Other choice, ok I admit that's quite unusual but I suggest you to have a look at vintage Voigtländer Kontur "dark" viewfinder. It's to be used with both eyes open, the main one looking in the non see-through but seeing the frame of teh picture and the other eye seeing the area in front of you. Your brain is making 1 image of the 2 and miracle you can see what will be in the pic inside of the frame floating in front of you.
That's really great specialy while shooting moving things.
Off course impossible to use for one-eyed people.
Remark, different models exist:
- for 35mm camera mounted with 50mm lens (attention named 35mm refering to film format not to lens focal)
- for medium 6x6 with 80mm lens
- for medium 6x9 with 105 lens
For 35mm camera mounted with 50mm lens, 2 versions are available, one with close focus correcting parallaxe second grid (original ref 335/36) and a second one with only the main frame (335/23).
Some people don't like the Kontur but it's the favorite of other...