"David Bowie" special eye lenses (will your eyes tell the difference?) (1 Viewer)

[yarrellii]

Today, while on the field, I noticed something I hadn't realised about my recently repaired Canon IS III 12x36 eyelenses... I have a "David Bowie" special edition...



... each eye piece displays a different colour!!!

Joking aside, I guess this is due to different coatings, because each eyepiece actually belongs to a different Canon device. I recently dropped the binoculars while on holiday, but I was lucky to be traveling towards The Netherlands. There I was again lucky to have the Canon serviced by De Kijkerspecialist, who discovered that the binoculars have landed on one of the eyepieces and it was subsequently broken. But he happened to have an old Canon 12x36 for spare parts. So I got an old eyepiece installed and now I'm more than happy to be able to use the Canon again. But alas, I just discovered the difference in colour/coatings.

So far I haven't noticed anything wrong. Probably there's more difference between my own eyes than there is between the performance of the eyepieces. But just out of curiosity, I wonder how much of a difference can your brain "match"/manage. You know, the same way when you have your binoculars slightly out of alignment but your brain still presents a perfectly nice image (only to give you a terrible headache the moment you put your binoculars down).

How much of a colour/performance/contrast difference can our brain manage before you notice something?

 

[[email protected]]

I think most people would notice a difference in coatings between two oculars right away. Because the coatings are different and are performing differently, it would be almost like having a binocular that was out of alignment. I am sure if you used them for a long time, yours eyes would feel fatigued. The transmission is probably even different with older and newer coatings.

 

[Binastro]

Turn it upside down.

You probably won't notice the difference.

Soviet binoculars typically have different coating colours.
The images seem fine.

Green grass with my unaided eyes is a different colour in each eye.

In addition, one of my eyes sees stars 60% fainter than the other.

Regards,
B.

 

[dorubird]

How much of a colour/performance/contrast difference can our brain manage before you notice something?

I bet you won't see any difference! Our brain anyway sums up both images into one! Keep enjoying your Canon!

 

[Maljunulo]

Turn it upside down.

You probably won't notice the difference.

You beat me to it.

 

[Patudo]

As best as I can gather, the colour of the reflections from modern multi-coatings doesn't have a relationship with the area of the colour spectrum (if any) favoured. With the old single coatings the colour of the reflections did indicate that more of that wavelength was reflected away - so a blue/purple look to the reflections likely indicated a warmer colour cast. That's not the case now - I think either here or CN there have been photos of Leicas (I think?) where the objectives had different colour reflections with no discernible difference in terms of colour rendition etc.

It would certainly be interesting, though, to look through your 12x36 one barrel at a time and see what differences you might (or might not) perceive. With the same eye obviously - one of my eyes sees things a little more green and the other slightly more red! My right eye is also sharper than my left, I'm pretty sure, but has less accommodation.

 

[yarrellii]

@[email protected] @Binastro @Patudo @dorubird @Maljunulo
Thanks all for the ideas an input. Maybe I should have made clear that "the test of time" was already done, and that since they were repaired back in August, I've been birding for a month now (not the busiest birding month actually) and haven't noticed anything at all. It was only yesterday that, while packing back the Canon the light must have come at a special angle to make the coatings show their distinctive hue. In fact, not even when I pick them up after repair (when you obviously examine their performance as if they were new) did I notice. So that goes to show... In fact, my question was about the limit that a brain could stand before saying "Hey, there's something funny going on here".

Today, I've put the Canon on a tripod and spend quite a while carefully comparing the view through each eyepieces (with the same eye!). And it's really hard to tell. In fact, I think it's one of those times where your brain starts playing tricks with your perception and at the end you just don't know if you are seeing what you want to see or what you've been told.

In the end I think there might be a very (very) subtle difference, so subtle that I might even be making this up, who knows. I think the old eyepiece (new for my Canon) has an slightly (but very slightly) less bright view with a very (but very) slight warmer hue. But then, it can be just my tiring eye after looking back and forth through each eyepiece. Sharpness, contrast and CA seem just the same. If I look for it, I can perceive a subtle warmer hue or, to put it in other words, the original eyepiece from my IS III displays a slightly cooler/true to life colour. But I'm splitting hairs here. I think if you look long enough, you can find subtle differences between both tubes from the same binocular!!!

I took the idea from Dennis to take a picture through each one of the eyepieces. I locked speed, aperture and ISO, but I forgot to lock WB. To make things worse, due to the long eyecups or the Canon, it was really difficult to take a picture with a "homogeneous" light, say, a constant amount of light throughout the entire field. I can do it with other binos, but not with the Canon easily without getting kidney-beaning. In short: take the following pictures with a HUGE grain of salt.

Above, the left eyepiece (original IS III). Below, the right (replaced, presumably from a IS II, with the purple hue).



Forget about the darkening on the left edge, it's due to the position of the camera. Anyway, I chose that wall because it gave me nice subjects to judge CA, brightness and colour rendition. If you watch the bottom image and pay close attention to the brighter wall (on the left) you can see it's slightly less bright, or warmer if you like. After going back and fort 1000 times, I think the sign saying Campillo appeared (to my eyes) of "bluer shade of blue" on the left-original (top image) than on the right-replaced (bottom image), which had an ever (ever) so slightly tendency towards green.

It's been an entertaining test, but it hasn't added a lot to my perception that on the field is hard to notice anything.

 

[dorubird]

For example, in astronomical and microscopic binoviewers you have a slightly darker path. And yet our brain combines the images into one without noticing the difference. We can make a exaggerate experience and put an astronomical yellow filter over one of the eyepieces, so that when you look at the exit pupils from a distance there is an obvious difference in color and transmission. But what happens when you look through these binoculars? Then our brain will combine the two images and the result will be a slightly darker image than without the filter. If you did not know about the filter, you would not realize that it is on the eyepieces. The compensation at the brain level is amazing.

 

[dorubird]

If we put a UHC filter, which will cut a lot of the visible spectrum, then we will notice a visual discomfort as if we had something on our eyes. This is somehow the limit you were talking about "Hey, there's something funny going on here".
I just did these tests right now

 

[yarrellii]

@dorubird Very interesting. Reading what you wrote, I remember I once had a military 7x40 IOR with a reticle (that was quite a beast in terms of sharpness and contrast, such a pleasant, albeit yellow, view). Obviously the reticle was just on one of the eyepieces, but if I remember correctly, you saw it as if it was on both, isn't it?

 

[yarrellii]

One thing I forgot to mention about the replacement of the right eyepiece is that there is one are where there has been a noticeable improvement, drift of the dioptre correction ring. As I've wrote in the thread were I review the 12x36 IS III this has always been extremely annoying. The slightest movement moved the diotre correction, so I had to readjust it several times during a single birding session. Not only taking the binoculars out of the case caused this, but also the mere rub against your chest. When I bought a 10x30 IS II, I could see that, despite being basically the same pieces, in my 10x30 the dioptre correction ring had a reasonable resistance. Well, I'm happy to report that the eyepiece I have now has nearly the same resistance as my 10x30, which means I don't have to adjust it every time I use the binoculars. This was something I've never suffered in the past with any of the binoculars I've had, but I can now see how it can be quite a hassle.

 

[dorubird]

@dorubird Very interesting. Reading what you wrote, I remember I once had a military 7x40 IOR with a reticle (that was quite a beast in terms of sharpness and contrast, such a pleasant, albeit yellow, view). Obviously the reticle was just on one of the eyepieces, but if I remember correctly, you saw it as if it was on both, isn't it?

Yes! IOR is a binocular made in Romania and it really has a very good contrast. The IR filter version was only on one of the tubes and was used to observe IR military signaling at a distance. There are also versions with a reticle with a measuring scale. But all the binoculars also came with two yellow fog filters that could be put on the eyepieces!

 

[Maljunulo]

I am not convinced that anti-reflection coatings have any significant effect on the "color balance" (or whatever you want to call it) of the instrument.

Anyone have any numbers or curves?

 

[yarrellii]

@Maljunulo Yes, I remember reading something in the line of what you are saying here in BF: that simply because a multicoated lens reflects a particular vcolour (say blue or brown or green) that doesn't necessarily mean that the image through the binoculars will have a colour bias or hue that you can guess by the coating colours.

 

[MiddleRiver]

This would drive me CRAZY. Non-starter for me! Sorry...

 

[Ted Y.]

Yes! IOR is a binocular made in Romania and it really has a very good contrast. The IR filter version was only on one of the tubes and was used to observe IR military signaling at a distance. There are also versions with a reticle with a measuring scale. But all the binoculars also came with two yellow fog filters that could be put on the eyepieces!

I read it have a yellow view. Why?

 

[Maljunulo]

This would drive me CRAZY. Non-starter for me! Sorry...

If it’s of no significance, or any effect is undetectable, why does it matter?

 

[Binastro]

Yellow view either deliberate choice of glass type or impurities.

Many of my Soviet binoculars have a yellow cast, but I never noticed until birdforum minutely discusses hues.

Barr and Stroud binoculars have grey glass from best Scottish sand, as do my Bresser 15x60s probably Chinese grey glass.

Why does the Barr and Stroud 7x50 have a filter wheel?

Why do mirror lenses have various rear filters?

Why did French cars have yellow headlamps?
It probably seemed like a good idea at the time.

Why does LED lighting have peculiar spectrums.

Why does Neptune have a peculiar spectrum?

Why are screens blue?

Questions, questions.

Probably take a pick of answers.

Regards,
B.

 

[MiddleRiver]

If it’s of no significance, or any effect is undetectable, why does it matter?

For the same reason we split hairs over IQ on this forum... because it disturbs my OCD desire for perfection.

 

[Maljunulo]

Good enough, as long as you have acknowledged where the problem lies.