On Technical Image Quality
There are few photographers who don’t like the look of film. Because film was the primary medium used to photograph for nearly a century, it became the expectation. What people like about film can vary. Some will say the grain or highlight detail, while others will just know that there is something about it that makes their eyes feel good. Neither is right or wrong.
Today we have digital camera that are getting better and better in regard to technical image quality (iq). So much is made of a sensors ability to garner detail and render color that there is an entire website devoted to ranking sensors. DXOmark is a resource used by many to get baseline information. They measure two key components to discuss here: dynamic range and color bit rate depth. In the past three years remarkable progress has been made on these fronts. Nikon has improved color depth on average by about 10-15%. Likewise dynamic range is now above 13 stops on average and above 14 stops for high end cameras.
Anyone who has worked with Canon and Nikon knows that generally Nikons have more color richness and dynamic range. However, Canon offers a better variety of lenses and often has more front facing features in their machines. Thus, the classic battle continues. Whatever. After doing a little research there are some interesting discoveries to share that I had not seen in one place. Maybe this will help some people.
Dynamic range is tricky. It is believed that the average person in moderate light can discern detail over 9-11 stops of range. Remember, we are looking at the bulk of a bell curve. When I learned this, it explained several things I had noticed about images in my own library created on the two different major systems. Canon created images seem more realistic (in my words) and Nikon images were more hyper-realistic (in my words).
The same seemingly holds true for color depth. According to what I could find. The average human eye is not capable of 24 bit color determination. Apparently, the 24 bit number represents the human color spectrum. So some people will not discern shades that another will. In fact, color spectrum discernment that is only 20 bits is still within the normal spectrum and would not be considered color blindness. Again, this explains what a friend told me after seeing an image taken on a full-frame Nikon in dim light. He described it as “better than reality.”
Hold Nikon shooters, don’t mob. That just means it is a difference, not better or worse. Back to film which, according to what I could find, film COULD capture about 14 stops of dynamic range. Film also evenly captured across the dynamic range. But remember that pushing or pulling film (which had to be done depending on light) could reduce the range by up to 5 stops. That explains the muted look of film when shot in extreme dark or extreme sunlight.
My point possibly comes from the number of filters I see in use on digital images. Most of them seem to mute some part of the dynamic range or color spectrum. I am finding myself reducing saturation and using filters when human subjects are involved. Is this a trend or compensation for what naturally appeals to the human eye?