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06-05-2007, 07:48 AM   #1
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Did I get a lemon?

I'm curious about the metering on my K10D. I was trying to play around with the metering, and noticed that it doesn't give a proper exposure setting when I'm zoomed in using my kit lens, but it does when zoomed out.

To minimize differences between the different exposure modes, I set it to spot metering and pointed at the exact same spot on my test subject. Here are the results.

The test subject is a panda-shaped wrist supporter and the center of the VF is pointed at the panda's belly for the two shots.

Tele setting:


Wide setting:


I noticed that with the shooting modes I tried (P and M), the camera would not give a setting other than shutter=4 and aperture=5.6, even when using the green button in the M mode. For reference, the old 300D I switched from would give a setting with a super long shutter speed, but it did give the proper exposure.

I love my K10D, and I'd rather have this fixed than turn back on Pentax altogether, as some would probably do. I just need opinions first if I really did get a dud camera before I make use of the warranty.

Sad that I had to be given a rough entry to the Pentax world, but it happens with any brand. I'm not leaving just yet. Haha.

Your help would be much appreciated.

06-05-2007, 08:08 AM   #2
ISH
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I believe your pictures are labeled incorrectly. Actually I don't think either are properly exposed. The top one being under and the other being over.
06-05-2007, 08:20 AM   #3
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Nope. I bet.

Nope, I bet.

What you see is in fact a particular character of the Pentax DSLR metering system - a very wonky metering system with poor consistency and accuracy, usually underexposure for Spot and low to very low IQ multi-segment metering as well.

Frankly speaking but nonetheless, I guess you have user error on your part, since with white or dark/black objects for Spot metering, you need to apply +ve and -ve EV compensation respectively to make things look right as it is. Alternatively, you should meter on mid-grey target which I cannot see any in your test scene.

For more details on the topic and all relevant technical stuff involved, see my homepage.
06-05-2007, 08:28 AM   #4
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You have cropped these pictures to same FOV?

Please show us the original picture area of pictures too.

I suppose that both pictures have different amount of light and dark areas and thus they shoud be differently exposed. In the wide picture the tv and wrist supporter prepresent smaller part of the entire picture and are so exposed differently. You have to learn to know how metering system "see" the picture. There is many good photo handbooks out there

Willingness to learn new things is an prerequisite for owning an SLR. It is just a tool, you have to know how to use it.

06-05-2007, 08:34 AM   #5
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QuoteOriginally posted by RiceHigh Quote
Nope, I bet.

What you see is in fact a particular character of the Pentax DSLR metering system - a very wonky metering system with poor consistency and accuracy, usually underexposure for Spot and low to very low IQ multi-segment metering as well.
Jesus...... stop this stupidity and/or buy better tool for yourself. It is interesting that others are satisfied.... all metering systems have their "characteristics", even Canons, you have to just learn to live with them, work them round. All other experienced users do this sooner or later, but you, poor fellow....
06-05-2007, 09:17 AM   #6
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Hello,

first off:
As some have already mentioned. Black/white is a REALLY bad combination to 'test' the exposure on like this. (Due to the 18% gray average that the meter tries to achieve).

Do you have a general problem with this on your pictures, or is it just this 'test' ?

RiceHigh:
I'm trying very hard not to become angry with you right now. I hope I succeed in staying calm while I type this.
I wonder how EVERY test I've read have concluded with that K10D is a very good camera, and that it's among the top achievers if the metering system were so poor and inaccurate as you lead people to believe. Can you please answer me to that ? Just a straight answer.

Next question :
If Pentax K10D does such a lousy job of metering, you should have no problem to provide me with irrefutable proof, from several sources, that you are indeed correct.
(No, your blog does not count).

Next question :
How is it that most of my pictures, and I suppose other peoples too, are correctly exposed then ?
Are we all good photographers that know the sunny 16, and how to get a proper exposure under almost any circumstances ?
(I know I'm not. I've only shot like 1600 with my camera, and even less with my compact I had earlier).

I'm so sick and tired of you.
If there ever comes one positive post from you, I think I might just drop over dead from shock.
Your posts (the way they are today) simply build up and generate frustration, not because I fear you are right or even *think* you are right, but because they drain energy from 'positive' people that try to contribute.

I also think that for someone who poses as a 'neutral researcher', you are a poor one, at the best. K10D is winning some tests, and are certainly in the top in the other tests. Yet you make it out to look like it's the worst camera ever built (let me generalize this to any Pentax camera that you have ever mentioned). Why is that ? Why are you doing that, when it's not true ?

If people actually read your blog before they are going to buy a camera they will NEVER AGAIN consider a Pentax, even though they are among the top performers out there.

No, K10D is not the perfect camera.
No, Pentax is not the perfect brand.
But they TRY. And they do good work, and deliver good products.
Why do you have to make them out to be LESS than what they are ?

I believe that you do more damage to Pentax and the Pentax community than Nikonians and Canonians could EVER do even if they tried.

*End of LONG LONG LONG rant*

Regards,
Beej80

Last edited by Beej80; 06-05-2007 at 09:19 AM. Reason: Structure
06-05-2007, 09:57 AM   #7
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Hi Vizner, do you have other lenses you could test with? Maybe there is a problem with the 18-55? Also as others have suggested, try a different subject, black and white gives ALL (canon and nikon included) metering systems fits.

NaCl(and btw, ignore RH, he measures stuff to death, but never takes any photos...I doubt he knows how)H2O
06-05-2007, 10:21 AM   #8
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This may be a dumb question, but you ARE re-metering when you zoom in with your kit lens, aren't you? I see where you're using the manual metering mode in some of your testing. The kit lens is a variable aperture lens, so it's going to lose a little light as you zoom in and you'll have to change your settings a touch to get the proper exposure.

06-05-2007, 11:09 AM   #9
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Does the shutter and aperture values flash when zoomed in? Then itís simply to dark for the metering and the camera gives up. You need more light or a brighter lens, or adjust the values manually.
06-05-2007, 11:44 AM   #10
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QuoteOriginally posted by vinzer Quote
To minimize differences between the different exposure modes, I set it to spot metering and pointed at the exact same spot on my test subject. Here are the results.
I don't think your composition is precise enough for a valid comparison. By my eye, the underexposed picture may have the white belly in the center and the 'overexposed' picture may have the black 'arm' in the center. This might cause what you're seeing.

QuoteOriginally posted by vinzer Quote
I noticed that with the shooting modes I tried (P and M), the camera would not give a setting other than shutter=4 and aperture=5.6, even when using the green button in the M mode. For reference, the old 300D I switched from would give a setting with a super long shutter speed, but it did give the proper exposure.
I would expect 'M' with green button to give the same results as P, though there is probably a wrench in the works here. What you may be seing but not paying attention to is Auto-ISO in action. When in 'P', your sensitivity is probably being manipulated by Auto ISO because you're already at max aperture (for tele end of kit lens) and a very slow shutter speed. There is no Auto-ISO at 'M' mode--IIRC, it is fixed to the low end of the auto range. You can verify this at shooting time with the OK button and review it later in the EXIF. So if you had the same fixed ISO setting in P and M, I would expect the same exposure if you use the green button.

As for your 300D or some other older DSLR's, I would expect that even if Auto ISO is enabled, it probably doesn't move in 1/2 or 1/3 EV steps and instead only offers 1EV steps (100, 200, 400, 800, 1600, 3200) so you would be less likely to see the shutter & aperture remaining constant with only ISO adjustments. As for metering differences, it would not necessarily be surprising that given a tricky scene like in your test, different make/model bodies may meter a little differently. Not only are their meters (and possibly lenses) different, but the bodies may implement different program lines, etc.

QuoteOriginally posted by vinzer Quote
I love my K10D, and I'd rather have this fixed than turn back on Pentax altogether, as some would probably do. I just need opinions first if I really did get a dud camera before I make use of the warranty.

Sad that I had to be given a rough entry to the Pentax world, but it happens with any brand. I'm not leaving just yet. Haha.

Your help would be much appreciated.
I am guessing the fault here is a tricky scene and dubious testing techniques. No camera is going to be perfect, and I suspect that in terms of metering, Pentax might be a little less consistent than some others--but not so much that I would consider changing for that reason; any camera will be fooled sometimes. I think you will get more consistent results using the matrix metering and learn to apply compensation or use AE-L as necessary. Spot metering has its purpose, but its use is more of an advanced technique that requires special attention.
06-05-2007, 12:18 PM   #11
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agree with (most) of the above - you're metering a bad test subject, and unless you compensate your exposure will be off. And the "spot" meter isn't a super-small angle spot meter either- it's a ever-so-slightly larger than the center circle area, I think?

It's all about compensation with any metering system - every camera I've had I usually end up adjusting the exposure somewhat from what the meter "tells me" is correct.
06-05-2007, 01:23 PM   #12
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Try something less contrasty

I would agree with some of the other posters.......try the test again with a less contrasty subject. You cannot be sure that your "wide" shot (the first one) didnt have a much larger proportion of the white radiator in it, which led to the underexposure.
06-05-2007, 02:40 PM   #13
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QuoteOriginally posted by vinzer Quote
Okay, here's the addendum. Haha.

Harald: Yup, there is a willingness to learn on my part. This isn't my first DSLR, though, just my first Pentax, so I do have to re-learn the quirks of the system. Just wanna see if I did get a lemon. The original pictures are at home, I'll try to post the un-cropped ones later tonight.

Beej80: I threw out the evaluative metering on these ones and used spot metering. In well-lighted scenes, the K10D works great. But I was trying to see how it does in low-light, since there will be times when I take my photography there. It's just weird how the K10D doesn't want to suggest to me a shutter speed lower than 1/4th, and switching over to M mode, the meter seems to be content (EV bar at 0.0) with the 1/4th shutter speed and f/5.6 (which resulted in a dark photo at the 55mm setting of the kit lens). Also, while everyone else seems to get overexposed pictures using their manual lenses, mine starts overexposed at higher apertures and progressively gets underexposed as I switch to lower apertures. Thoughts?
Sorry, I didnt notice the spot metering thing when I read your text. It is obvious that someone using spot is experienced or willling to learn....

K10D specification it says that "Metering Range: EV 0 - 21 (at Standard Output Sensitivity 100 with 50mm F1.4 lens)".
Isnt 1/4 sec and f:5.6 outside that area?
If we agree that, it shoudnt surprice us that we get slight irregular and erratic measurement results.....
06-05-2007, 02:49 PM   #14
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Thanks for the replies!

Sorry if my cropping (with the wide setting) doesn't closely match the tele one. But I will confirm that both images were metered using spot metering and aimed at the belly of the panda.

I thought that it might have been the evaluative metering that's giving the different exposure settings, so I used spot in both pictures.

I'll add more when I get to work in a bit. My mom's nagging me.
06-05-2007, 02:53 PM   #15
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If your using natural light try switching to artificial light as well.
It really doesn't take much of a lighting change to really effect some photos.
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