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ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia

Where are the aspherics? (1 Viewer)

Binastro

Well-known member
The pupil of the eye is not comparable to a camera sensor.

If comparing, then the retina, which is curved is more comparable to a camera sensor.

The retina has varying resolution. Only the centre is fine resolution.

The pupil of the eye determines the speed of the eye's lens.
Best performance is with about 2.5mm pupil.

B.
 

moyang_mm

Member
The pupil of the eye is not comparable to a camera sensor.

If comparing, then the retina, which is curved is more comparable to a camera sensor.

The retina has varying resolution. Only the centre is fine resolution.

The pupil of the eye determines the speed of the eye's lens.
Best performance is with about 2.5mm pupil.

B.

Yes, you are right. My point is that we only pay attention to the very center of the retina, whereas in cameras the entire image circle needs to be corrected.

The lenses on smartphones are much simpler (usually only 6 or so elements without ED or ASPH) because the sensor is so small.
 

tenex

reality-based
Also our eyes are pretty lousy optically. It is just a single-element lens. But we have the most advanced image processing system, the brain, that magically mitigates all the optical issues of the eyes. This could also explain why binoculars use less sophisticated optical formulas, because the brains have already addressed some of the aberrations.
Hmm, regular complaints on this forum about CA, astigmatism, coma etc don't suggest that the brain can correct optical aberrations. But the point is well taken that binoculars are built to a lower optical standard than camera lenses because users aren't recording, enlarging, and scrutinizing their output. On the other hand, the alphas at least seem expensive enough that one could expect better...
 

moyang_mm

Member
On the other hand, the alphas at least seem expensive enough that one could expect better...

I think the "alpha" binoculars are very much overpriced due to the lack of economy of scale and the lack of competition.

Look at the internals of a Canon EF 70-200mm f/2.8L IS II, which features five ED glass and one fluorite crystal, and 23 elements in 19 groups in total. It is also made in Japan. Not to mention it also has auto focus and image stabilization. Yet it only sells for about the same price as a pair of "alpha" binoculars.
 

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PYRTLE

Old Berkshire Boy
I think the "alpha" binoculars are very much overpriced due to the lack of economy of scale and the lack of competition.

Look at the internals of a Canon EF 70-200mm f/2.8L IS II, which features five ED glass and one fluorite crystal, and 23 elements in 19 groups in total. It is also made in Japan. Not to mention it also has auto focus and image stabilization. Yet it only sells for about the same price as a pair of "alpha" binoculars.


Yep, then multiply that by 2!

Not the same price now is it. But I see where you guys are coming from. An alpha porro prism is always going to be noticably heavier and physically larger than a roof which is not within the demographics of what the end user is after these days.
 

Binastro

Well-known member
My 1950s Kodak Brownie 127, of which millions were made in Britain, had a curved film plane but only had a meniscus lens.

It produced good 4cm x 6cm negatives.

The British Purma Plus with gravity shutter also had a curved film plane.

The eye's lens does not have to cover a flat sensor.

There are curved digital sensors but they are expensive.

B.
 

PYRTLE

Old Berkshire Boy
A fairer comparison should be between telephoto lenses and alpha spotting scopes?

Yep, that would be a similar comparison in many ways, but the thread is about binoculars. CJ has answered and mirrored some of my thoughts in a previous post.

Too large, heavy and cumbersome for the modern user. No mass market or interest for any of the European alpha brands to engineer, model or produce such units. Technology moves on in a different direction.

How many Questars do you see in use for birding these days, yet in the 80s and 90s we queued up to look through one at a distant wader or whatever. A brilliant optic at that time but difficult to get used to.
 
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Binastro

Well-known member
A spotting scope of high quality is made to higher optical standards than even the best camera lenses.

I have tested very large numbers of photo lenses visually and only a handful can be used at even 100x, where the Swarovski 65mm should be fine at 100x.

The only ones approaching telescope standard were a Tewe 600mm f/5 Petzval design, a Vivitar 600mm f/8 solid cat and a Soviet Maksutov lens. The Ross 50 inch f/8 was pretty good.

Many camera lenses are terrible when used visually.

a camera lens and eyepiece is a poor substitute for a good telescope.
Even a low priced long focus astro scope will completely outclass a camera lens and eyepiece.

Yes, top spotting scopes are expensive. Probably low volume items.
Some broadcast quality lenses are close to astro standard, but can cost $200,000.

B.
 

moyang_mm

Member
Many camera lenses are terrible when used visually.

a camera lens and eyepiece is a poor substitute for a good telescope.
Even a low priced long focus astro scope will completely outclass a camera lens and eyepiece.

Yes, top spotting scopes are expensive. Probably low volume items.
Some broadcast quality lenses are close to astro standard, but can cost $200,000.

B.

Top spotting scope with DSLR digiscoping adapters is no substitute for good telephoto lens either. They are optimized differently.

The point is optically telescope is simpler than telephoto lenses. Were the market for scopes as competitive as the market for camera lenses, telescope should be cheaper than camera lenses.
 

Patudo

Well-known member
I think the "alpha" binoculars are very much overpriced due to the lack of economy of scale and the lack of competition.

I agree there is probably not a great deal of demand for "alpha" binoculars, but there seems to me that between the big three European manufacturers, Nikon, and a couple of other manufacturers (Kowa, Meopta, Canon) whose products could conceivably appear in the short list of individuals seeking a first class binocular, there seems to be pretty stiff competition for what demand there is.

I would also disagree that "alpha" binoculars are very much overpriced - it is beyond my budget to buy alpha binoculars new, but I would say the prices reflect what is needed for the design and manufacturing of top tier binoculars to be done in Europe and Japan. Their success in doing so can be seen by the fact that your earlier posts asked about Swarovski products rather than eg. Vortex.
 
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Colombia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Colombia
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