[madison_wi_gal]

I looked in the forum before asking, there are a few threads but pretty old ones.

In my testing of my new K-3 III and "new" (to me) K-01 (plus a K-30 tossed in) I note that i have some variance in exposure (one was because of center weighted vs. pattern, that was my bad, and one was because it was metering off of a dark spot) but there still is some variety. I can fix it in DxO/DCU but I wonder if my settings are non-optimal?

I've done a complete 180º since my first post and shoot in RAW now, mostly because I bought DxO and also use DCU so I want to play with as many parameters as I can. I'll eventually switch to RAW+ for convenience once I know more about my cameras.

Is there some general advice for using a 18% gray card or a white piece of paper or something before shooting? I read somewhere here that Pentaxes use 12% gray vs 18% gray. I also read just aim at some grass. I also read that some folks just set their EV for -1.0 or -0.7.

I did change my settings on the K-3 III as per this

I'm confused!

I did read this but need a bit more help, maybe.

Last note: the vast majority of my photo subjects are landscapes, foliage and animals.

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Last edited by madison_wi_gal; 05-29-2022 at 06:30 PM. Reason: added clackers

[cpk]

This may help: Understanding White Balance

Here's another link: https://photographylife.com/definition/white-balance

[MarkJerling]

18% grey cards can be used for two purposes, as a useful tool for setting exposure, especially for portrait or stills use, and as a means to get more accurate white balance correction.

For the most part, I tend to simply use Lightroom and correct to make the scene match what I remember. (Rightly or wrongly!)

I found some interesting discussion here re 12% vs 18%: Light Meters Calibrated for 12% Gray Not 18% - PentaxForums.com

[madison_wi_gal]

I found some interesting discussion here re 12% vs 18%: Light Meters Calibrated for 12% Gray Not 18% - PentaxForums.com

Yes, that was one of the ones that I saw that made my confusion worse.

[MarkJerling]

Yes, that was one of the ones that I saw that made my confusion worse.

I think the last few posts in that thread are quite helpful.

[pschlute]

For the most part, I tend to simply use Lightroom and correct to make the scene match what I remember. (Rightly or wrongly!)

This is actually a very important point, and not as flippant as it may sound at first reading. If one is shooting at sunrise or sunset for example, one can get the WB "wrong" by using the AUTO WB settings. These are scenes where the warm or cool light will enhance the picture, and render it more as we remember seeing it. Allowing the camera to "correct" the WB will not improve the image.

For the OP important thing to remember is when shooting raw, the WB is not baked into the raw data, and can be changed in PP. WB will affect the preview the camera displays and any jpeg output in RAW + JPEG. It will also have an effect if ones raw converter is set to WB "as shot" as default setting.

Another point worth mentioning is that if one is taking a number of images of the same subject (especially faces), consistency is important. The AUTO WB setting can change how a person's skin tones render depending on what other objects are in the frame. For this reason I generally always leave the WB set to Daylight in the camera settings.

[Ian Stuart Forsyth]

Is there some general advice for using a 18% gray card or a white piece of paper or something before shooting? I read somewhere here that Pentaxes use 12% gray vs 18% gray. I also read just aim at some grass. I also read that some folks just set their EV for -1.0 or -0.7.

Using a target for WB it is best to use something lighter than 18% This can introduce errors into the WB scaling, most 18% cards are not neutral in color and using something lower as for lightness you can introduce error from noise introduced from the capture.
There is also other things that need to be considered, if the target is set perpendicular to the light source will give you one reading will turning the target 45 degrees to the light source will give you another. ( this is all if you want from the standpoint accurate WB)
\
Most of the time most don't need to go this far as it is more a mater of taste and how often wants white to appear

A lot of the time photographers choose to shoot in light that is warm ( golden light ) and many times select a warm WB to reflect the scene .
About the only time one is really concerned with correct Wb is for color accuracy in preproduction work

All the snow is white but what is the correct WB ?
Taste ?

[subsea]

Another point to note is that the idea of setting EV to -1.0 or -0.7 (or any other value: I used to use -0.5) has nothing to do with WB. It's essentially just slightly underexposing your image to avoid blowing out the highlights. If you overexpose the highlights, you can no longer recover image detail from those areas. Recovering detail from underexposed areas is much simpler than recovering detail from overexposed areas when post-processing your RAW files. The same technique was commonly used when shooting slide film, because that film had the same characteristics: you could recover detail from underexposed areas of the image, but not from overexposed areas when developing the slides, so it became common to shoot slide film with a slight underexposure. This also had the benefit of yielding more highly saturated colors on the slides. To some extent, that's no longer necessary with the K-3III, because the camera has a "highlight-weighted" metering mode which evaluates the scene and automatically adjusts the exposure to protect the highlights. I've found that mode to be particularly useful when shooting landscapes (or sunsets) that include the sun in the frame.

[kypfer]

... I also read just aim at some grass. I also read that some folks just set their EV for -1.0 or -0.7.

From my experience, a grey card can be useful for getting the overall exposure of a scene correct, rather like an ambient light reading. It's not (necessarily) designed to be a perfect colour reflector for white balance purposes.
Aiming at sunlit grass to set the white balance is useful when using an i/r filter because it allows emphasis on the reflected i/r radiation, which, after all is said and done, is what you're trying to capture with the i/r filter fitted
For accurate white balance readings, again, only in my experience, taking the manufacturer's advice to use a piece of white paper has always worked
Exposure compensation can be necessary to cope with small areas of highly reflective highlight against a darker background. A gull or similar on or against a dark sea will usually over expose in bright sunlight, anything up to a stop, but I wouldn't suggest always under exposing was a good idea unless you don't mind risking losing deep shadow detail on occasion. Exposure bracketing can be advantageous in difficult situations.

[madison_wi_gal]

Another point to note is that the idea of setting EV to -1.0 or -0.7 (or any other value: I used to use -0.5) has nothing to do with WB. It's essentially just slightly underexposing your image to avoid blowing out the highlights. If you overexpose the highlights, you can no longer recover image detail from those areas. Recovering detail from underexposed areas is much simpler than recovering detail from overexposed areas when post-processing your RAW files. The same technique was commonly used when shooting slide film, because that film had the same characteristics: you could recover detail from underexposed areas of the image, but not from overexposed areas when developing the slides, so it became common to shoot slide film with a slight underexposure. This also had the benefit of yielding more highly saturated colors on the slides. To some extent, that's no longer necessary with the K-3III, because the camera has a "highlight-weighted" metering mode which evaluates the scene and automatically adjusts the exposure to protect the highlights. I've found that mode to be particularly useful when shooting landscapes (or sunsets) that include the sun in the frame.

Yes. I just added that since I had read that some adjust the EV down. Thanks, that makes sense.

[35mmfilmfan]

Many of my pix are taken across water (highly reflective, and tastes horrible !), or of birds with white plumage (swans, egrets, spoonbills etc). For this reason I usually have EC set for at least -1, sometimes -1.3, which I can correct in post, just to try to maintain detail in highlights.

[dms]

You can in post set a reasonable WB from the white of the eye, or sometimes any white/gray area in the image. (Gray and white being the same thing, just white has the higher/highest reflectance in the scene.) As noted earlier you don't usually want to reduce the desired effect of sunset, stage lighting, etc. by setting WB to make white/gray look white/gray.

Also with K-5 thru K-1 (no accelerator), the sensor/in camera processing has DR that drops 1 stop for every doubling of iso, after roughly iso 200~400, so instead of - ev you may want to simply leave camera at low iso** and adjust exposure in post--this prevents overexposure and the darks are as good as if one used the higher iso w/o adjusting in post (for me the biggest advantage of using raw). Lots of sites have DR vs exposure for most/all the higher end digital cameras.
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** My bad, this only works where you keep the measured exposure at high iso, and then reduce the iso for the shot. For me in theatre photography I don't use light meter, I set low shutter speed and smallish aperture (e.g., 1/30s and f/4), and low iso.

[Just1MoreDave]

Your different cameras will all see exposure and white balance differently. The K-r has 16-segment metering, the K-30 is 77-segment, the K-3 III is 307,000 segment RGB, and I'm not sure what the K-01 does. If you get a K-p (86,000 segment RGB) you will have covered all possible Pentax DSLR metering schemes. If Pentax made changes in the spot or center-weighting metering at the same time, you could be looking at up to a dozen different opinions on light.

Along with metering tech, they've changed auto white balance intelligence over the years. I have learned what the light is like around my house and state over the years, so I feel like my guess is as good as the camera's.

[madison_wi_gal]

If you get a K-p

AAAAAgggh!

Waiting for Limited to show up on Pentax Marketplace.

[pacerr]

An objective evaluation of 'white balance' must be based upon the incident light source.


As you've discovered, reflected light is subject to too many uncontrolled variables in the scene and alternative TTL metering modes. But reflected light controls the exposure of the scene.

With the prevalence of TTL, in-camera metering we seem to have lost awareness of incident light.