There is no one answer to your questions. A lot (nearly all) of it is up to personal taste.
But here's some thoughts in no particular order:
- Try to figure out what you care about. You say you find "a drum scan of a medium format film negative to be more pleasing than a XP100MP file" - this could mean a dozen things. It could mean you like the color palette of a particular film emulsion more than the default color rendering of an IQ3 100mp in Capture One. If that were the case something like the
DT Capture One Style Pack could help even the ground by opening you to a variety of initial looks. It could mean you prefer the look of film grain to the clean signal from an IQ3 100mp. In that case the Film Grain tool of Capture One might be a good place to look; it is the closest to actual film grain I've ever seen because they actual do a physics model of the individual grains of film reacting to the "light". Once you figure out, more specifically, what you find pleasing about a particular camera, or lens, or piece of film you're better able to figure out what other gear used with what workflows you will also find pleasing.
- "How much resolution is in film?" is one of the hardest questions you'll find to answer in a way that is both technically accurate and practically useful, and well researched and carefully considered answers can vary considerably (though "150mp for 35mm" is definitely in the laughable range). It's also one I've had a great deal of experience answering due to being the designer and product manager of the
DT Film Scanner. An 8x10 in absolutely perfect conditions (fine-grain emulsion, film held flat in the holder, lens in perfect condition at ideal aperture, focus perfect, scanned to absolute perfection, cable release actuated gently, zero movement during exposure even with the big fat bellows acting like a wind sail) can hold a shocking amount of information; definitely more than a 100mp back (says a guy who sells 100mp backs for a living). That said, the number of 8x10 frames (historic or modern) that I've seen that meet these criteria are vanishingly small, and in practice even anal retentive shooters are likely to get much more subject detail using a 100mp camera than an 8x10 even in the studio, let alone in the field.
- Don't hyperfocus on resolution. It's an important technical consideration for some kinds of images (e.g. landscape, architecture, art reproduction) but it's only one of many technical considerations. Don't get me wrong, when I see a beautifully captured image from the IQ3 100mp that is super sharp it really leaves your jaw on the floor. But a beautifully crafted 5mp image will beat a shoddily 400mp image. And a 16mp camera you have with you takes a
far better image than an 8x10 camera you leave at home. From my point of view there are five categories of considerations for a prospective camera buyer/user:
technical (resolution, lens sharpness, dynamic range, vibration etc),
aesthetic (color, ),
practical (size, weight, ease of use),
initial cost (self explanatory),
ownership (cost to operate, support, service, warranty, frequency of updates, ability to upgrade).
- There's no substitute for working with a
specialized medium format dealer and playing with actual cameras for extended time and getting their practical aid. For example if you showed me an 8x10 drum scan and an IQ3 100mp and started describing what it is you like about the 8x10 I can show you whether or not those things are possible with the IQ3 100mp. If you tell me what you enjoyed was the process of loading the sheet of film, and watching the image come up in the dark room tray then I'm going to tell you that you're better off staying with 8x10. If you tell me you enjoyed holding a wooden camera where every adjustment is mechanical and the shutter makes a nice wurring sound I'm going to tell you to try a
tech camera. If you tell me it's the look of the film grain or the color palette I'm going to show you to what extent those can and cannot be recreated as the default look for the Phase.
But the shortest answer to your question, in my (highly biased) opinion is:
- If you're okay with a tripod and your subjects don't move much then an IQ3 100mp on a
tech camera with Rodenstock lenses
- If you want something portable an
Phase One IQ3 100mp on an XF- If the above is out of your budget replace the 100mp above with an
refurbished Phase One IQ180.