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08-04-2010, 04:23 PM   #1
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In my opinion my K-x shows very under exposed pictures.

I have always had an issue with under exposed pictures taken on normal settings on the k-x. I have read people just bump up the dial 1/3-2/3 stops to compensate. But I do that sometimes and there still is very little difference. I also think the pictures are very under exposed to the point where I need to bump them up a good deal in photoshop. I am just going to attach a couple of pics to show. The second one is me ROUGHLY editing the pic in photoshop to what I think is a better exposure.

(Sorry for 2 posts but these 2 topics Ive been meaning to post now for a long time, I finally found the time. Im going to add a third topic here.)

The two or three dark dots you see there are dirt on my lense somewhere. Does anyone know of good cleaning tips? Ive read never to use compressed air guns, nor lens cleaning fluid. Should I buy one of those hand powered air squirters?

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08-04-2010, 04:30 PM   #2
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if you go check out the beginners Q & A section someone made a really good top to bottom guide on cleaning the sensor.

As for the under exposure, I have found that it varies situation to situation, in a forest it constantly over exposed by 1/3. That's why I always bracket whenever possible, and shoot at different apertures just to make sure I always get the shot
08-04-2010, 04:40 PM   #3
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A large proportion of the scene is bright sky and light reflected off the water, which is affecting the meter reading. Camera is trying to prevent overexposure of the sky, hence the underexposure.
Before blaming the camera, learn how to assess exposure and how to compensate for such situations.
08-04-2010, 05:03 PM   #4
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I think under exposure is common on Pentax DSLRs, at least it is on my K10D. I find that if I don't bump the exposure upward at least 1/2 to 3/4 of a stop my photos will all consistently be under exposed. I don't know why they set the cameras up in this manner, I assume they would rather under expose highlights than to burn them out with over exposure. I don't know but that is how it seems. The problem with under exposure is the noise that is introduced into the photo.

08-04-2010, 05:10 PM   #5
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Depends on what part of the picture you're looking at. This type of photo would benefit from some post processing to bring out the hills without blowing out the sky.

As for the spots, they are not on your lens.

https://www.pentaxforums.com/forums/pentax-beginners-corner-q/109456-dirty-sensor.html

08-04-2010, 05:28 PM - 1 Like   #6
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Water and sky are properly exposed.

There is one thing you beginners dont understand in most cases. Camera and its exposure system cannot know what is the main subject in your picture.

It is only you who knows that, and so you have to decide to expose the picture accordingly. If your main target is in the shadow or in the darker part of the picture, you have to compensate accordingly.

Second issue is that exposure metering system is allways trying to make the main parts of the picture as light as middle gray. This means that it will not be very bright in the picture but average. If you want it differently, make an appropriate exposure correction.

In your examples sky and water are quite nicely in the middle gray area, thus exposure is quite correct. If you want it differently, please use corrections or manual mode.

This is typical beginners exposure mistake, and cannot be corrected using any automatic functions.

I repeat: camera cannot know which is your main target and thus uses average settings and tries to avoid burning any part of the picture to completely white.

If you want some part of the picture brighter, or/and want sacrifice bright areas, please do so, manually. But dont blame your equipments whe your understanding and skills are poor.

So, if there is something to be enhanced, it is your skills as an photographer, not the camera.
08-04-2010, 06:04 PM   #7
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Nice detail in the clouds, well preserved. Nicely done.
Rocket blower might help with the junk in the sensor!.
Cheers, Mike.
08-04-2010, 06:07 PM   #8
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+1 for the Harald's post. The first image is not under-exposed - it seems to have controlled a difficult scene well - but your editing has blown the highlights in the clouds.

Camera metering sees everything as mid-tone grey. If you use metering and want to expose for a particular subject, you need to adjust the metering to how lit the subject is relative to mid-tone grey, remembering that the 3 auto-metering choices see different areas within your frame.


Last edited by CWyatt; 08-04-2010 at 06:21 PM.
08-04-2010, 06:50 PM   #9
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QuoteOriginally posted by Billium28 Quote
I am just going to attach a couple of pics to show. The second one is me ROUGHLY editing the pic in photoshop to what I think is a better exposure.
Even #2 is underexposed. The land is clearly still too dark. The highlights (clouds) are going to blow out without some extra processing. I think the camera metered "correctly", however.

I don't cry too much about "blown highlights" unless it is the actual subject.

And, yes a Giotti rocket blower will work wonders on dust. And turn off the camera when changing lenses.
08-04-2010, 07:31 PM   #10
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Take a picture of A uniform surface like a sidewalk or paved road and tell us where the histogram is centered. If it is in the middle your exposure is correct
08-04-2010, 07:35 PM   #11
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That depends on the processing.. I could do a lot more with this if I had a better file to work with...

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08-04-2010, 07:36 PM   #12
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Actually, the histogram shouldn't even be the middle, but rather about half a stop left of center. Anyhow, I agree with everyone else here - th camera exposed correctly according to traditional photographic standards and what ISO dictates: it tried to make the scene average in value but without blowing highlights. Scenes that are brighter than average or that have bright highlights - or, as in this case - need positive compensation with *any* properly functioning camera. This is exactly as describied as virtually every book ever written on photography.
08-07-2010, 10:16 AM   #13
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I have a K-x. Before I had a K-m. They both underexpose. Actually I check histogram and a +1 generally solves the problem. What I have found was that underexposure is less if AE metering is in multi segment.
What bother me more is pour contrast. I solve most of the pic exposure problem with batch auto-contrast with the whole file of shots. Of course this is done only with mass jpeg pictures.
08-10-2010, 08:15 PM   #14
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If +1 compensation doesn't blow out highlights or otherwise produce overexposed pictures (eg, average value comes out brighter than 18% gray, peak of histogram comes out at or right of center instead of to the left where ISO standards dictate it should)) most of the time, something is wrong. Could you post pictures?
09-02-2010, 05:10 AM   #15
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I have to say that my limited experience with less-than-a-month old Pentax K-x is similar to what OP said. I didn't actually think about it until I read this thread, and I realize that many of the pictures I took needs to have their exposure raised to make it balanced. It's as if the histogram is always tend to the left. Now I'm not blaming this on K-x exclusively, since this may be a normal occurrence with any DSLR. Maybe others can enlighten me in this issue.

I do not find this a problem, though. Since I do a lot of low light photography without a tripod, I understand that higher exposure means either slower shutter speed, high ISO, or too wide aperture - all of which I tried to avoid. So in this case, the left-leaning exposure is good and I can work on correcting it in post processing.

Last edited by ipank123; 09-03-2010 at 06:10 AM. Reason: edited for clarity
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