Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
08-21-2015, 09:03 PM   #1
Senior Member

Join Date: Apr 2015
Posts: 157
645Z Aperture Problem

My Z has developed a problem. The aperture will randomly change after taking a picture. For example, when shooting in manual, if the aperture was set to 11, it might randomly shift to f10 or f13 without my making a change for the next shot. It has been doing this for the last few outings.

Is this a known problem with the Z? I really hate the idea of sending it in for repair for a problem like this, especially since I bought it in Canada and not the US.


08-21-2015, 09:57 PM   #2
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 47,261
If you have instant review on, the e-dials still affect the shutter speed and aperture. Is that throwing you off perhaps?

Adam Webmaster (Site Usage Guide | Site Help | My Photography) server and development costs are user-supported. You can help cover these 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:

08-21-2015, 10:16 PM   #3
Senior Member

Join Date: Apr 2015
Posts: 157
Original Poster
Thanks for the reply. I will check my settings to see if that is the problem.
08-21-2015, 10:28 PM   #4
Senior Member
Racerdew's Avatar

Join Date: Apr 2011
Location: Thousand Oaks, CA
Photos: Gallery | Albums
Posts: 284
Adam's the man!

08-22-2015, 02:40 AM   #5
Site Supporter
Site Supporter

Join Date: Feb 2011
Location: Syracuse, NY
Posts: 646
QuoteOriginally posted by Adam Quote
If you have instant review on, the e-dials still affect the shutter speed and aperture. Is that throwing you off perhaps?
I experience this problem when I try to zoom in to the instant review pic before it is displayed where you can zoom in, usually after a series of shots. Instead of zooming in (with the dial) it changes the aperture 1/3 stop instead.
08-22-2015, 05:11 AM   #6

Join Date: May 2010
Location: London
Posts: 604
The explanation given above is probably it, but just one silly thing to exclude - you don't have the camera set to auto bracket do you?
08-22-2015, 09:33 AM   #7
Senior Member

Join Date: Apr 2015
Posts: 157
Original Poster
No, I don't have it set to auto bracket. I do use the 2 sec delay when on tripod. In general I don't purposely use the multitude of settings available in the camera and have a lot to learn about them, just shoot in manual.

Later when I have a chance I'll experiment with settings.
08-22-2015, 06:23 PM   #8
Senior Member

Join Date: Apr 2015
Posts: 157
Original Poster
I've not been able to figure what was going on. Today first off the problem was there. The battery was low and after changing the battery the aperture shifts have not been reoccurring.

From the responses from the forum I conclude that this is not a common problem.

08-23-2015, 08:16 AM   #9
Senior Member

Join Date: Nov 2010
Location: Calgary, Alberta
Posts: 272
Also make sure you're running the latest firmware. A number of goofy glitches in the Z have been fixed over the months.
05-21-2018, 10:51 AM   #10
New Member

Join Date: Dec 2015
Posts: 3
@PhilRich - did you figure this out? My 645z developed the same issue.

  • 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!
645d, 645z, 645z aperture, aperture, aperture malfunction, camera, change, medium format
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
Aperture flickering problem Tomtkt Photographic Technique 2 12-08-2014 01:54 AM
645z low shutter noise reduction problem ss99 Pentax Medium Format 5 11-04-2014 07:12 PM
645Z no card in camera problem elsdad Pentax Medium Format 2 09-06-2014 02:45 PM
Odd aperture situation with 645Z Royce Howland Pentax Medium Format 21 09-01-2014 08:11 AM
A 85mm Auto Aperture Problem jrpower10 Troubleshooting and Beginner Help 6 09-16-2013 09:53 AM

All times are GMT -7. The time now is 06:21 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]