Fredrick -
For what you're contemplating, it is essential to get information that is accurate. While this can be difficult because anecdotal feedback from users can be highly subjective, nonetheless the feedback is valuable, especially if you are able to confirm for yourself what can be confirmed.
Find someone who is trustworthy....and someone you can trust (not always the same thing). Verify as much as possible, opinions and results.
Perhaps you don't have access to actual demo gear for the products you're considering (I'm hoping that there is an accessible and good dealer for you to actually do this). In the event you do not, you might want to reach out and see if someone can provide you with sample files of subject matter you might typically shoot that is captured with all the products you're considering and at the same time. It is difficult to get a real handle on comparative image quality from manufacturer sample files.
I will say that there is no question Leaf is absolutely a consideration as well as Phase One. But I also feel that the P30+ might be a non-starter for you in the event you'll be utilizing movement-based solution (tilt/shift lenses/bodies, etc). The P30+ is not ideal for this type of photography (well documented).
You should consider an Aptus 22 or 28 or perhaps a pre-owned Phase One P25+/45+ (or even P45 non Plus possibly). The biggest advantage to you for Phase One might be the longer exposure capabilities of the 3 products I mentioned (not all Phase One products excel at long exposure). The Leaf products offer excellent image quality if used within their capabilities (shorter exposure durations, as one example).
You will potentially have a decision to make regarding larger sensor size or higher megapixel. For example, the Leaf Aptus-II 28 (also known as Aptus-II 6) is a 28MP, 44mm x 33mm sensor with a starting ISO of 50. The Aptus-II 22 (also known as Aptus-II 5) is a 22MP, 48mm x 36mm sensor with a starting ISO of 25. In the USA, they sell for the same price ($7,990). So you have an interesting choice to consider with those 2 products, for example. This brings up questions - does the 6 additional megapixels of the Aptus-II 28 really make that much of a difference (not significantly, IMO, but YMMV). Will you value the larger sensor more? For landscape, the answer is often yes. However, the starting ISO of 50 for the Aptus-II 28 may be preferable to the ISO 25 of the Aptus-II 22, the Aptus-II 28 is also a newer generation sensor, etc, etc. There are some real considerations you'll need to wade through, and that is why you really need to be careful on the information you receive and accept. Do not pay any heed to the Brian Hirschfeld Aptus-II 10 review, he is, unfortunately, severely mis-informed about the product.
Based on your budget, I really don't see any reason why you cannot put together a good technical camera outfit with a decent digital back like a new Leaf Aptus-II 22/28 or Phase One pre-owned P25+/45 (or perhaps even P45+ on a stretch). The Schneider 47mm would be a good performing, reasonably priced lens to start with. You could pair it with a Cambo Wide to enable shifting for wider views if you really were intent on the direction of a tilt-shift medium format system.
In the conditions you listed (extreme cold), your biggest challenge is mostly going to be sustaining battery power. Batteries, lots and lots of batteries, as well protected as possible from the cold.
Best of luck to you. These are all really good products that can deliver excellent results, but they're expensive, and it really sucks if you don't get the most or best you can for all the money that you'll be spending. As much as we may not wish to admit it, it's often those seemingly little intangible things that give you that nagging burn after you've bought. The details matter.
Steve Hendrix
