Like many things in life, the question of which binoculars are best for you -- it depends. Large, medium or small binoculars can all have their positive and negative points. I will explain.
Before getting to your question about large, medium or small binoculars, a few general notes:
- Glass quality. In life, you get what you pay for. Higher quality glass gives you not just sharper images but also provides you better low light capabilities than would less expensive glass. There are several quality glass manufacturers out there; Japanese, European for example.
- Objective lens size. Objective lenses (the end piece of glass) can range in size from 22 to 56mm (diameter). Smaller diameter objective lenses weigh less but the smaller size means that your field of view will be narrower - meaning you can's see as much. On the other hand, larger objective lenses like the 56mm objective lenses offer better light gathering, a much wider field of view but to get these attributes you will be carrying a much larger and likely heavier set of binoculars. Many consider 42mm binos to be the perfect trade-off for most users.
- Power. Binoculars come in both adjustable and fixed power setting from 4 to 20 power. Right off the bat, adjustable power binoculars are generally heavier because of the mechanisms and amount of glass required for adjustable features. Low powered binoculars provide closer views but many times their power can cause undue shaking therefore tripods or other methods of steadying them may be necessary. Likewise, lower powered binoculars provide wider field of views but may not provide as much detail as more powerful models.
- Body materials. Materials can range from aluminum, magnesium, as well as plastic composites. Likewise some binoculars may have canvas or vinyl coverings.
At the end of the day, the user will need to do research and figure out what their budget is. Then the user would need to figure out the intended uses and environment the binos will be used in. Conditions include cold, wet, heat, altitude, as well as how often the user goes from cold to hot (increasing the chances of internal fogging). Likewise, a benchrest shooter is normally much less worried about weight and size of their optics than say a hunter who has to carry everything on their person - often for long distances up and down hills. Similarly, will the user be in wet and humid conditions? If yes, then the user needs to select water proof binos as opposed to water resistant ones. And one final note, related where we started this paragraph with - bino costs. If the shooter is spending tens of thousands on the hunt of a life time then that user would need to consider getting the best optics possible -- because optic failure on the hunt of a life time isn't the best way to make memories of a lifetime.
In closing, do your research, figure out what's best for you and based on these variances - make the decision that best suits your lifestyle and limitations.
And, yes, like much in life - akin to your selection of binos .....it depends.
Have fun.
