Hi all. Anyone have any ideas of the best way to put crop marks on the Leica S focusing screen to achieve a 4:3 aspect ratio through the viewfinder rather than its native 3:2 ratio? In a perfect world, Leica would have built this functionality in, like on my D800, so that it shades the viewfinder and "tags" the image appropriately when you change aspect ratio modes. But, since that's not the case, I am trying to think if there's a way for me to hand-draw/etch on the screen itself a translucent or hash-line in the appropriate places so that I can at least pre-visualize in 4:3 when appropriate. I can then apply the corresponding crop to the relevant batch of images on the back end.
(I'm aware that I can just shoot 3:2 and crop to 4:3 later without doing anything to the focusing screen, which is what I've been doing thus far where appropriate. As noted above, however, being able to pre-visualize it through the screen will help me with camera positioning, distance, etc., while shooting. I'm also aware that other medium formal brands have a native 4:3 ratio, so hopefully we can skip the "just buy a [Brand X]" advice...).
Has anyone done this? If so, what did you use to mark the crop on your focusing screen? And, for bonus points: if anyone knows the precise mathematical measurements where I'd mark this off on the left/right of the screen (when held horizontally) that would be great.
I'm picturing something like looking through the viewfinder of a Leica M, where the areas outside of the frame area are delineated by a white line (although unlike an M, I'd probably want to make hash line rather than a solid line). Thus, my first thought -- draw the lines with a Sharpie -- seems like a bad idea, because it would be too difficult to ignore when NOT trying to shoot in 4:3. My second thought -- draw the lines with a white grease pen -- also seems like a bad idea, because such residue inside a digital camera can't be a good idea. My third thought -- literally etch it into the glass with a pin or X-acto knife or something -- might work, but I can't envision how how deeply I'd have to etch in order for it to be visible, and whether I'd have to etch it so deeply that I'd be at risk of cracking the screen from the pressure.
