I was talking to the owner of the shop where I get my pictures printed the other day about the relationship between megapixels and image quality. We both agreed the relationship is not as clear as most people think and as proof he showed me a 30 X 40 print made from an 8 Mp image. However, he argued, as soon as you try to say something like that on the Internet, someone with “credentials” will produce a graph that shows you can’t make anything bigger than an 8 X 10 with that size image. I agreed, of course, it’s one of the main reasons I have been slow to upgrade my equipment; I simply haven’t been caught up in all the hoopla over megapixels and image quality. (See note below)
However, performance at high ISO’s is a very different thing. The newest generation of sensors are wonderous in their ability to produce clear sharp and relatively noise free images at extremely high ISOs. I have seen shots taken at ISO 3200 that looked as good as the images my camera makes at ISO 200. And there seems to be no end in sight as to how high the ISO range will grow. Nikon will soon be introducing a camera that can capture images at ISO 25,000. No word yet on the image quality at that range is astonishing, We’ll be doing landscapes by starlight if ISOs go any higher!
Note: What the printer did not mention were the things that lent this image to be enlarged in this way. For one thing it was mounted on a wall near the ceiling and above the sales shelves and it was a high contrast image; a fluorescent blue jellyfish on a black background. Nevertheless, his point was valid; the relationship between megapixels and enlargements is not as simple as most people would like to think.