Why shoot in RAW?

Why Shoot in RAW?

RAW File Format

Some cameras offer a choice of image format that includes JPEG, TIFF, and RAW. The JPEG format utilises lossy compression and the TIFF format is lossless. While we want to retain as much detail as possible, lossless compression comes at a price: a substantial increase in file size. Instead, utilise the highest in-camera JPEG quality setting and results will be indistinguishable from TIFF files.

Raw files are also lossless, but another breed entirely. When you shoot in raw mode data from the sensor is directly recorded with no adjustments. Camera settings you made for saturation, contrast, sharpening, and colour space are ignored with the expectation that you will specify these parameters later in Photoshop. This means you can take pictures without concern for these factors. Later, in a more relaxed setting, you can make adjustments in Adobe Camera Raw (ACR).

In addition to the above adjustments, you can specify white balance. Although you can correct white balance in Photoshop proper, the Temperature/Tint sliders in ACR are intuitive to use and often do a superior job because they're operating on linear data.

While significant progress can be made rescuing clipped highlights, similar gains are not as dramatic for shadow detail. The major improvement is the fact that you're dealing with increased bit depth in raw images, so stretched shadows will transition smoothly. However this improvement is only apparent in very extreme cases. Consequently shadow detail is similar for both raw and JPEG files.

Photographers not shooting raw, but who are careful to expose properly (expose to the right), sometimes find their efforts are in vain. Even though they scrutinise the histogram, and verify there are no truncated values, the resulting image imported into Photoshop has blown highlights.

If you expose to the right (ETTR), and specify sRGB for in-camera processing, you're sure to encounter clipped highlights with monochrome scenes. There are several remedies to avoid blown highlights:

No ETTR and specify sRGB for in-camera processing and Photoshop's working color space
ETTR and specify aRGB for in-camera processing and Photoshop's working color space
ETTR and specify raw for in-camera processing

Underexposing, the first choice, is the simplest workflow. Choosing aRGB as a workspace often yields good results, but shooting raw is the best choice. This yields a digital negative that can be transformed to the color space of your choice (aRGB or sRGB) with satisfactory results.

While 12-bit sensor data may contain extended dynamic range, it should be mentioned that 8-bit and 16-bit images, in standard 2.2 gamma color space, have the same dynamic range. In this case 16-bit images have a finer resolution, or more tonal values, than 8-bit images over the same dynamic range.

Raw vs JPEG

Deciding which format to use can be problematic. Raw files require additional processing. If you're a sports photographer and shoot hundreds of images a day, extra steps are the last thing you need. If you take ten pictures a week, and strive for perfection, then raw makes sense.

While the raw format offers potential for improvement, gains are often small. For example, you can't look at an image and identify whether or not it was originally shot raw. White balance is usually okay. Blown highlights are the exception rather than the rule.

High noise levels are the result of shooting at high ISO settings. At lower ISO settings the change in noise with respect to exposure is far less dramatic. Let's face it. If you're shooting at a high ISO are you in a position to increase exposure to avoid noise? Perhaps JPEG, with lower noise levels due to in-camera processing, might be a better option.

If you find shooting raw a hassle, shoot JPEGs. Under most circumstances results are comparable. Although exposing to the right works well for raw, it's not such a great idea for JPEGs due to truncation issues. If you're concerned about exposure accuracy, and your camera supports Adobe RGB, utilize this colour space and blown highlights becomes less of an issue. As an added plus you're recording images in a colour space with a larger gamut. This gives the potential for prints with better colour. Unfortunately, you'll still be faced with blown highlights if you attempt to convert Adobe RGB to sRGB for email or the internet.

What about Pro Photo RGB? It has an even wider gamut. Unfortunately the gamut is so wide that the space between adjacent colours can cause banding. To avoid banding with Pro Photo RGB you'll need to process images in 16-bit mode. The downside is increased file sizes, memory requirements, and reduced functionality in Photoshop.

So which should you use? Raw or JPEG? Good question. Our choice is the raw format. We enjoy the precise control and white balance adjustments possible with the raw format.

Responses and Testimonials:

Carl says:

RAW all the way. For me the exposure latitude inherent in RAW makes the difference in file size worth while. Storage media is cheap — cheaper than film ever was — and for me shooting RAW vs jpg is similar to shooting negative vs polaroid: you can do a whole lot more with your neg.

This is always a contentious topic, for some reason, so it should form some interesting discussion. I know that some of the top wedding photographers in the country shoot jpg and don’t see the point of RAW.

Steve says:

I’ve had RAW save my hide a number of times. Especially when you shoot where there’s consistent lighting, such as an event. Under these circumstances, if your exposures, white balance, or flash settings are off - all of which are surprisingly easy to do, a good RAW workflow will let you fix all the images at once. Once one image is corrected, the changes can be applied to all with a couple of clicks.

While while some tools might let you do at least part of this in JPEG, a good RAW workflow also lets you undo the changes equally quickly (again to all images at once) since the actual changes are made only in metadata (and to the rendered presentation) without manipulating the actual stored image data.

A related topic is: if you shoot RAW, what format do you use for storage and manipulation, once the image is retrieved from the camera - native (CRW/CR2/NEF, etc. with sidecars) or standard/general (DNG).

I would argue strongly for DNG since it saves the headache of tracking images in pairs. Think of the hassles of keeping file pairs in sync through rename and moves. Yes, some RAW processors don’t support DNG; and others have their own sidecar formats (ex: Bibble). While Bibble is a fantastic product, using it with Bridge and Photoshop will necessiate you having to track your original raw file, plus an .XMP created by Bridge as well as a .BIB from Bibble. Now think of the headaches of tracking file triplets through moves and renames. Yes, there are tools that will do all this, but if you use a DNG-based workflow you can bypass the whole mess.

Gary says:

RAW always:

1. RAW = lossless, JPG every time you open / change / save the JPG it degrades in quality.
2. White Balance, I’m sure I’m not the only one who has needed to fix this after the event.
3. Exposure, better dynamic range in RAW allow more post processing options.

Siziay says:

I’m shooting mostly with a Lumix L1 right now, and in RAW mode (which I always use) it also makes a JPEG as well, so I guess I shoot in both…the RAW is great for reasons most people have already mentioned, particularly when you forget to change your white balance, or when you don’t have time because there’s a shot you just have to get.

Having both formats allows you to find a particular shot quite fast on a card without knowing the filename (since I don’t seem to be able to make OSX preview my RAW images in the Finder).

I also edit all my photos (even JPEGS from my point-and-shoot ) even if just to check levels, and rename them and save them in a particular folder, so it’s not much extra work for the shots that don’t need much tweaking.