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Please can someone help me with my newb viewfinder struggles?
I would have thought that one should use a 90mm viewfinder for a 90mm lens, however I see a 21mm viewfinder is recommended for the Travelwide 45 because "21mm on 35mm corresponds to the vertical FOV of 90mm on 4x5".
I know angle of view can be expressed in vertical, horizontal and diagonal planes, but why pick vertical and not horizontal?
Hi everyone! Welcome, Zuiko!
Chauncey, the distance is indeed set at infinity, and we'll ship the camera with shims so that you can fine tune the focus .
We've contacted a few retailers but will contact a few more—good idea! Unfortunately there's not much they can do for us at this point except tweet or share the link, but every little bit helps!
Hi Simon,Quote:
Originally Posted by Simon Liddiard
I made that decision because I'm more often trying to figure out if vertical elements are in or out of the frame, versus horizontal elements. For example, I wanted the brightline to help me see if I could fit the top of a building or the top of someone's head. But it's more or less arbitrary which axis you choose.
Hope this helps!
Thank you Ben. So I could choose a 90mm viewfinder, but unless it was designed for 4x5 the aspect ratio would be different, e.g. 1.5:1 for 35mm and 1.25:1 for 4x5.
Presumably this could be resolved by masking or am I barking up the wrong tree here?
It's not the aspect ratio you need to worry about but the FoV. A VF for a 90mm on 35mm film is a short tele, not a wide-angle, and would have the FoV of a 300-360mm lens on 4x5.
Perhaps a photo will be worth all the explanations one could write. I just whipped this up using a photo I was working on (that was shot with a 90mm) showing basically what a 21mm vs. a 25mm viewfinder will be (approximately) compared to the image. Of course I haven't taken into account parallax and such.
This arises from the differences in aspect ratio of the 35mm format:
http://www.oceanstarproductions.com/...viewfinder.jpg
A 90mm lens for 96x120mm film (4x5 in most holders, some vary by a wee bit) has the following angles of view in degrees: horizontal: 67, vertical: 56, diagonal: 81Quote:
Originally Posted by Simon Liddiard
A 21mm lens for 24x36mm film has the following angles of view in degrees: horizontal: 81, vertical: 59, diagonal: 91
A 28mm lens for 24x36 gets you, in degrees: h: 65, v: 46, d: 75
That's part of the problem comparing 4:5 ratio film to 2:3 ratio film, you have to pick whether vertical, horizontal or diagonal is the best to compare. If you could get a 4:5 mask for your 21mm viewfinder, that would probably be the best.
Hmm, the nice thing about a brightline finder is that you can see beyond the lines, so personally I wouldn't mask it. Ultimately with a point and shoot camera, the viewfinder is just giving you a general idea (ie, the framelines are not outrageously accurate). That lack of accuracy actually helps me relax and just shoot!Quote:
Originally Posted by Simon Liddiard
Ah right, of course! Angle of view / field of view as specified by the manufacturer https://www.schneideroptics.com/info.../6,8-90mm.html
So if the angle of view of the Angulon 90/6.8 is 81 degrees circular which is then constrained by the dimensions of 4x5 (horiz, vert or diag)
What he said!
Quote:
Originally Posted by Simon Liddiard