Postprocessing – Calibrate the exposure in RawTherapee using a grayscale

I just got a gray card that I wanted to use for white balance calibration. It comes with a grayscale with 11 levels:

L 18.9 | Ev −2 | Ev −1.5 | Ev −1 | Ev −0.5 | L 50 Ev 0 | Ev +0.5 | Ev +1 | Ev +1.5 | Ev +2 | L 98.2

How do I use this chart to calibrate post exposure with RawTherapee? Should I hire L* to 18.9% at the black end and 92.2% at the white end? And are "black" and "exposure compensation" the right settings to adjust?

This answer to unclear whether Gray Card can be used for exposure in post production? provides clues, but RawTherapee's highlights and shadows sliders don't seem to have the expected effect.

Postprocessing – fear of underexposure despite correct exposure in the editing program?

Your question seems to have more to do with the brightness of the image on the display than with the "exposure". This depends on a calibrated monitor and a screen brightness that corresponds to the ambient conditions.

One tool I use is a gamma test strip … I have embedded it into the Lightroom surface as an "identity tag".

Enter the image description here

If I can't see the difference between the dark squares in the top row, my monitor is too dark. If I can't see the difference between the brightest squares in the bottom row, my monitor is too bright. And if I can't see the gradation steps in the midtones clearly, the gamma is off (needs to be recalibrated).

Another trick you can use is that something that is white on the monitor should be about as bright as a piece of white paper in the same ambient light (a little brighter).

However, you can never control how your picture appears on everyone else's screens. Just let go of this idea.

When shooting dark scenes, "overexposure" or "exposure to the right" is most advantageous (use of aperture / shutter speed; not ISO). This way, you can record more data in the dark areas so you can work with something. You can withdraw it at any time by post.

This is the test strip:

Enter the image description here

Postprocessing – underexposure despite correct exposure in the processing program?

I am constantly afraid that my pictures are underexposed because I play with light and shadow a lot and like to take pictures at night. Although the image appears to be well exposed in my photo editing program, except for the dark areas that I have intentionally darkened, I cannot worry that I still find it underexposed. In such situations, I always adjust the brightness of my laptop / smartphone screen to ensure that I can still see something when the brightness level is set to the lowest level. I know this has less to do with equipment and technical issues, but I really need some opinions from you. I also know that technically there is no proper exposure. However, if the viewer cannot see the components of an image to be viewed, it is bad.

Thank you so much! Here is the link to my picture

What mathematical operation does the raw exposure slider do in Photoshop? And how is it different from adjusting exposure when the file is opened?

If I open a raw file in Photoshop without changing the raw exposure and compare it to the same file with a raw exposure change of -0.2; When I examine the linear values, it seems that a different math operation has been applied to each pixel. What does it actually do? I was expecting linear scaling. Then when I use Settings-> Exposure at +0.2, I don't return to the same values, why?

What are these exposure corrections actually doing?

Illumination – Fixed camera and light settings return different exposure

I have this situation when photographing still life photos of e-commerce products, for example leather shoes or leather bags:

  • Table with white paper as a white background.
  • Two flash lights with umbrellas on each side at an angle of about 45 ° (triggered by the flash shoe trigger on the camera) adjust the power manually, no TTL.
  • Canon 70D camera on tripod.
  • Camera settings in "M": 35 mm, ISO 100, 1/160, f8.0, measurement mode: evaluation measurement. AWB Automatic white balance activated.

With these fixed settings, all images should have the same exposure regardless of the object in the image.

Instead, I get different exposures depending on the object I'm photographing:

  • If the subject is large (such as 50% of the frame) and, for example, brown or dark blue, the general exposure appears darker.
  • If the object is small (like 20% of the frame) and, for example, yellow or pink, the general exposure appears better illuminated.
  • I have some cases where there is a big exposure difference for everyone despite fixed settings.

I've been facing this problem for a long time and am fixing it in post production with Camera Raw. I researched and tested on the camera with various settings to understand why it works, but I can't figure it out

It looks like there's some kind of auto exposure that I can't control or that I can't find in the camera settings.

Unfortunately I cannot add an example because I cannot publish the product photos.

I would like to know whether it is possible to achieve the same exact exposure results with precise camera settings without the camera performing an automatic exposure (or similar).

EDIT: I cropped the same area on two different images with the same settings overall, but as you can see, the white background, which should be gray, is darker and lighter. It is not a shadow because the more or less brightness also affects the object itself. Overall, the picture looks brighter or darker.
The black areas are the objects that I had to delete because I cannot view or publish them.

EDIT2: When examining it in Adobe Bridge, I found a very strange thing, even if the settings for both images in the metadata are f8.0 1/160 ISO 100 35 mm. The Exif data says: 24 mm maximum value f / 3.8 for the first image, maximum value of 135 mm 1: 5.7 for the second image. This is pretty strange … is it possible that there is a hardware error in the lens sensors?

Enter the image description here

Measurement – where are the exposure sensors of a mirrorless camera located?

Measuring the main image sensor is a very slow method. Sony Mirroless cameras are completely unusable for rapidly changing scenes. RX 100 is really bad when you take it out of your pocket or switch from one scene to the next. Even better 5D series for real work. But does anyone know of a camera with a sensor-reflecting exposure sensor?

Also asked by dpreview, but they agreed with the providers: "Please, we don't want to talk about the problem because dpreview makes its money from marketing."

UPDATED: Problem solved! Exposure compensation was the problem. Underexposed photos, photos in manual mode

Photo taken with the exact settings I am currently taking a photo course on Photzy.com and haven't used my camera in Manuel mode in YEARS … The last time I used manual mode was in high school over 20 years ago. To say I'm a little rusty is an understatement. Other than that, I follow her instructions on a T to get a photo in manual mode with the correct exposure and get a very dark picture. I tried to reach them, but of course they say that this is proven to be a good photo. There must be something that is not sitting properly on my camera. I have no idea what it could be. Any help would be appreciated

The attached photo was taken with the settings I should use:

Nikon D7000
In a room with lots of natural light
Recording mode: Manual
Measurement mode: matrix
ISO: 1600
Aperture setting: f 5.6
Shutter speed: I use the light meter and set it to 0.

All of this should give me a good photo, right? Well, I get a very dark picture. Could there be another setting on my camera that is not set up correctly?

A little bit about the room … white walls, wall made of 2 sliding glass doors in the west (behind me when I take the picture) a sliding glass door in the east. 1:30 p.m. High vaulted ceilings, sunny day outside.

Thank you very much

Exposure – Why is part of my picture under-exposed when using flash?

I tried to teach myself the basics of flash photography. I have a problem that I don't know is a user error or an error with my device.

I am using a Canon EOS 1100D with a Neewer NW565EX flash mounted on the camera, with the flash set to E-TTL and the following settings made on the camera:

  • Exposure 1 / 60s at f / 8.0
  • ISO 800

The picture above shows a narrow band with "correct" exposure, but the rest of the picture is underexposed.

1100D:
Image of 1100D with the correct exposure band above.

I tried the same flash on an EOS 400D with the same settings and got a correct exposure for the whole picture.

400D:
Correctly exposed image of 400D

Everything I can find online for this speaks about the maximum synchronization speed of the camera. For the 1100D this is 1/200, so this shouldn't be a problem at 1/60. Am I getting it wrong or is there a problem with the 1100D?

Exposure – underexposed photos, manual mode

I am currently taking a photo course on Photzy.com and have not used my camera in Manuel mode for YEARS … The last time I used manual mode was in high school over 20 years ago. To say I'm a little rusty is an understatement. Other than that, I follow her instructions on a T to get a photo in manual mode with the correct exposure and get a very dark picture. I tried to reach them, but of course they say that this is proven to be a good photo. There must be something that is not sitting properly on my camera. I have no idea what it could be. Any help would be appreciated

Nikon D7000
In a room with lots of natural light
Recording mode: Manual
Measurement mode: matrix
ISO: 1600
Aperture setting: f 5.6
Shutter speed: I use the light meter and set it to 0.

All of this should give me a good photo, right? Well, I get a very dark picture. Could there be another setting on my camera that is not set up correctly?

Thank you very much