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02-13-2011, 05:17 AM   #1
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DSLR lens with SLR tele-converter

Hi,

I was wondering if you can use and old SLR tele-converter with a DSLR lens. I know you can use old lenses, I'm just a bit worried about combining the two "formats".

Thanks

02-13-2011, 05:39 AM   #2
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QuoteOriginally posted by kiafrika Quote
Hi,

I was wondering if you can use and old SLR tele-converter with a DSLR lens. I know you can use old lenses, I'm just a bit worried about combining the two "formats".

Thanks
Stop worrying. There can be compatibility issues with specific lens/TC combinations but they aren't related to slr/dslr "formats."

DA* 300mm f4 + A 2x-S TC + K-5
02-13-2011, 06:32 AM   #3
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AWESOME SHOT! How far away where you from the Cardinal?
02-13-2011, 07:02 AM   #4
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Great shot Dave! That looks like a great match for the DA*

02-13-2011, 07:55 AM   #5
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QuoteOriginally posted by dadipentak Quote
Stop worrying. There can be compatibility issues with specific lens/TC combinations but they aren't related to slr/dslr "formats."
Can you be more specific? One of the questions that I would have is how to control aperture on that DA* (no aperture ring) if one has a TC from the time that Pentax introduced the K-mount? As far as I know the camera will have no means of opening/closing the aperture to a specific value.

Gorgeous shot, by the way.
02-13-2011, 10:01 AM   #6
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QuoteOriginally posted by sterretje Quote
As far as I know the camera will have no means of opening/closing the aperture to a specific value.
That's not strictly true. TC's (like lenses) have varying capabilities depending on model and age. A TC that has the electrical contacts such as those used on 'A' series lenses or later will be able to open/close the aperture. My Takumar A-2x works just fine with my DA 18-55. Just set the aperture with wheel on the camera & it works.
02-13-2011, 10:24 AM   #7
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QuoteOriginally posted by sterretje Quote
Can you be more specific? One of the questions that I would have is how to control aperture on that DA* (no aperture ring) if one has a TC from the time that Pentax introduced the K-mount? As far as I know the camera will have no means of opening/closing the aperture to a specific value.
Ah well, yes, I guess there will be a problem if the TC doesn't communicate aperture settings from the camera to the lens (or if you can't set aperture via the camera) But I think of that as more specific than "slr/dslr".

And thanks for the comments on the photo. I have to say it kind of blew me away, too (I wish I could get results like that on a reasonably consistent basis.) I shot it from the bathroom window from a distance of about 50 feet.
02-13-2011, 11:20 AM   #8
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Thanks jatrax and dadipentak. My interpretation of kiafrika's question was if he could basically use any old K-mount TC with a 'digital' lens (which implies DA in my view).

And the answer derived from your replies is 'no'.

02-14-2011, 02:08 AM   #9
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Hi thanks for all your comments,

I am a beginner and I am now very confused.

I shall try to be more specific.

I have a K-x with the standard 18-55, and the 50-200 which comes with the kit. I have been given an old TC and wondered if I could use it. It is a Vivitar MC tele Converter 2x PK-A/R-PK .

Thanks again
02-14-2011, 02:58 AM   #10
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QuoteOriginally posted by kiafrika Quote
Hi thanks for all your comments,

I am a beginner and I am now very confused.

I shall try to be more specific.

I have a K-x with the standard 18-55, and the 50-200 which comes with the kit. I have been given an old TC and wondered if I could use it. It is a Vivitar MC tele Converter 2x PK-A/R-PK .

Thanks again
I have the same TC, AF did not work with that TC.
I took out the glass and now use it as a macro extender....

Bert
02-14-2011, 05:02 AM   #11
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Vivitar sold TC's from various sources, with different builds, with the same model ID. But I digress. These old PK TC's have only a mechanical aperture linkage. I haven't a 50-200 lens, but my 18-55 also has that mechanical linkage. And I still have a Vivitar 2X Auto TC. So I thought, "Let's put them together and see what happens!" The results:

M mode: If a PK lens has an aperture ring, I can set the aperture, aim at a subject, push the Green button for metering and exposure, and my K20D stops-down the lens. But the DA18-55 has no ring. So I hit the Green button anyway, and the lens stops down... and from the metered time, I'd say it goes all the way down to f/40 at 55mm. With the 2X TC, the lens is effectively 36-110mm f/44-80. So this method only 'works' if you want the smallest aperture -- which means, diffraction fuzziness. Ugh.

Av (or any other) mode: I aim. I focus. I shoot. Metering is automatic. An image is captured. But there is no way to control the aperture, so it defaults to being wide open, which is f/5.6 at 55mm. With the 2X TC, the lens is effectively 36-110mm f/7-11. So this method *does* actually work, just with no stopping-down to increase sharpness or otherwise influence exposure.

OP's question dealt with mixing two formats. No problem there! The TC doesn't vignette the image, doesn't damage the camera, nothing like that. All that are lost are 1) image quality (which would happen with any unmatched lens+TC pair) and 2) control. Aw hell, I'm out of control myself, sometimes. But in Av or any mode except M-B-X, the TC + kit.lens combo *will* work. How *well* they work is another question. Cheers!
02-14-2011, 09:39 AM   #12
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QuoteOriginally posted by kiafrika Quote
I have a K-x with the standard 18-55, and the 50-200 which comes with the kit. I have been given an old TC and wondered if I could use it. It is a Vivitar MC tele Converter 2x PK-A/R-PK .
RioRico gave you the long version. Here is a shorter one:

1) There is no problem mixing film and digital components as such. With a few rare exceptions they will work fine.

2) In order for the TC / DA 18-55 combination to work properly in Av mode by controlling the aperture you need a TC with the electrical pins to pass through the signals. If your TC has these then it will work if not then no it will not work as I think you want. As RioRico notes it CAN work, but not (I think) as you want. If you post a picture of your TC we can tell you if it has the pins, although they are easy to spot.

If you want to use a TC and have the aperture controlled get a TC with the pins, they are on ebay all the time for next to nothing.
02-14-2011, 10:39 AM   #13
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There were plenty of TCs made long before the film/digital transition that support aperture adjustment.

Basically any TC that has autofocus linkages should also have the correct aperture control linkages (mechanical and electrical). Power zoom TCs (rare but they exist) were all designed before the DSLR era but actually support SDM.
02-15-2011, 12:21 PM   #14
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QuoteOriginally posted by kiafrika Quote

It is a Vivitar MC tele Converter 2x PK-A/R-PK .
This TC has 6 contacts and your DSLR has 7. If you scratch the paint off at this point https://www.pentaxforums.com/forums/pentax-beginners-corner-q/120756-rant-aut...anymore-2.html (page 2, photo posted by SOldBear), the camera operates in auto everything except no AF. If you find the TC degrades the IQ more than you expect, you can remove the glass elements and you will have a PK/A extension tube for macro work.
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