Thursday 19 February 2015

Camera Raw Essentials

There are two primary formats that digital cameras capture today, RAW and JPEG. But what can be confusing is that there are a lot of different flavors of raw. It's sort of a generic term that people use to describe the unprocessed data that the camera captures. For example Nikon's raw format is .mef and Canon's raw format is .crw. These file formats are all very similar and that they contain much of the same information such as meta data about the camera settings and image information. But there's just no standard way of writing a RAW file, so each one has its own unique order to the data.
There s one RAW format that's not proprietary, and that's the DNG format. Many people convert their files into DNG because of the fact that it's an openly-documented file format in hopes that their files will be able to opened farther into the future and if they're kept in a proprietary format. Adobe's the creator of the DNG format and more information can be found on their website. It's important to know that if you compare the quality of a RAW format versus a JPEG, there's more information in a RAW file.
For example capturing in RAW creates images with greater dynamic range, larger color spaces and, therefore, allows more flexibility in post processing. Basically you can make larger adjustments to your RAW files without losing image quality. Capturing in the JPEG format while rendering a smaller file that's faster to download forces the camera software to process the file using lossy compression, which throws away thousands of colors and tonal values. The end result is that you can't make as dramatic changes without losing quality.
Basically, capturing RAW gives you a bigger box of crayons to work with, so let's take a look at this example. I'm going to select these two images that are of the same scene, but one is a DNG or a RAW file, and the other is a JPEG file. Now in order to open these both in the camera raw, instead of using file open or double-clicking on them, I'm going to click on the open in camera raw icon. Then in order to see this full screen, I'll click on the full screen preview We can see that I have my 2 files open. The jpg file and the dmg file.
And that I can move back and forth between them by just clicking on their icons. What I'm going to do is, we'll perform a simple autoadjustment on the dmg file. And you can see that it's recovered a lot of information in the highlight area. Because this image was overexposed to begin with. I'll go ahead and move the highlight slider to the left even more to recover a little bit more information. Then we'll do the same thing to the JPEG. I'll select it and click Auto. And then move my Highlight slider down.
Now, let's zoom in to this area here. I'll click once, one more time so that we're viewing at 100%, and I'll use the space bar in order to temporarily access the hand tool, or you can click on the hand tool. And then just scoot this over. I want to make sure that I'm viewing the upper left hand corner, so here's the result of the processing on the JPEG and if I move to the DNG file and we zoom in either by clicking with a zoom tool or by selecting 100% and using the hand tool in order to scroll to the top of the image and we can see that there's a lot more information...
Being held in those highlight areas with the DNG file. So again, here's the JPG file you can see that we don't have a lot of detail in those highlights. And here it is compared to the DNG. Now even though we're pulling back in the detail in the highlights, this isn't to say that you shouldn't do your best to make the correct exposure in camera It's just to point out that if you need to make changes to your Photograph, you'll have more information to work with if you capture in Raw. Of course, if you really over expose your image, then even capturing in raw might not save you. If there's no information in the highlights, nothing can bring back information that's not there.
Of course, there are times when capturing in jpg has it's advantages. 1st, all the files are going to be much smaller. And therefore faster to download. Therefore, some experienced photographers like maybe and event photographer that's photographing each participant with the same background and a controlled lighting condition. Or who's confident that their images will not need corrections might capture in JPEG. But for most of us, I would recommend that, if given the option, capture in RAW, so that you have the ability to make corrections in post without compromising any image quality. In order to back out of the Camera RAW dialogue box without making any changes to this image, I'm going to select Cancel And then I'll choose yes. So there we can see the advantage of Raw over Jpeg in the ability to pull out information after capture.

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