Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-08-2015, 06:04 AM   #1
New Member




Join Date: Jun 2010
Location: Singapore, SA
Posts: 16
Exposure issues with K5

I've been using K5 for about 2 year now but recently I am experiencing some issues with the exposure of the camera.

I am on multi segment and aperture mode. If i open the aperture e.g(F3.5) the picture gets underexpose and if i close the aperture e.g(F6.3) the picture get more exposed. I thought the aperture is only for controlling the depth of field, why is it affecting my exposure when ISO and shutter are set to auto and the light meter shows that the picture is properly metered.

2nd, the write speed of the camera is getting from bad to worse. I've upgrade my scandisk card from 30mb/s to 45mb/s to 60mb/s but it doesn't seems to help with the write speed.

Seriously need some help with the issues on hand.

06-08-2015, 06:13 AM   #2
Site Supporter




Join Date: Apr 2014
Location: Flushing, Michigan
Photos: Albums
Posts: 113
QuoteOriginally posted by leezihao Quote
I've been using K5 for about 2 year now but recently I am experiencing some issues with the exposure of the camera.

I am on multi segment and aperture mode. If i open the aperture e.g(F3.5) the picture gets underexpose and if i close the aperture e.g(F6.3) the picture get more exposed. I thought the aperture is only for controlling the depth of field, why is it affecting my exposure when ISO and shutter are set to auto and the light meter shows that the picture is properly metered.

2nd, the write speed of the camera is getting from bad to worse. I've upgrade my scandisk card from 30mb/s to 45mb/s to 60mb/s but it doesn't seems to help with the write speed.

Seriously need some help with the issues on hand.
did you ever update the camera from the web? I didn't think you could "change settings" while in the AUTO-MODE?? I certainly can't guess the answer to your problem.....sorry....RJM
06-08-2015, 06:21 AM   #3
New Member




Join Date: Jun 2010
Location: Singapore, SA
Posts: 16
Original Poster
QuoteOriginally posted by photoramone Quote
did you ever update the camera from the web? I didn't think you could "change settings" while in the AUTO-MODE?? I certainly can't guess the answer to your problem.....sorry....RJM
I m not on full auto mode, i m on aperture mode which enables me to change the aperture while the camera help to set the shutter speed and iso to correct the metering. But I haven't update the camera software before since I got it from the previous owner.
06-08-2015, 06:22 AM   #4
Loyal Site Supporter
TER-OR's Avatar

Join Date: Apr 2009
Location: Dundee, IL
Photos: Gallery | Albums
Posts: 5,416
That exposure behavior really sounds like the ISO is not responding correctly. I'd do two things regarding firmware - make sure you've got the camera's firmware updated, and then reset the camera to factory conditions. Perhaps you've got some program setting messed up. Just a thought, and simple enough to do.

Beyond that, the lens might not be performing correctly. Make sure the contacts are clean. Make sure the aperture lever moves freely.

If I read correctly, you're operating in Av mode? What happens if you switch modes - green, TAv etc.?

06-08-2015, 08:59 AM   #5
Loyal Site Supporter
narual's Avatar

Join Date: Jun 2013
Location: South Bend (Notre Dame), Indiana
Posts: 1,937
Are you using a modern lens with autofocus or a manual lens?

I have my K5 gimmicked with a little piece of foil that makes it think any M lens is an A lens, and because they changed the way apertures work between the M (or third party) and A lenses, that makes the exposures in AV mode iffy like that, especially if I don't have the lens set to f/22 or whatever the max is for a given lens.
06-08-2015, 10:53 AM   #6
Pentaxian




Join Date: Jan 2011
Location: New York
Posts: 3,016
QuoteOriginally posted by leezihao Quote
I am on multi segment and aperture mode. If i open the aperture e.g(F3.5) the picture gets underexpose and if i close the aperture e.g(F6.3) the picture get more exposed. I thought the aperture is only for controlling the depth of field, why is it affecting my exposure when ISO and shutter are set to auto and the light meter shows that the picture is properly metered.
Might be a mechanical aperture issue. When you change from f3.5 to f6.3, the camera recalculates the shutter speed and ISO to give a proper exposure. Then, when you press the shutter release, if the aperture stays stuck at 3.5, you'll get an overexposed photo because the camera calculated everything assuming the 6.3 aperture.

Remove the lens and make sure the aperture lever is moving smoothly. Remount the lens and take a selfie closeup at f16 - look into the lens and confirm that you see the aperture snap close as you take the picture.

What lens(es) are having the problem? Try a different lens to rule out a lens problem.

QuoteQuote:
2nd, the write speed of the camera is getting from bad to worse. I've upgrade my scandisk card from 30mb/s to 45mb/s to 60mb/s but it doesn't seems to help with the write speed.
Have you changed any settings? Changing to DNG+JPG format increases the amount of data that has to be written to the card and would explain a longer write time. Enabling lens distortion or chromatic aberration correction increase the amount of processing the camera has to do.

Review your settings and consider doing a factory reset if you can't find anything wrong.
06-09-2015, 08:08 AM   #7
New Member




Join Date: Jun 2010
Location: Singapore, SA
Posts: 16
Original Poster
QuoteOriginally posted by TER-OR Quote
That exposure behavior really sounds like the ISO is not responding correctly. I'd do two things regarding firmware - make sure you've got the camera's firmware updated, and then reset the camera to factory conditions. Perhaps you've got some program setting messed up. Just a thought, and simple enough to do.

Beyond that, the lens might not be performing correctly. Make sure the contacts are clean. Make sure the aperture lever moves freely.

If I read correctly, you're operating in Av mode? What happens if you switch modes - green, TAv etc.?
The problem persists with TAv setting.

I am using the Pentax SMC DA 18-135mm WR lens, if that helps. Recently I have noticed that the lens is creeping when it is hanging on my sling. Hopefully that is not the cause of the problem.

Am going to try the recommendations over the weekend. Will start with updating the firmware and resetting to factory default setting and see if its going to solve the problem.

Thank you everyone that have replied so far
06-09-2015, 08:10 AM   #8
Loyal Site Supporter
narual's Avatar

Join Date: Jun 2013
Location: South Bend (Notre Dame), Indiana
Posts: 1,937
lens creep is pretty normal. Don't worry about it. If it bothers you you can get a LensBand or something.

06-14-2015, 02:13 AM   #9
New Member




Join Date: Jun 2010
Location: Singapore, SA
Posts: 16
Original Poster
QuoteOriginally posted by DeadJohn Quote
Might be a mechanical aperture issue. When you change from f3.5 to f6.3, the camera recalculates the shutter speed and ISO to give a proper exposure. Then, when you press the shutter release, if the aperture stays stuck at 3.5, you'll get an overexposed photo because the camera calculated everything assuming the 6.3 aperture.

Remove the lens and make sure the aperture lever is moving smoothly. Remount the lens and take a selfie closeup at f16 - look into the lens and confirm that you see the aperture snap close as you take the picture.

What lens(es) are having the problem? Try a different lens to rule out a lens problem.



Have you changed any settings? Changing to DNG+JPG format increases the amount of data that has to be written to the card and would explain a longer write time. Enabling lens distortion or chromatic aberration correction increase the amount of processing the camera has to do.

Review your settings and consider doing a factory reset if you can't find anything wrong.
I've updated the K5 software to the latest v1.16 and reset all the camera setting. Tested out the camera with 2 lens namely Pentax DA 18-135mm and Pentax FA 35mm but problem persist.

I tried to change the aperture on the FA 35mm manually when it is not connected to the camera and it works fine. But when I connect it to the camera, the aperture stays stuck at F2.0 when I look through the lens even though I have adjusted using the camera dial to change to F22 and tried to take a picture with it.

Problem of the slow writing speed was resolved upon resetting the camera setting.
06-14-2015, 09:04 AM   #10
Pentaxian




Join Date: Jan 2011
Location: New York
Posts: 3,016
QuoteOriginally posted by leezihao Quote
I've updated the K5 software to the latest v1.16 and reset all the camera setting. Tested out the camera with 2 lens namely Pentax DA 18-135mm and Pentax FA 35mm but problem persist.

I tried to change the aperture on the FA 35mm manually when it is not connected to the camera and it works fine. But when I connect it to the camera, the aperture stays stuck at F2.0 when I look through the lens even though I have adjusted using the camera dial to change to F22 and tried to take a picture with it.

Problem of the slow writing speed was resolved upon resetting the camera setting.
Since it's happening with multiple lenses and after a reset, the most likely fault is a broken aperture mechanism in your camera. Sounds like it's time for repair or replacement.

If you like tinkering take a look at the mount area to see if anything got stuck in the aperture control area. That is unlikely but could be a quick DIY repair.
06-16-2015, 07:23 AM   #11
New Member




Join Date: Jun 2010
Location: Singapore, SA
Posts: 16
Original Poster
If that is the case, anybody can direct me to the service center in Singapore?
08-03-2015, 08:29 AM   #12
New Member




Join Date: Jun 2010
Location: Singapore, SA
Posts: 16
Original Poster
Finally sent my camera for repair and the technician is kind enough to tell me that the faulty item is actually my lens instead of the camera body.
It is a faulty aperture level and it has been replaced and problem fixed.

Thank you all for your kind advises. And may this reignite my Pentax journey
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!
aperture, camera, exposure, exposure issues, help, issues, k5, pentax help, photography, picture, troubleshooting, write
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K5 II sometimes I have issues with shutter release digitaleagle12 Pentax K-5 9 04-19-2015 05:58 PM
Multiple exposure combined with wireless pttl flash do not work with Pentax K5? 645user Pentax K-5 10 01-14-2015 03:11 PM
Hello! I have a K-30 with exposure issues elijah Troubleshooting and Beginner Help 9 08-14-2013 07:07 AM
MAJOR issues with my K5!! Senseriffic Pentax K-5 21 12-11-2012 09:10 AM
Autofocus issues 50mm with new K5 ptax Troubleshooting and Beginner Help 13 12-05-2011 09:56 PM



All times are GMT -7. The time now is 05:23 AM. | See also: NikonForums.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