RAW, Jpeg - advantages, disadvantages

Discussion in 'Beginner Questions' started by endbr, Sep 3, 2010.

  1. What is the difference in RAW vs. Jpeg vs. other shooting preferences? Advantages, disadvantages of both?
  2. mike dixon

    mike dixon Moderator

  3. aweee.
    knew i should have looked around abit first ;)
  4. They are two different kinds of image file (graphic file) formats. A file format is the internal structure of the data.
    RAW files are proprietary to the camera manufacturer, that is to say, Nikon has their own raw file format, Canon has their own raw file format, Olympus has their own raw, file format, etc, etc, etc. Its called a raw file because the camera system is designed to capture the immediate digital data straight off the image sensor chip and save that to file without doing any processing to it whatsoever. So the data in a raw file is 'essentially' exactly what the image sensor captured at the precise instant of exposure. The data is raw, that is, nothing has been done to it to process it, enhance it, manipulate it, compress it, or improve it.
    JPEG, on the other hand, is a highly processed file format whereby the camera uses 'compression formulas' (compex mathematical equations) to 'sift' the image file, figure out where tiny pieces of image can be removed (all through the image) without doing major damage to the overall image - this results in file compression that makes the JPEG copy of the image substantially smaller in file size. Albiet, the cost is slight loss in fine image details. So the JPEG file format is loosely called a 'lossy compression' (because some original image information is lost compared to the original data).
    Another standard format, supported on many digital cameras, is TIFF. This is also a processed file format, and is also compressed, but the designers of the TIFF structure used different mathematical formulas to effect a 'lossless compression'. So the camera processes the original image information, compressing it somewhat, but using formulas that retained 100% of the original image content. So you do not get the loss of fine details, like you do with JPEG, but you still have substantial file sizes, but not as big as a raw file.
    And there are different levels of JPEG files. Usually from large sizes down to small sizes. The rule of thumb is that as you go down the scale, the system is applying more aggressive compression on the original image data in order to achieve increasingly smaller file size. But the more aggressive the compression factor, the more eroision of fine image details will occur. This might not be visible on a laptop screen. But it probably will be visible if you make a large size print and compae against a similar size print of the original image file, say from raw or tiff.
    The main advantage of shooting in raw is that you capture 100% of what the sensor chip 'saw', you effectively prevent the camera from altering any of that data, you save it to a raw file, and you can then precisely alter it (according to your own tastes and preferences) on your computer. To do that, you use a program called a 'raw file editor', or some call it a 'raw converter. But the idea is simple, you, the photographer gets to decide how that image is going to be altered, according to your needs and the requirements of your task.
    The disadvantages of shooting is raw mode is that you tend to create very large picture files because the picture data comes straight off the sensor and is not altered by the camera. So there is no compression or processing done to cut down that file. Also, by their very nature raw files are proprietary - there is no one 'standard' raw file across the industry - and that means that you MUST select the right type of software app that you are SURE is able to read and edit that particular STRAIN of raw file coming from particular BRAND and MODEL of camera. This makes your choice of software selection much more particular.
    The advantage of shooting in JPEG mode is that by incurring a tiny amt of image loss you end up with substantially smaller file sizes. The smaller file sizes mean more pictures can be stored on your picture card, and the smaller files are more easily handled, manipulated, and copied from point A to point B. In some venues and applications, the slight amount of image loss is fine, and the reduction in file size is practical and desireable. For example, for family fun, non-critical snapshots, where nobody is going to need to examine the fine detail with a magnifying glass, then JPEG is just fine.
    JPEG is also a fine format to use if your main intention and design for the pictures is to send them by email or post them on the web. For example, sending pics of Jr to the grand-parents. In these cases, you need good overall image quality but small file sizes for transmission across a network.
    JPEG is also a very common standard format for graphics files. That means that MANY different image editing programs, from the 'least of these' to 'the greatest', will be able to load, handle,manipulate, view, print, and many times convert, a jpeg file. So if your project needs a file format that will accept a slight loss in image details, while garunteeing it can be read by the largest possible audience for a long time, then JPEG is again a good choice.
    BUT, some venues and some projects want absolutely the best image detail they can squeeze out of the camera system with little or no loss at all. These are the guys that actually do put the magnifying glass to the image to try and discern as much intelligence as possible for their mission. (Think of hi-res images coming back from a Martian crawler, or of CIA analyst types, spending hours intensely study satelite images of foreign industrial complexes). In these type scenarios, the do not want any image detail loss, so they would prefer something like a TIFF format, which retains 100% image information with modest compression.
    Also, there is the questions of 'image archival'. By that we mean, whats the best way and format to use to store these images for a really long time and still reasonably hope to be able to work with them in the future. When measured against that reference, I think raw files are at a disadvantage because camera systems are progressing and changing all the time. Just becuase camera software app ABC can work with raw version 123 is NOT a garuntee that the software 20 years from now will be compatible with version 123. It is not uncommon, even in these days, to hear reports that a user upgraded his software and now cannot view his (older) camera files. So, in my opinion, when it comes to long-term image archival, TIFF enjoys the advantage simply because it is non-proprietary, and has been a standard format for a long time, with huge format support across a wide variety of programs. TIFF is also lossless and moderately compressed which is a plus for long-term archival strategies.
    This is a good question, and its a good exercise to think through which format is best for you and your needs on a shoot by shoot basis. But what you want to AVOID is a mindset that always says 'this mode is best' or 'that mode is best' in every situation and every session for all time. You need to think about what you are going to do with thes files, how much image detail loss you can afford to have and still satisfy the need, and how long you realistically expect to hold on to these files. Other factors may also come into play.Some places will ask you to shoot in a specific format so your picture will be compatible with their process. In that instance, you have to use their format, or convert from your format into their format.
    If you REALLY want to stay up late nights and fill your brain with details on t his topic, see if you can track down a copy of 'The Encyclopedia of Graphic File Formats', published quite some time back by O'Reilly, the same guys that publish a lot of Unix books. This massive tome goes over a number of file formats (including JPEG and TIFF) and gives you the complete inside/outside/upside/downside information about MANY types of picture files.
    Dont forget to check your camera manual to get specific info about which file formats your particular camera will support, and which levels of Jpeg and Raw are supported.
  5. Erica.....I'll just add that there are very experienced pros, (I am one of them), who do famously shooting jpgs around 90% of the time......so don't get too bogged down in this......regards, Robert
  6. RAW is a lot more hassle and I've yet to see as good of results as simply shooting jpeg to begin with.
  7. I don't find raw to be a hassle, I simply shoot jpeg + raw, if the jpeg is good enough I don't convert the raw, but in cases where I want to adjust the color balance I find it much easier to work with the raw image.
  8. RAW is more of a hassle than shooing jpeg, but then isn't using a DSLR more of a hassle than simply using a P&S?.
    An events photographer may take 1000s of photos and he needs those photos in a hurry. In that case, yes, he is better served taking them as jpegs in the first place.
    As a nature photographer I find it best to shoot RAW, tweak the files as needed and then save as jpegs. These results ARE better than if I simply processed as jpegs in the first place.
  9. Most labs that I've used for wedding work, prefer RAW. JPEGS leave them very little "wiggle room". Or so several lab managers have warned me. Your mileage and lab polices may vary.
  10. mike dixon

    mike dixon Moderator

    I'm locking this thread. The Beginner's forum is not the place to espouse your personal dogma regarding RAW vs. JPEG. We don't need another ten-page religious "debate" on the subject.

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