Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Reply
 
Thread Tools Search this Thread
Old Oct 1, 2006, 7:03 PM   #1
Member
 
Join Date: Apr 2005
Posts: 78
Default

I've noticed that many of the shots have blown highlights as shown in image review in the camera.

I'm using Multi-pattern metering, so it's evaluating the whole image and even if I set it to -0.5 Exposure Compensation I still have the problem.

I realise that if I have shiny surfaces or the sky is in the picture or the subjects are in direct sunlight I should expect blown highlights.

Here is a scene that should be easy to meter - no direct sunlight (there are no shadows ) yet still the white dress has blown highlights which means that the will be no detail in prints. I shouldn't have to use Exp Compensation in such a low-contrast situation !

Is this camera faulty or aren't multi-pattern automatic metering systems able to cope even with this easy scene ?

Here is the original and also after processing to show the blown highlights that were flashing in the camera (Midtone Compress +40 in PSP)

http://s23.photobucket.com/albums/b356/MikeAus/Pentax%20istDL/

Mike Sydney Australia

MikeAusA200 is offline   Reply With Quote
Sponsored Links
Old Oct 1, 2006, 9:00 PM   #2
Senior Member
 
nadnerb's Avatar
 
Join Date: Aug 2005
Location: Bath, UK
Posts: 319
Default

Firstly, I don't think theres anything wrong with the camera.

I think that because the dress is only a small part of the photo the exposure has been set to the darker areas in the picture (as there is more overall)

It would have been better to use spot metering on the dress in this situation.
nadnerb is offline   Reply With Quote
Old Oct 1, 2006, 9:47 PM   #3
Senior Member
 
mtngal's Avatar
 
Join Date: Nov 2005
Location: Frazier Park, CA
Posts: 16,056
Default

What a lovely scene! I rarely use the matrix metering mode, and will definitely use spot metering if there's something white. I've had a difficult time getting any detail in pictures of white azalias planted outside my office, even using spot metering. While this picture appears to be a simple one, the presence of that white dress starts to push things too much. As your second picture shows, the loss of detail was only in the dress, the rest of the scene had detail.

One other factor that might be in play here is if you took the picture as a jpg or asraw. I've found with the DS that sometimes the camera does capture detail in a part of the photo that appears to be blown out, where that detail is lost if it had been shot with jpg. I don't find that so much with the K100D - if the highlights are blown, they are really gone.
mtngal is offline   Reply With Quote
Old Oct 1, 2006, 10:12 PM   #4
Member
 
Join Date: Apr 2005
Posts: 78
Default

Well, I can only say I'm disappointed with DSLR metering - I've loaded a photo taken with an Olympus Mju/Stylus 300 sub-compact with white sails covering a small part of the scene. The bright parts of the sails have not blown - only the tinywhite painted equipment just above the black hull.

The posing for the wedding photo is thanks to the brilliant Professional Photographer Shane O'Neill - I was just "free-loading" at my nephew's wedding. You should see some of the other poses !!!

Mike Sydney Australia
MikeAusA200 is offline   Reply With Quote
Old Oct 2, 2006, 2:36 AM   #5
Senior Member
 
Join Date: Sep 2004
Location: Wigan, UK
Posts: 568
Default

the sailship photo form olympus is properly exposed without blown highlighst because half of it is clear bright blue sky while wedding photo from DSLR has dark bacground with two very bright subjects in the middle. matrix metering is good when brightness of scene is well balanced, if you have something really brighter or darker it won't be exposed properly. if you tried to shoot both scenes again using olympus for wedding and pentax for ship you'd get similar results. this is not very easy scene to meter, even with spot metering white dress would be properly exposed but rest might be too dark. it would be easier to correct it with layers in Photoshop though.

greg
gfurm is offline   Reply With Quote
Old Oct 2, 2006, 2:48 AM   #6
Member
 
Join Date: Apr 2005
Posts: 78
Default

Surely the whole point of Multi-pattern metering is to expose correctly for digital - i.e. for the highlights - not for the average plus a margin for the guessed highlight !

The white sails are much brighter than the blue sky, so I don't see that reducing the exposure sufficiently.

Mike
MikeAusA200 is offline   Reply With Quote
Old Oct 2, 2006, 3:47 AM   #7
Senior Member
 
nadnerb's Avatar
 
Join Date: Aug 2005
Location: Bath, UK
Posts: 319
Default

You can't compare those 2 photos though as the lighting conditions are very different.

The boat is obviously well lit as its a nice day with a bright blue sky.
In that scene almost everything is receiving the same even amount of light from the sun.

Compare that to the wedding photo with bright sunlight and varying levels of light in different parts of the scene. Not to mention the couple are standing just inside the building where its dark. Its not an easy scene for the camera at all. It would be difficult to shoot this with any digital camera.

Cameras can only record a certain range of light at one time.
For simplicity lets say there are 10 levels of light ranging from 1(dark) to 10(very bright light)
Now lets say a camera can only capture a range of 7 levels, which means whatever settings you use, you will lose 3 levels of light.

You could set your camera to record levels 1-7. (eg. slow shutter)
This would capture detail in all the dark areas, but any bright lights will be blown.
You could also set your camera to record levels 4-10. (eg. fast shutter)
This would capture the previously blown highlights but wouldnt show as much detail in the shadows.
There's no way to capture all 10 levels (Well it's possible, but not in a single shot) so you'll either have dark shadows, or blown highlights if you have a wide range of light levels.

The boat picture has been exposed to the bright sails and the sky. Notice how under the bridge its dark with no detail? That's the same as whats happened in the wedding scene, but in reverse. Its exposed to the surroundings, blowing out detail in the dress.
nadnerb is offline   Reply With Quote
Old Oct 2, 2006, 5:54 AM   #8
Senior Member
 
Join Date: Sep 2004
Location: Wigan, UK
Posts: 568
Default

the multi pattern average metering works by dividing scene for 16 smaller regions and finding correct exposure for each of them, then averaging them. so if you have 15 zones with low brightness (let's say 4 on scale from 1 to 10) and one very bright (let's say 9) it will expose for ((15x4)+9)/16 which is 4.3 on our scale of brightness (sorry for this math but I think it's the easiest way to explain it). so it's exposing for average brightness of a scene of 4.3 but because you have very bright area of 9 this area is overexposed. that's why you have 3 meternig modes to choose from, multi segment for even bright scenes, centre weighted for bigger difference between subject in centre of frame and bacground and spot metering for situation like on your wedding photo.

the result also depends on how many metering zone camera uses for multi pattern. multi segment metering is not a wonder thing which will make all your photos correctly exposed. that's why for shooting landscape you have to use ND grad filters, to lower brightness of the sky so camera meter can do it's job properly.

and you have to remember that diffrerence in brightness between white sail nad clear blue sky is much smaller than white dress and grey rock wall.

hope that helps

greg
gfurm is offline   Reply With Quote
Old Oct 2, 2006, 6:10 AM   #9
Senior Member
 
danielchtong's Avatar
 
Join Date: Dec 2005
Posts: 2,890
Default

I second that. Also he may try a ND filter say +1 or +2. Given the harsh lighting situation, that is not even an issue with the metering.

Daniel


gfurm wrote:
Quote:
the sailship photo form olympus is properly exposed without blown highlighst because half of it is clear bright blue sky while wedding photo from DSLR has dark bacground with two very bright subjects in the middle. matrix metering is good when brightness of scene is well balanced, if you have something really brighter or darker it won't be exposed properly. if you tried to shoot both scenes again using olympus for wedding and pentax for ship you'd get similar results. this is not very easy scene to meter, even with spot metering white dress would be properly exposed but rest might be too dark. it would be easier to correct it with layers in Photoshop though.

greg
danielchtong is offline   Reply With Quote
Old Oct 2, 2006, 4:24 PM   #10
Senior Member
 
jabilson007's Avatar
 
Join Date: Jul 2006
Posts: 182
Default

I have been battling this problem since I purchase my DL in July. I have tried all 3 metering modes, ND filters, polarizers, and RAW. My best results have been with using P mode, Natural tone, Jpeg Best, Saturation +1, Sharpness +1, Contrast -1(this is the key), Center weighted metering, Spot focusing, Single AF mode and an Exposure compensation of 0.5-1.0. Try this and report back your results. I don't like shooting RAW because of all the post processing to be done and it eats up drive space. All in all I am not totally pleased with the response of this camera. It is the least expensive DSLR available and I suppose the results confirm that. When I have time I'll post some samples.
jabilson007 is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 6:57 AM.