Technical Advantages of RAW and JPEG
Other than enhanced control over the process are there technical reasons for shooting RAW instead? A few years ago we would have proclaimed a resounding "Yes" to answer this question. Demosacing requires a lot of processing power, and just a few years ago you could easily demonstrate that RAW shooting and computer processing provided higher resolution images than those that could be produced "in-camera".
The answer to this question today is not as clear. With each generation of new cameras that truth becomes less the case. DSLR processing power has been growing by leaps and bounds, and we have now reached the point where JPEG images from the Nikon D300 and Olympus E-3, for example, actually test higher resolution that the RAW images they capture. Processing power continues to get cheaper every day and this old argument for RAW instead for highest resolution is disappearing as processing power and in-camera software sophistication continue to grow.
One area where RAW still has tremendous value is the area of white balance control. Despite the phenomenal improvement in digital imaging overall, auto white balance still seems a mystery function in many of the latest DSLR cameras. White balance is part of the JPEG processing and it is often difficult to precisely adjust White Balance in a JPEG after the fact. With RAW images, however, correcting White Balance or completely shifting it for creative impact is a very easy task in most RAW software like Adobe Photoshop RAW.
One very significant drawback of RAW is that the quality of RAW conversion is totally dependent on the software that is used for RAW conversion. Many programs are too "universal" in scope to squeeze the most from any particular camera's RAW images. Other programs are closely tied to a particular camera (like those that come with DSLR cameras) and this "home-grown" software is sometimes lacking in options and image-processing sophistication. RAW processing software is definitely improving and the trend line is clearly toward better and more useful solutions.
The other huge disadvantage of shooting RAW is time. A JPEG file is immediately ready to use in some form; a RAW file requires some post-processing to even see the image.
Many pros and hobbyists shoot JPEG + RAW when results are crucial. This allows the option of the easy to use JPEG when it gives the photographer what they need and the RAW image for thoughtful manipulation when the JPEG fails to deliver the result or the photographer wants more control over the finished image.
While processing power is growing rapidly in digital cameras it is still true that the digital camera is not nearly as powerful as a computer as your desktop or notebook computer. Thus the digital camera makes compromises to speed processing and image conversion that might not be made if more processing power were available. This is both a negative as well as a plus. You can be sure that the in-camera processing is very efficient and specifically tailored to your sensor and possibly your lens if the lens contains a ROM (like all Olympus lenses and many other electronic lenses from other makers). The desktop computer definitely has more power, but image processing from RAW means the conversion is still dependent on the quality and flexibility of the software used for that conversion process.
Facebook
Twitter
RSS
22 Comments
View All Comments
Wesley Fink - Tuesday, May 20, 2008 - link
The goal was to produce a fair comparison and as staed in the article we do have the TIFF files available. The purpose was never to show there is minimal difference in RAW and JPEG. As we were preparing to post there were concerns that the TIFFs, at 45mb each, might cripple our server as a direct image view "click to see". That is the ONLY reason we converted to Maximum JPEG format directly from the RAW file.Since there is some interest we will likely produce a ZIP of the TIFFS and create a download link on the RAW examples page.
Wesley Fink - Tuesday, May 20, 2008 - link
Another option would be to post a ZIP of the RAW files. The latest Adobe Camera RAW can handle the PEF format in either Photoshop CS3 or Elements 5 and 6. OR we could save in Adobe DNG format and the DNG files could be read in almost any recent Photoshop or Elements - but not other programs. If either of these is a preferred option please let us know in these comments and we will go with what readers want.pinto4402 - Tuesday, May 20, 2008 - link
A ZIP file of images in RAW or DNG format would be great. I don't think any other review site is doing this. Although I won't download them each time I read an article, I would absolutely look at them VERY carefully if I'm interested in a camera.pinto4402 - Tuesday, May 20, 2008 - link
For your sample images, have you thought about using a high quality mannequin head (sounds creepy, I know), or silk flowers? Although not perfect, this would be much preferable to the product boxes you’ve been using. This will allow you to precisely control your test protocol while at the same time obtaining useful information about the imaging capabilities of cameras being tested).Overall, your camera reviews are better than average and if you’re serious about it, why not make your testing as good as possible?
haplo602 - Tuesday, May 20, 2008 - link
"Serious photo hobbyists will also be facing difficult decisions today and even more so in the near future. The cost of larger and larger sensors has been dropping rapidly; and CMOS sensor development from all the sensor manufacturers is also a factor in lowering costs and increasing resolution. Like it or not Canon and Nikon have already begun segregating their SLR line into full-frame and APS-C sensors. Those who wondered why Sony was introducing mainly full-frame lenses will finally get their answer later this year with Sony's 24.6MP full-frame flagship model."This exactly makes me a happy film shooter :-) There's one disdvantage to full frame sensors however. They increase demand for full frame lenses and increase the prices for me :-(
Anyway good article. I'd have one comment and one request.
Comment: There was lots of heated discussion about your sample images (there is one again so far). Would be good if you could shoot manual with f/4.0 and whatever shutter reading for the selected ISO but same for all cameras to make the captured EV consistent. This should in theory lead to all images having same brightness. Of course that will vary by camera processing, but at least you get one more point you can compare from the same series of shots.
Request: Can you make an article on the processing path of different camera makes and sensors ? You covered the digital conversion so far, but the A/D part would be nice to have too. F.e how ISO is controlled (analog gain or digital interpolation) etc. Also explanation what a higher bit-depth sensor means (12 vs 16 bit sensor and A/D). I know these things are pretty basic, but this will create some common group which you can reference in the future and avoid stupid questions (well some of them at least).
7thSerapHim - Tuesday, May 20, 2008 - link
Does anyone agree that a better object with clearly defined lines and colors should be used instead, for the comparison crops?Most of the time these mass-produced product boxes have mediocre color matching and well-defined lines so it shouldn't be used as a 100% comparison crop.
The shots also seem to have a substantial amount of chromatic aberration, or maybe just due to pixel peeping, hmmm...
sprockkets - Tuesday, May 20, 2008 - link
JPEG compression control would be nice on the p&s. The Canon SD1000 has compression artifacts all over, thus making the pictures it takes look worse than a $90 Nikon.dblevitan - Tuesday, May 20, 2008 - link
There are two key advantages of RAW that you missed and that could be useful to even people who are slighly interested in improving images.First, RAW provides 12 or 14 bits/pixel while JPEG only provides 8 bits. This is extremely relevant if you edit at all in Photoshop/Lightroom because any kind of level adjustment (even auto) will cause more color degradation with an 8 bit image than with a 16 bit image (which is what the 12 bit RAW files are generally processed into).
Second, RAW provides a better chance of recovering improperly exposed images by allowing at least 1/2 stop of exposure correction without any penalty and often more without significant issues. With JPEG you simply won't get this.
Wesley Fink - Tuesday, May 20, 2008 - link
You are absolutely correct that while JPEG is 24 bits per pixel it is only 8 bits per color channel (red, green, blue). The Pentax K20D is specified as a 14-bit A/D processor.Photoshop and other processing software, as you point out, normally processes this in 16-bit. However, it really doesn't matter in the end how the program processed it or saved it, what matters is the input bit depth. Many are not aware of this, but Photoshop also processes JPEGS as 16-bit on more powerful computers, but this just speeds up processing because you start with 8-bit and save as 8-bit with JPEG. There is no real advantage processing 12-bit files as 16-bit except processing speed as you don't gain real resolution improvements.
I agree RAW SHOULD allow more dynamic range, but some of the newest models like the Nikon D300 can actually do just as well or better in dynamic range in JPEG. However, in general what you say is true although it is changing as the processing power in DSLRs is improving.
What we really need is a higher bit-width JPEG standard. Let's hope the JPEG standards committee is hard at work on just that.
Bull Dog - Monday, May 19, 2008 - link
Is it just me or is the third page missing?