Over the years, camera companies have been going head to head in the battle for the best camera sensor. This battle has always focused around the amount of megapixels a camera has to offer, and as of lately, how high the ISO can go. Because of this most consumers, including a significant amount of photography veterans, think that megapixel count is the end-all be-all of sensor technology, with ISO following up as a close second. At this point in the game though, I wish the sensor battle would switch gears and focus more on the dynamic range.
What is Dynamic range?
To sum it up, dynamic range is basically the amount of light the sensor can capture when taking an exposure. In order to understand this, it helps to imagine a pixel on your sensor as a bucket. This bucket is being filled up with light as you take an image. When the bucket overflows with light, you are left with clipped highlights; likewise if the bucket does not gather enough light, you are left with clipped shadows. These clipped areas will be seen in the frame as solid white (clipped highlights) or solid black (clipped shadows) blobs that have zero detail. There is obviously a little more to it, but that’s the quick basics of it.
The below image shows an over dramatized example of this. The red areas represent the clipped highlights and the blue areas represent the clipped shadows. I obviously edited the image to look like this just to show what these loses in detail look like. Also, keep in mind that these clipped areas will look worse in print then they do on a screen.
You can see that the image has clipped highlights and shadows by looking at the histogram. Because the graph is pushed up against both end points, we know we are losing detail.
Megapixel and ISO
When I say that I could care less about megapixel count and ISO range, I do not mean they are useless features, I just think that they have reached a point where they don't need to be as heavily developed. When I upgraded cameras, I specifically did not want one of the super high megapixel superstar cameras. I simply didn’t want to deal with that large of a file or the storage space that accompanies it. It definitely has its uses in certain aspects of photography, but the majority of people can do just fine with much less. As for ISO, I love the direction this is going and I do love the ability to shoot in lower light; however, It’s pretty rare that I’m in a situation where I’m at a high ISO limit and I’m not already planning to use my flash anyway. For what I do, low light is normally terrible light. It’s not that I can’t shoot in it, it’s that it is just not the look and feel I’m going for.
Why you should care
The reason this has become so apparent for me lately is due to my recent upgrade to the Nikon D750. This camera does not have the best dynamic range on the market, but it is only .3Evs away from it (according to DXOMark). When I first got this camera I was editing my files like I did with my old Sony A900 and I quickly realized how much more room I had to push the files. The detail hidden within the shadows of these files is amazing. Looking back at the bucket example, if you fill up the bucket to the point that it overflows, you get clipped highlights. Clipped highlights and shadows are unfixable (for the most part). However when dealing with this much dynamic range, we can fill the bucket right up to the point of clipped highlights and because there is so much info left in the shadows, the shadow detail can be brought back in post.
Here is an example, the below image was shot exposing for the grass. Imagine there is an interesting subject here that I want to be exposed properly. Since I exposed for the grass though, the sky now has blown highlights. This can be seen by dragging the exposure slider in Lightroom all the way down. With the exposure all the down, you can now see the solid white blobs of white that cannot be recovered.
Now let’s look at an image where I exposed for the sky instead. Because the sky is where all the bright highlights are, I no longer have the unrecoverable white blobs in the clouds and the sun has much better definition.
The trick here, is that the shadows within the second image are not clipped. This is because of the high dynamic range that the sensor offers. What I did was fill the bucket right to the point that it was overflowing, which also filled up the shadows with as much detail as possible before losing detail in the highlights. I have basically taken in as much detail as possible without clipping on either side. Now with some basic adjustments within Lightroom, I can bring back detail from those shadows. Below is an example of bringing back shadow detail compared to trying to bring back highlight detail (unrecoverable clipped highlights). You can easily tell which is which.
The above examples are extreme cases, but it gives you a good idea of the possibilities. When we take this into the real world, you can see the benefits that dynamic range has to offer.
Let’s bring it together
In conclusion, I’m not saying that megapixel count and ISO are pointless. I just could care less about these, because from this point in time moving forward, they will always be equal or greater than what they are today. That’s why dynamic range is my favorite. It has the most potential to affect your final image with future improvements. The process I used to recover shadows in the examples above, do have their drawbacks, such as added noise (depending on how far you push the file), but imagine shooting in full sun and having full shadow detail without the need for extreme post production and added noise.
Has an improved sensor improved your photography? What is the next advancement you would like to see?