I was thinking that it was likely that our interest in camera optics might spill over into other optical areas and hope this isn't too off-topic. I had some time on my hands today while nursing a minor knee injury and did some comparing of a few binoculars that I own. I was surprised at how well a new set of cheapies worked that I recently purchased for abuse as a pair to be left suffering in my vehicle....
It was a bright day, looking west at about 3:00 with the sun quite high in the sky. I had some good targets for reference from 20 to 200 yards of various colors, etc. The 4 sets that I currently use are a Gold Ring front focus 9x25 Leupold (made in Portugal by Leitz I was told), a 7x50 PCFII Pentax (Porro Prism), an 8x43 DCF Pentax roof prism and some newly purchased Nikon Action 8X40 Porro's (these are the ones with the molded apochromatic element).
Even switching back and forth, they all seemed very sharp in the bright light of the day. The 7X50's had less color contrast and a more muted rendition. I hadn't thought of them that way in my normal use of them as a hunting set at dawn and dusk (which they excel at and are great light gatherers). I believe I was seeing the effect of flare as the primary factor in this. The little Leupolds are nice and I've gradually learned to deal with the front focus reasonably well. They suffer from jitters induced by their magnification and small size and I find I'm always looking for something to brace against when using them. Color and snap were good on these but these suffer from low-light issues, I've learned. The 8x43's have stunning color and contrast, are quite substantial and heavy for their medium body size but are great pieces of glass. Even though they have a certain "wow" factor, surprisingly, I really couldn't make out subtle details much better with these. I've also noticed a slight chromatic aberration with these on metallic, sun-lit edges but can't see any other optical flaws at all.
The nice surprise was the inexpensive Nikons.... I paid $45 for some factory refurbs that were absolutely like new. They are about as sharp as the others, at least in the center and had very nice color and contrast. These have to be about the best bargain I've seen in binoculars and are a great example of efficient design and manufacture. Maybe in the price class that the Nikons are in, I may have gotten lucky and received one that all of the specs were spot on? I'm certain that this type of performance would have been in the $200-$400 range 10 years ago. I just got the Nikons in the past month or so and have had the others for quite a while but this is the first time I've spread them all out and did a thoughtful comparison. I usually just grab the set that fits the situation at hand and have been happy with them.
I have some old 9 X25 Nikon compacts that I gave away.... They were sharp and contrasty but fogged up easily when fall/winter hunting so I got to not trust them for that duty. I also had a set of German-made Exacta roof prisms a few years ago (I believe 8x40's) that I bought via mail order and they were somewhat disappointing. I also recently had a 20X60 and 16x50 Pentax PCFII but I didn't care for either one. I didn't have uses for the magnification that I thought I would and the optics weren't all that dazzling on either one. Both had color fringing and didn't seem that sharp. I had purchased them based upon the good experience with the 7x50's.
That's my little missive on low to medium grade binoculars that I've been using. Perhaps some of my experiences would be helpful to you if you're shopping in these price and type categories.