 PM   #9
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The "signal" is analogue and is quantised (that is, it doesn't report focal length continuously every mm, but rather in steps).
04-07-2008, 11:01 PM   #10
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QuoteOriginally posted by Entropy Quote
Maybe this has been answered already - Does the K20D have some method where the user can input a focal length multiplier for when a teleconverter is in use?

One small thing that frustrates me is how SR capability of my K10D is degraded with a teleconverter - The camera thinks a 300mm lens is attached (Tamron 70-300 at the far end) when it's actually a shade under 450mm (1.4x TC). I have yet to find a way to override lens FL for lenses that report a FL to the camera - and it would be much easier to just have the camera calculate it automatically.
Wouldn't putting a bit of tape over the electrical connectors covert the lens to an M-lens, therefore allowing you to enter manually? I have never tested this, and of course it takes away a lot of the features of the lens, but could potentially allow you to take a photo.
04-07-2008, 11:16 PM   #11
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Unless the teleconvertor tells the camera that it's mounted, there is no way in software to perform this fix.
04-08-2008, 12:29 AM   #12
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QuoteOriginally posted by JMS Quote
Unless the teleconvertor tells the camera that it's mounted, there is no way in software to perform this fix.
You could enter a teleconverter factor in the SR menu just like you can enter focal lenghth of older lenses. A really simple solution.
04-08-2008, 03:28 AM   #13
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QuoteOriginally posted by Matjazz Quote
You could enter a teleconverter factor in the SR menu just like you can enter focal lenghth of older lenses. A really simple solution.
That wasa the solution I proposed over a year ago.

All TCs for AF pass the lens focal length and focusing information through the 7th contact on the K Mount (furthest away from the lens locking pin) and therefore you cant block this data or AF does not work correctly. BUT a simple menu, for a TC correction factor, either at boot up or through themenu screens, function button or what ever would fix the problem for good.
04-08-2008, 05:28 PM   #14
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QuoteOriginally posted by Lowell Goudge Quote
this has been an soustanding and Known issue for over a year now on K10D and K100D, and there is no excuse on pantax's part.
QuoteOriginally posted by Matjazz Quote
Too bad they didn't solve it with a firmware update.
There will be no more firmware updates for the K10D ever. Period.

This is unwavering, and they are quite proud of this fact.
04-09-2008, 02:54 AM   #15
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QuoteOriginally posted by mutley Quote
There will be no more firmware updates for the K10D ever. Period.

This is unwavering, and they are quite proud of this fact.
Damn Pentax
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