Sprocket Rocket Exposure Tests
Nikon D300, AF-S Nikkor 18-200mm f/3.5-5.6
Those of you familiar with the Sunny Sixteen rule will see that there is something fishy about Lomography’s suggestion to use ISO 400 speed film in the Sprocket Rocket.
It is supposed to have a shutter speed of 1/100 second and “sunny” aperture of f/16. This would mean you should use ISO 100 speed film for shooting in direct sunlight.
I have experienced and others have noted that the Sprocket Rocket is quite “light hungry”, which simply translates into its published specifications being incorrect!
I shot two rolls of Fuji Provia 400F slide film together, one in my Sprocket Rocket and the other in my Nikon F100 with a 20mm lens. The results confirm my suspicions:
- The “sunny” aperture is more like f/22 and the “cloudy” aperture f/16, both about one stop darker than documented
- If you press the shutter release very quickly, you can speed up the shutter dropping another stop of light from reaching the film!
This would indeed mean that you should be shooting ISO 200 to 400 speed film in your Sprocket Rocket depending on whether you are slow or quick on the trigger.
On the bright side (har!), with practice you could get three stops of exposure variability out of the Sprocket Rocket via the aperture settings and good finger speed control.
