John Barsness has a book titled "Optics For The Hunter" that is very well done as all of his writing is. He does a great job of explaining the compromises that must be made in selecting optics.
The OP never said what the main use for his compact binocular is but I will agree with most of the posters here that high magnification, small objective diameter & light weight are usually not a good choice.
I currently have Swarovski binoculars in 7x30, 8x30 & 10x50 plus a 35 year old Leitz 10x40B (all roof prism). I prefer the 7x30 Swarovski over the 8x version & I always thought the Leitz 10x40 B (great glass in it's day) would have been better in 8x.
The 10x50 Swarovski glasses are wonderful in low light & for glassing all day long when you are not too far from a vehicle but heavy suckers if you are doing much walking around.
If I was going to look for a compact binocular in the 20 to 25 mm objective range I would look for something in 6x & the best quality I could find. Good luck finding that as everyone seems to think 10x or up is a must these days no matter what the objective size.
