This weeks post is more fundamental than post processing and is linked to the new highlight recovery algorithm that was released in Lightroom 4. This version of Lightroom is able to extract more information from the highlights of an image than was ever possible in previous version of Lightroom. This post is a summary of the extended document written by Bruce Faser (Document is available here and is referred to from the Camera Raw In Depth article here).
When you are creating the image inside the camera, the best thing you can do is to make sure that you expose the image based on the histogram data. The job of the histogram is to show the Highlights, Mid-tones and Shadow areas of the image. The image below clearly shows a correctly exposed histogram and and all tones are nicely distributed across the whole range.
If we analyse the information that is shown here, we can see that the highlights of the image are to the right hand side mid-tones in the middle and shadow information to the left.
If an image is under exposed then the histogram will look something like this
If an image is over exposed then it will look like the following
Both of above examples are considered to be not correctly exposed (unless of course you are using this for a creative purpose).
The objective here is to make the image with a fully distributed histogram. To make sure that we do this, we want to capture the maximum number of pixels for the range of the image, In fact, we are trying to ensure that we include as many highlights as posible, otherwise known as “Exposing to the right”.
The reason why we shoot for the highlights in digital photography is that we want to record the most pixels possible for every frame taken. Taking the example in the document referenced above, if there are 4096 levels of image data in a 12 bit image, then half the levels are in the upper mid tones (i.e. 2048), in the lower mid tones there are half as many (i.e. 1024), in the shadow there are half of this again (i.e. 512) and in the extreme shadows there are half again (i.e. 64). Images that are biased for the shadows are represented in many different ways.
- 1. Shadow areas are murky and have no detail and may contain a lot of noise (sensor dependent)
- 2. File sizes are different for each image, as not all data is used.
- 3. Images are dark out of the camera and look noisy when the exposure is increased.
The best thing to do is when in the camera make sure you are shooting RAW (later inside Lightroom 4 or Camera RAW we can make sure that the image data is fully maximised). Also, i would recommend that you turn on Shadow and Highlight Clipping in the camera settings (most cameras have this and if you are not sure where to find it, please consult the manual). Once this feature has been turned on, any shadow clipping/highlight clipping will most likely appear as flashing images/part of an image on the back of the camera’s LCD screen.
To make sure that we always capture the most amount of data possible, you need to make sure that all highlights are captured but not blown out (you have a little flexibility with Lightroom 4 here by using the new algorithms). It is most likely that you will need to either to a Manual mode in the camera when shooting your images and this can take practice to get right. Or you may need to alter the amount of additional exposure that camera applies to it’s metering (typically you will use this when in camera modes (A and P)). This information will be covered in your cameras manual.
When you are taking the picture, check the histogram and alter the exposure so that the recorded highlights are just below the clipping point (you will see flashing in the LCD if they are clipping), so just dial down the exposure a little and re-shoot). Lightroom 4 with it’s new Highlight recovery is able to pull back highlight information even when a little over exposed. The best way to test this is to take a few shots and try the new sliders in Lightroom 4 to see how much you can push the camera.
Shooting this way has a few pro’s and con’s
- It can be a little frustrating, but my opinion is that you will get more detailed shots and have more information to work with in Lightroom 4.
- You may miss the shot! this is a big one, but remember there are many other shots to focus on.
- It will slow your picture taking down and allow you to focus on the craft of photography.
- You will get more pixels for your shot and ultimately cleaner images.
- Final images will have more punch and feel brighter.
- Your image making will improve as you start to think about exposure.
I hope this helps your image making process.
We all check our images on the back of the camera to check that we “got the shot”, i feel that can lead to removing images prematurely and judging quality and composure and removing based on the time screen. Once thing that i have started to do is to shoot the JPG’s in Black and White. So when the image is viewed on the LCD you will see a Black and White image and not a colour one. This for me, allows me to think about the image as an object as opposed to the actual colour image that i just shot, it disconnects me and allows me to think about composition and form of the image as opposed to the picture. To try this technique there will be a setting in your camera that will allow your camera to take RAW and JPG, then preview in Black and White. Why not try for a few frames to see what you think.
Remember that when you shoot in Black and White, the actual RAW file will contain all of the colour, however the JPGs will be in Black and White and not convertable back to colour.
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