21 votes

Could a "universal exposure" setting be practically possible?

A digital sensor isn't really best described as "reading data". A much better way to describe it is "collecting photons" that are then converted into data by measuring the microscopic electrical ...
Michael C's user avatar
  • 175k
14 votes

Could a "universal exposure" setting be practically possible?

We already have some of the technology for this. Our term for remembering the sensor readings at each exposure point is "video", and what you are asking for is reconstruction of an optimal still image ...
Adrian Cox's user avatar
11 votes

Could a "universal exposure" setting be practically possible?

The original question is based on incorrect assumption (about digital sensor not changing state during the exposure) but the concept is related to the Quanta Image Sensor (QIS) idea researched by Eric ...
szulat's user avatar
  • 5,060
9 votes

How does software exposure compensation work in RAW files?

You are not actually adding light, you are simply enhancing what little light you gathered. With a JPEG, "stretching" or "pushing" and "attenuating" are all done in the camera, and those enhancements ...
jrista's user avatar
  • 70.7k
7 votes

How does software exposure compensation work in RAW files?

There is nothing special or magical in RAW files. When it comes to exposure and balance, RAW files just store more information about colors, than JPEG files do. Either way, these colors consist of ...
szulat's user avatar
  • 5,060
5 votes
Accepted

why exposing with 18% gray card does not give IRE near 40?

18% reflectivity means it should reflect 18% of whatever linear light is actually on it. Gamma should compute 117 at 46%, but your picture shows the card to be in some shadows, so then it can't be 18%...
WayneF's user avatar
  • 12.9k
4 votes

What is the formula to calculate aperture ("diaphragme" in French)?

The equation is: $$ {N^2\over t} = \frac{E \times S}{C} $$ for \$N=\$ f-number; \$t=\$exposure time (in seconds); \$E=\$ illuminance; \$S=\$ ISO value; and \$C=\$ incident-light meter calibration ...
mattdm's user avatar
  • 143k
4 votes

How does software exposure compensation work in RAW files?

Most definitely not a stupid question: I actually wondered the same thing when I first got into shooting raw. Before you can really understand what's happening when you adjust exposure in software, ...
William Rogers's user avatar
3 votes

Fixed camera and light settings return different exposure

If you're holding all exposure parameters constant, then the next suspect for me would be your white-balance setting, which I don't see mentioned above; e.g., do you have auto-white-balance (AWB) ...
Jesse Stuart's user avatar
3 votes

I Dropped my nikon D3300

It sounds like the mirror assembly is damaged, leading to incorrect light meter readings. In an SLR, the light metering sensor is contained in the viewfinder that gets its light via the mirror. The ...
the_limey's user avatar
  • 538
3 votes

Could a "universal exposure" setting be practically possible?

Film physically changes over the period of time it's exposed. A digital sensor, though, doesn't; it's just reading data. That really depends on the type of sensor. The kind of CMOS sensors that are ...
Caleb's user avatar
  • 31.7k
2 votes

Can I save extremely washed out images in post-production?

Adjusting the exposure is a basic feature of the "developing" software. If you are shooting RAW images, you have more latitude in the image data than the normal presentation of such an image can ...
JDługosz's user avatar
  • 4,382
2 votes

Mathematical definition of EV on a RAW photo?

Your entire exercise seems to be built on somewhat of a false premise: That the initial image you see on your screen when opening a raw image file in ACR is a linear representation of the luminance ...
Michael C's user avatar
  • 175k
2 votes
Accepted

Where can I find color data for X-Rite ColorChecker Classic?

The reference data contains the CIELAB data for the following colour rendition charts: ColorChecker Classic before November 2014 ColorChecker Classic after November 2014 ColorChecker SG before ...
Kel Solaar's user avatar
2 votes
Accepted

Random EXIF data with same camera settings

I could finally verify that the problem was 100% caused by the lens. It was internally unstable and in certain position the internal connections were not communicating the right values to the camera ...
Mario's user avatar
  • 313
2 votes

Random EXIF data with same camera settings

It looks like you've probably got 'Safety Shift' enabled and set to option 1: 'Shutter speed/Aperture' in your 70D's menu. It's found under the "Custom Functions" menu at 'Menu → Custom Functions (...
Michael C's user avatar
  • 175k
2 votes

Simple function to simulate different shutter speed / exposure by changing RGB values of image

The Kodak Gray Scale is the benchmark for your needs. Density is express as a logarithmic value. 0.30 density is a doubling of exposure = 1 f-stop a 2X change in opacity of film 0.60 = 2 f-stops 0.90 =...
Alan Marcus's user avatar
  • 38.9k
2 votes

Simple function to simulate different shutter speed / exposure by changing RGB values of image

You can't really do that; at least not easily. As a general rule exposure in the (s)RGB color space is power 2.2; but first you have to normalize the number to a 0-1 base (i.e. 128 is .5 (% of 255max))...
Steven Kersting's user avatar
1 vote

How does the wireless flash protocol control exposure corrections?

The metering flashes are popped off one at a time before the shutter is activated for the exposure. The sequence is so rapid that it looks to our eyes like a singular pop, but it isn't. I don't know ...
Michael C's user avatar
  • 175k
1 vote
Accepted

Post-processing goal: three different exposures?

While there are multiple ways to do this, my preferred approach is exposure blending. You basically take multiple exposures from LR and blend them together in Photoshop using luminosity masks. You may ...
Ed on PCR's user avatar
  • 715
1 vote

What is the formula to calculate aperture ("diaphragme" in French)?

As you know, all optical filters absorb some light hence require an increased exposure to compensate. The magnitude of this increase is universally called the “filter factor”. This value is likely ...
Alan Marcus's user avatar
  • 38.9k
1 vote

Fixed camera and light settings return different exposure

You mentioned there's an exif data incoherence with the parameters you shot. Although this could be an error of internal parts of the lens (dirt or moisture in the metal tracks of the barrel, whatever....
Alpha-Isomethyl-Ionone's user avatar
1 vote

Fixed camera and light settings return different exposure

How repeatable is it? A few ideas: I've managed to significantly change light levels by standing between the light source and the subject :-) Are these always-on studio strobes or are they ...
Roger Krueger's user avatar
1 vote

Mathematical definition of EV on a RAW photo?

If I'm understanding what you are trying to do correctly, your starting point is fundamentally flawed. " ... takes in a matrix full of 12-bit RAW sensor values ..." OK so far. " ... and adjusts ...
user10216038's user avatar
  • 2,241
1 vote

How to programatically adjust exposure based on image metadata?

It depends on what programming language you have access to. It's easy to read exif data with MATLAB: https://blogs.mathworks.com/steve/2011/03/08/tips-for-reading-a-camera-raw-file-into-matlab/ but it ...
matohak's user avatar
  • 156
1 vote

Exposure compensation after images are taken

Q: "How do I compensate the exposure of a bunch of photos so I can stitch them together?". I too disagree with the formula, shouldn't it be: \$p' =\$ \$p + \left(p \times {k^2\over\tau\...
Rob's user avatar
  • 1,813
1 vote

Exposure correction for a portion of an image

Yes, it is possible, especially if you also have a NEF file besides the JPEG - Adobe Camera RAW (inside Photoshop or Lightroom) allows you to bring down highlights without affecting the darker areas ...
K. Minkov's user avatar
  • 2,055
1 vote

Could a "universal exposure" setting be practically possible?

Let's simplify the problem to understand why we will always have to make compromises. Let's invent the camera you want, but with only one monochrome pixel. It needs to be able to reliably receive and ...
Adam Davis's user avatar
1 vote

Could a "universal exposure" setting be practically possible?

Others have already explained why this won't work, technically. I want to touch on why it wouldn't work practically. If data storage were not an issue, is there any reason this couldn't be the norm,...
user's user avatar
  • 1,099

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