Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-19-2011, 08:35 PM   #1
New Member




Join Date: Dec 2010
Posts: 3
K-x metering issue (underexposing shots)

I've had a K-x for almost a year now and I'm having some trouble with underexposed images. It seems that I have to go to +1 on the exposure to get a properly exposed shot, otherwise it comes out too dark. The lens I'm using is a Tamron 17-50mm f2.8.

I also have a Lensbaby composer and when I shoot with that (aperture priority with the aperture set to match the Lensbaby) I need to crank the exposure up to almost +2.

Has anyone else experienced anything similar?

07-19-2011, 08:47 PM   #2
New Member




Join Date: Dec 2010
Posts: 3
Original Poster
By the way, I'm not trying to imply that the metering issue is dependent on lens selection because, logically, I can't think of a reason it would be. I'm just explaining my observations.
07-19-2011, 08:47 PM   #3
Veteran Member




Join Date: Nov 2009
Location: Iowa
Photos: Albums
Posts: 2,269
Yep. And not just with my K-x. It also happens with the K100D & *istDS. I've discovered that some lenses consistently under or over-expose by a stop or so, no matter what body they're on. Some lenses just vary a little. I'd just make a mental note of which lenses underexpose, and when you mount the lens, set your exposure comp & forget it. That's probably why it's there.
07-19-2011, 08:58 PM   #4
Site Supporter
K57XR's Avatar

Join Date: Feb 2011
Location: Colorado, USA
Posts: 811
Same here with the 17-50 on my K-x. I shoot RAW so it isn't really an issue, for me at least. If you google "Tamron 17-50 underexposed" you'll get results from years back, some from this very forum.

07-19-2011, 09:02 PM   #5
Veteran Member
NicoleAu's Avatar

Join Date: Jul 2010
Location: Central Coast, NSW, Australia
Photos: Gallery
Posts: 539
Yep, I think Pentax cameras have a tendency to underexpose. I usually adjust in pp, unless I need high key shots.
07-19-2011, 09:21 PM   #6
Pentaxian
twitch's Avatar

Join Date: Nov 2009
Posts: 4,571
I've heard that about the Tam 17-50.

I found my K-x usually needs +1/3 for my DA lenses, and +0 for my FA's.
07-20-2011, 05:40 PM   #7
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,576
My 17-50 also under-exposes by about 1 stop. It is the only lens I own that does so.
I also own two other modern Tamron lenses and they meter fine.

It may have something to do with the fact that non-Pentax lenses by default will only work in center-weighted AE metering mode on the K-x/K-r/K-5 etc etc, not the full matrix AE metering. Full matrix metering only works with newer Pentax lenses. It can make a noticeable difference to some scenes - eg backlit subjects etc.

Shooting in RAW is an effective remedy for the issue, but it is still a nuisance nonetheless. There must be something in the way the 17-50's electronics report the settings of the lens to the camera body.
07-21-2011, 12:48 AM   #8
Veteran Member




Join Date: Jan 2009
Location: Budapest
Posts: 821
QuoteOriginally posted by rawr Quote
non-Pentax lenses by default will only work in center-weighted AE metering mode on the K-x/K-r/K-5 etc etc, not the full matrix AE metering. Full matrix metering only works with newer Pentax lenses.
No, this isn't true. Matrix metering is available and works with any AF lens. You're limited to center-weighted with MF lenses since they obviously can't transmit focus distance info.

07-21-2011, 01:50 AM   #9
Senior Member




Join Date: May 2010
Location: Bangalore
Photos: Albums
Posts: 174
I am using K-x for over a year now and by default my K-x under exposes and so I calibrated by using a default +1/3 EV compensation with my DA 16-45 and other Pentax lenses. I think that's where it properly meters for medium tones. Photographer John Shaw explained this in his book "Nature Photography Field Guide".

Guna
07-21-2011, 07:14 AM   #10
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,576
QuoteOriginally posted by simico Quote
Matrix metering is available and works with any AF lens.
The Pentax manuals for the K-x, K200D, K-7 amd K-5 suggest otherwise, but I could be wrong I guess in interpreting what they say.

I also know that (for example) my Tamron 17-50 when set to matrix AE metering does a worse job metering scenes than the DAL 18-55 kit lens. The Tamron always performs as if it is doing center AE metering, whereas the Pentax kit lens clearly meters differently when set to matrix than when set to center AE.

Maybe it is just my sample of the Tamron lens.
07-21-2011, 07:45 AM   #11
New Member




Join Date: Dec 2010
Posts: 3
Original Poster
Okay, whew...I thought there was something wrong with my camera. Thanks all for the info!
07-21-2011, 07:55 AM   #12
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,631
QuoteOriginally posted by gut1kor Quote
I am using K-x for over a year now and by default my K-x under exposes and so I calibrated by using a default +1/3 EV compensation with my DA 16-45 and other Pentax lenses.
Are you shooting jpegs? I shoot raw and I don't expose for mid-tones. I expose to protect highlights, so IMO the K-x overexposes.

I took a lot of photos recently on a trip to Paris, about 2/3 with the K20D and 1/3 with K-x. Conditions were difficult, a lot of outdoors shots with high contrast and dim churches with bright windows. I had to back off -1Ev and boost midtones on virtually every single K-x shot. Most of the K20D photos needed no adjustment in post.
07-21-2011, 07:46 PM   #13
Senior Member




Join Date: May 2010
Location: Bangalore
Photos: Albums
Posts: 174
QuoteOriginally posted by audiobomber Quote
Are you shooting jpegs? I shoot raw and I don't expose for mid-tones. I expose to protect highlights, so IMO the K-x overexposes.
yes, initially. But lately I have been shooting in RAW and using center weighted metering. But for any critical subjects, I use spot metering in which case I had to meter based on the tonality of the subject. This process is working fine as of now. BTW I shoot in AV mode only.
07-23-2011, 01:42 PM   #14
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
As usual, it would help if you posted samples. Usually when people report udnerexpose, there turns out to be a simple explanation - like them not realizing how much a bright highlight or background or a lighter-than-average subject can affect exposure. But it's also possible there is a problem. Pictures (with Exif intact) would help determine which is the case.
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, dslr, exposure, k-x, lensbaby, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Spotmatic F Metering Issue Periodista Pentax Film SLR Discussion 4 09-22-2010 04:18 PM
Help - Metering issue neoyoda Pentax DSLR Discussion 7 09-18-2010 12:52 PM
Pentax MX metering issue deadwolfbones Pentax Film SLR Discussion 9 09-07-2010 10:39 AM
Metering Issue Using M Prime (Kx) Iceburg98 Troubleshooting and Beginner Help 21 04-16-2010 11:26 AM
ZX-M metering issue LMRacing Pentax Film SLR Discussion 5 09-13-2009 07:41 PM



All times are GMT -7. The time now is 05:28 PM. | 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