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10-20-2018, 08:07 PM   #1
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K-30 underexposed pics - is or me or the camera?

Lately I've been unhappy with a lot of my shots with my K-30 (with Sigma 18-250) - the latest ones seem underexposed and to have a brown cast. I've read another thread where bright sunlight appears to result in underexposed shots, and I've read about the K-30 aperture motor problem, but I'd like some feedback on these please. Apologies for the dirty lens by the way.

The 2nd pic was taken immediately after the 1st - just zoomed in.

The last pic is how I expected the 2nd last one to look like.

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10-20-2018, 08:23 PM   #2
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Looking at your first image, Exposure 1/250 and Aperture F/5.6 - all good.
Your second image, Exposure Time 1/2000 and Aperture F/5.6 - it's no surprise that this image is darker.

Your fourth and fifth images are interesting, however:
Your fourth image, Exposure Time 1/320 and Aperture F/13.0, appears the same in your fifth image. That sort of behaviour may be the aperture solenoid, but that would not hold true for the difference between the first and second shots.
10-20-2018, 08:36 PM   #3
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I don't think I changed settings between 1st and 2nd - would have been aperture priority - set on f5.6, auto ISO.
The last pic was PPed from the raw.
10-20-2018, 08:56 PM   #4
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Do you accidentally have your exposure metering set to spot? If so, change it to either center weighted or matrix and I'll bet the problem goes away. Here's a link that may help Camera metering modes explained

10-20-2018, 09:03 PM   #5
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Looks like the problematic ones are both in spot and center-weighted metering. As a go-to, you should be using matrix metering unless the lighting itself is tough.

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10-21-2018, 01:07 AM   #6
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Spot metering is ok- only if you know how and when to use it. For most situations, matrix is the way to go.
10-21-2018, 07:21 AM   #7
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Yeah, spot metering was selcted. If you only only at the center part of the badly exposed pictures, the center spot is perfectly exposed. In #1, it exposed for the patch of trees in background, on #2 it exposed for the white part in front the building (which end up 18% grey as it should), #3 expowed for the white cloud and so on... So, the camera just have done what you ask it to do: just exposed for a small patch in the center without taking care of the whole picture.

As other said, matrix metering is the way to go unless having a good reason to switch to matrix or spot metering. Spot metering is really tricky to use and should be reserved for very specific sitiuations.
10-21-2018, 02:49 PM   #8
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EXIF on 4th picture (whale) says centered weighted averaging for meter mode.

10-21-2018, 03:40 PM   #9
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Well, the difference between the 1st and 2nd photo is easy to explain. The 1st is shot at f/5.6 and 1/250 sec and the 2nd at f/5.6 and 1/2000 sec, so of course the result with the same lighting conditions will be very different. Spot metering is the likely culprit. Same with photo 3 shot at 1/1600 sec shutter speed. No doubt you believed the meter's indication for exposure, since you were shooting in the manual mode. One reason for shooting in Manual mode is to meter off a chosen section of your scene, then reposition the camera for your shot. Your set exposure will then remain where you put it, even though the meter will now be showing an off-centered over or under exposure. This is also the way spot metering is used. If you do this and just point the camera without consideration of the lighting present, just the way you want to frame your shot, and set exposure by the meter indication, it may not go well.

In the case of the whale's tail, center-weighted metering was selected (why?). Within the central portion of the frame there's snowy mountains and bright sky included, which can cause the meter to indicate less exposure. Center-weighted can be misleading also, depending on what is within the frame. For this type of shot, matrix would be the best type of metering. If wanting to use the spot meter, you'd need to train the camera on a mid-tone area of the scene for your meter reading, then reposition the camera for the shot. With the Pentax Hyper Manual feature, you can quickly do this by using the green button to take the reading and set the exposure.
10-21-2018, 04:05 PM   #10
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One thing to consider is the manual white balance of the first two photos because they were taken simultaneously unlike the other photos of different time and dates.
When you fully pressed the shutter button and displayed on Lcd the captured image, did you press any arrow on the controller to specify the light measuring area? or press the green button to select the center as your choice. If you did not specify the measuring area, the resulting photo takes the kelvin temperature settings.
10-21-2018, 04:24 PM   #11
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QuoteOriginally posted by Penview52 Quote
One thing to consider is the manual white balance of the first two photos because they were taken simultaneously unlike the other photos of different time and dates.
When you fully pressed the shutter button and displayed on Lcd the captured image, did you press any arrow on the controller to specify the light measuring area? or press the green button to select the center as your choice. If you did not specify the measuring area, the resulting photo takes the kelvin temperature settings.
I just noticed that manual white balance was used instead of auto white balance. Usually with Pentax DSLR cameras of recent years, the auto white balance turns out quite well. The exception might be some artificial lighting situations. But I still think the improper use of metering was the main problem with exposure in these examples.

The matrix metering takes all sections of the frame into evaluation. But even it can be fooled by extreme lighting situations, hence the reason for having the SCENE modes on amateur-oriented camera models. Pentax offers more advanced features and build quality on such cameras than other brands do, so even advanced photographers purchase them, sometimes as secondary models to their main camera. I own the K-S2 as my smallest, lightest model, and enjoy the fact that it also has a very good complement of advanced amenities. I have never used any of the SCENE modes, but they are a good convenience for others who might use the camera, and also a selling point. There are SCENE settings for numerous situations, like snow scenes, for example. With a lot of bright snow, the camera's meter, even matrix, will sense "too much bright white" and will back down exposure, resulting in gray snow and dark people. When you know what to expect, you don't need the SCENE mode to compensate. If you want to continue using any of the auto-exposure modes- "P", Av, Tv, etc. you simply use the exposure comp button to increase exposure by around 1-1/2 stop or so and keep shooting. If using Manual mode, and spot meter, you choose a mid-tone area to set your exposure and go from there.

Last edited by mikesbike; 10-21-2018 at 04:45 PM.
10-22-2018, 01:36 AM   #12
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OK, it looks like it's me. The underexposed shots were probably from using not the best metering, and other things were maybe getting adjustments wrong under pressure in bright light. I've no idea how 'manual white balance' could have got set, as I don't touch that knowingly.

I was hoping you'd say the camera, because I want an excuse to get a KP, or at least a K-70. ... and maybe a DA 18-135mm F3.5-5.6 ED AL [IF] DC WR.
10-22-2018, 04:43 AM   #13
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Center weighted metering was used in SLRs until matrix metering became available in the 80s. Pentax DSLRs default from matrix to center weighted meter with lenses that do not have "A" contacts, e.g. K, M, M42, T-mount and many 3rd party lenses.

I recall there being an article in Popular/Modern Photography on Minolta's center weighted metering pattern in the X series was designed to de-emphasize the upper portion of the landscape frame to account for the majority of pictures (from Minolta's analysis) have bright sky. A pattern that the other manufacturers soon copied.

Nikon soon pioneered the matrix metering system and still excel in that area.
10-22-2018, 06:21 AM   #14
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Jim - just little understanding about manual white balance is needed, as you said....." I've no idea how 'manual white balance' could have got set, as I don't touch that knowingly".

After taking a shot the image is seen on lcd and press green button to select the center image as measurement of light to take the whole image similar to the center, but do not press the shutter again because it will not process the correct color temperature of that next photo shoot., ( maybe it resulted as dark photo as i do not know the effect of it ) until camera is ready for the next shot.

Just take the auto white balance ( AWB ) and camera will select the best for you.
I believed that either you set as spot or center weighted is acceptable by practice and you will see the difference.

Other point to consider is clean your lens because this affect the auto focusing function of the camera.
10-22-2018, 07:28 AM   #15
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one other thing to consider in the first and second shots. the sun is behind the photographer is there an issue with light entering the viewfinder?
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