I made this video for the Sony a7S, on how I originally chose my Nikon primes:
Note: I say ‘multiply’ when talking about the bokeh factor, but I really meant ‘add’.
Bokeh Factor = Aperture + Crop factor
E.g., here are how my lenses stack up (All of this is approximate, but it’s great as a general rule of thumb):
- 14mm T3.1 becomes a 21mm T4.6 in APS-C mode
- 28mm f/2.8 becomes a 42mm f/4.3 in APS-C mode
- 50mm f/1.2 becomes a 75mm f/2.7 in APS-C mode
- 135mm f/2 becomes a 200mm f/3.5 in APS-C mode
If using ClearImage Zoom, then this is what the same lenses become at 2x:
- 14mm T3.1 becomes a 28mm T5.1 in APS-C mode
- 28mm f/2.8 becomes a 56mm f/4.8 in APS-C mode
- 50mm f/1.2 becomes a 100mm f/2.4 in APS-C mode
- 135mm f/2 becomes a 270mm f/4 in APS-C mode
You get the same light levels, so there is no change in exposure – only the bokeh. So, in effect, I have the full range from 14-270mm with just four lenses. Right now I’m thinking of adding a 200 or 300mm lens but that will have to wait.
