Update on replacement 8x25 and on stock availability
In previous posts (#19 and 39) in this thread, I described my purchase of a Zeiss 8x25 Terra, its floppy hinges, and the excellent (though slow, because of stock availability) customer service of Zeiss in sending me a replacement with tighter hinges (though not tight as preferred) and smoother focus. At the time, I had the feeling that the optics were nice in many ways but that something was off with obtaining critical sharpness. First impressions about that sort of issue are usually a red flag, but I tried to be optimistic when I wrote the following.
...The view doesn't seem lacking in any way by itself, though in side-by-side comparison to my Leica 8x20 Ultravid, the finest details are not as easy to see in the Zeiss. Perhaps it is just a matter of relative familiarity with the bins. Perhaps, as with my Zeiss 8x32 FL, it is a matter of requiring perfect eye placement to prevent astigmatism and other aberrations, unlike my experiences with Leica, Swarovski, and Nikon bins, which seem more tolerant of eye placement... Overall, I'm pleased with the Zeiss 8x25 Terra. I think it will be an excellent bin for my intended purpose--to provide a good bin to an 8 year-old with small IPD. She'll also appreciate the easy reach to the focus knob and the close (under 6 foot) close focus...
Well, since then I've had time to give the bins a thorough trial, play with the diopter, get to know them etc, and I can now say with confidence that they are optically flawed. My Zeiss 8x20 Victory and Leica 8x20 Ultravid are far superior, which is to say razor sharp by comparison. Used by themselves, with low expectations, or by someone with low acuity, these 8x25 Terra would probably be considered a fine binocular. What's wrong? Something about the left side keeps it from reaching critical focus, even in the center. Since I'm left eye dominant, it is especially bothersome to me. I haven't done a boosted magnification star test, and I don't really care what is wrong because it's a moot point since the verdict is that I find them unusable. I do note, at night, that I get big spike off the roof prisms, but that is true on both left and right sides. On a positive note, the zero position of the diopter is accurate, and both left and right sides focus in perfect synchrony, so if it weren't for whatever is ever-so-slightly-off that keeps the left side from reaching that last bit of focus, they'd be a breath of fresh air (or long-time reliable Japanese precision) compared to the mechanically imprecise bins (generally of Chinese manufacture) we so often see these days at this price point.
What's my next step? I called Zeiss and spoke to their excellent customer service. They will do another replacement, but unfortunately, the new stock is still not in and I was told wouldn't be in until June some time, so I'm holding on to these in the mean time for my 8 year old friend to use. I was also told that the issues with the floppy hinges and other mechanical issues were supposed to be addressed with production of this incoming stock.
--AP