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04-02-2011, 03:48 PM   #1
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Some basic questions

I'm thinking of switching from the Lumix G1 to Pentax K-r for access to legacy lenses without the 2x mag factor and more third party lenses. I really like the articulating screen on the G1. It's disappointing that not even the high end Pentax models have one but I can live without it. So my questions are: How well do legacy lenses work? I'm particularly interested in using fast prime lenses wide open for portraits. I know there's no auto focus but does the diaphragm automatically stop down? How loud is the shutter? I've heard it's pretty loud. Are there adapters to use lenses from other systems like Olympus OM and Leica SM? How good are the kit lenses? Is there a wide selection of reasonably priced, high quality third party lenses like Sigma? Thanks.

04-02-2011, 04:58 PM   #2
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Just about everyone here knows more than me but I can answer at least one of your questions. Any Pentax A also know as KA will work on any Pentax DSLR and stop up or down for the aperture leaving you to only deal with the manual focus.

The Pentax M lenses can be used on most models in full manual mode. That is not true for the k2000. The same is true for the older screw mounts.

BTW, welcome aboard.
04-02-2011, 05:46 PM   #3
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You can't use M or M42 lenses in the K2000 (Km)? News to me. Why not?

To Geos, the only thing I'll say is that there enough options available in the K mount you don't need to worry about adapting other lenses (which in most cases cannot be done without major surgery) to the K mount cameras. If you goal is a K-r, I know of no Pentax Type lenses that will not work in some way. The Simplest to use as far as legacy lenses go are the Pentax A type lenses.

Welcome aboard and good luck..

04-02-2011, 05:55 PM   #4
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QuoteOriginally posted by JeffJS Quote
You can't use M or M42 lenses in the K2000 (Km)? News to me. Why not?

You can use them. They shoot wide open in any mode mode other than full manual.. There is no way to set the f/stop for any of the program modes. This is one time I would love for you or anyone to prove me wrong and tell me how to do it. Please!

04-02-2011, 06:10 PM   #5
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QuoteOriginally posted by Geos Quote
I know there's no auto focus but does the diaphragm automatically stop down?
Yes, the diaphragm does automatically stop down on all the K-mount lenses. You lose automatic diaphragm with the screwmount lenses. 645 and 67 medium format lenses can also be used via adapters. Leica R lenses can be used if you change the mount on the lens.

QuoteOriginally posted by Geos Quote
How well do legacy lenses work?
The old, pre-A series K mount lenses work quite well (or at least as well as they did on the old manual focus cameras like the K1000). SR and focus indication works, and you can get metering by tapping a little green button placed near the shutter release button on most models. Matrix metering does not work, and some complaints have been made about metering accuracy with certain Pentax DSLR models. I shoot mostly landscapes with my older lenses and merely expose to the histogram, so it's never been issue for me, but it can be for those who aren't shooting as deliberately.
04-02-2011, 11:29 PM   #6
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QuoteOriginally posted by Colbyt Quote
Just about everyone here knows more than me but I can answer at least one of your questions. Any Pentax A also know as KA will work on any Pentax DSLR and stop up or down for the aperture leaving you to only deal with the manual focus.

The Pentax M lenses can be used on most models in full manual mode. That is not true for the k2000. The same is true for the older screw mounts.

BTW, welcome aboard.
QuoteOriginally posted by Colbyt Quote
You can use them. They shoot wide open in any mode mode other than full manual.. There is no way to set the f/stop for any of the program modes. This is one time I would love for you or anyone to prove me wrong and tell me how to do it. Please!
Well now...do they or don't they?

The k2000/Km is no special exception. I'm not sure what you mean by, "program modes", but, whether you use the K-r, Km, k5 or what have you, M and M42 lenses have the same functionality on each:
M lenses are limited to manual mode.
M42 lenses may be used in either M or Av*
.

No matter what Pentax camera you have you can't make either the M or the M42 function in any other mode. Other modes require the camera to adjust the aperture of the lens. This can't happen on a manually set aperture.

*To get M42 lenses to work properly on my Km I have to either short the bottom most pin (a bit of foil works), or I have to adjust the exposure compensation to Ev +2.

[edit]I forgot to add that on the M42 lenses you'll either have to be sure the lens is set to Manual mode, or the pin that stops the lens down is jammed. No digital body can slap the pin to stop it down.

Last edited by wasser; 04-02-2011 at 11:35 PM.
04-02-2011, 11:37 PM   #7
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QuoteOriginally posted by Colbyt Quote
You can use them. They shoot wide open in any mode mode other than full manual.. There is no way to set the f/stop for any of the program modes. This is one time I would love for you or anyone to prove me wrong and tell me how to do it. Please!
QuoteOriginally posted by wasser Quote
Well now...do they or don't they?

The k2000/Km is no special exception. I'm not sure what you mean by, "program modes", but, whether you use the K-r, Km, k5 or what have you, M and M42 lenses have the same functionality on each:
M lenses are limited to manual mode.
M42 lenses may be used in either M or Av
*
.

No matter what Pentax camera you have you can't make either the M or the M42 function in any other mode. Other modes require the camera to adjust the aperture of the lens. This can't happen on a manually set aperture.

*To get M42 lenses to work properly on my Km I have to either short the bottom most pin (a bit of foil works), or I have to adjust the exposure compensation to Ev +2.

[edit]I forgot to add that on the M42 lenses you'll either have to be sure the lens is set to Manual mode, or the pin that stops the lens down is jammed. No digital body can slap the pin to stop it down.
What he said.The other cameras are no different.

There is however, a Cheat for M and K type lenses (non A). Set the lens to it's smallest aperture (f22). Whle viewing the lens from the front (it helps if you hold the viewfinder up to light), unlock the lens by pressing the release that you use to remove the lens. Turn the lens about 10 degrees counter clockwise as if you are removing it. When you see the aperture closed as far as it will go, stop.

You now have an M lens that will behave like an M42 lens and you can use the lens in Av. You can use them in Tv and other modes as well but the camera will still default to Av unless you are in M mode. What you Also have is a lens that is no longer locked on to the mount. So be careful with this method.




Last edited by JeffJS; 04-02-2011 at 11:45 PM.
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