Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Reply
 
Thread Tools Search this Thread
Old Nov 6, 2010, 10:09 PM   #11
Senior Member
 
VTphotog's Avatar
 
Join Date: Mar 2005
Location: Extreme Northeastern Vermont, USA
Posts: 4,214
Default

Moving the aperture ring away from the 'A' position disables communication between lens and camera - gives the same effect as using manual only lens. Aperture value won't be displayed.
On *ist, to set exposure with this setup, I use the DOF preview lever, in manual, to give me suggested shutter speed. In Av mode, with my camera, it adjusts automatically. As Jim says, you probably have to make the change in your menu for this, and maybe use the green button rather than DOF lever.

brian
VTphotog is offline   Reply With Quote
Old Nov 7, 2010, 12:06 PM   #12
Senior Member
 
hnikesch's Avatar
 
Join Date: Jan 2006
Location: Michigan
Posts: 1,810
Default

I have the K2000 and I believe the only thing missing in a200user's post above is you must meter the exposure before taking the shot by pushing the +/-AV button (to the rear left of the shutter button. You select the Aperture on the lens ring, Select manual on the mode dial, push the AV button the camera will stop down the lens, select the shutter speed and ISO (if auto ISO is set) and take the exposure then push the shutter. If you don't like the shutter speed the camera selected then change the aperture and push the AV button again. You can leave the PK-M lens ring in auto if the lens has a manual select, the AV button will stop down the lens. BTW The K2000 does not have a green button or DOF lever. You do have to enable the aperture ring custom menu item 19. If you have a PK -A lens it works just like the kit lens except manual focus, leave the lens aperture ring on A

Hans

BTW is you are using a M42 lens with a PK adapter you must set the lens to Manual and stop down the lens before pushing the AV button
__________________
Hans

...It is better to burn a roll of film than curse the darkness. Equip. K30, Q7, DAL 55-300, DA 35 f2.4, DA 50 f1.8 DA 18-135, SMC-M 28 f3.5, SMC M 50 f1.4, Canon P&S S100 w/CHDK Beta, Panasonic DMC-GM5, Flickr:

Last edited by hnikesch; Nov 7, 2010 at 12:44 PM.
hnikesch is offline   Reply With Quote
Old Nov 7, 2010, 12:51 PM   #13
Senior Member
 
VTphotog's Avatar
 
Join Date: Mar 2005
Location: Extreme Northeastern Vermont, USA
Posts: 4,214
Default

No green button or DOF lever? No wonder it is complicated. If I have to replace my camera, I'm going to have to re-learn everything.

brian
VTphotog is offline   Reply With Quote
Old Nov 9, 2010, 1:18 PM   #14
Senior Member
 
tsquare's Avatar
 
Join Date: Feb 2004
Location: Virginia
Posts: 231
Default

I'm glad the OP started this thread as I am having some of the same types of problems. I have the K20D, and I currently have a SMC Takumar, 55mm, f/1.8 mounted, using the Pentax adaptor. And I have the use of the "A" ring permitted. If I am understanding the exposure setting process, I set the mode to "M", set the aperture via the aperture ring (let's say 5.6), push the shutter 1/2 down, then press the green button to stop it down, and then take the shot. BTW, the lens has a "manual/auto" slider. If I want the lens to be in "manual", then the slider needs to be toward "automatic", so that "manual" is exposed. Does this sound correct? If I set the mode to AV, do I go through the same process?
tsquare is offline   Reply With Quote
Old Nov 9, 2010, 2:50 PM   #15
Senior Member
 
mtngal's Avatar
 
Join Date: Nov 2005
Location: Frazier Park, CA
Posts: 16,052
Default

Can't really help with the Takumar, I don't have any M42 screw-mount lenses. From what I understand, the camera can't communicate with the lens at all, no lever like with the manual K-mount lenses. The green button won't stop the lens down, you need to do that on the lens.
mtngal is offline   Reply With Quote
Old Nov 9, 2010, 4:34 PM   #16
Senior Member
 
VTphotog's Avatar
 
Join Date: Mar 2005
Location: Extreme Northeastern Vermont, USA
Posts: 4,214
Default

I believe, that if you have set the aperture manually, then the green button just meters the exposure, and may(not sure on your camera) set the shutter speed.
Basically all the camera is going to do is give you its opinion of what the exposure should be, but it is up to you to set it. You can consider the exposure meter to be like the old match needle meters in that when you adjust settings to get a zero reading you have set to the proper exposure. (I think this is what the OP was getting at?)

brian
VTphotog is offline   Reply With Quote
Old Nov 12, 2010, 5:40 AM   #17
Senior Member
 
mole's Avatar
 
Join Date: Mar 2009
Posts: 8,522
Default

With my K-M (same as K2000) it seems that metering is much less accurate with older manual (A & m42) lenses than it is with modern DA lenses. I usually have to adjust the EV a bit as I change the F-stop. Once you learn how a specific lens interacts with the metering system, it's a bit easier...
mole is offline   Reply With Quote
Old Nov 12, 2010, 5:58 AM   #18
Senior Member
 
VTphotog's Avatar
 
Join Date: Mar 2005
Location: Extreme Northeastern Vermont, USA
Posts: 4,214
Default

I recall that there was a difference in the way the aperture was operated in some of the older lenses, which does make for metering inaccuracy when used with newer cameras. The mechanical linkage was made (IIRC) logarithmic, so the camera could use a linear function to move the linkage. Later, as cameras got smarter, the camera did the math, and the mechanical linkage in the lens was made linear. (or vice versa) .
Also, the camera's metering with manual lenses, reverts to center weighted averaging.

brian
VTphotog is offline   Reply With Quote
Old Nov 12, 2010, 4:39 PM   #19
Senior Member
 
hnikesch's Avatar
 
Join Date: Jan 2006
Location: Michigan
Posts: 1,810
Default

Quote:
Originally Posted by tsquare View Post
I'm glad the OP started this thread as I am having some of the same types of problems. I have the K20D, and I currently have a SMC Takumar, 55mm, f/1.8 mounted, using the Pentax adaptor. And I have the use of the "A" ring permitted. If I am understanding the exposure setting process, I set the mode to "M", set the aperture via the aperture ring (let's say 5.6), push the shutter 1/2 down, then press the green button to stop it down, and then take the shot. BTW, the lens has a "manual/auto" slider. If I want the lens to be in "manual", then the slider needs to be toward "automatic", so that "manual" is exposed. Does this sound correct? If I set the mode to AV, do I go through the same process?
If the K20D is like my K2000 then you can push the Green (+/-AV on the K2000) button before pushing the shutter, the meter reading is retained until you release the shutter, the rest sounds correct, that would work on my m42 lens
__________________
Hans

...It is better to burn a roll of film than curse the darkness. Equip. K30, Q7, DAL 55-300, DA 35 f2.4, DA 50 f1.8 DA 18-135, SMC-M 28 f3.5, SMC M 50 f1.4, Canon P&S S100 w/CHDK Beta, Panasonic DMC-GM5, Flickr:
hnikesch is offline   Reply With Quote
Old Nov 12, 2010, 7:16 PM   #20
Senior Member
 
fofa's Avatar
 
Join Date: Oct 2005
Posts: 547
Default

Well the PK-A lens does seem to work on scene selection mode. Just like a regular DA or my F lens. Still trying to get a good exposure with the M lens. It might be adjusting the exposure as Mole suggests. Thanks everyone you have been a help.
fofa is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 3:17 AM.