Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-13-2010, 12:27 PM   #1
Junior Member




Join Date: Dec 2008
Location: Taipei
Posts: 34
Inconsistent color balance in K7

Just got the K7, and tonight, while I was playing hockey, a buddy shot the game.

Had the camera set to TAv mode, Auto White Balance, re-adjusting every 3 secs. Thing is, he was taking rapid fire shots, and the first couple came out bright and beautiful, but the subsequent 2 or 3 are definitely off -- more sickly yellow than white. The time lapse is under a second or two, so I think they ought to have the same WB setting, and the lighting conditions are consistent enough, so that's not the issue.

Have I gone wrong somewhere?

On the left, you'll see five images, shot within 2 seconds of one another, straight out of the can.
On the right, the same images, run through auto color and tone filters on PS4 to highlight the differences.



Oh, settings.
#1, #2: 1/320, f/3.5, ISO800
#3, #4, #5: 1/320, f/3.5, ISO1000
Shot with a 50~135, f/2.8. Should have been set at 2.8, but my friend didn't know that.

The ISO shift explains why the first two are slightly brighter, but not why #1 is brighter than #2, and not why the final three are all very different.

Same deal. Identical settings, photos taken within a second of each other.



I'm sure there's a good explanation out there, but I've no clue and would greatly appreciate guidance.
Thanks.


Last edited by Jaboney; 03-13-2010 at 01:07 PM. Reason: Image added.
03-13-2010, 12:35 PM   #2
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,211
Perhaps auto WB was the wrong setting?
03-13-2010, 12:44 PM   #3
Junior Member




Join Date: Dec 2008
Location: Taipei
Posts: 34
Original Poster
That may be. But the lighting is very inconsistent, not to mention dark, and I have no idea how to shoot the entire playing surface without resorting to Auto White Balance.

These shots were taken fractions of a second apart, so the play hasn't moved far and the lighting is pretty much the same between shots. There shouldn't be such a profound difference in outcome.
03-13-2010, 03:31 PM   #4
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,211
Sorry . I can't help you - I've never used auto WB on mine. I've never had shifts on any of my inside stuff, I disable as much automation as I can .

03-13-2010, 03:37 PM   #5
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,043
That looks like a problem with the lights being out of phase when you were shooting.
I've had the same thing happen when shooting under florescent lights.

Last edited by Wheatfield; 03-13-2010 at 04:54 PM. Reason: spelling
03-13-2010, 04:12 PM   #6
Pentaxian




Join Date: Oct 2006
Location: Chicago suburb, IL, USA
Posts: 1,535
QuoteOriginally posted by Jaboney Quote
That may be. But the lighting is very inconsistent, not to mention dark, and I have no idea how to shoot the entire playing surface without resorting to Auto White Balance.

These shots were taken fractions of a second apart, so the play hasn't moved far and the lighting is pretty much the same between shots. There shouldn't be such a profound difference in outcome.
Hi Jaboney,

With reasonably consistent lighting, I would think Custom WB set on a white section of the ice would be more appropriate to consistent color. The few times I've shot ice hockey, this has worked for me with everything from a P&S to DSLRs. Although I find AWB on the K7 to be very good 95% of the time, it can be fooled, and sometimes inexplicably. . . as in your examples.

Scott
03-13-2010, 04:14 PM   #7
Veteran Member
GoremanX's Avatar

Join Date: Dec 2009
Location: Georgia, VT
Photos: Albums
Posts: 1,652
Yep, looks like some of the lights might be on different circuits, and you're catching some of them in a different phase than the others. If you watched the Olympics at all, you probably noticed the "flickering" that happened to the lighting when they were showing replays at super-slow speed. The video camera was capturing frames at such a high rate, it was catching the alternating current of the lights that we don't normally perceive. When that flickering happens on different circuits, it can really mess up your shots.

Also, if you had AutoWB set, that would cause fluctuations in colours from shot to shot. Just like exposure, the amount of white in your picture can mess up the WB. When taking pictures of hockey players on ice, you should have a specific white balance set.

You mentioned that the lighting was very consistent, so why were you using an automatic mode? If lighting was consistent, you could have left the camera in Manual mode with the exact same settings for the whole shooting session and every picture would've turned out the same. The varying amount of ice in your pictures makes the light meter mess up for each shot.
03-13-2010, 09:59 PM   #8
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
Fluorescent lighting looks consistent to our eyes, but not to a camera that takes pictures in under 1/60". It's easy to get exactly the sort of results you see when shooting in fluorescent lighting.

03-13-2010, 10:22 PM   #9
Junior Member




Join Date: Dec 2008
Location: Taipei
Posts: 34
Original Poster
Hmm... catching the action in different cycles of overhead lights seems a likely explanation. The situation would be far better, I expect, if the arena would turn on more than 1/3 of the lights.

I used to have a K100D and would reset the WB each time I moved to a different part of the rink, but still, as the play moved down or across the ice, results would change. My hope was that the K7's superior 'brain' would compensate for those changes on it's own. I'm much happier with the image quality, and it's not that difficult to make corrections after the fact, but we shoot so many photos each game, and play so many times each week... the time adds up.

Interestingly, the video appears to be far brighter and more consistent.

Thanks all.
03-13-2010, 10:39 PM   #10
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,043
The video is likely shooting at a slower shutter speed. This is not a problem with the camera, this is a problem with your exposure time being short enough to catch varying spectrums of light.
In other words, this is an operator error.
03-14-2010, 09:43 AM   #11
Junior Member




Join Date: Dec 2008
Location: Taipei
Posts: 34
Original Poster
QuoteOriginally posted by Wheatfield Quote
In other words, this is an operator error.
Good call. Tonight I did the shooting. Played around with the White Balance, changed the focusing method. Found a sweet spot, locked there, and got fabulous results. There's still a fair degree of variation between essentially identical shots, but once again, I am a very happy camper.
03-14-2010, 10:07 AM   #12
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,043
QuoteOriginally posted by Jaboney Quote
Good call. Tonight I did the shooting. Played around with the White Balance, changed the focusing method. Found a sweet spot, locked there, and got fabulous results. There's still a fair degree of variation between essentially identical shots, but once again, I am a very happy camper.
Excellent. I have a wonderful series of my dog doing a recall at the training hall which uses florescent lights. I was shooting at a high enough speed to give me more or less the same thing that you got.

I definitely fall into the learn by screwing it up category.

You can eliminate more of the variation by dropping your shutter speed a bit so that the shutter is open long enough to catch the entire light phase, but this may not be acceptable for other reasons, such as needing to freeze the action.
I don't shoot a lot of hockey, certainly not enough to be any good at it, but I think I would just crank in a stop or so of plus exposure comp to make sure the pictures were bright enough and dial them back if needed.
A buddy of mine shoots a lot of hockey during the season, I could ask him what he does if you like.
03-14-2010, 11:27 AM   #13
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,211
One other thing that might get you more consistent results, the K-7 also performs fine tuning with Wb when set. Play around with custom setting 11
04-05-2010, 03:28 AM   #14
Junior Member




Join Date: Dec 2008
Location: Taipei
Posts: 34
Original Poster
Thanks again for the pointers.

I got far better results after manually adjusting the white balance. Better results again after installing the latest firmware. Unsurprisingly, I got VASTLY better results this weekend when the arena hosted a major tournament and turned on ALL the lights, rather than 25% of them as they usually do.






Quite happy with the video as well. Going to have to start outputting files in superior formats and get on Vimeo to do it justice. On other nights, there's an occasional white 'flash' in video mode. Haven't yet pinned down why. Didn't have any problem this night.

[YT]http://www.youtube.com/watch?v=pwApKITyrMw[/YT]
04-05-2010, 09:29 AM   #15
Veteran Member




Join Date: Mar 2007
Location: Toronto (for now)
Posts: 1,749
This is why we shoot RAW. Takes about 3 miliseconds to get the WB for all images identical.
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!
auto, balance, camera, color, color balance, f/3.5, images, k7, pentax help, photography, settings, shot
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need photoshop color balance help spystyle Troubleshooting and Beginner Help 8 11-30-2009 07:17 AM
Inconsistent prints Old Film Guy Troubleshooting and Beginner Help 5 08-31-2009 06:56 PM
RAW vs Manual White Balance for Color Cast Correction JCharles Pentax DSLR Discussion 18 11-09-2008 07:35 AM
Do oversaturation and warmer color balance sound like sickness? Adnan EROL Photo Critique 7 11-12-2007 06:19 PM
Auto white balance vs. daylight balance outdoors. fevbusch Pentax DSLR Discussion 7 02-18-2007 03:04 PM



All times are GMT -7. The time now is 04:46 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