You may not like my response.
Personally, I find the "zoom" or "variable power" binoculars to have little use especially when you are talking about the compact models. My reasoning is fairly simple. Compact models produce a fairly dim image to start with because of their smaller objective size and smaller exit pupil. Now, throw in a zoom feature and the field of view shrinks considerably as does the exit pupil as the magnification increases. A 25 mm objective lens coupled with a 24 power magnification yields an exit pupil of around 1 mm. Very little light gets through that small of an aperture even on a bright sunny day. Couple that with the fact that it is extremely difficult to hold something like that steady enough to really take advantage of the increase in magnification and you are left with a feature without any real practicalbenefit.
In my opinion you would be better off either buying two fixed power bins or just settling for one magnification that you are comfortable with. A very educated and talented individual on the subject of optics once said that it is the quality of the glass and the quality of the coatings used on the glass that determines how much detail can be resolved at any given distance not necessarily the magnification itself.
If you want to stick with a compact model then I would suggest either the Bushnell Legend 8x24, the Nikon Travelite 5 8x24 or the Nikon Prostaff ATB. The reverse porro design of these models will yield a fairly bright image (relatively speaking) while still keeping the cost down to a respectable level. A compact roof prism model would cost significantly more to produce as fine of an image.
Hope this helps somewhat.
8-24 power binoculars
