Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
02-26-2013, 01:29 AM   #1
Veteran Member

Join Date: Dec 2012
Photos: Gallery
Posts: 696
Green Button -- am still confused

Could use help explaining how the Green Button works!

Using a Pentax A 50mm f/1.4.

What happens when I push the GB on Manual... or on Av, or Tv?

I've read that, on M Manual, with the aperture set to your selection, that pushing the Green button will automatically set -- and lock -- the correct shutter speed. When I push it, the camera clicks twice, but nothing happens.

In dim indoor light, where I can get a decent picture at 1/50, f/2.8, ISO 1600 ... I reset the speed to 1/400, which made a very dark picture. Tried it again, pushing the Green Button, then taking the picture. No change, still very dark. The Green Button did not reset the shutter speed to 1/50.

And -- before all this -- yes, I set Custom menu 3, Aperture Ring setting, to Enable.

What am I missing?

02-26-2013, 01:44 AM   #2
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
Why do you need to use Aperture Ring setting, to Enable when it's an A lens?

Anyway when you select a mode the functions of the buttons are displayed on the LCD screen i believe.

For the exposure, check if you have set EV compensation or have bracketing on by any chance.
02-26-2013, 02:10 AM   #3
Veteran Member

Join Date: Dec 2012
Photos: Gallery
Posts: 696
Original Poster
Anvh -- it is set to Enable, because if it isn't, I can't push the shutter button down, or see any of the info on the screen. When I set it to Enable, the shutter button works, and the info is all there, and the histogram. The lens is an A-type... it says "SMC PENTAX-A 1:1.4 50mm" on it.

In Manual, I don't see any EV compensation... and it is in single-shot, not bracketing or HDR.
02-26-2013, 02:14 AM   #4
Veteran Member
VisualDarkness's Avatar

Join Date: Nov 2011
Location: Uppsala, Sweden
Photos: Gallery
Posts: 4,441
If you set the aperture ring on the lens to the "A" setting you can control the aperture from the camera instead and have real time metering.

02-26-2013, 02:22 AM   #5

Join Date: Oct 2011
Location: Savannah, GA
Posts: 5,152
You also need to set the green button to the correct action under "button customization". Set it to "tv shift" for M/Tav mode -- that means shutter speed. I don't believe that is the default. That setting, along with setting "using aperture ring" to enable will allow so-called "green button metering" in M mode.
02-26-2013, 02:23 AM   #6
altopiet's Avatar

Join Date: Sep 2010
Location: The Gem of the Karoo, South Africa
Photos: Gallery | Albums
Posts: 2,222
Although you can use the lens in M mode, by selecting the aperture on the lens, then using the green button to select the corrct shutter speed for the exposure, I would leave it on A, and use the camera settings to establish the correct exposure. The green button is mainly for use with the older, completely manual lenses, that don't have the A option on the lens.
02-26-2013, 03:01 AM   #7
Na Horuk's Avatar

Join Date: Feb 2012
Location: Slovenia, probably
Photos: Gallery | Albums
Posts: 11,189
For manual lenses you can use the green button to meter. In M mode, you push the GB and the camera will stop down to the selected aperture and set the shutter speed. In Av the camera is constantly metering, but it won't stop down regardless what number you set on the lens. For manual lenses (like M or K series) you need to have "allow aperture ring" enabled.

But! You have an A lens. You can set the aperture to A and the camera can do anything with it! So turn the camera off, set the lens to A, then turn it back on. Now you can also use Av mode and stuff. You can set the aperture on the camera and it will meter automatically, just like with a DA lens. Basically, you are mostly missing AF. The camera might not let you shoot if you have focus lock priority or catch in focus turned on. Those can be useful tools, but make sure you know how to use them. CiF will be especially useful for that lens, but it will only use the centre AF point.
02-26-2013, 11:41 AM   #8

Join Date: Oct 2011
Location: Savannah, GA
Posts: 5,152
And when using 'A' mode, you get full matrix metering (and your flash exposures will be correct). So no reason to ever take an A lens off of A unless it is on a tube or bellows where you might need to.

02-26-2013, 12:50 PM   #9
Veteran Member

Join Date: Dec 2012
Photos: Gallery
Posts: 696
Original Poster
Thanks for the quick help! You've cleared up my confusion... I really appreciate the tips. Am coming to APS-C and the K-01 from an Olympus XZ-1, which is basically an excellent P&S, and works somewhat differently. To paraphrase Dr. King -- "Clear at last! Clear at last! Thank God almighty, it's clear at last!"

For my type-A lens... leave the aperture ring on A!

  • 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!
aperture, button, k-01, k01, mirrorless, pentax k-01, picture, reset, shutter
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
Green button and AE-L button voyager13 Troubleshooting and Beginner Help 7 06-28-2012 12:26 PM
green button slip Pentax K-30 & K-50 3 06-09-2012 01:03 PM
Green button or +/- button for meter? kidblue Pentax SLR Lens Discussion 15 07-29-2011 07:10 PM
i am so confused! jennverr Film Processing, Scanning, and Darkroom 6 06-02-2011 07:31 AM
confused about lenses - still! slr_neophyte Troubleshooting and Beginner Help 15 05-25-2011 06:14 AM

All times are GMT -7. The time now is 09:27 PM. | 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]