Pic-1
I had witnessed a previous transit of Mercury some time in the late 80's, and have a photo somewhere in the house.
Both First and Second contacts had taken place by the time the sun had risen above my eastern boundary, but the planet was still within a diameter in from the edge of the sun (Pic-1).
Pic-1
Pic-2
Pic-2 is at mid-transit (more or less), Pic-3 was taken about an hour later, and Pic-4 as near to Third contact as I could judge through the camera viewfinder.
Pic-3
Pic-4
I used an Agfa print film 100 ASA in a Pentax body at 1/30 second exposure, and I used a "two times" adapter attached to the Cassegrain focus of my eight inch 'scope, giving an effective focal length of 4 metres. The film was processed at the local "Foto First". The prints were scanned, and converted to grey scale for easier inclusion in Canopus.
Melvyn Hannibal