Lee wrote:
On 30/08/2013 13:49, Bill Wright wrote:
AnthonyL wrote:
I'd like to know/measure the speed (rpm) of a small electric 3 blade
fan. Any easy ideas?

Put a thin white line on one blade. Photograph the fan whilst it rotates
at various shutter speeds. Calculate the RPM from the angular movement
of the line at each shutter speed. Average the result.

Bill

I had a similar thought and, convinced someone must have written an app
to do it, went looking in both the Android and iOS market. Was somewhat
surprised no one has written one yet. Unless the camera hardware isn't
up to it

My programming skills certainly aren't!

Lee
On a related topic a guy I knew in the 60s who repaired cameras used to
adjust rollerblind shutters by photographing a TV screen and counting
the TV lines on the picture.

Who remembers the white square in the corner of the neg frame caused by
the Zenit mirror not returning quickly enough?

Bill