Hi, John. The observations I brought up in this thread are the result of side-by-side comparisons. Interestingly, so are Kimmo's observations the result of direct side-by-side comparison - and his, of course, in a more rigorously scientific environment than mine. My point here is that most of these differences will only be plainly visible when directly compared to a superior performer. I was pleased with the resolution of my 8x32 FL, until I compared it to several 8x32 Trinovids. Only then could I fully appreciate the shortcomings of the FL with regard to center resolution. A newspaper at a distance of 15 feet, easily read with the Trinovid, was obviously less well resolved by the 8x32 FL. I have repeated this test - and several others - many hundreds of times. My observations in these reasonably well controlled side-by-side direct comparisons are what I wanted to share here - FWIW. I have also concluded that, without something to compare results to, it is next to impossible to reach any meaningful conclusions. This is equally true with camera optics. Again and again, lenses that are legendary for superb optical performance have been easily surpassed by the successor model. We were perfectly pleased with the performance of "lens A" until "lens B" revealed it's shortcomings. I don't mean to imply that my observations are more valid than anyone elses, but rather this is an attempt to explain how I arrived at certain conclusions.
Hi Angleo, it's me again. :hi:
I don't own any Zeiss or Leica bins, but maybe that qualifies me to comment in this discussion. What you said about side-by-side comparisons has a truthiness quality, but I'm not sure it's really valid. In this I tend to side with John.
The way I see it, all "resolution" tests involving a formal chart, or an informal newspaper, are at best
aided visual resolution tests (technically, grating acuity). The resolution of the optics, at least the objective's, is imbedded in the aerial image hovering inside the binocular at its focal plane. For any well designed and manufactured instrument this resolution is considerably greater than what the eye needs, for this type of acuity testing, when it is
normalized for the magnification of the instrument. Therein lies one rub: are the magnifications exactly equal? Pushed to the limit, it will make a difference even if the bins are tripod mounted, which in many cases they are not. Therein lies the second rub: vibration effects. The third rub lies in procedural effects, and in particular observer
bias. I'll bet you two beers for a month of Sundays that Zeiss owners, on average, find their bins have equal or greater resolution —and Leica owners the opposite.
There are several reasons for the instrument to degrade, of course, and Kimmo mentioned some of them. He also mentioned that in at least one sample the optical resolution was as good as any he ever seen (or words to that effect). So, apart from quality control issues, which may be a valid complaint, is there any basis for saying that an FL or Ultravid is necessarily better at aiding the observer's visual acuity? When I consider the raft of other potential non-equivalences in side-by-side testing, including head/binocular coupling, side lighting, selective transmission, ambient lighting, color balance at the retina, etc. my conclusion is that's it's better not to draw conclusions about what's better. Note that I haven't said anything about
human variability, which can interact with any combination of the above variables, so that what's best for one observer can be less than best for another.
To me the answer is to avoid side-by-side product comparisons for purposes of product advocacy, even though it seems to be common sense to make them. I agree, entirely, of course, that viewing comparisons are essential in order for the individual to make buyiing decisions and that includes within-model comparisions to assure one doesn't get a lemon.
Incidentally, IMO the comparison of camera lenses is entirely different in that one can compare prints or projections that are external to the eye.
Can we still have a beer?
Ed
