Alaskan Haar

It's lightly raining today. There are clouds at multiple levels, some fog, and lots of drizzle. This is a view of the Chugach Mountains south of the Matanuska Valley. It's not really haar, but it's pretty close.

My rainy day assignment: learn something about your lens.

I have a Nikon D200 DSLR. I most commonly use a 17-55mm DX ED wide angle zoom lens. I have read that lenses have a 'sweet spot' that provides the best focus that is a couple of f-stops above the lowest for the lens. For this particular lens, I wanted to know where was the 'sweet spot', or where are the 'weak spots'.

So I wondered if I could determine or see a difference or a change in image quality in my lens due to varying the f-stop/shutter speed settings.

I did a series of shots of the view above with the same settings, varying the f-stop/shutter speed. f/8 came out to be the sharpest for near, edge and center of the image, close to smack dab in the middle of the f-stop range.

So I did some google searching and reading to see what others that know what they are doing came up with, i.e., technical reviews of the lens. Guess what, around f/8 is the center of the 'sweet spot'. This may not be a big shocker to the educated!

I learned about other characteristics of the lens; chromatic aberration, distortion, vignetting, and blur/sharpness. I determined that it is easier and better to just read some good technical reviews about the lens you are using and apply that information instead of experimenting, but it was a fun assignment anyway and the photo technical nerds confirmed the results of my experimental.

I found this cool depth of field calculator while I was snooping around. I have a DoF dial, but the website calculator was fun to play with.

Technical, I know, but the rainy days can do that to you! (yawn)