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12-27-2013, 05:06 PM   #1
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K-50 and manual lens

Had my K-50 for a few weeks and tried a manual lens for the first time, an SMC Takumar 50mm f1.4 I can't access control of the aperture. With both mode and focus set on manual, I've tried auto and manual setting on the lens. I tried both aperture ring settings on the camera menu. I've tried both auto and manual ISO settings. If I'm reading the manual correctly, the panel where there should be an "f" value and an icon indicating rear dial control, all I get is a flashing "F- -". Same situation with a Super Tak 35mm

What am I missing please?

Thank you

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12-27-2013, 05:23 PM   #2
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Using Older Lenses on the PENTAX K-50 | Ricoh Imaging Support

ISO should not be set to auto

Setting the "Using Aperture Ring" to enabled should stop the flashing "F--" but will only display the aperture on "A" type lenses when set to "A" (use the eDial to set the aperture).
12-27-2013, 05:52 PM   #4
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There is a thread at Pentax Beginners Corner stickied to the top on using older lenses, even has a video. That should help you out.

12-27-2013, 05:57 PM   #5
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Welcome to the wisdom of the ancients*. Shooting with a M42 thread-mount lens is a fully manual operation. You are in control.
  • Turn the aperture ring on the lens to choose the desired aperture
  • Move the slider "switch" on the lens barrel from "A" to "M" to stop down the lens for shooting**
The key is to remember "Lens open for focusing" and "Lens stopped down for meter/exposure". Metering with your K-50 is supposed to be pretty straightforward using the green button in "M" mode, but a few recent threads have cast that assumption into doubt in regards to M42 lenses. Since I don't own the camera, I can't provide first-hand advice or instruction for metering.

Have fun!


Steve

* Using the A/M switch this way is a feature built into your SMC Tak that allowed backwards compatibility to older M42 bodies (think 1950s) not having aperture actuation coupling. Strangely, your modern camera falls into that category.

** Note: This is actually pretty important and has nothing to do with your K-50...with your SMC Takumar lenses the A/M switch is "locked" unless mounted to a body or to the M42 adapter or the rear cap is in place. Do not force the switch if not mounted to something! This is done with a small pin that protrudes from the mount face. Note too that this pin may be problematic when mounting to non-Pentax bodies, teleconverters, bellows, or extension tubes that have exposed screw holes on the mount face.

Last edited by stevebrot; 12-27-2013 at 06:29 PM.
12-27-2013, 11:19 PM   #6
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QuoteOriginally posted by Not a Number Quote
Using Older Lenses on the PENTAX K-50 | Ricoh Imaging Support

ISO should not be set to auto

Setting the "Using Aperture Ring" to enabled should stop the flashing "F--" but will only display the aperture on "A" type lenses when set to "A" (use the eDial to set the aperture).
Thank you because this works wonderfully well. However, this is a semi-automatic process and the manual states that I should be able to set aperture using the rear wheel. Is the manual wrong? I've been setting shutter speed and aperture on my K-01, using the bar indicator, and rather enjoy it. I'd be quite disappointed if the K-50 is unable to do this.
12-27-2013, 11:47 PM   #7
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QuoteOriginally posted by Banskojoe Quote
Thank you because this works wonderfully well. However, this is a semi-automatic process and the manual states that I should be able to set aperture using the rear wheel. Is the manual wrong? I've been setting shutter speed and aperture on my K-01, using the bar indicator, and rather enjoy it. I'd be quite disappointed if the K-50 is unable to do this.
You can use the bar indicator on your K-50, I would expect. I can use it on my K10D. But you must set the aperture on the lens and use M mode. I often use the over/under exposure bar indicator when using my two M series lenses. I set the shutter switch to optical preview in the menus. When using a manual aperture lens, going into optical preview will stop down the lens and show the exposure bar. You may then change the aperture on the lens - after releasing the preview* - or change the shutter speed to set the exposure compensation you wish using the gauge. The manual reference to the e-dial refers only to lenses without aperture rings, or lenses with the aperture ring set to the A position.

[Edit] *Even if you can change the aperture with the preview engaged, it will strain the mechanical linkages. Don't do that.

Last edited by Canada_Rockies; 12-27-2013 at 11:49 PM. Reason: Added caveat
12-28-2013, 04:34 AM   #8
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QuoteOriginally posted by Canada_Rockies Quote
You can use the bar indicator on your K-50, I would expect. I can use it on my K10D.
As I recall from earlier discussion the bar meter only works with "A" type lenses and higher on the K-30, K-01, k-500 and K-50. Stop down metering with M, K and screwmount lenses on these bodies is done with the green button.

Focus/compose with lens wide open, set f-stop on aperture ring, press the green button. The camera will stop down M, K, or A lenses to the set f-stop and meter the image and set the shutter speed. You stop down screwmount lenses manually with either the man/auto switch on the lens, to the preset or counting the clicks from wide open to your desired f-stop - depending on the lens. You can then adjust these setting via the aperture ring or the shutter speed with the eDial. Press the shutter button. Yes, it is clumsy but slightly less so than using a hand-held meter.

You may find the green button doesn't work with your screw-mount lenses. See these threads:
https://www.pentaxforums.com/forums/151-pentax-k-30-k-50/245275-green-button-...-mode-m42.html
https://www.pentaxforums.com/forums/120-general-technical-troubleshooting/230...g-problem.html

10-10-2014, 12:00 AM   #9
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I'm not going to start a new thread on this as it seems relevant to this one.
I bought a k-50 six months ago. My first dslr or Ilc camera of any kind. Loving it.
I just got hold of a pentax-a 28mm as well as a vivitar m mount 28mm.
The article at robertsdonovan.com was very helpful.
A mount in A mode works great. No need for green button
M mount works as per "Tom Otto" suggestions at the article on Robert Donovan's site. I.e. Don't let the mount click into place, and then shutter speed and ISO settings are handled by camera. What exactly is happening there and why does clicking the mount into place turn these off?
Also the green button doesn't seem to be doing anything. Nor does DOF preview. Am I missing some setting?
10-10-2014, 07:29 AM   #10
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QuoteOriginally posted by TzalamChadash Quote
I'm not going to start a new thread on this as it seems relevant to this one.
I bought a k-50 six months ago. My first dslr or Ilc camera of any kind. Loving it.
I just got hold of a pentax-a 28mm as well as a vivitar m mount 28mm.
The article at robertsdonovan.com was very helpful.
A mount in A mode works great. No need for green button
M mount works as per "Tom Otto" suggestions at the article on Robert Donovan's site. I.e. Don't let the mount click into place, and then shutter speed and ISO settings are handled by camera. What exactly is happening there and why does clicking the mount into place turn these off?
Also the green button doesn't seem to be doing anything. Nor does DOF preview. Am I missing some setting?
Mounts without the A position on the aperture ring only work in manual mode because of a mechanical difference between the current mount and the earliest K mounts. There are those who use the not-quite-locked system, but I don't feel like having a lens fall off because it isn't locked into position. Here is what you do to use M and K mounts (K preceded M).

Lock the lens into position.
Set the aperture you wish to use.
Press the green button
Your camera will stop down and set the shutter speed.

Manual metering method:
Hold the power switch in the preview position
You will see an indicator in the viewfinder for over/under exposure.
Adjust either shutter speed with speed dial or aperture to set the exposure you want.
10-10-2014, 12:07 PM   #11
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QuoteOriginally posted by TzalamChadash Quote
Don't let the mount click into place, and then shutter speed and ISO settings are handled by camera.
Urban legend. The results using the not-quite-locked method are inconsistent from lens to lens due to variability in how the actuator coupling is implemented. The body reacts the same regardless of whether the lens is locked. It has no sensors to tell it else wise. What changes is the angle of the aperture actuator controller bar in the body to the lever on the lens. Turn the lens far enough and it will stop down to the setting on the aperture ring. You can then use the lens in Av mode as opposed to M mode.

The only magic is when your lens levitates rather than hitting the ground when you change focus or aperture and it comes off the camera. What, your lens does not levitate? Pity...


Steve

---------- Post added 10-10-14 at 12:12 PM ----------

QuoteOriginally posted by Canada_Rockies Quote
Lock the lens into position.
Set the aperture you wish to use.
Press the green button
Your camera will stop down and set the shutter speed.
I would only add one additional step to Albert's very good summary.
  • Continue with these settings until either the subject or the light changes
This is rather counter-intuitive in these days when the automated metering changes constantly, but for those of us that started photography with a hand-held meter or stop-down TTL metering, that was the best way to work. For the most part, you don't need constant metering.


Steve

(...shoots with a number of non-metered cameras...has very good exposure consistency frame-to-frame...)
10-10-2014, 05:11 PM - 1 Like   #12
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QuoteOriginally posted by stevebrot Quote
I would only add one additional step to Albert's very good summary.
  • Continue with these settings until either the subject or the light changes
This is rather counter-intuitive in these days when the automated metering changes constantly, but for those of us that started photography with a hand-held meter or stop-down TTL metering, that was the best way to work. For the most part, you don't need constant metering.
I should have put that in there. My bad. Thanks, Steve.
12-20-2015, 12:40 PM   #13
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Hey Guys,

what if I wanted to have full manual control over my camera. Say I set the shutter speed to 1/100 make 3 fast consecutive shots I expect all 3 to have shutter speed of 1/100.

However currently on an M Lens, I get three different speeds using this method.

Any fix for this ?

Thanks.
12-20-2015, 05:40 PM   #14
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M and K lenses can only be properly controlled in M Manual mode. There is a detailed overview as a sticky at the top of the newbie listings.

  1. The camera must be in M (manual) mode on the mode dial.
  2. In the cameras menus, Custom Setting "Using Aperture Ring" must be set to "Enable.
  3. The camera can automatically set the shutter speed by setting the aperture to the desired level and pressing the Green button.
  4. Change the aperture and repeat until you get the desired shutter speed.
  5. The camera will now use only the shutter speed and aperture selected.
12-20-2015, 10:31 PM   #15
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problem was I had bracketing on. (headbang)

Otherwise the behavior of the camera is normal ;-)

Thanks
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