It's a pity opera glasses, which fold flat enough not make a bulge in the pocket of a penguin suit or a lady's smart evening bag and don't weigh enough to deform either, don't go up to really high powers.
That said, though I have a small collection of opera glasses both recent and vintage, when I want binoculars on my bike, I take the smaller of the twitcher's glasses which hang over a chair in our living room for looking out onto the birds that live the trees in the patio between the living room and the stables sun trap. They're just more convenient in their sturdy leather case and they work better in sunlight. As you can tell, I don't care about weight on day trips, but if I were taking your tours, Matt, I'd surely not want to lug around a couple of pounds of glass and metal and ditto leather.
