A COMPARISON OF THE DIFFERENCE BETWEEN JPEG,  RAW  AND TIFF

Lyzette Botha

INTRODUCTION

The question is: Should I shoot JPEG or RAW? And what about TIFF?

JPGs (same as JPEGs) are normal digital camera images. Cameras create JPG images from raw image sensor data based on your settings like Sharpness and White Balance. The camera makes the JPG and then the raw data evaporates as soon as the JPG is recorded.

RAW files are just the raw sensor data. Most fancy digital cameras allow you to save the raw data instead of the actual JPG picture. If you do, you have to do the processing yourself later in your computer to make JPG or other kinds of pictures you can see. Some cameras have a handy RAW + JPG mode which saves both the raw data and the JPG picture. RAW files are really only half-baked images; you have to finish them later before you can use them.

Everyone's needs vary. Some photographers prefer to make adjustments in-camera and use the JPGs directly. They get the look they need with JPGs and prefer to spend their time making more photos. Others prefer to spend time later twiddling in RAW.

TIFFs (also called .TIF) are very large files used for saving processed images. TIFFs are used only in tethered studio applications, if ever, for camera capture. Tiffs don't have any of the post-processing advantages of RAW and have enormous file sizes that will completely clog up any workflow if you are shooting many images on cards.

TIFF (or PSD, the format native to Photoshop) is perfectly fine for archiving files after you've played around with them or for sending to a client on CD. Just don't set your camera to this format for recording on cards since it's cumbersome.

THE TRUTH ABOUT JPEG

JPEG has been criticized for the fact that every time you save a JPEG image some image data is lost due to compression. There is a cumulative effect since this occurs every time you save the image. Over time the effects become noticeable as artifacts in the image - distortions not present in the original image. They can manifest themselves as apparent colour shifts due to compression, banding, boxy areas, and a general loss of sharpness - none of which is good.

The amount of image degradation might be overstated. There is a perception that any hi-resolution JPEG image sharpened and saved before printing will be somehow flawed. This is not true. Image degradation is most noticeable in low-resolution images, and doesn't represent a significant problem in high-resolution images unless they're being worked on repeatedly. How many times you can save an image before artifacts become visible depends on a number of variables such as file size, amount of compression used, and the nature of the image itself, such as how much continuous tone area the image contains (blue skies for example). As a general rule, thumb image artifacts are a problem for low- or high-resolution JPEGs that will be blown up considerably before printing.

JPG is the standard used by prolific shooters. It gives great quality and offers the fastest speed for everything. It is the most popular and compatible image format. It is especially popular for the things for which digital cameras are best suited in the first place, like news, sports and events. With JPG you can shoot hundreds or thousands of images at a time and the files are ready for release with no further processing. JPGs done properly, as digital cameras do when set to NORMAL or FINE, give great results you can use immediately. Of course you need a professional digital camera that provides the exact in-camera adjustments, like subtle white balance control.

Professional journalists like Karl Grobl who need to produce results shoot JPG. When Karl returned from a two month series of assignments in Asia he brought back 20 Gigabytes of JPGs, and those were just the keepers. Karl no longer has the time to piddle with anything in Photoshop: if the image isn't perfect as shot it gets deleted. Karl has a ton of images he needs to get to a ton of clients, and then he's off on the next assignment. There is just no time to wait for things like RAW file processing.

JPEGs have one considerable advantage over RAW files - size. While the exact difference will vary depending on whose camera you're shooting with, JPEGs will always be significantly smaller files than RAW files. 

Cameras create their JPGs from the 12 bit or more RAW data as it comes off the sensor. Your contrast, white balance, sharpening and everything are applied to the RAW data in-camera, and only afterwards is the file compressed and stored as a JPG. You'll see no additional artifacts since that's all done before the JPG conversion. 

JPEG will provide high quality, publishable images, but there are times when photographers may want to consider shooting in Raw mode.

SOMETIMES YOU WANT TO GO RAW

Shooting in RAW mode allows you to save every bit of detail that the camera captured, and it gives you the ability to look at all of the camera's settings and change them afterwards. If you captured an image in raw mode you can go back a year, even five years later, and change your decisions on a variety of camera settings. 

It's important to understand that a print of the raw file without any changes will look identical to a high resolution JPEG file captured at the same time. What you're getting with a RAW file is the ability to make changes later on. 

Advantages of Raw

Before you shoot down RAW mode and say "I can just do it in PhotoShop", imagine this scenario: You go out and do a model shoot. On your laptop screen everything looks OK. You shoot the equivalent of 15 rolls of film or 540 images. A day later you're looking at the images on your workstation and you notice the white balance is off a bit on all the images. This is the equivalent of using the wrong film type and/or filters for the available light.

If you shot in JPEG you'd have a choice of editing 540 images in PhotoShop or redoing the entire shoot. Both are expensive and bad options. But if you did the shoot in raw mode you have the option of changing the white balance after the image is captured.

The ability to change camera settings later can be a great learning tool. With so many variations available using in-camera settings, it's no longer just a matter of bracketing to see the effects of different exposures.

Let's say you shoot mostly landscapes. It's near sunset and the light is tricky. You set up on a tripod and bracket at 2/3rds of a stop above and below the meter reading in raw mode.

Now back at your desk load the images and choose the one you feel is the best starting point. You can now experiment with the tone, saturation and white balance. White balance is probably the most misunderstood setting in digital photography and the accuracy of white balance settings varies greatly from camera to camera and under differing conditions.

Is auto white balance the best answer - or do your images look better with some white balance compensation dialled in? How about sharpness? Are you better off doing some sharpening in-camera, or doing it all in PhotoShop? If there's no difference, let the camera do it and save yourself a step later. But beware! The amount of sharpening you want to do may change with the subject you're shooting or the size of the print you'll be making.

The mantra "start with a high quality image" should always be your guide. If you rely on making a lot of adjustments afterwards, you'll spend more time behind the keyboard than behind the camera and that is not an acceptable option. 

But if you're on a critical shoot or in a once in a lifetime location under tricky light, then shooting raw gives you the option to go back in time and make a different set of decisions should the worst happen. 

Disadvantages of RAW

Using RAW files obviously takes a lot more time and patience. You only want to go through this trouble if for some reason you're unsure of what settings to use. It's like either having a complete car that runs (JPG), or a science project in a million pieces that still needs assembly before you can drive it (RAW). You can't really change exposure after a RAW file is shot, although the software that opens this data gives one the option to rescale the data and give the impression of changing exposure. You can get this same synthetic lightening from JPGs, too, although only RAW allows some ability to correct overexposure.

1.     Raw image files are big. They capture the raw image data off the camera's image sensor, plus additional data on camera settings.   

     Because of the big files, a plug in can take 30 seconds just to open a RAW file, and that's after you manually chose all the settings with which you want the file to open – often with an unsatisfying preview - so that you might have to try a few times till you get it right. Multiply this by 500 shots made at a wedding and you can see why it's just not happening.

2.  Time is money to people who need to make money from photography. RAW takes too long: too long to record to the card, especially with compressed versions, takes up too much space on the card so more cards are required, takes longer to transfer to a computer, longer to back up to CDs and takes more CDs.

We simply don't have the time to waste for all the files to download and
then especially to wait while hundreds of RAW files open up the hard way
before we can see them. You could have had all that processing done right in the camera for free.

3. The formats are not standardized. With Nikon and Canon at least the
latest version Photoshop CS can open the RAW formats, but otherwise you
have to revert to using each manufacturer's proprietary software. If you can't run the reader software then you won't be able to read your image files and they are lost forever. Thus we see why RAW files are not at all like a negative that you can read in 50 or 100 years.

4.  Because it's not standardized, you can't send these files to clients or anyone and expect them to open. Also if you do, and they can read them, then you have lost control over how your file looks, since they may choose to open it differently. (Of course if your client asks for RAW give it to them.) If you shoot RAW you have to open each file and convert it to something like JPG or TIFF before you can send it out. This costs time you simply don't have to spend if you had shot JPG to begin with. This is one thing for just a few shots, especially if you are going to play with them in Photoshop anyway, but if you are doing this for money you are probably dealing with hundreds and hundreds of files everyday and there just is not enough time.

5. Each camera maker has its own incompatible format. One cannot save
files in RAW format either.

6.  Different software opens up the files differently. I see one thing with Photoshop's Camera RAW plug in, one thing with Nikon's plug in, and different things on different versions of iView even in different screens! In this way RAW is like a digital negative: the colors and sharpness look different every time you try to print it! Pros need images that always look the right color; the color we captured in the first place, which is why slide film is far more popular than negative film professionally.

CONCLUSION: WHICH SHOULD YOU SHOOT?

If you shoot hundreds or thousands of images in a day shoot JPG and don't worry. The quality is the same for almost all intents and purposes as RAW, and the RAW files would take gigabytes or tens of gigabytes and resultant hours to download, convert, catalogue and burn to backup CDs. In fact, if you shoot this much then JPG can give better quality since attempting to shoot this much RAW will constipate your workflow and you could miss making some images entirely. You'd always be running out of memory cards or time or whatever.

If you love to tweak your images one-by one and shoot less than about a hundred shots at a time then RAW could be for you. In fact, if you prefer the look you can get from RAW (it may be different from JPG in some cases depending on software) you can let your computer batch process images and save the results as JPGs, too.

One's preference for JPG or RAW depends on what you're trying to do. Each format has no absolute goodness; it's all about how appropriate they are to your particular work. Everyone's needs vary.

You may prefer one or the other. If you don't like the in-camera options, shoot unsharpened JPGs and sharpen elsewhere. Likewise, if you set the wrong white balance or underexposed you can always correct it later using, for instance, Photoshop's Levels, Curves and/or Color Balance features, among others.

Some people who shoot RAW don't realize that white balance can be adjusted in Photoshop even from JPGs. Some cameras, like the Casio EX-Z750, allow correction of JPGs for White Balance and exposure after they've been shot as well.

 ARCHIVING

If you shoot JPG, just archive the camera original JPG files.

If you shoot RAW you should also archive everything in a standard JPG or
TIFF format so you'll be assured of having the best chance of being able
to open and use the files in the future.

 Lizette: Part-time lecturer, advertising and graphic design and Sips Evening Photography student 2005