I could use a hand figuring this out. Right now, my Alpa is perfectly shimmed for my H5D-50 (CCD) back, so that using the HPF ring produces nice sharp images, wide open. However -- the ground glass doesn't perfectly match the HPF's focus. For example, if I set the HPF ring at 2.00 meters to focus on an object 2.00 meters away, that object will be sharp on my digital back but not on the ground glass. To get it optimally sharp on the ground glass, I need to focus slightly closer.
I'd like to shoot both digital and film with the system. (And I'm assuming the ground glass matches my film backs, which I haven't tested yet.)
How can I get it so that the HPF, digital back, ground glass and film backs all match each other in terms of focus? That way I could trust the HPF and Disto whether shooting digital or film.
I do understand how to adjust the helicoid's point of infinity focus. One thought I had is, perhaps I need to adjust the lens so that infinity on the lens shows sharp infinity on the ground glass, and then shim the back to match that same infinity point? The problem with that procedure is, it's quite difficult to discern exact infinity sharpness on the ground glass, even with the Silvestri 12x loupe. Objects are extremely small at that distance.
Hope that's all clear. Any ideas? Thanks in advance.
Ethan
I'd like to shoot both digital and film with the system. (And I'm assuming the ground glass matches my film backs, which I haven't tested yet.)
How can I get it so that the HPF, digital back, ground glass and film backs all match each other in terms of focus? That way I could trust the HPF and Disto whether shooting digital or film.
I do understand how to adjust the helicoid's point of infinity focus. One thought I had is, perhaps I need to adjust the lens so that infinity on the lens shows sharp infinity on the ground glass, and then shim the back to match that same infinity point? The problem with that procedure is, it's quite difficult to discern exact infinity sharpness on the ground glass, even with the Silvestri 12x loupe. Objects are extremely small at that distance.
Hope that's all clear. Any ideas? Thanks in advance.
Ethan