In a thread on the “Cloudynights Binoculars” forum about a review of the SRBC 12x56 and 15x56, forum member Koh made two interesting “by the way” remarks in his post of Nov. 16:
quote
“…..at 15x magnification, the persistent issue of needing to adjust diopter settings when switching focus between near and far distances—common in roof-prism binoculars within this price range—remains. I am particularly sensitive to diopter adjustments between my eyes, and among all the binoculars I’ve used, the only ones I can truly consider "true CF-style" binoculars are the flagship models from Zeiss, Leica, Swarovski, and Nikon. Even the Zeiss Conquest HD requires very fine diopter adjustments during near-to-far focus transitions to achieve the precise focus I desire.….”
“….the "rainbow-colored light streaking" phenomenon ….. does not occur if the interpupillary distance and eye relief are correctly adjusted. For those observing rainbow streaks while viewing bright point light sources, I recommend readjusting the interpupillary distance and eye relief to resolve the issue.”
unquote
While the second of the quoted remarks appears self explanatory (and should be noticed by those experiencing “rainbow streaks”, esp. when using an SRBC model where this effect seems to have been more prominent than with other models), the first remark may deserve further reflection.
I think many people who have had experience with a variety of binoculars may have experienced the fact that in some models, but not in others, they had to adjust the diopter when changing focus distance, at least if they are sensitive to diopter adjustments between their eyes. I am myself very sensitive in this respect and found the described “flaw” annoying in a number of my binoculars.
I am with Koh in that I usually don’t have to adjust the diopter when switching focus distance in my Zeiss, Leica, Swarovski and Nikon binoculars, but the same is true for many more brands as well.
In others, I may have to adjust diopter: funnily, in most of my Kowas, but also in one of the GPOs, in several Opticron models, in two of the Meoptas, to name just a few examples.
Koh seems to infer from his experience that
a) this only happens with binoculars other than“flagship” premium models (he names them “true CF-style binoculars”
)
b) this is common in roof prism binoculars in the medium price category.
While I have some sympathy for his argument a), my experience tells me that the conclusion under b) is false, since I own several porro I binoculars where the need to adjust diopter when focusing annoys me (in porro binoculars, the rocking bridge can be one reason for the discussed effect, but the phenomenon goes beyond that).
What’s the experience of other users?
quote
“…..at 15x magnification, the persistent issue of needing to adjust diopter settings when switching focus between near and far distances—common in roof-prism binoculars within this price range—remains. I am particularly sensitive to diopter adjustments between my eyes, and among all the binoculars I’ve used, the only ones I can truly consider "true CF-style" binoculars are the flagship models from Zeiss, Leica, Swarovski, and Nikon. Even the Zeiss Conquest HD requires very fine diopter adjustments during near-to-far focus transitions to achieve the precise focus I desire.….”
“….the "rainbow-colored light streaking" phenomenon ….. does not occur if the interpupillary distance and eye relief are correctly adjusted. For those observing rainbow streaks while viewing bright point light sources, I recommend readjusting the interpupillary distance and eye relief to resolve the issue.”
unquote
While the second of the quoted remarks appears self explanatory (and should be noticed by those experiencing “rainbow streaks”, esp. when using an SRBC model where this effect seems to have been more prominent than with other models), the first remark may deserve further reflection.
I think many people who have had experience with a variety of binoculars may have experienced the fact that in some models, but not in others, they had to adjust the diopter when changing focus distance, at least if they are sensitive to diopter adjustments between their eyes. I am myself very sensitive in this respect and found the described “flaw” annoying in a number of my binoculars.
I am with Koh in that I usually don’t have to adjust the diopter when switching focus distance in my Zeiss, Leica, Swarovski and Nikon binoculars, but the same is true for many more brands as well.
In others, I may have to adjust diopter: funnily, in most of my Kowas, but also in one of the GPOs, in several Opticron models, in two of the Meoptas, to name just a few examples.
Koh seems to infer from his experience that
a) this only happens with binoculars other than“flagship” premium models (he names them “true CF-style binoculars”
)b) this is common in roof prism binoculars in the medium price category.
While I have some sympathy for his argument a), my experience tells me that the conclusion under b) is false, since I own several porro I binoculars where the need to adjust diopter when focusing annoys me (in porro binoculars, the rocking bridge can be one reason for the discussed effect, but the phenomenon goes beyond that).
What’s the experience of other users?
Last edited:
