Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
07-27-2013, 09:07 PM   #1
New Member

Join Date: Jul 2013
Posts: 10
old lens and K10


I have recently acquired a K10 and would like to be able to use my pre digital lenses. For example my Asahi SMC Pentax M 1.2 50mm. I put it on the camera and set the focal length. How do I then control exposure. I guess it should be on Manual. Am I ( or the camera) able to control the shutter speed and the aperture somehow?


07-27-2013, 09:09 PM   #2
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,140
A text & video guide is available here:

Adam Webmaster (Site Usage Guide | Site Help | My Photography)'s high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

07-28-2013, 10:33 AM   #3
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,450
The camera manual is your friend (free download from, though the information it provides for vintage lens use is a bit spotty.

The link Adam provided is a great resource and is where we generally refer noobs so they can get started with their older glass.

Beyond that, here are few bullet points:
  • There is a setting in the "Custom Setting" menu called "Using Aperture Ring". That should be set to "Permitted".
  • Manual mode (M) is used with K-mount lenses lacking the "A" contacts. As you might imagine, it is the same as a manual exposure film camera. You set the aperture using the ring on the lens and the shutter speed using the front control dial on the camera.
  • Metering is a complicated matter. In theory, you can use green button (stop-down) metering and indeed this will give you settings that are based on the camera's program line for the amount of light striking the meter's sensors. Unfortunately, those settings are often off by as much as 2-3 stops. The reasons are complicated, but the short solution* is to use those settings as a start point. Use the preview image in the rear LCD along with the image histogram as hints to get the correct exposure. Alternatives include using a hand-held meter or estimating using "Sunny-16" rule.
I know this sound cumbersome, but it is not really too much trouble. I do the majority of my K10D shooting with vintage lenses and have been generally happy with the experience and the results.


*Unfortunately, there is no long solution either with the K10D. This issue exists for other brands (e.g. Nikon) and is related to mathematical corrections dialed into the metering system. Recent model Pentax dSLRs (K-7 and newer) do a much better job.
07-29-2013, 08:39 PM   #4

This is a really good read for me, Must admit that you are one of the best bloggers I ever saw.Thanks for posting this informative article.

07-30-2013, 08:46 AM   #5
Loyal Site Supporter
TER-OR's Avatar

Join Date: Apr 2009
Location: Dundee, IL
Photos: Gallery | Albums
Posts: 5,834
You will also want to record RAW files, you can adjust them in post-processing far more than jpeg. Using RAW it's preferable to underexpose a bit more than overexpose. The sensor records a lot of data in dark areas, but this isn't true for overexposed "blown" areas.

Also, if you don't have a lens hood for the old lens, get one of those rubber collapsible ones, it makes a HUGE difference.

I'll also say the Magic Lantern guide for the K10 was a huge help to me as a beginner, but it doesn't do a lot for showing how to use the older fully manual lenses. The ability to operate in fully manual mode was an attractor to Pentax for me.

  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, control, dslr, k10, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentax K01 and AF on old sigma lens rdo Pentax K-01 16 06-27-2013 03:08 PM
Image quality between an old lens and a brand new lens with similar basic properties? Codazzle Pentax SLR Lens Discussion 40 08-13-2011 06:56 AM
Old Remote Shutter Releases and K10 jagojay Troubleshooting and Beginner Help 2 11-12-2010 06:24 PM
Project 52, Week 32 - Young and Old (or New and Old)....Winners! dayah Weekly Photo Challenges 9 01-26-2009 12:36 PM
K10 and an old Flash? Snowcat Pentax DSLR Discussion 26 12-30-2007 04:21 AM

All times are GMT -7. The time now is 11:46 AM. | See also:, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]