Long-story short, I just purchased a used P65+ (doing the house flipping equivalent with Phase One backs, on my way to “IQ-something-full-frame”), and I would like to know where the “useable” ISO stops.
By “useable”, I mean low-light landscapes where I would need a 30-second to 1-minute exposure.
Thanks,
J.D.
That back features a Teledyne Dalsa sensor without Long Exposure mode.
It can do a reasonable mid-ISO exposure (ISO200)
It can do a reasonably mid-long exposure (e.g. 30 seconds)
It cannot do both simultaneously - at all.
That is you can do a 30-60 second exposure at ISO50. Or you can do a very short exposure (e.g. 1/250th) at ISO 200 or even ISO400 depending on your post processing and preferences. But you cannot do a 30-60 second exposure at ISO 200, or even anything close to it. Even a few seconds at mid ISO starts to push the limits of this back.
Hopefully your dealer shared some relevant raw files to you before you purchased so that this won't come as a disappointment.
One of the Dalsa sensors with Long Exposure mode (IQ2 60mp, IQ3 80mp) or one of the Kodak sensors would be a moderate improvement in this regard. One of the CMOS sensors (Credo 50, IQ1 50mp, IQ3 50mp, IQ1 100mp, IQ3 100mp) would be a large improvement in this regard.