Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-29-2010, 03:35 AM   #1
Inactive Account




Join Date: Feb 2010
Posts: 17
Pentax K7 and underexposure

Hi again,
unfortunaltey I still have some troubles in the exposure thing with my brand new Pentax K7 (I had a similar thread about the lens Sigma 2,8 18-50, which is fixed meanwhile by Sigma) - think I shouldn't buy things on mondays

After that the K7 itself stil was too dark and I returned it to Pentax (Germany) for calibration (of course it's still under warranty) and got it back last week (after three weeks).

When picking it up in the the shop I made some tests there and didn't find any changes! (BTW the shop salesmen completely agreed that the shots were far too dark). Now after the shop called Pentax Germany I got the following statement:
  • they did a firmware update (which is strange because it was already 1.03)
  • the exposure behaviour can not be changed as the default with Pentax K7 is to darken the pictures in order to save highlights!! (meaning: It's not a bug it's a feature)

Hard to believe the latter as there is a menue setting for highlight saving that was set to "off" and I always thought this means "off".

So my question is: Does anybody encounter the same? Is it normal that taking a grey card picture the K7 gives you a histogramm that shows the peak at roughly 25% of the x-axis. Do I really have to set my exposure bias to a standard +0,7 with a brand new 1.000 camera?

Ulrich

04-29-2010, 03:53 AM   #2
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,352
You need to post some shots. Also do a test against a block wall with uniform daylight. Remember the peak of the histogram in a s ene is not necessairly the metering point
04-29-2010, 04:01 AM   #3
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 15,344
The K7 to me consistently under exposes at about .3 to .7 EV. At the same time, they are right that blowing highlights is a bad thing. Just dial in +.3 or .7 EV compensation and go with it. It really is more about taste than anything else (and avoiding blowing highlights). Truthfully, the K7 exposes brighter than the K20 or K10 is much less likely to be fooled by shiny objects in a photo.
04-29-2010, 04:08 AM   #4
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,243
QuoteOriginally posted by Rondec Quote
The K7 to me consistently under exposes at about .3 to .7 EV. At the same time, they are right that blowing highlights is a bad thing. Just dial in +.3 or .7 EV compensation and go with it. It really is more about taste than anything else (and avoiding blowing highlights). Truthfully, the K7 exposes brighter than the K20 or K10 is much less likely to be fooled by shiny objects in a photo.
More or less my reading of the situation too, and I just live with it as well. Bracketing is your friend.

04-29-2010, 04:33 AM   #5
Veteran Member
Jasvox's Avatar

Join Date: Oct 2007
Location: Melbourne, Australia
Posts: 3,110
I am finding the only time I notice my K-7 underexposing is with one particular lens that I have. When I shoot with it, I usually compensate by increasing expose by .03 to .07 and that seems to keep it true. Also, on another lens I frequently use, I find it slightly over exposes. On my primes, it exposes perfectly. Are you getting underexposure with all of your lenses?

Jason
04-29-2010, 05:08 AM   #6
Veteran Member




Join Date: Jun 2009
Location: Philadelphia
Posts: 478
QuoteOriginally posted by Rondec Quote
The K7 to me consistently under exposes at about .3 to .7 EV. At the same time, they are right that blowing highlights is a bad thing. Just dial in +.3 or .7 EV compensation and go with it. It really is more about taste than anything else (and avoiding blowing highlights). Truthfully, the K7 exposes brighter than the K20 or K10 is much less likely to be fooled by shiny objects in a photo.
Same here. I'm used to Olympus which tends to expose to the right (at least used to with older models). For the K-7, I usually hit exposure compensation for a + 1/3 or 2/3.
04-29-2010, 06:22 AM   #7
Veteran Member




Join Date: Dec 2009
Location: Bucharest
Posts: 482
I had the same problem.

Check if you have set the automatic exposure compensation to ON

The behaviour of this setting is that, if you use matrix metering it evaluates the exposure of the whole frame and, if you shoot something darker with a more lightened backgrount, the K 7will underexpose the image in order to preserve background detail

Later, if you use automatic fix in some post processing you should see (at least I did) that the image is greatly improved while preserving details on all the frame.

That might be an explanation.
04-29-2010, 06:40 AM   #8
Veteran Member




Join Date: Aug 2007
Photos: Gallery
Posts: 1,563
QuoteOriginally posted by ulrich Quote

the exposure behaviour can not be changed as the default with Pentax K7 is to darken the pictures in order to save highlights!! (meaning: It's not a bug it's a feature)


Ulrich
Ulrich,

I'm sorry you feel this way, since to my experience the K-7 is a very fine camera.
Perhaps it is something different than you are used to.

Two things: first, I guess the statement that the K-7 sensor is better in low light than in high light is correct.
See: Pentax K-7 Review: 18. Photographic tests (DR): Digital Photography Review
You can also check the DR analysis of the Canon 7D bydpreview for another comparison with the K-7.

So, yes, if you want you could up the Ev value, either while shooting or in post processing.
I advise you to do that in PP. You'll preserve more detail.

One more thing. I have camera's of different brands, and after a few years with Pentax, I believe that the Pentax "darker" representation is much more often correct = like the environmental conditions when the photo was made.
Let me refrase. I think most camera's make photos too light, perhaps avoiding noise. As also most P&S camera's make photo's too sharp.

Maybe it is all a matter of taste?

- Bert

04-29-2010, 12:45 PM   #9
Inactive Account




Join Date: Feb 2010
Posts: 17
Original Poster
K7 and underexposure

Thanks a lot for all your replies. That all brings me back to "my" K7 again. I fact I really like the K7 as I was looking for a rock solid but "light" body. I would neither like to carry a Nikon D300 in my rucksack for days nor a plastic body in rough conditions.

Anyway it was just this exposure thing that confused me, but this thread made me feel confident that it's not my camera that fails, but it's Pentax style, which makes it a lot easier to live with it.
@Jasvox. Only had a difference with my (new) Sigma lens 2.8/18-50compared to my old 3-4 MF Pentax Tokina lenses (from LX days.....). But now after Sigma fixed it they are all within the same level.

Thank again! Great camery ... and a great forum

Ulrich
04-29-2010, 05:36 PM   #10
hcc
Pentaxian
hcc's Avatar

Join Date: Nov 2009
Location: Brisbane, Australia
Photos: Gallery | Albums
Posts: 3,501
QuoteOriginally posted by Nass Quote
" Originally posted by Rondec The K7 to me consistently under exposes at about .3 to .7 EV. At the same time, they are right that blowing highlights is a bad thing. Just dial in +.3 or .7 EV compensation and go with it. It really is more about taste than anything else (and avoiding blowing highlights). Truthfully, the K7 exposes brighter than the K20 or K10 is much less likely to be fooled by shiny objects in a photo."
More or less my reading of the situation too, and I just live with it as well. Bracketing is your friend.
Same for me.

I modify the exposure during PP however, using PCDU 4..

Last edited by hcc; 04-29-2010 at 05:45 PM. Reason: Typo
04-30-2010, 09:00 PM   #11
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by ulrich Quote
Is it normal that taking a grey card picture the K7 gives you a histogramm that shows the peak at roughly 25% of the x-axis.
Roughly 25%? No. ISO standards call for it to be about 1/3 to 1/2 a stop left of center - which would put it at maybe 40% or so. But how it performs on a grey card isn't really the issue - it's how it performs in real life scenes. It's of course normal to need positive compensation on scenes that are brighter than average or that are backlit or contain light sources or bright reflections. But there should also be situations where you would need negative compensation - scenes darker than average.
05-13-2010, 01:33 PM   #12
Senior Member




Join Date: Oct 2009
Location: DC Metro, USA
Posts: 212
My K-7 underexposes about 1/3 - 2/3 stop, I kind of like it this way since I like to 'tune up' the brightness myself rather than letting the in-camera JPEG engine taking over My Nikon overexposes about the same amount.
05-13-2010, 01:45 PM   #13
Veteran Member
MJB DIGITAL's Avatar

Join Date: Jul 2007
Location: st. louis
Posts: 1,173
shoot manual?
05-13-2010, 03:15 PM   #14
Site Supporter
SpecialK's Avatar

Join Date: Dec 2006
Location: So California
Photos: Gallery
Posts: 14,633
QuoteQuote:
shoot manual?
Shooting mode is immaterial. The light meter reads the same regardless of the mode.
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!
brand, camera, dslr, exposure, germany, k7, pentax, pentax k7, photography, shop, sigma
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
MZ-7 and underexposure photolady95 Pentax Film SLR Discussion 89 07-09-2009 09:44 AM
underexposure karq Photographic Technique 11 12-10-2008 07:51 AM
K10D underexposure + Pentax Colorado jshurak Pentax DSLR Discussion 17 04-12-2008 10:54 AM
problem with underexposure joaosoares5 Pentax DSLR Discussion 7 03-23-2008 08:50 AM
Pentax 18-55 Kit lens underexposure? PentaxScott Pentax DSLR Discussion 11 01-18-2008 08:11 AM



All times are GMT -7. The time now is 06:07 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