I mean specifically over time, the geared shift mechanism becomes sticky, at least on the Arca system. Over time, you need to get it re-lubed and checked.
I have an XT, and the rotating system is not that practical because you can't tilt anymore with XT glass in vertical sensor orientation. That's a fundamental design flaw and not to be underestimated as a nuisance. Essentially, if you want it in portrait mode or do a two-way stitch in portrait mode, you lose tilt on XT glass, as it becomes swing.
Also, the recorded metadata is nice, but with Alpa cameras, you can add detents at 5mm increments and a stitching detent at 18mm, which is the ideal position for a two-way flat stitch with a 4mm overlap on the short end of the sensor. For example, if you do stitching or just shift, you can save LCC and distortion correction presets in C1 for say 10mm rise, 15mm rise of 18mm shift left and right with 10mm rise, etc.; so the benefit of the metadata is negated + you can save real LCC presets correcting for magenta cast while the XT only correct distortion automatically and vignetting. Detents are also more precise for repeatability compared to free geared movements.
Regarding the construction solidity of the Cambo XT: sometimes it sags a bit with the digital back. And with the lens metadata, I get a -1 x value, even though it should be dialed in without rise and fall. That's something that would never happen with an Alpa – you'll see this if you own one, regarding stiffness and solidity of the construction.
The geared knob movement in the Arca is super annoying once you've experienced the quick shift of the Alpa on the inner bearing rails with detents. They have a nice tactile feel, making it super fast to dial in. It’s also annoying with the XT compared to rails, which are blazing fast.
I fully agree with
@akaru on the fact that you don’t have back adapters, which increases the risk of scratching the sensor. I once switched in the field between an Alpa TC and the XT and precisely scratched the bottom part of the back lightly, just below the sensor. It’s not a major problem, but I got lucky.
Finally, the Alpa system has other nifty tricks up its sleeve. Besides the symmetric construction, which lets you test lens symmetry as you mentioned, yo
u can move the tilt spacers between the front and back because everything is symmetric, including the front and back adapters. Having back tilt allows you to correct perspective in architectural photography in a complementary way than just front rise.
It’s an advanced technique mostly used in larger view cameras, but the Alpa lets you do it, and to me, that’s a fundamental advantage. Besides, you can stack tilt adapters and use them in any combination for double back or front tilt, or a mix of tilt and swing in any direction. That’s hard to beat. Back tilt also allows you to work more in the sweet spot of the lens.
Lastly, add to that some other ecosystem benefits, such as:
- The Linhof Alpa roll film back with a custom Alpa direct adapter connection, meaning extremely flat film (within the Linhof rollfilm back) and planar alignment of the film plane to the lenses no matter what (because of the integrated Alpa back interface), which results in ultra-high-quality, sharp 6x9 negatives with Rodie HR-W glass every time (with Arca Horseman, I sometimes have film planarity issues, leading to slight unsharpness in one corner);
- Shimmable back adapters for total calibration of your lens-back system;
- The guarantee that all lenses are double-tested before sale at Alpa, on top of the Rodenstock QC, meaning they really are perfect;
- The TC and Pano, which are unique - its nice to have the TC option for impromptu lightweight outings.
On lens availability: It’s true that the 43XL and 60XL, as well as the 28XL and 120 ASPH, are nearly impossible to find, with the former having hit price points of 10k plus, so if you are dead set on these, it’s a problem.
On the other hand, a modern architectural photography kit comprised of the 32HR + 50HR + 90HR + 180HR is absolutely brilliant.
If you have the cash, it's the best system in my opinion.
Did I mention that you can screw on a shade clamp onto the top or side of the camera for ultimate flare control in the field?
Lastly - Alpa looks and feels awesome, Cambo always felt cheap to me and I never liked the look of their products – it may not matter, but with Alpa I always am happy to use it and take it in hand; difficult to describe; a bit like an Apple Macbook vs. an Asus Laptop.
