I just bought a Linhof Techno and is looking to get a second hand back sometime in the coming months. I want it to be cheap so I mainly look into an older back with a 22 megapixel 36x48mm sensor. I've dropped the idea of tethered-only backs, the self-contained backs are low cost enough.
Main alternatives are:
Phase One P25
Leaf Aptus 22
Leaf Aptus 75 (33 megapixel)
For Leaf I've noted that the later models 54s and 75s actually seems to be worse. Faster but noisier, possibly only at high ISO though. For Phase One there is the P25+ but it is often sold at a price as high as for the Aptus 75, and then I would probably prefer getting the Aptus. There is little to find about the P25 though, and since it is so much cheaper than the P25+ I wonder if it is much worse image quality, or if it is just more or less screen, speed and live preview that differs.
I will only shoot at base ISO, so high ISO performance is mostly irrelevant. LCC performance is important since I'm going to use it on a tech camera with movements. Build quality is important since it will be an old back, and repairs can easily cost a large part of the purchase price. Replacing a Leaf fan costs €1200 for example. "Long" exposures must be noise free to 30 seconds, if it is noise free to 2 - 5 minutes then it is a big plus, above that time it is just a bonus. I have so far been unable to find long exposure performance indications of these backs, except for the P25+ which should be good. Dynamic range is also important, no pattern noise please, I've had enough of that with my Canon sensors. Leaf centerfold might be a dynamic range problem, don't know. I've read somewhere that P25 may have lower dynamic range than P25+, but I don't know if that is true for base ISO. Color reproduction I'm ok with anything, I always manage to tweak colors to my liking in post-processing. Blooming protection is quite important, it must not be significantly worse than the competition.
Old backs also seem to be a bit "hackish", at least at the time of release so it seems to be a bit of a risk, when you buy old second hand like this your plan is not to pay support fees to the manufacturer to have the thing working. There can be strange issues like centerfold with the Leafs, and user interfaces that may be problematic. Concerning user interface there are two features I want to use - histogram, preferably with highlight clipping indicators, and check focus at 100% zoom. Possibly the P25 screen is too poor for focus check (~230x170 pixel screen it seems, while the others have 320x240)? The Aptus GUI looks kind of ok, but sloooooooow, I wonder if P25 is equally slow, have not seen that in action.
Do you have any recommendations?
