Do you think there will eventually be a trend towards larger than 56mm objectives ?
I know there are a few, very few, out there, but they are exceptional.
I know there are a few, very few, out there, but they are exceptional.
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Getting into spotting scope territory. The fact is, a 56 mm end bell will not faithfully resolve more than 29 x power. So for long range shooting and spotting one needs an ever larger objective to obtain resolution rather than just seeing the object bigger. Obviously, there’s a market for this, but I’m not a fan.
I’m not a mathematician, but there was an article in Guns and Ammo magazine many years ago, about optical resolution. Based on that article I made a chart, which is not at hand right now, that showed the outer limit of resolution based on size of the objective. Above 29x, in the example above, the object will appear larger, but will not be clearer. When I get back to my office I’ll post this.
Hensoldt has the monster 72mm.
I do not know of any currently larger.
www.hensoldt.net OBTW Hensoldt was/is/might be...Zeiss.
AND.....there's a ton of scopes above 29x with a 56mm or LESS objective.
I do not know of any currently larger.
6-24 x 72 - Long range telescopic sight | HENSOLDT
Telescopic sight for extremely precise adjustability and very high magnification
www.hensoldt.net AND.....there's a ton of scopes above 29x with a 56mm or LESS objective.
Only tried the 72mm Hensoldt once. I’m still dreaming about finding one used for a reasonable price.Hensoldt has the monster 72mm.
I do not know of any currently larger.
OBTW Hensoldt was/is/might be...Zeiss.6-24 x 72 - Long range telescopic sight | HENSOLDT
Telescopic sight for extremely precise adjustability and very high magnification
AND.....there's a ton of scopes above 29x with a 56mm or LESS objective.
The optical design is outdated, but it is still the biggest wow factor I’ve ever encountered.
Hensoldt is Zeiss. Zeiss even used to make a scope model called the “Carl Zeiss Hensoldt ZF”. I went googling to find an image.Hensoldt has the monster 72mm.
I do not know of any currently larger.
OBTW Hensoldt was/is/might be...Zeiss.6-24 x 72 - Long range telescopic sight | HENSOLDT
Telescopic sight for extremely precise adjustability and very high magnification
AND.....there's a ton of scopes above 29x with a 56mm or LESS objective.
Are they no longer affiliated? I thought Hensoldt was a sister company of Zeiss, sort of like Swaro & Kahles?
Or, do you mean they don’t make that model anymore? Because I know the model was discontinued a long time ago.
Hensoldt was sold quite a few years ago. It was part of Airbus for a while. Then Airbus spun most of its sensors and optics off as Hensoldt into a standalone company that mostly focused on EO and EM products for aerospace/defense. It is a $2B company. Day optics for Hensoldt has importance approximately equivalent to how much an elephant cares about a dark spot on a left testicle of a mosquito sitting on its ass.
They have a small day optics division that occasionally bids on military tenders. I keep on hearing that they want to re-enter commercial riflescope world, but I have my doubts.
ILya
Just keep making spotter 45s with reticles.
It's the one thing they do right, and do better than anyone else by far.
It's the one thing they do right, and do better than anyone else by far.
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Good info, thanks.
Thereby confirming their unimportance.
ILya
The 6-24x72 is a monster and is a great optic, I regularly shoot 2 of them and love them. Low light image is awesome.
My favorite image quality scope is still an old Hensodlt 3-12x56 SFP. It is honestly difficult to not get a good sight picture - it is that good.
All that said, I hate >20X optics - above 20X, I have never seen a field need for it, and I don't need to see my heartbeat in the reticle. I know they have their place, but I ain't in that place, so carry on.
My favorite image quality scope is still an old Hensodlt 3-12x56 SFP. It is honestly difficult to not get a good sight picture - it is that good.
All that said, I hate >20X optics - above 20X, I have never seen a field need for it, and I don't need to see my heartbeat in the reticle. I know they have their place, but I ain't in that place, so carry on.
I’m sure the devil is in the assumptions.
Some similar math mentioned in this 2005 article
Optical Resolution: How Sharp Is Sharp?
"A slightly different problem exists with variable-power instruments such as spotting scopes and high-powered riflescopes, in which magnification ranges regularly exceed the theoretical-resolution limits of the objectives. The classic example is a 15-60x60 mm spotting scope, where the highest magnification of 60X is roughly twice as high as the 31.6X maximum sharp power the 1.9-second theoretical resolution of a 60 mm objective can produce, i.e., 60÷1.9=31.6. However, most viewers won’t notice a serious loss of sharpness until the power exceeds 45X, which explains why zoom eyepieces for 60 mm spotting scopes usually top out at 45X."
Optical Resolution: How Sharp Is Sharp?
"A slightly different problem exists with variable-power instruments such as spotting scopes and high-powered riflescopes, in which magnification ranges regularly exceed the theoretical-resolution limits of the objectives. The classic example is a 15-60x60 mm spotting scope, where the highest magnification of 60X is roughly twice as high as the 31.6X maximum sharp power the 1.9-second theoretical resolution of a 60 mm objective can produce, i.e., 60÷1.9=31.6. However, most viewers won’t notice a serious loss of sharpness until the power exceeds 45X, which explains why zoom eyepieces for 60 mm spotting scopes usually top out at 45X."
That's for point sources. It is reasonably applicable when you are looking at stars. For objects of complex shapes, it is not quite that simple because of how a human brain processes images.
The eye/brain combination does a funky super resolution equivalent of a multi-frame capture and layers object recognition on top of it.
We use somewhat similar approach to be able to push past the Nyquist limit of image sensors.
Also, this assumes that all eyes are capable of the same ~1MOA native resolution which is patently incorrect, especially as you get older.
I have been doing resolution measurement for nearly 30 years and I can tell you with a great deal of certainty that I need more magnification now to see the same level of detail that I could resolve with lower magnification 20 years ago. On the other hand, I can pick out an elk at distance better now than I could 10 years ago. That's the pattern recognition part.
Human vision is not quite that simple.
ILya
Maybe it's my OCD kicking up some dust, but I read the article, so even though I agree w/some of what it tries to say about resolution, I don't go along w/how he says it, so I'll say this....
Resolution is the ability to see 2 objects that are very close together and still being able to see that they are 2 distinct objects via the kind of similar discussions/considerations but different by degree of the Dawes vs Rayleigh limits (and the issue of being able to see a distinct slit bet. the 2 objects).
Also this discussion when talking about "airy disks" and the trail off around their edges caused by wave interference.
Resolution is also a discussion of the ability of an optic to transfer contrast/resolution from the object/object plane to the image plane usually described in graphs as a percentage of contrast via the Modulation Transfer Function.
An optic is pointed @ the 1951 USAF resolution target and it's vision checked kind of like how humans go to the docter's office to get their eyes checked where this target has either black or white on it and the abrupt transitions between the two (the issue of resolution/contrast would also be about defining edges).
The optic being tested tries to reproduce that black and white and the abrupt transitions between the two, but if it can't do it 100% (actually no optic can), it will end up rendering less distinct areas than the test target producing a grey scale, or said another way, it produces an image of the object w/grey areas which are a kind of a blurred/merging together of the original black and white values and this grey/greyscale doesn't exist in the original test target @ the object plane.
This is expressed as a percentage loss in contrast via the MTF.
There's no grey areas/and degree of grey scale in the test target, only black and white, so when the optic can't reproduce that 100%, the optic will then produce areas that change that black and white from the object/object plane to a "muddled grey" and as it gets worse the percentage will keep going down from 100%.
One issue about the way the article discusses all this.....
There's coma-flare-astigmatism-distortion (barrel/pincushion)--------aberration(chromatic[longitudinal-axial]/spherical[positive-negative])-------diffraction limiting-----------------curvature of field, which all to a major or to a limited extent affect resolution regardless of the size of an optics front objective.
Optics/the front objective project images as a "field", which isn't flat, so there's curvature of field, and because of that curvature, and as the central portion registers on the film plane/ chip or whatever, then resolution (and illumination) will drop off to the edges.
So the above is also a consideration of the "drop off" of resolution/illumination from the center to the edges, apart from and in addition to the idea of an airy disk which "trails off" to the edges because of "wave" interference.
YES, taking an image of a point light source like a distant star is going to produce an "airy disk" because of the trail off due to the wave interference caused in the optical system taking the image.
It's all of the problems in a system that limit the resolution of a system, not just the math indicating what the front objective is doing.
So while the article does in fact touch on all of this the way it does, I don't believe that you can turn around and suggest that a 56mm objective is some kind of brick wall.
BOTTOM LINE; any claim of an optic reaching any kind of theoretical limit or how it should perform, should be backed up by lab testing by professionals documenting how the optic actually performs.
I have a Mamiya 100-200 MF Zoom, which looked very sharp when I looked through it. Despite that, years ago, I had a spirited debate w/a guy who suggested that this optic could not be very sharp and presented some very involved math to back that up.
It was a waste of time to keep arguing about it, so I took the lens to a friend of mine who's also a Rollei repair tech and he slapped the lens on his collimator and announced to me that it was one of the sharpest lenses he's ever tested, and he's tested Rollei and Carl Zeiss.
Your math can be correct, you can still be wrong via leaving out something/some aspect you should've included in your calculations, or the reverse, by extending your calculations beyond a specific point to include something where the math really doesn't apply.
I don't agree at all w/his suggestion about testing optics which should be done by the best professionals who've spent a career in testing optics; ditto getting a comprehensive examination of your eyesight at somewhere like the Stein inst. re whether any particular problem is on UR end.
Somebody like Koshkin who tests resolution every day would probably have the most detailed nuance about this, but what struck me about what he said touched on my belief that God is obviously the greatest lens designer in the universe. He took his sweet time and millions of years to get it right and the rest of us are playing "catch-up".
Resolution is the ability to see 2 objects that are very close together and still being able to see that they are 2 distinct objects via the kind of similar discussions/considerations but different by degree of the Dawes vs Rayleigh limits (and the issue of being able to see a distinct slit bet. the 2 objects).
Also this discussion when talking about "airy disks" and the trail off around their edges caused by wave interference.
Resolution is also a discussion of the ability of an optic to transfer contrast/resolution from the object/object plane to the image plane usually described in graphs as a percentage of contrast via the Modulation Transfer Function.
An optic is pointed @ the 1951 USAF resolution target and it's vision checked kind of like how humans go to the docter's office to get their eyes checked where this target has either black or white on it and the abrupt transitions between the two (the issue of resolution/contrast would also be about defining edges).
The optic being tested tries to reproduce that black and white and the abrupt transitions between the two, but if it can't do it 100% (actually no optic can), it will end up rendering less distinct areas than the test target producing a grey scale, or said another way, it produces an image of the object w/grey areas which are a kind of a blurred/merging together of the original black and white values and this grey/greyscale doesn't exist in the original test target @ the object plane.
This is expressed as a percentage loss in contrast via the MTF.
There's no grey areas/and degree of grey scale in the test target, only black and white, so when the optic can't reproduce that 100%, the optic will then produce areas that change that black and white from the object/object plane to a "muddled grey" and as it gets worse the percentage will keep going down from 100%.
One issue about the way the article discusses all this.....
There's coma-flare-astigmatism-distortion (barrel/pincushion)--------aberration(chromatic[longitudinal-axial]/spherical[positive-negative])-------diffraction limiting-----------------curvature of field, which all to a major or to a limited extent affect resolution regardless of the size of an optics front objective.
Optics/the front objective project images as a "field", which isn't flat, so there's curvature of field, and because of that curvature, and as the central portion registers on the film plane/ chip or whatever, then resolution (and illumination) will drop off to the edges.
So the above is also a consideration of the "drop off" of resolution/illumination from the center to the edges, apart from and in addition to the idea of an airy disk which "trails off" to the edges because of "wave" interference.
YES, taking an image of a point light source like a distant star is going to produce an "airy disk" because of the trail off due to the wave interference caused in the optical system taking the image.
It's all of the problems in a system that limit the resolution of a system, not just the math indicating what the front objective is doing.
So while the article does in fact touch on all of this the way it does, I don't believe that you can turn around and suggest that a 56mm objective is some kind of brick wall.
BOTTOM LINE; any claim of an optic reaching any kind of theoretical limit or how it should perform, should be backed up by lab testing by professionals documenting how the optic actually performs.
I have a Mamiya 100-200 MF Zoom, which looked very sharp when I looked through it. Despite that, years ago, I had a spirited debate w/a guy who suggested that this optic could not be very sharp and presented some very involved math to back that up.
It was a waste of time to keep arguing about it, so I took the lens to a friend of mine who's also a Rollei repair tech and he slapped the lens on his collimator and announced to me that it was one of the sharpest lenses he's ever tested, and he's tested Rollei and Carl Zeiss.
Your math can be correct, you can still be wrong via leaving out something/some aspect you should've included in your calculations, or the reverse, by extending your calculations beyond a specific point to include something where the math really doesn't apply.
I don't agree at all w/his suggestion about testing optics which should be done by the best professionals who've spent a career in testing optics; ditto getting a comprehensive examination of your eyesight at somewhere like the Stein inst. re whether any particular problem is on UR end.
Somebody like Koshkin who tests resolution every day would probably have the most detailed nuance about this, but what struck me about what he said touched on my belief that God is obviously the greatest lens designer in the universe. He took his sweet time and millions of years to get it right and the rest of us are playing "catch-up".
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For my dayjob, I run this company's US office: www.ci-systems.com
We build test systems for this kind of stuff for everything from riflescopes to satellite imagers and a bunch of other stuff along the way.
ILya
Didn't USO like a really really long time ago have some crazy scope with like 100m objective or something insane like that?
Based on an article in Guns and Ammo Magazine many years ago, I made a chart of the max resolution according to objective size.
Objective size: Max Resolution Power
20 - 10
36 - 18
40 - 21
44 - 23
50 - 26
56 - 29
62 - 32
85 - 45
S&B just came out with a 6-36 power on a 56 end bell scope. The image at 36x is bigger, but does not have more resolution than a 25x or 27x scope in the same PMII line.
Objective size: Max Resolution Power
20 - 10
36 - 18
40 - 21
44 - 23
50 - 26
56 - 29
62 - 32
85 - 45
S&B just came out with a 6-36 power on a 56 end bell scope. The image at 36x is bigger, but does not have more resolution than a 25x or 27x scope in the same PMII line.
This really stinks
I definitely noticed this as well. I call it a falloff of visual acuity and why I now mention in my reviews that my resolution tests are based on my eyes, in my test environment, with current atmospherics at that particular time - I don't trust my eyes enough to test a scope and then test another scope a year (or so) later and think that I can make an accurate comparison, so I try to test all the scopes together to rule out external variables (as best I can).
So would pattern recognition be something that can be "trained"?
Agreed, I think our brains ability to interpret what our eyes see has an effect on our perception of how good or how bad an optical system may be. CA is a good example of this (I think) because some are bothered by it, and some never seem to notice it but it is something that affects every optical system regardless of how our brain interprets it (or how we convince ourselves to ignore it).
Back to the original post about objective size - there is no rule that says a manufacturer cannot make a larger objective scope (the Henny 6-24x72 being a good example of this) but there is also the issue of clearance of the objective bell above the barrel, but with the increase of adjustable cheek (riser) stocks this may not be as big of an issue as it once was. Why 56mm was determined as the de facto standard among the sport optics industry would be an interesting investigation - why not 55mm, why not 60mm? Will there be future scope designs that capitalize on this? Blaser has their 4-20x58 which is the most recent design I am aware of with >56mm, did they pick 58mm just to differentiate themselves (probably)? I also think cost weighs into the equation, maybe most of the sport optics glass suppliers already have everything setup for the typical glass elements within the scope and spec'ing an objective larger than 56mm means wherever you are sourcing your glass from has to have the equipment to do this, but maybe I'm wrong and 60mm is just as easy to manufacture as 56mm? And then there is the law of diminishing returns, will a 5-25x60 get you anything more (usable) than a 5-25x56? Will eyebox be more forgiving? Will the image be brighter at higher magnifications? Is it worth paying $500 more for the scope or however much more the larger objective lens is vs. the standard?
Let me put this another way, if ZCO came out with an 8-40x72 that offered better eyebox and better low light performance (at higher mags) but cost $1000 more than the 8-40x56, how many people would choose the 72mm scope over the 56?
I can say this, I would pay extra money for a 56mm midrange scope over a 50mm counterpart to get the extra low light brightness. In fact, I did just that, as much as I like the Burris 3.3-18x50 I much prefer the benefits of the Steiner T6Xi 3-18x56 - bigger, brighter, better IMO
Hensoldt had their big 56's in the 3-12 and 4-16, Schmidt has its Ultra Bright series and now Steiner. But not everyone cares about low light performance... and since most hunters seem to only care about SFP (uneducated ones) there likely has not been a big enough market for large objective FFP midrange scopes, but hopefully that is changing.
Great questions and analysis Glassaholic.
To your questions 8-40x56 vs 8-40x72mm+$1000: I would probably go w/ the 72mm, pay the extra dough and carry the extra weight/profile. Like you, I pay extra for a 56mm over a 50mm. I have seen the difference in field performance of those two objective lens and 56mm outperforms by a wide margin TO ME. I do a good bit of blasting at the low light hours, especially the PM hours and that bit of extra performance = worth it to me.
I've seen in camera lens reviews the last 3-5 years a substantial increase in MTF for center and edge of the common focal length lenses and better performance with aberrations. Not sure how much of the increased performance is due to better glass and coatings vs optical design.
Have any of these improvements carried over to riflescopes?
( I suspect so with everyone advertising HD glass but have not followed the scope market that closely)
I do not know if it was anything carried over, but there has definitely been a significant image quality improvement in riflescopes in the last 15 years or so.
ILya
I found this quite interesting
How One Mathematician Solved a 2,000-Year-Old Camera Lens Problem
How One Mathematician Solved a 2,000-Year-Old Camera Lens Problem
56mm end bell was likely a deliberate choice. In Germany, night hunting is allowed and the quintessential binocular is 8x56 with a 7mm circle on the rear objective for this type of hunting. Popular riflescope is the same, which is a very consistent sight picture.
From my photo experiences I can definitely say that larger lenses are harder to make and expensive. All sharpness in photography is controlled by the aperture setting, and focus of course, which is geared to using the center sweet spot of the lens. In sport optics we can’t control aperture except in a very general sense of controlling the power on a variable scope. We pretty much only control focus to recognize sharpness. One of the hardest things to achieve is edge to edge sharpness, which is paramount for hunters. All good bins and scopes are judged by this and it usually separates the Alpha optics from the rest.
From my photo experiences I can definitely say that larger lenses are harder to make and expensive. All sharpness in photography is controlled by the aperture setting, and focus of course, which is geared to using the center sweet spot of the lens. In sport optics we can’t control aperture except in a very general sense of controlling the power on a variable scope. We pretty much only control focus to recognize sharpness. One of the hardest things to achieve is edge to edge sharpness, which is paramount for hunters. All good bins and scopes are judged by this and it usually separates the Alpha optics from the rest.
Yes. It is the basis of learning.
I'll be doing a livestream on this subject in a couple of hours.This really stinks
I definitely noticed this as well. I call it a falloff of visual acuity and why I now mention in my reviews that my resolution tests are based on my eyes, in my test environment, with current atmospherics at that particular time - I don't trust my eyes enough to test a scope and then test another scope a year (or so) later and think that I can make an accurate comparison, so I try to test all the scopes together to rule out external variables (as best I can).
So would pattern recognition be something that can be "trained"?
Agreed, I think our brains ability to interpret what our eyes see has an effect on our perception of how good or how bad an optical system may be. CA is a good example of this (I think) because some are bothered by it, and some never seem to notice it but it is something that affects every optical system regardless of how our brain interprets it (or how we convince ourselves to ignore it).
ILya
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