I recently had an opportunity to spend some time with a Zeiss Conquest 8x30 BT* and two pair of Victory 8x32s T* FL (one green and one black) and carefully compared these with each other and to my beloved Leitz. I will not repeat published specs.
To compare resolution, I looking at a variety of fine print, some black on white, some white on black, and some lower contrast examples like white on red, etc. I tried this both hand-held and using a tripod. The results were a little surprising. The BT and the green FL were equally razor sharp on axis, ever so slightly beating the Leitz. The black FL was slightly less sharp than the Leitz, although it took very careful observation to see this. When looking through any of these binoculars hand-held and at natural objects, the differences were not discernable.
I similarly compared the size of the sweet spots. The FLs and Leitz were comparable with the BT have just a slightly smaller sweet spot and more fuzziness toward the edges of the image. In use, the differences were not noticeable.
Chromatic aberration was visible in all three with the FL having the least, perhaps half that of the BT, and the Leitz more than the BT. This was tested by looking at a black bar against a very bright background starting on axis and then moving off axis. All three were very good on axis. In some particular observing conditions this would be noticeable.
In bright conditions, when light thruput is limited by the pupil of the eye, the FLs were remarkably bright, beating both the BT and Leitz. With dark adapted eyes, where the thruput is limited by the objective diameter, the Conquest was noticeably darker than the Leitz and FLs which were indistinguishable. This is pretty amazing considering the Leitz are 7x42 and the FLs 8x32.
I also compared contrast looking for fine features on a dark surface surrounded by a very bright background. I did not discern a difference. The Leitz have a very very slight yellow cast to the image compared to the Zeiss binos.
All had good eye relief that worked well when I tried them wearing glasses
I like smaller diameter eyecups that fit more deeply in to my eye orbits. The Leitz beat the BT by a wide margin, and the BT beat the FL. The diameter of the FL eyecups is almost too large for me. Of course the Leitz have the old fold-down rubber cups. The BT and FL have helical adjusting eyecups with the FL having several intermediate click stops.
The BT focus knob has some stick-tion, but in practice itís not bothersome. The Leitz and BT have separate diopter adjusters whereas the FL is combined with the focus knob. Getting the diopter adjustment spot-on is kind of a pain on the FLs, but once you know where it is, itís easy to set with the calibrated dial.
The BT strap attachments are metal whereas the FLís are plastic
I prefer the green and black FL to the all black FL, BT, and Leitz.
I paid $700 for the Leitz in 1990 and the BTs and FLs go for $469 and $1485 respectively.
Bottom line: I had to work hard to distinguish the between the performance of these four binos and think the Conquest BTs are an outstanding value.