Almost all DSLRs come with plenty of options governing aspects of image quality. They almost all affect JPEG output but which of those settings and options matter when you shoot raw? We’ll look at this briefly in this article and in more detail later.
Exposure settings matter, whether you shoot raw or JPEG
The exposure of a given scene will be determined by these settings:
- Shutter speed
- ISO setting
(The ISO setting in digital photography is not entirely straightforward and will perhaps get its own article. For now, we’re keeping things simple.)
As you’d expect, aperture, shutter speed and ISO setting all make a difference to the images that your camera records, whether you shoot raw or JPEG.
Secondary camera settings: do they affect raw files?
A DSLR’s menu system will offer control over other aspects of your image, whether you’ve told it you’re shooting raw or JPEG:
- Colour mode (Adobe RGB, sRGB)
- White balance
Sometimes you’ll see picture controls that change many secondary settings together. For example, your camera might offer an option like “Vivid”, which sets saturation higher and might also affect contrast and/or colour mode. These controls might also change the way colour appears, including small shifts in hue, sometimes emulating certain types of film.
Which of these secondary settings, if any, affect your raw files? Which of them should you be concerned about when shooting raw? And, again assuming you shoot raw, do they affect any other aspect of your photography.
Before answering them and explaining the answers, let’s categorise everything inside a raw file as being one of two things.
A note about raw files
Simplifying somewhat, everything inside a raw file is either a measurement of the light falling on a part of the sensor or it’s a note about camera settings. You could say that it’s either data (the values for light on the sensor) or metadata.
Let’s say that you take a shot on a current 24-megapixel DSLR. Inside the resulting raw file will be roughly 24 million values representing the light that fell on the sensor during the exposure, one value for each sensor element, or sensel. We can consider all this stuff to be the data that’s eventually turned into an image in your raw converter.
The metadata is a record of things like the shutter speed you used, the aperture, the type of camera, the type of lens you used, the white balance and sharpness settings, which saturation you’d specified and so on. Lots and lots of stuff, only some of it documented publicly by the camera manufacturer.
So which of the secondary settings listed above directly affect the data in your raw file?
The answer is: not a single one. Think of there being a note in the raw file that says: this photograph was shot with sharpness set to high and contrast to minimum, noise reduction set to zero and colour space set to Adobe RGB 1998; colour temperature was 5500K and the green-magenta bias was 30% magenta. Most raw converters, including Lightroom and Aperture, read the note and display large parts of your metadata but the only thing they use to influence their initial versions of your images is the white balance information. Everything else—including all the other secondary settings listed above—is ignored. Even the white balance setting is used only for the initial rendering.
Despite the presence of the metadata “note” inside your raw file, none of the 24 million values recorded by your 24-megapixel camera to represent the scene itself were directly affected by those secondary settings.
When you shoot JPEG, things are very different; each and every secondary setting above has a chance to affect each and every pixel of the JPEG. In the case of white balance or contrast, it is almost guaranteed to affect every pixel, often in a way that might limit the changes you can cleanly make later. That doesn’t mean JPEGs are bad or unusable, particularly if you’re in complete control of your light and white balance—it just means that the raw converter inside your camera is making decisions that it might be best to leave for later.
To be continued…
Although the secondary settings have no direct effect on the raw file, they do affect the histograms you see on the back of the camera. As a photographer, you might use those histograms to change the exposure settings (shutter speed, aperture, ISO) that you choose, perhaps as a result of exposure compensation that you dial in. The story isn’t over. We’ll revisit this topic soon.
And speaking of data and metadata…
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