Which additional costs should be calculated with before buying / upgrading a Pentacon Six or Exakta 66 ?
Shutter Speeds Problems
My experience is, that most Pentacon Six and many Exakta 66 cameras suffer from sticky grease. The shutter mechanism for short times between 1/500 and 1/125 is very sensitive to this. Aberrations of more than 2 EVs (Exposure Values, 1 EV = 1 f-stop step) are often found. Unfortunatly all cameras have been lubricated by use of grease by Pentacon. Therefore once in its life every Pentacon Six and Exakta 66 will need complete dismantling, thorough cleaning from all old grease and lubrication by use of modern synthetic clock oil. This lubrication will be long-term stable and won´t become sticky again. *)
Which Shutter Speeds Aberrations will remain?
Speeds between 1/500 and 1/125 will remain temperature sensitive to a certain degree. After the above mentioned cure these aberrations will be minimized to about + / - ½ EV (f-stop) at a temperature range of about 8 degrees Celcius up to about 30 degrees celcius (comparing to up to 3 EVs aberration before...). For view at a typical fast speeds measurement result after baierfoto CLA (Cleaning, Lubrication, Adjustment) please click.
The shutter mechanism responsible for speeds of 1/60 und slower is a better construction, less sensitive to lubrication and almost without tempereture sensitivity.
The 1/1000 is less temperature and lubrication sensitive than the 1/500 to 1/125 speeds, but often suffers from banding problems, meaning vertical areas of different exposure can be seen. The faster the nominal 1/1000 speed is, the more visible is the banding problem. So it is a compromise to leave the 1/1000 a bit slower when speeds are adjusted. If you should use the 1/1000 in landscape photography, you should rotate the camera by 90 degrees: Slight horizontal banding is much less disturbing in comparison to vertical banding. BTW: the accuracy of 1/1000 is a common problem of medium format focal plane shutters.
Before Upgrade of a Pentacon Six or Exakta 66 Camera
I will test speeds and send you a measurement pdf file. This check is free for cameras sent for upgrade. If CLA should be required, this costs normally 250 Euros (300 incl. VAT if applicable), but in combination with upgrade there are package prices (of course you can deny a CLA, if you are OK with the shutter speeds as they are):
Behaviour in Frost
Cameras with old grease lubrication do not allow speeds faster than 1/60. Especially the 1/125 often leads to an shutter staying open. Closing the shutter in this case is only possible by turning to a different shutter speed or cocking the shutter again.
Cameras with synthetic clock oil CLA (or fresh grease lubrication initially, too): In light frost the fast speeds are about one step (1 EV ) slower. Thus you may use the 1000th as 500th, das 500th as 250th and the 250th als 125th. The 1/125 setting is not needed as 1/60, because the speeds of 1/60 and slower are correct even in frost.
Long-term Stability
The synthetic watch oil shows extreme durability and stays in place (you can expect many years of steadyness). The above mentioned shutter aberrations stay the same. Even perfect exposure of transparencies in summer and winter will be possible.
*) Shutter curtains and tapes are made of rubber coated fabric. The Pentacon grease tends to sweat out spreading oil which affects the rubber coating. The clock oil which I use is „Dr. Tillwich Fluorstatic 70“, which does not tend to spread, and in addition would not affect rubber if ever getting there.