Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-17-2012, 04:22 PM   #1
Inactive Account




Join Date: Mar 2012
Photos: Albums
Posts: 6
K-5 Underexposure in "P" Mode

I have a new Pentax K-5.

I have noticed a significant underexposure problem in Program ("P") mode - atleast 1.5 stops. The green-mode exposure is correct (but green mode does not allow RAW).

While I understand that the issue can be corrected with photoshop (especially in RAW images), I would like to understand if this is normal or a defect.

Also, I was wondering if there are others in the forum who have faced a similar problem.

Regards, ASB

Equipment: Pentax K-5, Tamrom 17-50mm f2.8, Pentax 35mm f2.4

04-17-2012, 04:40 PM   #2
Site Supporter
SpecialK's Avatar

Join Date: Dec 2006
Location: So California
Photos: Gallery
Posts: 14,430
Here are some of mine...

https://www.pentaxforums.com/forums/pentax-k-5-forum/161077-odd-exposures.html
04-17-2012, 04:41 PM   #3
Senior Member




Join Date: May 2009
Location: Edmonton, AB
Posts: 245
People on this forum are a helpful bunch but you should post pictures to demonstrate the issue. From what I understand, underexposure can cause by bright background (eg. snow scene) or spot metering on a bright spot.
04-17-2012, 04:44 PM   #4
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,678
Indeed we do have to see the scenes you have captured, with intact EXIF to allow us to analyse the situation better. But generally auto exposure can vary according to the lighting balance on the scene, the metering mode and the AE-L mode (link with AF point or not).

04-17-2012, 04:46 PM   #5
asb
Inactive Account




Join Date: Mar 2012
Photos: Albums
Posts: 6
Original Poster
Thanks for your messages! I have actually taken exactly the same subject using "green" and "p" mode. Let me post the two images for you to review..
04-17-2012, 05:14 PM   #6
asb
Inactive Account




Join Date: Mar 2012
Photos: Albums
Posts: 6
Original Poster
Here are the images:

asb's Album: Exposure - PentaxForums.com

IMGP0926 : P mode
IMGP0927 : Green mode

Latter taken immediately after the former.
04-17-2012, 05:20 PM   #7
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,678
Something's not right with the metering - #1 is way off (1/800 at f/10) compared to #2 (1/250 f/4).
Reset your camera settings if you don't know about the things I mentioned before, and try shooting again, this time ensuring you don't move any of the e-dials when shooting in P mode.
04-17-2012, 05:23 PM   #8
Forum Member




Join Date: Dec 2010
Location: Southeast USA
Photos: Gallery
Posts: 91
The under exposed image was taken with spot meter and metered off the white towel which caused the under exposure. The other was taken with pattern metering which must be default for green mode. If you change the metering switch to pattern you should get the same exposure in either the P or green mode.


Last edited by dvest; 04-17-2012 at 05:30 PM.
04-17-2012, 05:29 PM   #9
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,678
That's the most likely explanation, though even still the towel is considerably underexposed.
04-17-2012, 05:32 PM   #10
MSL
Pentaxian
MSL's Avatar

Join Date: Feb 2012
Location: Greater Toronto Area
Photos: Albums
Posts: 3,359
Well spotted @dvest. It is worth looking at the manual (p.103) which shows which settings are used (or overridden) when shooting in green mode.
04-17-2012, 05:37 PM   #11
Forum Member




Join Date: Dec 2010
Location: Southeast USA
Photos: Gallery
Posts: 91
QuoteOriginally posted by Ash Quote
That's the most likely explanation, though even still the towel is considerably underexposed.
The towel is white but the meter is going for 18% gray which is what it's supposed to do. Looks like it is a little under exposed. To get the towel to come out white you would need to over expose.

Just noticed white balance is also set different on each image.

Last edited by dvest; 04-17-2012 at 05:52 PM.
04-17-2012, 05:57 PM   #12
Veteran Member
creampuff's Avatar

Join Date: May 2007
Location: Singapore
Photos: Gallery
Posts: 3,955
Rookie mistake not knowing how the metering modes differ. Nothing wrong with the camera, problem lies behind the camera.
04-17-2012, 06:38 PM   #13
MSL
Pentaxian
MSL's Avatar

Join Date: Feb 2012
Location: Greater Toronto Area
Photos: Albums
Posts: 3,359
QuoteOriginally posted by creampuff Quote
Rookie mistake not knowing how the metering modes differ. Nothing wrong with the camera, problem lies behind the camera.
Not sure if you meant this as a harsh comment, but it comes across like one, at least to me. If the OP had deliberately switched from spot to pattern metering that would be one thing, but here was a case of changing from one mode to another, only to find that the metering and possibly the white balance had been quietly set to something else. Certainly a case of needing to read the manual, but even then one could easily miss the one key page and still be lost.
04-17-2012, 06:45 PM   #14
Forum Member




Join Date: Dec 2010
Location: Southeast USA
Photos: Gallery
Posts: 91
I've had my share of mistakes and am pretty sure there will be more to come!
04-17-2012, 06:58 PM   #15
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,678
Green mode defaults to matrix metering. It's more likely that the OP had his metering dial set on spot metering the whole time and din't recognise its importance in metering.
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!
camera, dslr, k-5, k-5 ii, k-5 iis, k5, mode, pentax, pentax k-5, underexposure
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Post your "Park Bench" "or "Picnic Table" images tessfully Mini-Challenges, Games, and Photo Stories 1346 1 Day Ago 11:08 AM
Don't say Pentax "Q" in French ... "Q" = "cul" = "A--" Jean Poitiers Pentax Q 52 11-10-2013 06:25 AM
Play Mode - Error Message: "This image cannot be enlarged" brosen Pentax K-5 11 10-30-2011 09:59 PM
Program mode: "Auto" vs. "Normal"? PALADIN85020 Pentax K-5 3 02-13-2011 12:22 PM
K7 ... where has the metering "bar" gone in manual mode? jpzk Pentax DSLR Discussion 3 06-25-2010 07:26 AM



All times are GMT -7. The time now is 03:11 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