Hälsa Leif!
I am new to birdwatching (I took it up on retirement) so only post in present company with trepidation.
Leif, to encourage you I give you the example of someone else who practises underbinning in the field. In particular, where weight and waterproofing are not an issue, for local birdwatching I often take out a "Featherweight" 7x35 binocular, a 666gm true FOV 7.3*/apparent FOV 51.1* Swift Triton No748 7x35.
Except, even compared to using modern binoculars, I wouldn't call using the Triton "underbinning"!
Specification is an area where, coupled with good optical design and a high standard of manufacture, old binoculars still hold their own. I took a Brezhnev "Years of stagnation" Zomz 7x50--true FOV 7.1*/apparent FOV 49.7*--for test onto Pevensey Levels (where William the Conqueror landed: ie totally flat land near the sea), and found that I could lay it upon a bird in a bush, focus, accommodate and scrutinise the bird, probably quicker than using any other binocular I had previously tried.
I took the "Last of the Mohicans", the Minolta-badged supposedly Kamakura 7x35 EWA--true FOV 11*/apparent FOV 77*-- on a field trip to Lakenhurst Fen (also flat, with long, long sky views over marshland), and realised that, paradoxically, 7x magnification was a very good specification for skywatching (not just woodland birdwatching): Unlike 10x magnification--and to a lesser extent 8x magnification--birds did not easily drop out of focus and become invisible. Plus I found 11 degrees to be no "overkill" for big skies.
So I come to the Swift Triton, ie to the specification of the laughingly called "Featherweight" Japanese "Golden era" 7x35 binocular, a 600-700gm binocular with similar true & apparent fields of view to the typically true FOV 7.1*/apparent FOV 49.7* of the traditional 7x50 Porro binocular I cite above.
Essentially the Featherweight 7x35 binocular is a traditional 7x50 Porro binocular with its 50mm objective diameter, and in turn 7mm diameter eye pupil, reduced to achieve manageable "field" weight.
The specification is attractive, because (1) the ergonomic advantages of a 50* apparent FOV--digestible information load for the brain, low workload for the eyes, so speedy accommodation and identification of the bird--seem to have been passed over by the market in favour of the advantages of a wide true FOV; (2) the optical advantages of 7x magnification seem in similar fashion also to have been passed over by the market in favour of the advantages of 8x magnification.
I won't develop the point here. This is not the right post for that. But not to over egg the attractions of binoculars with small fields of view, people who have used them will know that, as a matter of "horses for courses", when the purpose of the user is to observe multiple or interacting birds, binoculars with wide fields of view most certainly do come into their own.
Stephen
Leif, apropos the cycling video, my town bicycle is a circa 1992 Raleigh Dune Dancer mountain bike kitted out like a "rat bike" to make it less attractive to thieves. I've got to shed my other old bikes, but I shall probably keep a circa 1988 Marin Bear Valley, or a circa 1988 Specialized Rockhopper Comp, as a spare. My town is full of such "hack bikes". But I am sure many riders, like me, have always tried to make them also a bike that is as far as possible a bike that is fun to ride. Call me an "underbiker" as well as an "underbinner"!
I'm sorry for all the phrases in double-commas and English references in this post: Since Google Translate, I have realised that if I cut such stuff out and write simply, stick to ordinary usage, and write grammatically correctly, friends etc abroad will be able to read me as easily as if I wrote in their own language. But on the present, largely non-technical subject of underbinning I indulge myself and write as I speak