Sunday, July 18, 2010
" The RAW vs JPG image format debate has come more to the fore in recent times with the introduction of specialized software for handling RAW images. If you use a digital camera and that camera is an SLR, then it most likely can record images in RAW format. In general, you should record your images at the highest resolution possible. If you only have a small memory card and are worried that you can only records a few RAW images on it, then it's time to buy a bigger card! . You can always shrink an image after it's taken but you can't enlarge a small one without introducing artifacts. At the very least, you should have your camera record images in Hires JPG format but RAW format is even better.
Any kind of JPG written to your camera's memory card will be processed in some way. JPGs, by their very nature, lose information in an image. If you repeatedly save a JPG, you'll lose more and more detail in it and see more artifacts appearing. Also, if you've set your camera up to do some image manipulation (e.g. contast/brightness adjustments), these will also be applied before your camera writes the image out to the memory card. In such cases, you could end up with images that have burned out highlights or shadows that are so deep that they contain no detail. Such areas of an image may be irreparable even with the likes of Adobe PhotoShop.
RAW images, on the other hand, are simply that - raw. What the camera sees is dumped (without any image manipulation whatsoever) onto the memory card. RAW images also tend to contain more information and detail and have larger file sizes than similar resolution JPGs. The problem with RAW files is that they've not been the easiest to work with; for example, Windows Explorer cannot show RAW files as thumbnail images so, unless you've renamed your image files with meaningful names, you won't know what the images are when you come back to them a couple of months later.
This is where software such as RAWShooter Essentials (RSE) comes in. This software lets digital photographers of all abilities import, view, edit and convert large batches of RAW files (to TIF files). RSE is currently free - it won't be for too long - so grab a copy now. Having used it, I can say it makes working with RAW files a doddle; much easier than using the software that came with my Canon EOS Digital Rebel.
With your converted RAW files, you have full control over what manipulations will be carried out to produce the final image, using packages such as Adobe PhotoShop,Adobe PhotoShop Elements or Paint Shop Pro. The better RAW conversion packages also include basic contrast, brightness and color management controls, so you may not even need a separate image manipulation package. Some even provide tools for compensating for over- or under-exposed images.
By shooting RAW images, you give yourself complete control over color and exposure and it's you, rather than the camera, that decides what adjustments are applied to reproduce the tones and contrast of the original scene. It also lets you maximize the quality of your final image for whatever output you want, whether that's on a monitor, as an inkjet print or sent to one of the digital photo labs for printing.
Various RAW conversion software is available to allow you to process digital images to the highest quality possible.Capture One and Breezebrowser are both highly regarded, although you have to pay for these. A demo version of Capture One is available so you can try before you buy."
In all,
not an image file per se (it will require special software to view, though this software is easy to get).
• typically a proprietary format (with the exception of Adobe’s DNG format that isn’t widely used yet).
• at least 8 bits per color – red, green, and blue (12-bits per X,Y location), though most DSLRs record 12-bit color (36-bits per location).
• uncompressed (an 8 megapixel camera will produce a 8 MB Raw file).
• the complete (lossless) data from the camera’s sensor.
• higher in dynamic range (ability to display highlights and shadows).
• lower in contrast (flatter, washed out looking).
• not as sharp.
• not suitable for printing directly from the camera or without post processing.
• read only (all changes are saved in an XMP “sidecar” file or to a JPEG or other image format).
• sometimes admissable in a court as evidence (as opposed to a changeable image format).
• waiting to be processed by your computer.
A jpeg file is:
• a standard format readable by any image program on the market or available open source.
• exactly 8-bits per color (12-bits per location).
• compressed (by looking for redundancy in the data like a ZIP file or stripping out what human can’t perceive like a MP3).
• fairly small in file size (an 8 megapixel camera will produce JPEG between 1 and 3 MB’s in size).
• lower in dynamic range.
• higher in contrast.
• sharper.
• immediately suitable for printing, sharing, or posting on the Web.
• not in need of correction most of the time (75% in my experience).
• able to be manipulated, though not without losing data each time an edit is made – even if it’s just to rotate the image (the opposite of lossless).
• processed by your camera.
& Jason Cher signed off @ 5:26 AM
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