Hello and welcome to my post on camera dynamic range. The question – what is camera dynamic range? – will come up sooner or later if you are interested in photography. The topic sounds something very scientific. It reminds us about high school physics and math. It is indeed a very scientific topic. But you are don’t need a PhD in optics to understand dynamic range. In this article I will try to discuss camera dynamic range in plain and simple language that everyone can understand. Hopefully after reading this article, you are’ll have a clear understanding of camera dynamic range.
What is Camera Dynamic range
The dynamic range in photography is the ability of your camera’s image sensor to capture the darkest and the brightest parts of the scene without loosing detail. If you have ever tried to take a photo on a full-moon lit night and only to see the resulting image looks nothing like what you are saw with your eyes. You may notice that the dark areas look grainy and lack detail. This is not because you are a bad photographer, its because your camera has exceeded its ability to go past certain level of darkness.
Similarly, if you took a photo in a bright sun light, there may be areas that are completely white and look washed out. Again your camera’s image sensor has exceeded its limit to go past certain level of brightness. Your image may look overexposed and lacking certain bright details.
The human sense of sight have the highest dynamic range. Although there are commercial cameras that can exceed human vision dynamic range, but the cost of those camera equipments goes into hundreds of thousand dollars. Think of dynamic range as machine vision vs human vision. Dynamic range not only applies to light but also to sound, electronics and many other scientific subjects.
Camera with a large dynamic range will produce images greater in detail on both ends of the spectrum. Typically, Digital SLR cameras have high dynamic range than compared with point and shoot or cell phone cameras. There is one more relative to dynamic range. It is the image latitude.
Lattitude is the flexibility of the image in terms of exposure and contrast. It is not to be confused with dynamic range. The ability of an image to retain as much detail as possible even if it has been under or over exposed is a measure of latitude. This is most useful in post processing. Modern digital SLR cameras allow shooting in RAW mode. It means most of the information that makes up the image is not permanently fixed. Variable such as exposure, contrast, brightness, color, and many more remain open to adjustments. To a great degree these variables can be altered in photo editing software such as Adobe Photoshop to achieve the desired results. This degree of alteration without loosing detail is the image latitude.
High Dynamic Range – HDR
Hight Dynamic Range or HDR is a technique that allow both ends of the dynamic range to be captured. In conventional photography, it is sometimes impossible to capture the darkest and brightest areas in the same photograph. You may achieve results that are too dark or too bright. HDR is a technology that solves this problem by merging several images together. HDR images can be stunning works of art as seen in some samples (courtesy wiki commons). This process is done with HDR image processing software.
Images courtesy wiki commons
The procedure for HDR photography is quite simple. It is done by taking the darkest photo and the brightest photo in your scene and few photos in between. Then these images are fed into an HDR image processing program that magically combine them into one photograph. Of course there are several variables you will have to play with to get the desired result. The image on the right demonstrates this concept,
To produce an HDR image you are will need:
- A digital camera preferably a digital SLR camera that allows automatic exposure bracket (AEB). Although AEB is not absolutely necessary, but it will help to prevent camera shake. Automatic exposure bracket is basically when you set the exposure ranges from darkest to brightest, and your camera will automatically take photographs with those specifications. If you don’t have this feature in your camera then you are must be very careful not to move the camera from its location. Otherwise camera shake would cause your images to blur and produce end results that are completely unrecognizable.
- A solid tripod is a must for HDR photography. As mentioned earlier, camera shake could be a big problem when shooting HDR. Don’t depend too much on the software to align your images. The software is only good for certain extent. The better aligned photos you have , the less work the software have to do. If you must manually adjust exposure after every shot, do it ever so carefully so your images don’t go out of alignment.
- The third thing you are will need is a software that does the image blending. There are a number of HDR image blending software out on the market. They range from $40 to $100 and upward. As a beginner or an enthusiast who is trying to keep things within a budget, there are some free versions of HDR software available.
HDR is becoming increasingly popular these days. It’s being incorporated into some low end point and shoot cameras. Even the cheap smart phones can produce some good acceptable HDR images. These cameras have built in HDR software that do all the work for you . All you have to do is select HDR and shoot. They are great if you like to simply point and shoot. But if you have a taste for photography and want to take your images to the next level, then a Digital SLR camera with auto exposure bracket option is recommended.
I hope this article has given you are some insight into the camera dynamic range. Dynamic range depends on the camera image sensor. Cameras with larger sensor such as full frame Digital SLR’s have a high dynamic range compared to cameras with smaller image sensor. Having a camera with high dynamic range will capture detailed images with both the darkest and brightest area of your photo. Next time you take a photo, try to think about the dynamic range and how it can help you are to create a balanced image. Please leave any questions or comment below. (All images courtesy wiki commons)