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08-02-2007, 02:08 PM   #16
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QuoteOriginally posted by switters Quote
Hmmm. I can't say I'm totally thrilled about this. I know every camera/system is different and has its quirks. But accurate exposure metering is just something I didn't have to think much about with the 20D, and I liked that.

Making sure the +1/2 or +1 exposure comp is always set, and remembering to overexpose in manual by that amount (which is the mode I shoot most often in) is kind of a hassle. But I guess if I love everything else about the K10D it's one I can learn to live with.

I could configure the User settings in Aperture Priority, for example, with +1/2 or +1EV compensation. I'll check the manual, but I'm assuming exposure compensation resets when the camera is turned off in other exposure modes?

Any other tips would be appreciated. I'll post a few pics later as well.
Couple of thoughts that may or may not apply:
1)There are few RAW histograms (none in a camera I believe). The histogram you see in most (if not all) cameras are based on the jpg rendering. A RAW file (prior to tone curve and gamma correction) is dark, ugly and tonally compressed with the best exposure.
2) RAW editors may have presets and their own idea of tone curves (and sharpening and exposure and white balance, ect) so they can be quite different from the "in-camera" histogram.
3) Accurate is really a matter of interpretation. Technically Pentax and Nikon (upper level models, lower can have meters tweaked ala Canon) have more "accurate" meters IF you consider the iso. Canon renders a more "accurate" image because of the iso fudge. Remember, technically they are "overexposing" by a 1/3-1/2 stop in a technical sense. Which one you prefer is a bit personal. I like the Pentax meter response in general and have no issues w/ darker images. To me they process better than losing highlights or having a lot of lost data in the brighter areas. I browsed a lot of Canon images before buying my D and didn't like the amount of blown areas in many "straight from the camera" images. I also noted that MANY of the best shots by the REALLY good photographers had a negative exp. bias dialed in per the EXIF...
I don't know if you ever saw a person named "Daniella" (I believe, but she seems to get banned frequently at dpreview ) but her bird photos are amazing and almost everyone had a neg exp bias dialed in...
I won't get into conversions and color spaces either since this is all really my own thought gatherings and subject to error....
this is a fun read as to HOW a RAW file is treated in the converter code (and of course how you can change things).
ufraw(1): Convert camera RAW images to standard ... - Linux man page


Last edited by jeffkrol; 08-03-2007 at 11:38 AM.
08-02-2007, 02:11 PM   #17
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QuoteOriginally posted by pmperry Quote
Hey that was my DPReview Post!
See now your famous!!!!!!!
Anyways that was one of the better, most thought out compairisons I found in awhile. I'd have done that myself but no hand-held meter.

Last edited by jeffkrol; 08-03-2007 at 11:37 AM.
08-03-2007, 07:33 AM   #18
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Okay, I had a chance to play around a bit with the 10D yesterday. It's a fantastic camera, with great features, but I'm really having trouble getting used to the differences in how it meters and exposes compared to Canon.

Here's what I've noticed so far:

- For a given exposure, the histogram in the camera is significantly different than the histogram I see when I import into Aperture. In camera, the histogram indicates an exposure about one full-stop lower than what I get when I open the image in Aperture (my RAW converter). I assume this is due to the differences in the tone curve the K10D uses for JPEG conversion in camera vs. what Aperture uses in RAW conversion - as was suggested by jeffkrol and others.

- Using +1/2 exposure comp. and exposing until the right side of the histogram goes just past the 3/4 tone line on the histogram in camera seems to produce a good result most of the time (i.e. when I open in Aperture the right edge of the histogram just touches the right side without any clipping)

- Spot and center-weighted metering seem to be much more reliable for most subjects.

My question is this: is there any way I can get the histogram and image preview in camera to more accurately reflect what I see in Aperture? Turning down saturation and contrast seem to have the opposite effect, since that merely makes the image/histogram appear even more underexposed in camera. (It also makes the image look pretty gross, which is somewhat of a problem when I'm using flash and trying to judge qualities of light and skin tones)

Obviously this is a fantastic camera - it wouldn't have so many fans and won so many awards if it wasn't. I'm just really having a hard time figuring it out. I appreciate all of your help.
08-03-2007, 07:48 AM   #19
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I just noticed this quote in the PopPhoto July/August 2007 issue which awarded the K10D the "Best Camera of 2007":

We could also "develop" RAW images as new JPEGs and "push" or "pull" their exposure in camera -- or change their size, quality, contrast, sharpness, saturation, and white balance as needed.

How do you "push" or "pull" an exposure in the K10D? This would solve my problem. If I could push the exposure by 2/3 stop, it would more accurately reflect what I see in my RAW converter.

08-03-2007, 10:05 AM   #20
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QuoteOriginally posted by switters Quote
Okay, I had a chance to play around a bit with the 10D yesterday. It's a fantastic camera, with great features, but I'm really having trouble getting used to the differences in how it meters and exposes compared to Canon.
I came from a 300D before moving on to the K10D. I also felt at first that the K10D underexposed quite a bit, and even thought of having the camera checked out. But you learn to live with it, and in fact, I'm even thankful for this since, as others mentioned, there's a lot more image detail to work with, as opposed to 0 EV pictures coming out with blown highlights, an absolute horror to fix in post.

We all have a learning curve. You'll eventually learn to go with the quirks, like I did. Keep at it!
08-03-2007, 11:55 AM   #21
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QuoteOriginally posted by switters Quote
Okay, I had a chance to play around a bit with the 10D yesterday. It's a fantastic camera, with great features, but I'm really having trouble getting used to the differences in how it meters and exposes compared to Canon.

My question is this: is there any way I can get the histogram and image preview in camera to more accurately reflect what I see in Aperture? Turning down saturation and contrast seem to have the opposite effect, since that merely makes the image/histogram appear even more underexposed in camera. (It also makes the image look pretty gross, which is somewhat of a problem when I'm using flash and trying to judge qualities of light and skin tones)

Obviously this is a fantastic camera - it wouldn't have so many fans and won so many awards if it wasn't. I'm just really having a hard time figuring it out. I appreciate all of your help.
Aperature is not a good match for Pentax OR ther is a setting you are missing. RAW files should "imbed" the tone curve used (as an example from ufraw: For Nikon users UFRaw has the advantage that it can read the camera's tone curves. APPARENTLY aperature cannot do this for Pentax). If aperature selects this (and any pre-sets are off) then the image should look the same. The other thing is the color space/monitor profile that could throw this all off (but hist should still be similar, they just won't look the same). Roland at dpreview reports that the WB is also mucked up by aperature
Re: K10D & RAW processing: Pentax SLR Talk Forum: Digital Photography Review
Found an interesting tid bits.
Apple - Support - Discussions Nikon D200 images underexposed ...
May want to try at Apple support. I'm not finding too many Pentax users who use it.
Apple - Support - Discussions Aperture
08-03-2007, 12:24 PM   #22
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QuoteOriginally posted by jeffkrol Quote
Aperature is not a good match for Pentax OR ther is a setting you are missing. RAW files should "imbed" the tone curve used (as an example from ufraw: For Nikon users UFRaw has the advantage that it can read the camera's tone curves. APPARENTLY aperature cannot do this for Pentax). If aperature selects this (and any pre-sets are off) then the image should look the same. The other thing is the color space/monitor profile that could throw this all off (but hist should still be similar, they just won't look the same). Roland at dpreview reports that the WB is also mucked up by aperature
Re: K10D & RAW processing: Pentax SLR Talk Forum: Digital Photography Review
Found an interesting tid bits.
Apple - Support - Discussions Nikon D200 images underexposed ...
May want to try at Apple support. I'm not finding too many Pentax users who use it.
Apple - Support - Discussions Aperture
Thanks again for your reply, Jeff. My understanding is that Apple individually profiles every camera they support to come up with the ideal RAW settings for that camera in Aperture. There is a "RAW fine-tuning" dialog in Aperture where I can select the "K10D" preset that has default values for sharpening, chroma blur and auto noise compensation.

Then there is a slider called "Boost" with values from 0 - 1 that controls the camera-specific color and contrast adjustments. At 1 Apple's K10D presets are fully applied, and at 0 they aren't applied at all.

When I set the "Boost" slider to "0", sure enough the image and histogram appear more like it does in camera. However, with Boost at "1" (with Apple's defaults for the K10D applied), the image looks much better and the histogram is 2/3 a stop to the right.

So... I guess my options are to turn off the "Boost" settings in the RAW fine tuning so that what I see in my camera is more like what I'll see in Aperture, or to learn to "translate" that difference in my head while shooting.

Or download Lightroom and try it again. I just prefer the interface of Aperture so much more.

I'll give the Apple Aperture forum a try. Thanks again for your help.
08-03-2007, 07:29 PM   #23
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One comment:

Many of you are probably aware that I'm quite critical of the AF-540FGZ's exposure performance on the K10D. Some recent experience and Switters' comments have made me realize that my measurements could be false. For the most part, I've been basing my judgement on the in-camera results (and also on the fact that ufraw in auto mode very consistently dials in +1 or more EC without blowing any highlights for flash pictures.) I was just doing some "full manual" work with a few flashes earlier tonight, and noticed that going from f/5.6 on my lens to f/8 (i.e. one stop) without changing any flash output settings resulted in a VERY small shift in the histogram, from my background inducing a peak just a little below the halfway mark to just a little above.

Unfortunately this makes it REALLY hard to chimp my exposures when I'm working with manual flash.

08-04-2007, 01:38 AM   #24
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QuoteOriginally posted by switters Quote
Thanks again for your reply, Jeff. My understanding is that Apple individually profiles every camera they support to come up with the ideal RAW settings for that camera in Aperture. There is a "RAW fine-tuning" dialog in Aperture where I can select the "K10D" preset that has default values for sharpening, chroma blur and auto noise compensation.

Then there is a slider called "Boost" with values from 0 - 1 that controls the camera-specific color and contrast adjustments. At 1 Apple's K10D presets are fully applied, and at 0 they aren't applied at all.

When I set the "Boost" slider to "0", sure enough the image and histogram appear more like it does in camera. However, with Boost at "1" (with Apple's defaults for the K10D applied), the image looks much better and the histogram is 2/3 a stop to the right.

So... I guess my options are to turn off the "Boost" settings in the RAW fine tuning so that what I see in my camera is more like what I'll see in Aperture, or to learn to "translate" that difference in my head while shooting.

Or download Lightroom and try it again. I just prefer the interface of Aperture so much more.

I'll give the Apple Aperture forum a try. Thanks again for your help.
In a quick check at Apple I see you posted and got one response. As a somewhat annoying but honest consideration of the whole exposure issue (not aperature related) I found this web site and this quote (the web site iteself is NOT a work of art but has some good advice):.
Zone System: Digital / 35mm / Medium Format!
The Skilled Photographer always questions the meter's authority and often overrides it. The Unskilled Photographer doesn't know the question! "
As a veteren of the "D" exposure wars my favorite quote became this from a Leica authority:
'The exposure meter is calibrated to some clearly defined standards and the user needs to adjust his working method and his subject matter to these values. It does not help to suppose all kinds of assumptions that do not exist.'
Erwin Puts
Words I always keep in mind and as long as your camera is Consistent, no problems....
08-04-2007, 09:46 AM   #25
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That's it!

QuoteOriginally posted by switters Quote
Why is this discrepancy occurring (where the histogram in camera is significantly different than the histogram in my RAW processor - Aperture)? Does it have something to do with the K10D's in-camera display? Has anyone else noticed such a discrepancy?
Of course! In-camera histogram is based on embedded JPEG, which is only one way to interpret RAW and it is designed conservatively to protect highlights at the expense of mid tones and shadows. Aperture interprets RAW file in a completely different way resulting in better result and better looking histogram. So everything is just fine -- if Aperture does what you like that's all that matters.

QuoteQuote:
I guess I'll have to learn how to "translate" my camera's histogram results into what will actually appear on my computer.
Not really -- just forget about it. I use spot meter and M mode and before I press shutter release I explore scene making sure all tonal values properly map to -3 to +3 reading. Then I know RAW processing will not be a problem, no matter what in-camera JPEG and histogram are showing. For that reason I seldom use in-camera histogram. I don't even use preview too much as well. In fact, most of the time I need back LCD just to access and change options. (With more buttons on the camera body or other ways to access options and settings I would not need it at all!)
08-09-2007, 07:09 AM   #26
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That's totally normal!

What you mention is totally normal. If one has used both the Canon and Pentax systems, it will not be difficult to spot such difference.

The multi-segment metering of any Pentax DSLR is of lower IQ indeed and that the CWA and Spot meters are not as accurate and tends to underexpose.

The case is made even worse with different Pentax lenses would yield rather difference exposure results and such inconsistency can cause much trouble.

I can see this problem has been dragged on for years since the first Pentax DSLR *ist D and this is still no sign of significant improvement in their latest K bodies.

Hopefully, the next generation of Pentax DSLRs can have this annoyance and bug removed. Anyway, dunno if this is the in-born limitation of the Pentax system though - but MZ film SLR cameras seem to be more accurate in the past.

QuoteOriginally posted by switters Quote
Okay, I received my K10D yesterday and the first lens (of several) I'm trying today - the 35/2. I'm freshly over from the Canon team (20D), so this is my first time taking the Pentax kit for a spin.

I'm amazed at how differently the two cameras meter and expose. I did some side by side tests and the K10D was underexposing consistently compared to the 20D. Often times the right side of the histogram was somewhere in the middle of the tonal range. These weren't particularly difficult shooting conditions, just some portraits indoors against a medium-toned wall. The Canon was getting it right every time.

I started out in evaluative metering, but then tried center-weighted and spot after the first few underexposures. I figured the K10D might be picking up on the lighter tones in the wall and biasing the exposure downward from that. When I spot and center metered directly on the model, however, there wasn't that much of a change in exposure.

I didn't read about this in any reviews and haven't seen it mentioned on forums. Has anyone here experience this? What metering mode do you find works best in general, and are there any "tricks" for getting proper exposure with the K10D that you've figured out.

Please note that although there is always room for user error , I was shooting the exact same picture with the Canon 20D and it was getting the exposure I expected.

Thanks for your help.
08-09-2007, 07:17 AM   #27
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This continues to be a frustrating issue for me. I love everything else about my K10D, but I have seriously considered returning it for this reason. Last night I was shooting indoors in tungsten light with a white wall as the background. It was an event so I didn't have much time to fiddle with settings or I would miss shots. Even at exposure compensation of +1.5 in aperture priority the right side of the histogram was smack in the middle. I could have gone to manual, but the light changed quite a bit throughout the room, so I didn't feel I had time to make those adjustments.

It's also true that different lenses have a different effect. I've found that the 50/1.4 underexposes much more than the new DA series. The 31 Ltd. seems better.

I'm gonna give it some more time, because there are so many other things I love about this system. But I'm really frustrated with the underexposure issue of the K10D, and that is even more true with the AF540 flash in P-TTL.
08-09-2007, 07:32 AM   #28
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QuoteOriginally posted by switters Quote
This continues to be a frustrating issue for me. I love everything else about my K10D, but I have seriously considered returning it for this reason. Last night I was shooting indoors in tungsten light with a white wall as the background. It was an event so I didn't have much time to fiddle with settings or I would miss shots. Even at exposure compensation of +1.5 in aperture priority the right side of the histogram was smack in the middle. I could have gone to manual, but the light changed quite a bit throughout the room, so I didn't feel I had time to make those adjustments.
Pentax DSLRs underexpose more with tungsten light and/or at dimmer environments. So, it the tungsten lighting level is low, it will underexpose most! (both conditions are valid as such)

QuoteQuote:
It's also true that different lenses have a different effect. I've found that the 50/1.4 underexposes much more than the new DA series. The 31 Ltd. seems better.
I have the same experience. But I can say this is not generally lens series dependent. It is more lens model dependent or even more specific lens unit dependent. The exposure inconsistency will vary with individual different lens, in short.

QuoteQuote:
I'm gonna give it some more time, because there are so many other things I love about this system. But I'm really frustrated with the underexposure issue of the K10D, and that is even more true with the AF540 flash in P-TTL.
Yes, I find the same, too, again.

In fact, I have done more to measure the ambient light underexposure problem in great details and summarize all these in my homepage:- RiceHigh's (Pentax) DSLR and Lens Measurbation Page on Exposure Accuracy and More..

As for the P-TTL underexposure problem, I have also done the measurement (or called measurbation :-)) to verify this too (and to check for the possible amount of EV compensation required). Just see my this report:- P-TTL Vs TTL
08-09-2007, 10:59 AM   #29
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Fair Warning Notice: None of those tests show a control group in order to show that the tests are indeed valid, these tests seem to be done with a single istD camera with no mention of wether it had been certified or checked by Pentax beforehand, wether it was a NIB model or other. Neither does it mention what firmware version was used or if it was retested with subsequent firmware revisions. Nor do these specious tests correlate to the K100D or K10D cameras and their associated firmware versions.

And lastly that these tests were 'done' on JPEGs, the entire test conclusion if entirely valid could then be an issue with the internal conversion software from RAW to JPG and not the metering of the camera. if you shoot in RAW you nullify any argument ricehigh may pretend to make.
08-09-2007, 11:05 AM   #30
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I am certainly not an expert, don't claim to be, and am not making claims about anyone's camera other than my own.

I'm just a guy who had a Canon 20D & 430EX that worked pretty well for him in terms of exposure & metering. I moved to the K10D for its feature set and for the lovely Pentax primes, which I prefer shooting with. All I'm saying is that I'm finding the ambient and flash exposure metering & P-TTL to be much more difficult, for me at least, to get good results with.

Obviously the K10D is a fantastic camera or it wouldn't have so many fans.
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