Jerry,
How many days or weeks do you spend in the optometrist's chair deciding which lens is sharpest? ;-)
Just want to point out a little morsel of information that might put things in perspective. The ISO resolution standard that all the major players work by is 240/D. I'll skip the maths, but if that level or resolution was uniform acoss the objective it would translate effectivelyas 20/16 acuity cut off. Fortunately most come out a bit better than that, but not every sample, or every model.
I've resolution tested about 30 binoculars that I either own, or have had for at least a couple of weeks to review. The stopped down values (20mm for an 8x) range from an amazing 5.8" to the pretty miserable 14.5". That approximates to 20/7.7 and 20/19. That will give you a pretty good idea if a binocular will look soft for your eyesight. Even that $25 roof have sufficient resolution for those with 20/20 vision but differences in microcontrast or sharpness with better binoculars might still be evident. You will have to take my word for it that I can see such differences in resolution, but it was easier a couple of years ago when my acuity was 20/11or 20/9 with two eyes... on a good day!
To keep things simple, rather than use arcsecond or VA values I'll just use a 'Typo score' of 1 to 10 for the rest of this post and roughly cover the arcsecond equivalent of equivalent of 20/20 to 20/8, so even 1 will be quite acceptable for some. These are visual estimates in most cases are based on comparison with my own binoculars and others available when the light is close to optimal for visual acuity. I don't rate resolution in poor light. If go to Birdfair or a retailer I'll normally take my ZenRay Prime 10x42 or Vanguard EDII 8x42 for reference. I would score those as an 8 and 8.5 respectively though I need a tripod for the decimal points. These were very good for the money when I got them, but the market is improving all the time and I would certainly look for better with newer, more expensive models (if I had the money). What follows are some memorable comparisons.
UK launch day for the Zeiss Terra.
Terra
S1: 3
S2: 6
S3: 5
S4: 9
Conquest HD
S1: 8
S1: 7
S3: 7
S4: 8
HT 8X42:
S1: 9
S2: 9+
S3: 8+
HT 8x54: 5
About 4 or 5 years ago on the Swarovski stand. I think there have been at least 4 versions of the ELSV 8.5x42, and this was when the second, and to my mind the worst version was around.
CL
S1: 3
S2: 3
S3: 3
S4: 4
ELSV 8x32
S1: 9
S2: 9
ELSV 8.5x42
S1: 7
S2: 7
SLC
S1: 9
S2: 8
Vortex Razor HD
8x42: 8
10x42: 8
10x50: 9+
Meopta Meostar
8x42: 8
10x42HD: 9
12x42HD: 10
Kowa Genesis 8.5×44: 10
KITE Bonelli 2.0: 10
Nikon EDG: 9+
Nikon Monarch HG: 7
Opticron DBA VHD: 7
The following is acompilations from different occations
Leica
UV: 8
UV: plus 9
Noctivid: 10
Trinovid HD: 8
Trinovid: 6
I think this illustrates that not only is there variation between models there is variation between samples. That is particularly evident at lower price points as the Terra samples show. I've seen samples of amongst the cheaper models from Vortex, Kowa, Opticron, Kowa, Minox, Celestron, Hawke and Nikon that would score 8 or occasionally 9, but that wouldn't represent the model as a whole. The Fujinon KF 8x32W, a Sightron clone I reviewed, scored a 10 (confirmed by testing) but I would be very surprised if that was representative of the model. I now have measured results of '10' for the Meostar HD12x50 and Kite Bonelli 2.0 as well.
I've now tried 4 samples of the Monarch HD on three separate occasion and I'd score them all a 7 for apparent resolution. I've said twice already I like the ergonomics and other characteristics, so I find that a disappointment. It's no surprise to me, as I have explained that others might judge it differently
Now Jerry, over to you. What's your acuity, and what are your resolution scores for those models? Obviously we need them backed up by resolution testing, "you should have the skills". In arcseconds please, I can take it.
David
