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Is the EII range restricted by eye piece design just like the SE ? (1 Viewer)
- Thread starter Torview
- Start date
. Hi Tor view,
any traditional binocular can have the specifications varied by changing the objectives.
while keeping the same eyepieces.
For instance the Soviet and Russian 8×30 is also available in 12×45 and 15×50.
The aperture and focal lengths of the objectives is all that changes.
There is also a 10×40 but this is a failure because I think they had to alter the F ratio and there are awful ghosts or rings of light at the edge of the field.
However, the first three are all good generally.
Many firms such as Minolta made 7×35, 8×40 and 10×50 just by changing the objectives.
The Russian extra wide-angle is made in 6×30, 7×35 8×40 and 10×50.
This is repeated by numerous firms and has been so for decades or even longer.
The Ross solar Ross is made in umpteen different versions but here I think that not only the objectives change but the eyepieces also change.
So with the Nikon E II I think you would get a good 8×30 wide-angle as well as the 10×35 that they make but then it would probably be a 12×42 or 12×45.
The objectives have to match the rear body if you keep the same eyepieces.
Of course is no reason why you cannot have different eyepieces but of course this increases the unit costs.
The same applies to roof prism binoculars but of course you have to match everything up and Ray trace to make sure there are no problems.
There are of course many roof prism ranges which are basically the same but with longer focus and larger aperture objectives as you go up in magnification.
any traditional binocular can have the specifications varied by changing the objectives.
while keeping the same eyepieces.
For instance the Soviet and Russian 8×30 is also available in 12×45 and 15×50.
The aperture and focal lengths of the objectives is all that changes.
There is also a 10×40 but this is a failure because I think they had to alter the F ratio and there are awful ghosts or rings of light at the edge of the field.
However, the first three are all good generally.
Many firms such as Minolta made 7×35, 8×40 and 10×50 just by changing the objectives.
The Russian extra wide-angle is made in 6×30, 7×35 8×40 and 10×50.
This is repeated by numerous firms and has been so for decades or even longer.
The Ross solar Ross is made in umpteen different versions but here I think that not only the objectives change but the eyepieces also change.
So with the Nikon E II I think you would get a good 8×30 wide-angle as well as the 10×35 that they make but then it would probably be a 12×42 or 12×45.
The objectives have to match the rear body if you keep the same eyepieces.
Of course is no reason why you cannot have different eyepieces but of course this increases the unit costs.
The same applies to roof prism binoculars but of course you have to match everything up and Ray trace to make sure there are no problems.
There are of course many roof prism ranges which are basically the same but with longer focus and larger aperture objectives as you go up in magnification.
. To illustrate why you cannot have the same binocular eyepieces in a proposed 8×50 Nikon E II.
Assuming the 8×30 version has objectives that are about F/4 then the focal length of the objectives is 120 mm about.
The eyepieces are therefore about 15 mm focal length and are also wide-angle eyepieces.
An 8 x 50 version using the same eyepieces would need an objective again of 120 mm focal length which would mean that the objectives are F/2.4.
This will not work.
Similarly an 8×40 version will need objectives of F/3 again unlikely to be workable unless they were highly exotic.
For an 8×50 you realistically need objectives of about 190 mm focal length.
So the eyepieces need to be about 24 mm focal length.
Wide-angle eyepieces of 24 mm focal length are quite large and would need probably a redesign of the prisms etc in the E II.
So no, I do not think that you will find 8×40 or 8×50 E II binoculars.
Assuming the 8×30 version has objectives that are about F/4 then the focal length of the objectives is 120 mm about.
The eyepieces are therefore about 15 mm focal length and are also wide-angle eyepieces.
An 8 x 50 version using the same eyepieces would need an objective again of 120 mm focal length which would mean that the objectives are F/2.4.
This will not work.
Similarly an 8×40 version will need objectives of F/3 again unlikely to be workable unless they were highly exotic.
For an 8×50 you realistically need objectives of about 190 mm focal length.
So the eyepieces need to be about 24 mm focal length.
Wide-angle eyepieces of 24 mm focal length are quite large and would need probably a redesign of the prisms etc in the E II.
So no, I do not think that you will find 8×40 or 8×50 E II binoculars.
. Hi Torview,
There is absolutely no reason why Nikon could not design a binocular similar to the E II in 8×40 with an 8.8° or 9° field of view and with high optical quality.
It would be larger of course than the 8×30.
The objectives would probably be about 150 mm focal length which would mean the eyepieces were about 18.5 or 19 mm focal length.
Wide-angle eyepieces in this focal length are still of a reasonable size.
Then you would have a 9×45 or a 10 x 50 using the same body and eyepieces.
And maybe a 7×35 and 6×30 using the same body and eyepieces.
As an astronomer I would appreciate a 12 x 56 but birdwatchers probably don't favour this size.
The problem is that most manufacturers don't want to make porroprism binoculars any more.
I would love such high quality binoculars with modern glass and modern coatings.
There is absolutely no reason why Nikon could not design a binocular similar to the E II in 8×40 with an 8.8° or 9° field of view and with high optical quality.
It would be larger of course than the 8×30.
The objectives would probably be about 150 mm focal length which would mean the eyepieces were about 18.5 or 19 mm focal length.
Wide-angle eyepieces in this focal length are still of a reasonable size.
Then you would have a 9×45 or a 10 x 50 using the same body and eyepieces.
And maybe a 7×35 and 6×30 using the same body and eyepieces.
As an astronomer I would appreciate a 12 x 56 but birdwatchers probably don't favour this size.
The problem is that most manufacturers don't want to make porroprism binoculars any more.
I would love such high quality binoculars with modern glass and modern coatings.
henry link
Well-known member
Torview,
Binastro has correctly identified the problems, but I think it would still be possible to make a pretty nice 8x40 E II without any big changes to the binocular body.
The objective in the 8x30 E II is actually 110mm, f/3.75. The eyepiece is about 13.75mm. The old E series 8x30 used exactly the same objective lens and that series included a 7x35. It was made by combining a 126mm, f3.6 objective with an 18mm eyepiece. F/3.6 is probably the focal ratio limit before the first aperture of the prism shelf in these binoculars begins to stop down the objective aperture. An 8x40 with the same speed objective could easily have been made with the same eyepiece. The apparent field would have been about 52º using the old E eyepiece with its 16mm fieldstop. The eyepiece fieldstop in the E II is about 17mm, but it could be increased to about 19mm and still fit into the current eyepiece housing. So, with no change to the prisms and some finessing of the objective focal ratio, the eyepiece focal length and fieldstop diameter it would be possible to make an 8x40 E II with around a 60-62º AFOV and eye relief of around 17-18mm.
Henry
Binastro has correctly identified the problems, but I think it would still be possible to make a pretty nice 8x40 E II without any big changes to the binocular body.
The objective in the 8x30 E II is actually 110mm, f/3.75. The eyepiece is about 13.75mm. The old E series 8x30 used exactly the same objective lens and that series included a 7x35. It was made by combining a 126mm, f3.6 objective with an 18mm eyepiece. F/3.6 is probably the focal ratio limit before the first aperture of the prism shelf in these binoculars begins to stop down the objective aperture. An 8x40 with the same speed objective could easily have been made with the same eyepiece. The apparent field would have been about 52º using the old E eyepiece with its 16mm fieldstop. The eyepiece fieldstop in the E II is about 17mm, but it could be increased to about 19mm and still fit into the current eyepiece housing. So, with no change to the prisms and some finessing of the objective focal ratio, the eyepiece focal length and fieldstop diameter it would be possible to make an 8x40 E II with around a 60-62º AFOV and eye relief of around 17-18mm.
Henry
Torview
Well-known member
I`m salivating just reading this, what a cracker this would be now with the duller days of Autumn setting in, could even be the only bino I`d ever need !
. Dear Henry,
thank you for giving the actual focal ratios, and eyepiece focal lengths and also the field stop sizes for the Nikon range resembling E II.
If the eyepiece is 13.75 mm focal length and the field stop 17 mm.
And if the proposed 40 mm aperture objective has an F ratio of F3 .6 giving 144 mm focal length then at eight times the eye piece focal length would indeed be 18 mm.
However, a field stop of only 19 mm would mean that the apparent field of view would be about 17% less with the 40 mm version. I'm doing this calculation in my head and I will check it later with a calculator.
If this is correct then the 8×40 E II would be nice but would have a rather restricted field of view compared with the current 8×30 and 10×35.
Also I don't know how the performance of the 18 mm eyepiece would compare with the present 13.75 mm eyepiece.
thank you for giving the actual focal ratios, and eyepiece focal lengths and also the field stop sizes for the Nikon range resembling E II.
If the eyepiece is 13.75 mm focal length and the field stop 17 mm.
And if the proposed 40 mm aperture objective has an F ratio of F3 .6 giving 144 mm focal length then at eight times the eye piece focal length would indeed be 18 mm.
However, a field stop of only 19 mm would mean that the apparent field of view would be about 17% less with the 40 mm version. I'm doing this calculation in my head and I will check it later with a calculator.
If this is correct then the 8×40 E II would be nice but would have a rather restricted field of view compared with the current 8×30 and 10×35.
Also I don't know how the performance of the 18 mm eyepiece would compare with the present 13.75 mm eyepiece.
henry link
Well-known member
It could be the same eyepiece design scaled up. I estimated the AFOV with 19mm fieldstop compared to the old 7x35 E with 16mm fieldstop. I'm leaving for vacation, so I'll be away from the computer for the next week.
Henry
Henry
. Thanks Henry,
just used a calculator and the 8×30 E II would have an apparent field of view 17.1% greater than the proposed 8×40.
However, the 8×40 binocular proposed would have an apparent field of view 14.6% less than the current E II using the figures given.
I will look at the old Nikon E but I don't really know its specifications as regards field of view.
Enjoy your vacation.
just used a calculator and the 8×30 E II would have an apparent field of view 17.1% greater than the proposed 8×40.
However, the 8×40 binocular proposed would have an apparent field of view 14.6% less than the current E II using the figures given.
I will look at the old Nikon E but I don't really know its specifications as regards field of view.
Enjoy your vacation.
Last edited:
brocknroller
porromaniac
Here's an anonymous review of the 8x30 EII on Excelsis. The reviewer tested the optics @ 56x. Now, I wonder who he could possibly be? :h?:
These (8x30 E2 - the upgraded version of the 8x30 E ) are among the few binoculars which show a good diffraction image ! When magnifying the primary image to 56x using an auxiliary telescope, the detail and contrast presented are closer to that shown in a good spotting scope than in a binocular. Overall correction of s.a. is excellent. They arrived in almost perfect alignment and collimation. Eyerelief is comfortable but not sufficient for full field viewing with eyeglasses.
I worried about field correction considering the design has been around for a while. My apprehension soon proved unfounded. The generously wide 70 degree field is significantly better corrected than the so called 'aspheric' designs I have seen. Construction is excellent, focusing smooth and precise. The overall result is a binocular which is extremely sharp and pleasant to look through.
Overall Rating: 10
Optics:10 Value:10
Weight: 1 (Unreliable Vote)
Date: 04/20/2004 02:17:26 pm PDT
8x30 EII reviews
<B>
These (8x30 E2 - the upgraded version of the 8x30 E ) are among the few binoculars which show a good diffraction image ! When magnifying the primary image to 56x using an auxiliary telescope, the detail and contrast presented are closer to that shown in a good spotting scope than in a binocular. Overall correction of s.a. is excellent. They arrived in almost perfect alignment and collimation. Eyerelief is comfortable but not sufficient for full field viewing with eyeglasses.
I worried about field correction considering the design has been around for a while. My apprehension soon proved unfounded. The generously wide 70 degree field is significantly better corrected than the so called 'aspheric' designs I have seen. Construction is excellent, focusing smooth and precise. The overall result is a binocular which is extremely sharp and pleasant to look through.
Overall Rating: 10
Optics:10 Value:10
Weight: 1 (Unreliable Vote)
Date: 04/20/2004 02:17:26 pm PDT
8x30 EII reviews
<B>
Last edited:
brocknroller
porromaniac
