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01-03-2009, 01:19 PM   #1
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K20D Exposure

I used my K20D this past week in Yellowstone. I came across two bison who began to butt heads. The light was flat and cloudy and a bit bright on a snowfield. I had the EV set to +1 stop and was bracketing -1 to +1. The images were still underexposed between 2 and 3 stops. The metering was set to multi-segment. Here's a sample image with PP in Lightroom 2.2. Any suggestions?


01-03-2009, 03:01 PM   #2
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dark subject + light background + matrix metering = pretty much totally unpredictable.

Try spot metering the bison, then knocking the EV's down a couple of stops.
01-03-2009, 03:53 PM   #3
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QuoteOriginally posted by wtlwdwgn Quote
I used my K20D this past week in Yellowstone. I came across two bison who began to butt heads. The light was flat and cloudy and a bit bright on a snowfield. I had the EV set to +1 stop and was bracketing -1 to +1. The images were still underexposed between 2 and 3 stops.
The image you posted is horribly *overexposed* - the detail in the ground is completely blown out. The camera was trying to preserve the detail in the ground - and actually, it would have been trying to make it look medium gray, not white. It is absolutely normal to have to dial in positive exposure ompensation when dealing with a scene dominated by white like this. Or you could have spot metered on the bison, or on some other medium-colored object nearby and then locked exposure using AE-L.
01-03-2009, 10:43 PM   #4
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Marc, I agree with you. I was trying to show detail in the two bulls and let the snow blow out. Even with exposure compensation there is still very little detail in the animals.

This is the original which is +1 EV and +1 bracket stop.


Here is a redone PP keeping more detail in the snow.


01-05-2009, 06:44 AM   #5
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What we have here is a dynamic range problem. Since bracketing three stops fails to produce a photo that keeps details in the snow AND the bison, the lighting conditions exceed the capability of the sensor. Not much you could do except perhaps use Fill flash (an external unit) to light the bison up, and allow the ambient exposure to keep the snow from blowing out. Cool photo, shame about the lighting though...

Marc - Spot metering the bison would have exposed the bison properly, but would have blown out the snow.
01-05-2009, 07:08 AM   #6
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QuoteOriginally posted by egordon99 Quote
What we have here is a dynamic range problem. Since bracketing three stops fails to produce a photo that keeps details in the snow AND the bison, the lighting conditions exceed the capability of the sensor. Not much you could do except perhaps use Fill flash (an external unit) to light the bison up, and allow the ambient exposure to keep the snow from blowing out. Cool photo, shame about the lighting though...

Marc - Spot metering the bison would have exposed the bison properly, but would have blown out the snow.
One thing I have experience with is snow pictures. That is almost an unphotographable scene.
For future, go to center weighted metering and set your exposure comp to something like +3.
Don't ever forget that as far as your meter is concerned, everything is gray card coloured, and you have to compensate for that when in extreme conditions.
01-05-2009, 11:44 AM   #7
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QuoteOriginally posted by egordon99 Quote
Marc - Spot metering the bison would have exposed the bison properly, but would have blown out the snow.
Of course. I didn't mean it would produce better results than adding exposure compensation did. Just that it would have been an alternate way to get the same result. Either way would give better detail and less noise in the bison than shooting the default matrix exposure and lightening in PP.
01-05-2009, 12:48 PM   #8
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Thanks all for the comments. I'm headed back in a few weeks and I'll give some of your suggestions a shot. I'll have to experiment with the K20's expanded DR too.

01-05-2009, 03:36 PM   #9
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Can you catch them at sunset?

I just switch to M mode and vary the aperture and shutter speed until I like what I get.
01-05-2009, 04:04 PM   #10
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Stuff the 3rd image in photoshop, boost the whole image levels a bit with one adjustement layer after which create another levels layer but paint the mask so that it only affects (boosts) the bisons. Maybe you can save the image that way.

EDIT: I experimented a bit with that 3rd image and got something done with it. I won't put the image anywhere though without your permission. Tell me if you want to see what I ended up with. Just a quick edit but the idea might be usable with the original file.

Last edited by Maffer; 01-05-2009 at 04:53 PM.
01-06-2009, 01:17 AM   #11
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QuoteOriginally posted by wtlwdwgn Quote
Marc, I agree with you. I was trying to show detail in the two bulls and let the snow blow out. Even with exposure compensation there is still very little detail in the animals.

This is the original which is +1 EV and +1 bracket stop.
http://wtlwdwgn.smugmug.com/photos/448330106_AQ5WV-O.jpg

Here is a redone PP keeping more detail in the snow.
http://wtlwdwgn.smugmug.com/photos/448320867_ncTRM-O-1.jpg
I am sure that your picture underexposed than it should be.

The subjects, which consistute a large portion of the central area of the frame, are just of deep and dark colours. Despite that the surroudings are white and bright, for typical more intelligent DSLRs with better exposure and metering system, the exposure would not be like that. I bet even you used Centre-weight average metering, the results would still be dark (whilst other Canon and Nikon DSLRs will do better).
01-06-2009, 05:38 AM   #12
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QuoteOriginally posted by RiceHigh Quote
I am sure that your picture underexposed than it should be.

The subjects, which consistute a large portion of the central area of the frame, are just of deep and dark colours. Despite that the surroudings are white and bright, for typical more intelligent DSLRs with better exposure and metering system, the exposure would not be like that. I bet even you used Centre-weight average metering, the results would still be dark (whilst other Canon and Nikon DSLRs will do better).
And then Canikon would blow out the snow. NO camera can "properly" render both the snow and the bison. Pentax makes the deliberate choice to try and avoid blown highlights (at the expense of shadow detail) while Canikon take the other approach. Once you get a feel for how the meter works, you'll be fine.
01-06-2009, 06:10 AM   #13
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QuoteOriginally posted by egordon99 Quote
And then Canikon would blow out the snow. NO camera can "properly" render both the snow and the bison. Pentax makes the deliberate choice to try and avoid blown highlights (at the expense of shadow detail) while Canikon take the other approach. Once you get a feel for how the meter works, you'll be fine.
How about the Pentax underexposed *both* the snow much and even more for the bulls? Its far from "highlight blowout" as you suppose.
01-06-2009, 06:48 AM   #14
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QuoteOriginally posted by RiceHigh Quote
I am sure that your picture underexposed than it should be.

The subjects, which consistute a large portion of the central area of the frame, are just of deep and dark colours. Despite that the surroudings are white and bright, for typical more intelligent DSLRs with better exposure and metering system, the exposure would not be like that. I bet even you used Centre-weight average metering, the results would still be dark (whilst other Canon and Nikon DSLRs will do better).
You don't shoot snow scenes very often do you?
Generally, I have to dial 3-4 stops of overexposure in when there is significant amounts of snow in the scene.
I don't know if a new Canon or Nikon would have done better without intervention, but I doubt it. I do know that every camera I've used, be it an Olympus OM-1, Nikon F2s, F3, Pentax LX or Pentax DSLR has metered snow as 18% gray, not 90% white.
I live with snow for as much as 6 months of the year. I know snow.
01-06-2009, 11:38 AM   #15
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QuoteOriginally posted by RiceHigh Quote
How about the Pentax underexposed *both* the snow much and even more for the bulls? Its far from "highlight blowout" as you suppose.
RH, read what egordon99 said. Then read it again. Forget about the "And then Canikon would blow out the snow" part, that's unimportant. The point about dynamic range is the thing to take away. Then again, I'm sure you consider a 12 or 14 bit sensor capable of capturing 12 or 14 stops of dynamic range respectively..

Metering with Pentax is what it is. The photo posted was using pattern, so even using centre weighting as you suggest *would* have helped, as would spot on the bison and snow to get a feel for the full range. Bottom line, there are ways to deal with the metering, like dialing a few stops of +EV. It's just a matter of knowing the tool, and while it's a shame that the OP is frustrated with the exposure of the scene, it is a tough one to capture regardless because of the dynamic range. I don't care what brand you use, it will take a bit of work to get the desired result in a scene like this.

Last edited by jamonation; 01-06-2009 at 11:39 AM. Reason: I really shouldn't dignify a troll with a response
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