I used to carry binoculars when camping, I have used a variety that ranged from the cheapest roof prism models to a pair of really sharp pre-WWiII Zeiss Jena 6 power (I do not recall lens diameter) ones that had no lens coatings.
But, when I bought a small superzoom camera that combined a good viewfinder (although it is an electronic viewfinder, not optical) with a powerful zoom lens, I pretty much stopped using binoculars and have not even carried them for the past few years. That camera is now is over six years old, but I like it so much that I have no plans to upgrade.
I am not disagreeing with anyone here, I am just saying that my preferences have changed.
The photos were all resized at 20 percent to reduce electronic size, but no other changes were made.
I'm with Mickeg here. I was interested in bird watching and was part of a forum (which I'd recommend for good balanced suggestions which factor performance vs price)
After having several pair of binoc's I found that I prefer a monocular. I found binoculars the normal choice but never found a combo which was a good compromise between magnification and size. A monocular helped a lot with bulk and that would be a large plus on a bicycle.
Keep in mind the needs of real birders are very different from what you likely seek. They spend small fortunes on highly corrected optics so that they can distinguish with confidence, birds that look identical (to normal humans
) but differ in subtle ways such as a pattern of color in feathers. The optics need to be very true in color so they are corrected for chromatic aberrations. there is no free lunch in optics and higly corrected lenses come with trade-offs. For example Leica optics for birding vs photography have very different optical qualities. And myths, and fanboyisms aside, there is no perfect set of lens choices, just as a Nomad is a certain kind of highly optimized bicycle which does not suit everyone. Keep that in mind so that a birder does not recommend the equivalent of a carbon fibre bike.
I personally would recommend a camera for several reasons. small size binoculars end at about 8x reach. more than that you sacrifice, too much, something. Weight, optics or price. I found that if traveling, versus being in a blind, that even 10x optics are not enough reach. and at more than 8x hand holding is a problem, unless you spring for more money, complexity and weight with stabilized optics.
A zoom of 300 (or 300 equivalent ) is going to give you about 6 or so equivalent magnification. That is why camera lenses kind of start at 300 but really at 400 to be considered birding lenses. But in reality the 300 is perfect. How come? with 12 megapixel or higher cameras, you can easily double the picture by cropping before ANY optical imperfections show up - if you have a trained eye. Most people don't notice a thing at 4x crop. So you get you bird and you get to take the memories of it with you. At more than about 400 mm, hand holding is for idiots and atmosperic conditions normally ruin the show and the shot anyways. Now if you really care about it, I would further recommend a prime, not a zoom lens. You don't need the zoom aspect for wildlife and a prime is simpler, with fewer lens groups, and so it is much lighter. It also does not need the same degree of correction. Correction is bad, past small doses (long story). A prime also does not introduce lens suck, if you like to cycle in dry dusty conditions and the primes don't tend to have poor veiling flare performance as much neither.
I'd go even further and recommend (though I've mostly shot with Canon and Nikon) a mirrorless setup. Olympus and Panasonic cameras are relatively cheap, and double the effective focal length. Their optics are so so, but they are corrected in software, which I was going to say is the way of the future, before catching myself. It is the way of today. It works marvelously and you get a lens for less than $2000 in the worst case (and often less that $1200) with the end results being one quarter the size of a Canon/Nikon lens at half or better price. lastly the image stabilization of camera lenses tend to be better for a cheaper price. (economics of scale?) and you really want image stabilization for wildlife. Unfortunately Olympus builds lenses with sensor image stabilization and you don't get the benefit of it through the viewfinder (only the shot) But you can put on a panasonic lens with optical stabilization and it makes a marvelous difference, every tremor of your hand is magically smoothed out. No 12 pound gimbal head needed.
. The Fuji camera are larger but I find I like them a lot better in hand (I have three of each of Fuji cameras, and Olympus cameras - along with an old Nikon D3 I never seem to pull out of the closet anymore) and the Fuji lenses are imho the best lenses per dollar by any manufacturer by far. They render much like Leica optics (where as Canon is more like the other end of the choice spectrum - Zeiss) They are heavier, also software corrected, but the lenses are much better optically at the same time, but still of reasonable size. They also reach diffraction much later, giving you a wider range of viable stops.
Sorry for the long ramble, hope some of it is useful. Oh ...and small binoculars suck for light gathering!
It all sound a bit like over-thinking things, and it may well be, but anyone who buys a Thorn bicycle obviously over thinks and over obsesses' the fine points of cycling ... so that all seems to be in order.
