Please forgive me for the total newbie question, but I am using a 4x5 for the first time this week. A friend has loaned me a Sinar F for a few weeks and I'm very surprised by how dark the ground glass is. I'm actually wondering if there is something wrong, because even under the dark cloth or with the bino attachment, it's really hard to see well enough to compose properly. There is a lot of fall off toward the corners as well, so it's very hard to see the edges of the shot. The only way I can see the edges is to look at the ground glass from about a 45 degree angle. I'm using a 90/6.8 wide open in my apartment which has wall to wall south facing windows with quite a bit of light, even when it's grey and raining like today. It's better with the 210/5.6, but still quite dark.
I can't imagine trying to use this in some of the dimly lit interiors that I have photographed with my digital-SLR. Is this normal and something you just have to get used to?