Believe me, if I could get there with a Phase One DF+ and a series of Mamiya/Phase One lenses, I would. Considerations.
1. Image quality, I don't feel that any Phase One, Mamiya lens solution will give you the same amount of 100% detail with wides, 23mm, 28mm, 35mm and 40mm. With the Phase One lenses I used, I was cropping the files back to get rid of soft edges and smearing. A 40mp image became more like 33 and a 60mp image was more like 50. I tend to compose where those original edges are part of the shot, and I don't what to crop them out. As you get into the 60MP to 80MP backs, the Mamiya/Phase lenses will perform even worse.
2. Ability to shift for short pans, a huge deal for me as I love the pano look. You will not get a true pano shifting a tech camera even 20mm but you can get what I call short pans, and these can be cropped down to a a true 3:1 ratio. By shifting the back, you can forget about being level, and just line up the shot and shoot. You can still work nodal, but most times in my work Nodal is not possible due to necessity to being level, especially true with wides. The only shift solution I know of for Phase is the old manual focus 50mm. It allowed 15 or 18mm of shift, but the 2 I had were not much good past 8mm and you still really need an LCC with this lens as the light fall off is considerable.
3. Tilt, I should have listed this first, but tilt for me is in almost every setup. Medium format seems to have a shallower DOF by nature and thus doesn't always lend itself to a wide open expansive shot, this becomes much more noticeable once you get past 40mm. The 55mm Mamiya AF lens is an excellent lens, but has a extremely shallow DOF even at F11. With backs that prefer to be at iso 35 or 50, F11 to F16 many times is way too underexposed, add wind and you are just out of luck many times. By tilting, you can adjust the DOF to your advantage, (very dependent on scene), so that I can get a hyperfocal of around 8 feet to infinity with the 28mm Rodenstock @ F8 and around 12-15 feet to infinity with the 60mm Schneider. You can't do this without focus stacking with a Phase One and traditional glass. By taking the time to learn your hyperfocal range for each lens, you can save a ton of time, I rarely use a range finder unless the 60mm or larger lenses are in use.
4. Tech camera workflow, some seem to love it, I don't but it is what it is. With no Live view ( I understand its there is Live View on the IQ backs it's just not very workable for me) focus becomes a paramount issue. It kept me away from tech cameras until late 2011. After working with Capture Integration, Rod Klukas and a few photographers working with tech gear, I realized that the real hang up was not on getting focus with the wides, just understanding where and what your hyperfocal was. I am not working macro, or selective focus with these lenses just looking for the best overall image focus. If you are looking at macro or very selective focus solutions, then I would lean towards a Phase Back, with AF and a visible viewfinder showing the actual image you are working with. Working up the files in post, is a bit more time consuming due to the incorporation of the LCC, but that becomes easier as you work through it. But you have to shoot an LCC other wise color-cast alone can ruin a shot, and with the Schneider, vignetting and color cast will not be recoverable.
5. The ability to use an aperture of F 4.5 through F8. As the Phase backs, will always perform best at their lowest iso, 35 or 50, many times you just can't get to F11 at iso 50 depending on the lighting and if you are needed filters (I almost always do). Wind alone can stop a shoot at iso 50 with a Mamiya 35mm F 3.5 which really only becomes good at around F11 (based on 3 years of shooting 3 different lenses). Here you are needed a shutter speed of 1/60, to 1/250th to help keep the motion blur in check. Knowing your tech lens at F 5.6 will still be extremely sharp with some DOF fall off is nice to know. You can still get to the shutter speed of 1/60 to 1/125 with the aperture range of F 5.6 to F 8. Depending on the shot setup, tilt can recover some of the lost DOF.
6. Setup time, for me it's just longer, considerably longer. With the Phase One DF/DF+, you work just like with a DSLR, mount, aim, set shoot. With the tech camera, setup is a bit more cumbersome at least for me. I carry the acra with the Phase One back attached, but no lens. You still have to attach the lens, mount camera to tripod, attach the cables, attache the viewfinder( I have started leaving it on now) attach the viewfinder mask, check focus settings, remember to wind the shutter then shoot. May not seem like much but as the day wears on it gets there. Did I mention hand holding, not really feasible with a tech camera, easy to do with the Phase One DF and lenses. Weight is about the same. I used to carrry the DF, 35mm, 55mm, 28mm, 75-150 (which is a beast), now I tend to carry the Arca 28mm, 40mm, and 60mm with a 105 at times (105mm is very light). In a situation where I am hiking many miles, this quickly drops to the 40mm, and 60mm as both of these lenses can shift to 15mm easily (25mm on the 60mm).
To echo Doug's comments, if you are after action or telephoto past around 120mm, then the Phase One DF and available lenses may be a solution. Mamiya's 150mm F2.8, 210mm, and 75-150 are all excellent lenses, their latest 240 LS amazing. I just don't shoot MF for that, as I will drop back to Nikon and Canon or even Fuji. For shooting landscapes with wides it's just the opposite and the results will show immediately. Posting images to show results is hard on the web, even crops, you need to have the equipment in front of you and viewing the results first hand.
Paul Caldwell
