Urnst wrote:
Do they? Thanks!
JPEG files contain 256 bits (brightness levels) per color channel.
Raw files are at least 4096 bits, and sometimes 16,384 bits per color channel.
In reality, that translates into 12 to 15 stops of dynamic range that can be captured in a raw file. A JPEG processed in camera (or in post) can contain about 5.5 stops of that.
Note that photo prints have a reflectivity range of around five stops, give or take the nature of the illumination used to view them.
The trick is to manipulate the raw capture to compress as much of the tonal range as is needed for your intended effect, and stuff it into that five stop range we can see on paper. There are tools in the camera to do that (rather crudely), but post-processing software can do it rather precisely.
Think back to the days of slide film. Exposure controlled density. Development controlled contrast, and with it, color balance. So development was RIGIDLY controlled. Blow the exposure, and your slide was too dark or too light. For my standards, latitude was +0.33, -.67 stops. More than a third of a stop over, the highlights would be burned out and detail-less. More than two thirds of a stop under, the shadows would be plugged up.
With JPEGs processed in camera, roughly the same rule of thumb applies. However, good post-processing can adjust an image to create an illusion of normality... up to a point. You can't put back into a JPEG what bad exposure took away from the top or bottom end of any of the three color channels.
With negative film, you got to play with the development a bit in black-and-white, but with color, altered development messed up the color balance about the same as it would with slide film. But assuming normal development, you had at least ten stops of dynamic range to work with. Sometimes, as with motion picture film and the processes used to develop it, you could have 20 stops of dynamic range to work with, albeit quality suffered beyond 12 stops in most instances. Negative film latitude was typically two stops over and 1.5 stops under, for acceptable prints.
With raw capture, and post processing, we can rein in the highlights and shadows, to discard intermediate tones and use the 256 available to represent the 4096 or 16384 reasonably well. The trick is to exercise restraint and taste while "cramming the dynamic range of reality into the narrow bandwidth of the medium," as one photo industry pundit puts it.
The same thing is done in audio recording, where the dynamic range of a vocal is heavily compressed so it "sits well" within a mix of musical instruments. That simply means that the quietest and loudest parts of a singer's delivery are intelligible, especially when heard on a car radio used on the highway.
Camera manufacturers put all sorts of controls on their camera menus that allow alteration of the default JPEG processing. A lot of folks have been told, MISTAKENLY, that camera manufacturers determine what a JPEG should look like. The truth is far more nuanced... They merely provide reasonable starting points for you. Casual users will accept them until they learn that they can adjust them, or save raw files and post-process their own realities.
Working with in-camera JPEG processing to achieve *professional level* results is possible, but it is actually a LOT HARDER than recording a raw file and processing it on a computer. It generally helps to control the lighting, to maintain a usable contrast range. White balance is a huge issue, so achieving a custom white balance at the camera for accurate JPEG processing is important. Pros use exposure and white balance targets (many types are available). Exposure must be dead-on accurate.
Entire pro industries use JPEG capture, but within thoughtful constraints that provide the desired results. The school portrait industry relies upon JPEG capture. But there is a rigid formula for it. Cameras are tested and menu settings adjusted to capture just the right subtleties. Lighting is controlled to within a 3:1 ratio (often 2.5:1 or 2:1). The subject is lit very softly, using large white umbrellas and soft boxes. The lighting never changes from subject to subject. Exposure and white balance are set from a target. The subject is always at the same distance from the camera and lights. Lab color correction is very slight (within about half a stop of the original recorded values), and is usually the same for all the subjects photographed on the same camera during the same session. The result is very high quality, with little to no effort in post-processing.
There is an argument in the photo industry that pits JPEG capture against raw capture. It should NOT be an argument! It should be JPEG AND raw capture, not JPEG vs. raw capture. They serve entirely different purposes.
JPEG processing in camera was an early feature demanded by the photojournalists who used the early dSLRs. They simply needed to be able to deliver the images in a ready-to-use format. That the camera automation became "good enough" for most people to accept most of the time was a plus. However, ALL automation has limits, and there are a great many instances where even the best automatic cameras fail us. That's when raw capture comes into play.
Just as I would never expect the mass portrait market (school portraits, big-box store studio portraits), or parts catalog photography, or eBay studio product photography, etc. to use raw capture, I would never expect TRUE PROFESSIONALS to photograph one-of-a-kind events such as weddings, SOLELY using JPEGs. To do so would be irresponsible.
There is no "argument." There is only appropriate usage. Let the use case determine your approach. I do, and that makes a huge difference for me.