calculating viewfinder coverage

Ok I hope this question isn't too stupid:
I've been pondering getting a pentacon six camera, just for the fun of it, but I'm a little worried about it's viewfinder coverage. (i'll only be using the waist level finder if I get one, and not the prisms that will diminish coverage even further)

Now a 6x6 negative is actually 55mmx55mm

I used to have a hasselblad 500 c/m and I know that it's finder showed 54mmx54mm.

Just for comparison, a kiev 60 shows 53mmx53mm

and a pentacon six allegedly show 51mmx51mm in the finder.

I read somewhere a long time ago that there are two different ways of calculating viewfinder coverage, but I have forgotten them.

But if I just divide 51 with 55 for the pentacon six, I come up with a coverage of 92 percent, and using the same method, 96 percent coverage for the kiev 60 and 98 percent for the hasselblad. But is this correct, and comparable to, say, the 94 percent coverage of my canon ftb as stated in that camera's manual?

I remember asking arax foto once how much of the actual image the viewfinder, in the kiev 60, covered, and I got the answer that it covered aproximately 90 percent.
I also remember reading somewhere that the hasselblad 500 c/m shows 94 percent of the actual image in the finder.

So obviously my method is not correct.

Can anybody tell me how much is a pentacon six' viewfinder coverage according to standard methods?


Regards
Mads

If you want to calculate the % of the surface covered, it would be: 51x51/55x55 x100= 86%

Peter

Hi Peter
Thank you so much. I hated math when I was small, and so a lot of these relatively simple formulas never stuck. Only much later did I realise how interesting math is. Oh well...

Thanks again
Mads

You can go on hating maths (i do, and never encountered a need not to).
After all, how often do you expect to be wanting to do maths in your head about how much you are missing in the viewfinder when using your camera to take pictures?
And no matter what the percentage, we will always get everything we see in the viewfinder on film. So why worry?

Hi q.g. you are, of course, right. What I failed to mention was that I like to print full frame with black borders, making a viewfinder with as high coverage as possible preferable to me.
And I wasn't referring to photography when I mentioned that I've come to find, well at least some, math interesting. Although that wasn't necessarily clear either.
Regards
Mads