The first thing that I need to get out of the way is: I didn’t buy this lens to use on a digital Canon or Sony camera. Call me old fashioned, but I bought this lens to use on a Contax 159 – 35mm film SLR. Having said that, the initial, quick test that I did with this lens after it arrived was indeed on a Canon – my 5DS R (samples below).
This was not a good idea. After about twenty shots, the camera made a noise like R2-D2 having an enema – then the dreaded ERR message appeared on the LCD panel. I switched off the camera, took off the lens and went indoors to make a cup of tea. Having enjoyed my tea, I switched the 5DS on – the display lit up, all happy, unperturbed by its recent violation – no harm done. More tea.
Later on that day, I decided to do some test shots with the 159. I’ve had the 159 for a couple of months now but have only used it with Yashica ML lenses. So, having mounted the 45mm Tessar on the 159 I released the shutter – which fires and closes, but then darkness. The 159’s mirror has raised but not returned – it is stuck.
What I was witness to here; was two separate problems with one single cause.
At infinity focus, or close to it – the rear element of the Tessar protrudes into the mirror box of the 5DS and stops the mirror from completing it cycle.
On the 159, the mirror had slipped forward on its mounting, by something like one millimetre.