Hot on the heels of the ‘is size really that important‘ post where the megapixel rating of digital cameras is discussed comes this blog post about sensor quality and dynamic range.

Regular blog readers will know that I prefer my 6 megapixel Fuji S5 Pro camera above all others for portraits, weddings and general people photography. The reason for this? Simple – dynamic range. A common criticism of digital cameras has been the dynamic range capabilities (or rather lack of) of the sensor. Dynamic range in photography describes the ratio between the maximum and minimum measurable light intensities, so effectively the range between black and white.

A camera with a very low dynamic range will show blown out highlights and no detail in shadows pretty quickly, whereas a one with a high dynamic range won’t! The Fuji gets around this problem by effectively having two banks of sensors. The second bank kick in when the first bank have reached 100%, and so can record the extra detail otherwise lost on other digital cameras. Technically this gives the camera 12 Megapixels, but in real terms I would say that it has two lots of six.

The two images in this post should help explain this. The image on the top is a RAW file from the S5 Pro with the special dynamic range capabilities of the sensor turned off. Note the background through the window is completely blown out and 100% white. Also, see how the skin tones on the forehead and the left shoulder have virtually merged into the blown out background.

The image on the bottom is a RAW file that has been processed in the Fuji Hyper Utility software with the dynamic range setting switched on. You can immediately see the difference in how much more detail is now visible, not only in the highlights of the images through the window in the background, but also in the shadows in the models hair. There’s been no post production trickery with these images, the only difference between the two is the dynamic range setting.

It’s argued that by using software such as Photoshop, and exposing accurately, there is no real benefit to cameras such as the S5 Pro, as any lost detail can be recovered through the software. I think that this is only true to a point, and that in extreme lighting conditions recovered highlights via software can suffer from excessive image noise or even colour distortion. For me there is no substitute to absolutely nailing it in the RAW file, leaving little manipulation needed to get the result you want.

It’s not just when photographing in tricky lighting conditions that the S5 Pro’s extended dynamic range comes in handy. A useful side effect is that it consistently renders skin tones beautifully, which therefore ticks another important box if you are a photographer who makes a living capturing images of people.

Fuji stopped making the S5 Pro this year, so I’m delighted that I managed to pick one up before stocks ran out. It’s not the perfect camera by any means. If you shoot in normal conditions and dynamic range just isn’t that important to you then you’re probably better off with a Nikon D200 (or the newer D300s), on which the S5 is heavily based. These Nikons have far faster card write speed, slightly quicker autofocus and a higher resolution sensor.

For what I shoot though these things just aren’t important – I don’t need 5 frames per second in a studio, and I’m very happy with the A1 sized enlargements that my S5 has produced so don’t need a higher resolution sensor. I would much rather have a camera that gives me a wider dynamic range that my subjects really benefit from and has been designed to produce a quality image rather than just a large one.

This entry was posted on Sunday, February 21st, 2010 at 1:20 pm and is filed under Technique. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.