5D Mk IV – 0.4 second, f/32 (+ 2 additional stops), ISO 100

Today was a pleasant 51 degrees. I was able to get on the back deck for the first time in a month and a half (at least) since the snow has melted. I took a similar shot on Day 16 of Project 365. The problem I had with Day 16 is I had to wait until dusk and froze my baguettes off (as Clark’s dad said). I had to wait until it was almost dark because I had no neutral density filter.

For this shot, I put on the 77mm 8-stop variable neutral density filter that I recently purchased. The Canon EF 70-200mm L II lens has a minimum aperture of f/32. Putting on the ND filter gives me the option to effectively add 8 additional stops to the lens. For example, after f/32, I have these additional full stops to aid in my shot selection: f32  f45  f64  f90  f128  f180 f256 f360  f512. That is awesome!

Very quickly, full F stops are basically an incremental pattern based upon the power of the square root of 2 (1.4). You only have to remember the F1.0 and F1.4 values to calculate full F stops. Starting with F1.0 (which I don’t know a lens that has this) two stops smaller is F2.0 (double the number), two more stops is F4 (double the number) two more stops f8 and so on. It’s the same with the f1.4 – two stops smaller is f2.8 (double the number), two stops smaller is f5.6 and so on. Thus, the progression is f1.0 f1.4 f2 f 2.8 f4 f5.6 f8 f11.2 (f11for short) and the list goes on.

Anyway, for this shot, I wanted to make it simple and similar to Day 16 to compare the pics with and without the ND filter. I set the filter to the maximum f512 and the ISO was 100 – this gave a shutter speed of 13 seconds. I was surprised that at that shutter speed, the turbine blades essentially disappeared (see picture below). Also, at that long of a shutter speed, the picture had a lot of blur because – well, things still move. the wind is making the grass and trees and camera shake and move. Also, look at the turbine tower – those blades are obviously making the tower move. In any case, it became a balancing act to get the right shutter speed and aperture.

I decided that I needed a shutter speed of around 1/2 second and 2 to 3 additional stops on the ND filter. The resulting shot is the Photo of the Day.