Ulophot
30-Jul-2020, 11:47
As one who likes to know his equipment well, I can only excuse the following oversight by noting that my Tachihara 4x5, purchased used several years ago, was my first field view and that I had been away from photography for more than a decade.
Anyway, in the course of pursuing something entirely different earlier today, I was astounded to find, in a belt pack hanging in the closet, the Wista loupe I had been convinced I had lost while gathering equipment from the car on a field trip more than three years ago with my monorail at Great Falls Park (the trip that "inspired" my replacing that 26-lb camera+tripod lug-bundle with an 11-lb pair including the Tachi).
I had eventually replaced the loupe with an identical, used one, but found that I needed to make an extension collar to focus on the ground surface of the glass. (In fact, I mentioned this at the time here, and I believe it was Bob Solomon who asked, reasonably enough, if I was really sure of my focus.)
Today, comparing the two led with this in mind led me to discover my cited oversight: that between loupe and GG is another pane, entirely clear. I have trouble ascertaining whether it is some kind of acrylic or special, perhaps shatter-resistant glass. I assume it to be a GG protector and not original equipment. In any case, I then discovered that the ground surface of the GG faces rearward. This make sense, I guess; better to focus through as little thickness as possible.
Now I'm curious: Is this a common configuration? Your experience or thoughts?
On my Omega monorail, I had a Fresnel lensward of the GG, cut side in contact with the ground surface, which is pretty standard -- though I have seen debate here (imagine that!).
Once I clean both, and double check my loupe focus, again, I'll probably put them back as they were. Perhaps I'll try with and without (reversing the G for the latter, of course) to see if significant flare or other issues arise with the clear pane.
Anyway, in the course of pursuing something entirely different earlier today, I was astounded to find, in a belt pack hanging in the closet, the Wista loupe I had been convinced I had lost while gathering equipment from the car on a field trip more than three years ago with my monorail at Great Falls Park (the trip that "inspired" my replacing that 26-lb camera+tripod lug-bundle with an 11-lb pair including the Tachi).
I had eventually replaced the loupe with an identical, used one, but found that I needed to make an extension collar to focus on the ground surface of the glass. (In fact, I mentioned this at the time here, and I believe it was Bob Solomon who asked, reasonably enough, if I was really sure of my focus.)
Today, comparing the two led with this in mind led me to discover my cited oversight: that between loupe and GG is another pane, entirely clear. I have trouble ascertaining whether it is some kind of acrylic or special, perhaps shatter-resistant glass. I assume it to be a GG protector and not original equipment. In any case, I then discovered that the ground surface of the GG faces rearward. This make sense, I guess; better to focus through as little thickness as possible.
Now I'm curious: Is this a common configuration? Your experience or thoughts?
On my Omega monorail, I had a Fresnel lensward of the GG, cut side in contact with the ground surface, which is pretty standard -- though I have seen debate here (imagine that!).
Once I clean both, and double check my loupe focus, again, I'll probably put them back as they were. Perhaps I'll try with and without (reversing the G for the latter, of course) to see if significant flare or other issues arise with the clear pane.