These are my top 3 reasons to shoot raw. I’ve been using Canon DSLRs since 2005 and have been shooting with Canon’s raw format (CR2) from day one.
Other camera brands either use their own formats like Nikon’s NEF (Nikon Electronic Format) and Sony’s ARW (Alpha Raw) or the non-proprietary DNG (Digital Negative Graphic) format in the case of some compact cameras and the latest iPhones.
What is a raw image?
A raw image file is basically a digital ‘negative’ which you process manually in software and export out as a JPEG, TIFF or other format to print, share or publish.
Raw formats, for the most part, include all the image data from the camera sensor so the image is unadulterated by in-camera processing, hence the term raw.
How is a Jpeg different?
Jpeg images are processed and compressed in-camera so data is lost but the files are much smaller and are ready to use.
A film analogy
Prior to using DSLRs in the early noughties I was post-scanning my film negatives or slides, or having digees made by labs at the time of processing.
Whether negative or positive (transparency/slide) film, the idea of never having the original film frame with it’s range of tones to return to for print enlargements or higher resolution scans for publishing would have been unthinkable.
To me it seemed only shooting JPEG was the equivalent of having prints made from a roll of film then using those prints to make future copies! Perhaps an over-simplified comparison but the point is I would always wanted the option for a better reproduction, as would my customers have. So the first of my big 3 should be pretty obvious by now though still deserves some explaining.
Top 3 Reasons I Shoot Raw
#1 Optimum quality control
Image quality is down to more than one element but I’ve grouped them here under one heading for simplicity.
A raw file offers a higher dynamic range with more values between the brightest and darkest areas of an image. This is especially useful in contrasty or low-light conditions. In Adobe Lightroom you also have options for selectively bringing out details in shadow areas or pulling back the highlights or lightest parts of the image.
JPEG images are recorded in 8 bits or 256 levels of brightness, most raw formats record 14 bits or 16,384 light values.
Raw files offer more exposure latitude for overall adjustment or selective adjustments to parts of an image. Plus, though we try to avoid under or over-exposure, the raw data offers a lifeline for bringing back detail in shadows and highlights.
You also have greater control over noise and sharpness which also contribute to image quality.
#2 Wide colour gamut
More colour data is recorded on a raw file and so you have more control of colour temperature, especially useful when shooting interiors and in artificial lighting.
Also because raw images contain such a wide colour gamut a broad range of colour profiles are available. Digital displays and the web use the sRGB colour space, used by min-labs and arguably the most practical colour space to use shooting JPEGs. Pictures for publication would ideally be supplied with an Adobe RGB (1998) profile.
Another colour space is ProPhoto RGB containing many more colour values, probably more than you are likely to use but nice to have the choice. Who knows how many colours will be usable in future. Many other profiles are also in use.
#3 Raw images can’t be overwritten
Not something all photographers think about. A raw file itself cannot be overwritten so it must be exported into another format. The original raw file and it’s data is retained for future editing.
I suppose the argument is a JPEG file can always be backed up. But how do you know if a JPEG file hasn’t been adjusted? Was it the original image or has it been modified?
Given each time you save a JPEG, it re-compresses it’s data, how many times the JPEG file was saved could also be an issue. You can backup modified Jpegs as TIFF which are a lossless (uncompressed) format but files can be even bigger than raw files and TIFF files can be overwritten.
There is now an alternative to keeping your original images as raw files and still retain all the data of the raw image. It’s called the Digital Negative Graphic, created by Adobe. Raw files can be exported as DNGs in Adobe Lightroom. The DNG format is also, supposedly, less likely to become unsupported by software long into the future because it is non-proprietary.
Arguments against raw
There are arguments against raw, many originating from the days when cameras were slower and memory was at a premium.
Most concerns relate to file size, processing time and the proprietary nature of the format. Personally I think these concerns tenuous, especially with today’s faster cameras and cheaper memory. As for concerns over the longevity of the raw format these can be easily insured against.
Raw and JPEG images can be shot together if images are needed quickly, so the option of having both ready-JPEGS and raw data files is always there.