I have tried several times in the past to measure the resolution of my binoculars using an Edmund Optics USAF 1951 glass slide and a 3x12 Zeiss tripler but failed, firstly because of the diificulty in affixing the tripler behind the binoculars' ocular and secondly because my old eyes require more than the modest 3x boost.
Henry Link has suggested using a second binocular as a booster, so today I set up my 8x33 Kowa Genesis on a second tripod behind the Swarovski 8x56 SLC.
The USAF glass slide was illuminated from the rear by a white translucent bedside lamp and I was intermittently able to see the vertical and horizontal lines of group 3, element 4 in both barrels.
This is a line spacing of 11,3 line pairs/mm and at the viewing distance (objective to slide) of 6,27 m translates to a resolution of 2,9 arcseconds.
The objectives of hand-held binoculars usually have fast focal ratios and one would not expect them to get close to the Dawes' limit, which for a 56 mm objective would be 2,07".
In this context I think 2,9" is an excellent result for the SLC.
John
Henry Link has suggested using a second binocular as a booster, so today I set up my 8x33 Kowa Genesis on a second tripod behind the Swarovski 8x56 SLC.
The USAF glass slide was illuminated from the rear by a white translucent bedside lamp and I was intermittently able to see the vertical and horizontal lines of group 3, element 4 in both barrels.
This is a line spacing of 11,3 line pairs/mm and at the viewing distance (objective to slide) of 6,27 m translates to a resolution of 2,9 arcseconds.
The objectives of hand-held binoculars usually have fast focal ratios and one would not expect them to get close to the Dawes' limit, which for a 56 mm objective would be 2,07".
In this context I think 2,9" is an excellent result for the SLC.
John