The field of view of these viewfinders is usually for a standard lens, so something around 50mm on film. That would include the Q Standard prime 01.

There were turret viewfinders that could be rotated for different fields of view, and also some had different brightlines in the finder for maybe a 50mm and 135mm lens. These are not good solutions though, an SLR is much better for interchangeable lenses.

Keep it simple, 01 prime and Pentax viewfinder match absolutely. Close up marks in these viewfinders just indicate what may be cut off in the view as you move closer. The lenses and viewfinders not being the same position introduces parallax errors. In other words, they have slightly different point of view that becomes more critical the closer we get.

This is the sort of third party viewfinder that was quite common at one time. Not bad, not a patch on the Pentax one, but still....if you can find one it will do the job.

These could be used on Pentax cameras so that's not a problem, but I don't think I have any images at an appropriate size. I'll have to resize some and I'm a bit occupied right now, so hopefully later on today.

I sold several last year on eBay. So keep an eye out there, but also camera fairs. Prices could be as little as £5 because of relatively little demand.

There are second hand viewfinders that would do. A Voigtlander one from the 1950s/60s would be excellent. Some others are just cheap and nasty.

What it's always set on, Av and around f/8 is about average.

To be honest, it's never going to happen that something leaps out at you so quickly that you've got time to fish the camera out of the bag, but no time to actually check what aperture it's set on.

If it does, it will be so momentous that the fine adjustments won't matter. The papers will still pay you megabucks for the shot.

Billingham Hadley Pro, plus any backup cases for extra items. But we like to travel fairly light.

The SRS price looks reasonable when you see what a beautiful jewel it is. The quality of the view through it is outstanding. Crystal clear and up with the best viewfinders of this type.

Likewise the GR viewfinder.

The lens duly arrived around noon, but since then other things have taken my attention.

I'll post some pictures as soon as I have a chance to shoot some.

True Jamie, but at least any dust in the viewfinder is just an irritation. It won't affect the image at all.

It happened on SLRs too, in the old, dark days of film. But, as you say, cameras are meant to be used.