Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-09-2011, 07:55 AM   #1
Senior Member




Join Date: Jun 2011
Location: Si Gn city, Việt Nam
Photos: Gallery | Albums
Posts: 185
Pentax K-r and Helios 44m-4: Av mode doesn't work?

Hi,

I am using a Helios 44m-4 with Pentax K-r. I notice that when I switch to Av mode, the output image is darker than image captured in M-mode (as you can see in the first image below). The expect result is as in the 2nd image, which is taken with M-mode (green button is pressed to measure the light source.)

My question is: Why does the Av-mode report wrong light parameter? Am I using Av mode in wrong way? Does the Av mode work with Helios lens?

Thank you very much.

Demo:

The first image: f/2.8, 1/45s, Av mode, link = http://vonhudieu.net/zen/picture.php?/381/category/18
The second image: f/2.8, 1/15s, M mode (green button pressed to measure light source.), link = http://vonhudieu.net/zen/picture.php?/382/category/18





12-09-2011, 08:36 AM - 1 Like   #2
Inactive Account




Join Date: Jul 2010
Photos: Gallery
Posts: 328
Hi

Un documented rule, when using M42 screw mount manual aperture lenses that do not have a clean metal mount
that grounds out the contacts" add +1.7 ev
Forget that Green button thing it just adds to your shutter count and makes you do 2 steps for each Pic !
Pentax should have had a metering on the half press shutter button or proper metering in Av mode,
My Sony A33 works with any lens and meters without the stopdown thing
12-09-2011, 08:37 AM - 1 Like   #3
Veteran Member
Philoslothical's Avatar

Join Date: May 2011
Posts: 1,723
Hi icy, as I mentioned in your last thread, you need to use old m42 lenses in M mode with green button metering to get a proper exposure. The camera has no way of knowing what aperture you're using with these lenses, so it makes the best guess it can on exposure, but it is not accurate.

QuoteOriginally posted by bobpur Quote
Forget that Green button thing it just adds to your shutter count and makes you do 2 steps for each Pic !
What on Earth are you talking about? The shutter doesn't fire when metering with the green button. That's just bad info.
12-09-2011, 01:08 PM   #4
Veteran Member




Join Date: Jan 2009
Location: Brisbane
Photos: Gallery
Posts: 1,421
QuoteOriginally posted by Philoslothical Quote
What on Earth are you talking about? The shutter doesn't fire when metering with the green button. That's just bad info.
the rest of the info is pretty accurate in my experience, but yeah not the green button bit!

12-09-2011, 05:27 PM   #5
icy
Senior Member




Join Date: Jun 2011
Location: Si Gn city, Việt Nam
Photos: Gallery | Albums
Posts: 185
Original Poster
QuoteOriginally posted by Philoslothical Quote
Hi icy, as I mentioned in your last thread, you need to use old m42 lenses in M mode with green button metering to get a proper exposure. The camera has no way of knowing what aperture you're using with these lenses, so it makes the best guess it can on exposure, but it is not accurate.
Oh I see it now Thank you very much!
12-09-2011, 05:54 PM   #6
Loyal Site Supporter
eddie1960's Avatar

Join Date: Aug 2010
Location: Toronto
Photos: Gallery | Albums
Posts: 12,271
well question has been answered.
but
holy smoke that tak looks like it's been through several war zones how's it performing
Reply

Bookmarks
  • 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!
av, camera, f/2.8, helios, image, k-r, kr, light, link, mode, pentax k-r
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sibling Rivalry: Helios 44M vs. Helios 44M-4 stevebrot Pentax SLR Lens Discussion 36 08-03-2013 09:31 AM
Can I use a Helios 44m on K-r? Eric_the_fish Pentax K-r 11 12-08-2011 03:02 AM
Helios 44M-4 needs your help... sushamyraj Pentax SLR Lens Discussion 8 10-02-2011 12:45 PM
Helios 44M-4 vs 44M teartear Pentax SLR Lens Discussion 27 08-24-2011 03:25 AM



All times are GMT -7. The time now is 08:29 AM. | See also: NikonForums.com, CanonForums.com 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?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top