Leica and chromatic aberration (2 Viewers)

Thinking back, I remember finding CA without looking for it as well.
When I first started birding I bought an inexpensive (maybe 40 bucks)
compact Bushnell roof. It had horrific CA and I didn't keep it. It was by far
the worst I ever saw. I owned the FL 8x32 for a short while and it is the best
I've ever seen in regards to CA control and overall still a top tier bino IMO.
Being that I prefer Leica over those other top brands it's safe to say that CA control
is not at the very top of my list of needs. With that said, I still need and desire CA to be controlled
reasonably well and I think it is in the 7x42 plus model.

I just tried the Canon 10x42 L in bright sunshine on white pillars, but not lit directly.
It was difficult to see CA dead centre, but easy towards the edge, but even here it is low compared to many binoculars.
If I got it set up as perfectly as possible with regard to eye position, it was indeed difficult to see CA dead centre, but I could detect it.
Most of this is learned vision. In normal use it would be overlooked.

With plain shades of Wilton carpet, each batch was slightly different, and it takes a long time to recognise very subtle changes in shade, which most people just cannot see. This skill just has to be learned.
The carpet was only made in 27 inch wide rolls, and women used to stitch the widths together to make a room sized carpet with a minimum extra 3 inches per length for turning at the edge when laying the carpet.
It is essential to use carpet from one batch only.
5 colours were possible in patterned Wilton, but many more in Axminster which has a double weft compared to the single weft in Wilton. The looms making them are different.
With single shade Wilton, but also with patterned carpet the carpet must be layed with the pile facing one way from the main window, as the colour is different if layed the wrong way.

If the carpet has a fault or damage, the whole room carpet needs changing unless one has some of the original batch available, as it is usually impossible to get a direct shade match.
Of course, if insured for damage or fault, the insurer will try to replace just the damaged part, but one is completely within ones rights to demand the whole room carpet is changed.

I suppose birds feathers also are subject to colour change depending on lighting direction.

The eye can learn a lot.
It is likely some women see subtle colours better, but men can become very skilled also.

I do not think superior acuity is a factor, and I will not change my mind. And David, I will never step back a bit, I will not be spoken to in a condescending way.

Andy W.

a·cu·i·ty (Definition)
əˈkyo͞oədē/
noun
noun: acuity

sharpness or keenness of thought, vision, or hearing.
"intellectual acuity"


I received superior "sharpness or keeness of vision" after I had Cataract Surgery and received lens implants in both eyes back in the 1990s. I regard this medical procedure as one of the great modern day miracles of medicine.

Bob

dries1 said:

I do not think superior acuity is a factor, and I will not change my mind. And David, I will never step back a bit, I will not be spoken to in a condescending way.

Andy W.

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Andy,

I rather think you might have misunderstood what I wrote, but apologies if it has caused offense.

David

Bob,

Great that you had successful and beneficial eye surgery in the 90's - that must have been some experience! I don't suppose you can remember if that in any way affected your ability to detect CA?

Mike.

I’ve owned and used a very nice 8x42 Ultravid BR since about 2009. My vision is very good, correctable to almost 20:10, my eye doctor calls it 20:12.5. At the time I compared the Ultravid to a 8.5x42 EL extensively. It was winter with lots of snow, so I had many opportunities to view high contrast objects, black raven against the white snow for instance.

Both binocs displayed noticeable CA, but it was worse in the Leicas. That said, I was able to pretty much null it out in both Bono’s by centering the image. I ultimately chose the Leicas due to a totality of factors, color saturation, sharp image, handling, big picture window ease of view, strap and case were all better for me than the Swaros.

I can definitely see CA, but it’s not a deal breaker for me. 90% of the time it’s a non factor, and in those rare cases I see it, I can null it out. If you’re particularly sensitive to CA I would probably not choose Leica’s as it seems to be the one weakness they possess.

Mike F said:

Bob,

Great that you had successful and beneficial eye surgery in the 90's - that must have been some experience! I don't suppose you can remember if that in any way affected your ability to detect CA?

Mike.

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It didn't make any difference in the long run even though, for a short period of time, it seemed that I was seeing some with one of my new lens implants without using glasses or binoculars.

This was shortly after the surgery on one eye which took place around 20 years ago. I have forgotten much about it but to the best of my recollection I intermittently saw a thin reddish ring around the view through that eye. I called my opthamologist about it and went in for an examination the next day. By then it was gone. I asked my doctor if I might have been seeing CA. He said it was possible but since it was gone he did not expect it to return and it did not.

I wasn't susceptible to it before the surgery and have not seen it in normal use since then.

If I look for it along the tops of distant mountain ridges I see a fine line of it; red above and green on the bottom and also if I look for it on the sunlit white vertical edges on the corners of my neighbors homes but I do not see it anywhere else. I'm usually looking for pincushion distortion when I am looking at these vertical edges and I will often see CA when doing this.

Other than that it never intrudes in my view during normal use while birding.

Bob

This thread is a perfect spot for Henry Link's standardized CA test - we could go back and forth on any bin and [Henry's] test would stop the speculation / subjective observations cold.

james holdsworth said:

This thread is a perfect spot for Henry Link's standardized CA test - we could go back and forth on any bin and [Henry's] test would stop the speculation / subjective observations cold.

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This would answer the question of whether a particular bino has CA or not, which would be good to know, but it wouldn't answer the questions: how much CA in the fov centre is necessary to make a significant impact on identifying birds and at what distances, nor would it answer why so many people can tune out a certain (undefined) level of CA and still identify the birds they want to without impairing their enjoyment.

For example, Conquest HD 8x32 has a certain amount of CA but that hasn't stopped it becoming a firm favourite of yours, mine and Chuck's.

Clearly CA isn't to be welcomed in any bino, and clearly many of us see a certain level of it in Leicas, but equally clearly many also enjoy their Leicas and don't find the CA a problem in their bird identification or general nature observation.

Lee

Perhaps there could be a sub-forum where some folks could discuss the rings in the tree (the specifics about the characteristics a glass in micro detail), or their bionic eyes. I for one enjoy nature observation with my glass, and enjoy that part of the forum with general observations/discussions about glass.
Everyone has their own likes and dislikes even with glass, like their food or cars for example, but that does not mean that some have to invoke their knowledge and opinion to others as a lecture.

I know there is an ignore button, and I am going to use it, I did not want to, but now understand why it was invented.


Andy W.

Troubador said:

This would answer the question of whether a particular bino has CA or not, which would be good to know, but it wouldn't answer the questions: how much CA in the fov centre is necessary to make a significant impact on identifying birds and at what distances, nor would it answer why so many people can tune out a certain (undefined) level of CA and still identify the birds they want to without impairing their enjoyment.

For example, Conquest HD 8x32 has a certain amount of CA but that hasn't stopped it becoming a firm favourite of yours, mine and Chuck's.

Clearly CA isn't to be welcomed in any bino, and clearly many of us see a certain level of it in Leicas, but equally clearly many also enjoy their Leicas and don't find the CA a problem in their bird identification or general nature observation.

Lee

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All subjective stuff with no real answers. All we can do is ascertain which bins have it, to what extent, and then the rest will always be subjective impressions.

james holdsworth said:

All subjective stuff with no real answers. All we can do is ascertain which bins have it, to what extent, and then the rest will always be subjective impressions.

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That's exactly the point, isn't it? We know that all binos have CA to a greater or lesser extent and that can be measured objectively, but the only thing that matters in reality is how much CA people see subjectively and how it affects their intended use. That they will only know by using a particular bino.

It would be interesting to have CA measurements for all binos but that wouldn't, I suspect, help people to choose which bino they might like overall, or would suit them in the field in practice.

Mike F said:

adhoc, is it possible that seeing CA is made more likely by some forms of loss of acuity? I don't know - it's just a thought.....

I'm 55 and have very good acuity AFAIK. At least opticians always talk about the fact that I have very good 'correctability' by which they mean that I have almost 20/20 vision which the right prescription. I'm am very slightly short sighted (-1.00) and have a slight astigmatism in both eyes, but otherwise no problems. I have my eyes checked regularly because there is a history of glaucoma in my family.

I can certainly induce CA in my 7x42 UVHD+ but I never see it in normal use. I've always thought that CA was largely a function of poor IPD and focus, but I'm no expert and defer to those who are. However, my only bin for years and years was a 10x25 BCA and I think that because of my experience of using that bin I am good at setting the IPD correctly. After all, if you don't set it right with a bin with an exit pupil of 2.5, you know about it pretty soon!

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Mike, Sorry about the very long delay in responding! I was away much that weekend and a few days after. Then there were various involvements (BTW including birds and conservation). Also I needed to read/re-read up some optics material before answering. I thought a couple times before to write and send this but could (did!) not get down to it.

CA due to loss of acuity in the user of a binocular. I am not aware if that is known. I am afraid I am not able to figure that out. May be it is possible due to some change in the shape or the material of the lens of the eye.

20/20. This figure was first assigned to this acuity in the past in circumstances that I cannot remember too well but explained this forum. Acuity sharper than that is common/very common. It seems to me that several/many who write on here are at about 20/15 or better. I had thought that correcting mild or middling myopia (short-sightedness) to one's "potential" acuity with glasses or contact lenses is always possible if no other problem intervenes. It seems that most opticians in many countries routinely do not test beyond 20/20. If this is so in your case then your acuity may be better than that.

CA due to incorrect IPD or focus. Mention of it in these forums is seldom due to those reasons!

Where I am it is difficult or impossible to sell a very pricey binocular if you do not like it. I have read a lot about CA in Leicas and before buying an Ultravid HD+ 7x42 wish to know some more about CA in it. I was particularly scared by Quincy88's "green fog of chromatic aberration"! Hence this thread.

My acuity is about 20/15. Among regular writers here in several/many it is keener and in several/many it is less keen than that. If that is not known and stated then (a) there is endless argument at cross purposes about sharpness of a given binocular, and (b) I am left not knowing if it will be sharp enough for me. That is why I have been proposing that reviewers state their acuity (and other relevant vision conditions).

I linked the two, CA and VA, in my last post above because I think that CA in some binocular, longitudinal as explained by Typo/David, and lateral as very fine fringing, may be visible only to those with better acuity than me.

David, thank you very much, for your explanation in my "absence", knowing of a risk in this situation, which was in fact realized. I appreciate this as I do your knowledge. Your response is of course more valuable than mine.

My thanks also to everyone who responded to me with their experiences and useful ideas. It seems to me that now, after this thread began, in other threads also CA has also been addressed more than usual, which I believe will be of help to many.

Personally, I had thought I may possibly be neurotic about CA (neurotic, Merriam-Webster basic: "often or always fearful or worried about something : tending to worry in a way that is not healthy or reasonable"). In my last "review", of the Zeiss Victory 8x25 I set down FWIW: "I am sensitive to color fringing in that it can be 'provoked' easily and here that occurs less than 1/2 way from the center of view. In actual use it was never obtrusive or even noticeable." Now I know that in the Ultravid 7x for me it will be. I may still go for it hoping I will be able to sum up as in one post above (Gilmore Girl) that I: "need and desire CA to be controlled reasonably well and I think it is in the 7x42 plus model"!

adhoc, no problem with the delayed response. I'm having trouble keeping up with everything at the moment and I haven't even been away!

I appreciate your comments regarding 20/20. I have to admit that I mistakenly thought when I posted my acuity as 20/20 that is was perfect vision, but I now realise that it's just a standard that opticians use that they aim to give everyone when they correct vision with glasses and they are probably not concerned with giving you the best possible correction, and certainly not concerned with finding out what your actually acuity is. As long as they can get you to 20/20 they're happy (and tell you that you should also be, hence the comments I remember). I do though also remember being able to read smaller lines of letters underneath the line which they seemed concerned that I could read, and when I read them received comments like, 'yes, very good', or, 'you don't have to be able to read that line'. Sorry for my ignorance - I'm here to learn!

I've been given some pointers by a member here on how to ascertain what my actual acuity is, and I'm going to look into that (excuse the pun) when I get the chance.

Your best bet with the 7x42 UVHD+ would be to somehow try before you buy, but living as I do in a (beautiful) part of Finland many miles from any major city, I appreciate that that can be easier said than done! All the best.

Michael.

adhoc said:

... Now I know that in the Ultravid 7x for me it will be. I may still go for it hoping I will be able to sum up as in one post above (Gilmore Girl) that I: "need and desire CA to be controlled reasonably well and I think it is in the 7x42 plus model"!

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Don't put too much stock in my experience. I don't think I'm nearly as picky as you when it comes to choosing a binocular (based on your posts I've read over time). My hunch is you'll see some CA in the 7x42 and won't tolerate it.
For me, it's minimal and I have no issues with it. I would move on from the Ultravid and save yourself the time and energy of having to return it. I could be wrong about that and probably shouldn't discourage. I just think if CA is a big deal for you then staying away from Ultravids and Noctivids is a good idea.

Try to find a Zeiss FL 7x42 which will have the best CA control, is still relatively light weight and has a great focus action. I only have experience with 8x32 FL and really liked it. CA control lived up to the hype here on the forum. That was one of the first things I checked for. There was very subtle fringing (barely noticeable) on the very outer edge and I couldn't detect any in the sweet spot. If I didn't have to wear glasses I'd probably have the FL 8x32 right now. Unfortunately, I don't find any 8x32 comfortable enough (for me) with glasses after using the 7x42 for so long now.

Gilmore Girl, thanks, that is useful to clarify my thinking at present. The Zeiss is too big though as I very much like smallness. Maybe I should go for the Opticron Discovery 7x42, USD 210 in UK/250 in US, much shorter than (even) the Uv. (link, comparison photo) and await a new smaller Nikon EDG 7x. If after some time there is no other small "alpha" 7x then it might be the Uv. despite that CA!

adhoc said:

Gilmore Girl, thanks, that is useful to clarify my thinking at present. The Zeiss is too big though as I very much like smallness. Maybe I should go for the Opticron Discovery 7x42, USD 210 in UK/250 in US, much shorter than (even) the Uv. (link, comparison photo) and await a new smaller Nikon EDG 7x. If after some time there is no other small "alpha" 7x then it might be the Uv. despite that CA!

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I didn't know another requirement for your 7x42 consideration is small-ish size.
The 42 FL's are long. I've never looked through any of the bigger FLs. I wouldn't mind trying the 7x42 sometime just out of curiosity. I also like smaller binos.
Unfortunately, there's very little choice in 7x now. How about 6.5x32 Meopro? They're hard to find now, but I saw one last year on eBay. Good luck on your search. You could still try the Uvid for a couple days and return if you can't tolerate the CA levels. I don't think it's bad at all, but sounds like you're pretty sensitive to it.

Thanks, but, copying from 2 fairly recent posts by me in BirdForum:

6.5x: "I was rather thrilled by the view of the Kowa YF 6x30 (porro, "clones with" Leupold Yosemite, very good optical quality, at less than USD 100) in a woodland setting due to its depth of field and 8.0-8.1 deg. FOV. You could see so much of birdlife, that is, different species and their movements, in one view. But I felt its 6x was inadequate for detail of the birds. Since then I have been hoping for such a view at 7x from some model of good optical quality. I would also, as you might remember, like a binocular to be smaller!"

Testing and returning: "Where I am it is nearly impossible to look for binoculars, getting one (from abroad) is a long process, returning is complicated if possible at all, and selling here is uncertain (finding takers for a model, even if the unit is in perfect order), and will be at a much lower price. (I have gone through that n times!)"

adhoc said:

Thanks, but, copying from 2 fairly recent posts by me in BirdForum:

6.5x: "I was rather thrilled by the view of the Kowa YF 6x30 (porro, "clones with" Leupold Yosemite, very good optical quality, at less than USD 100) in a woodland setting due to its depth of field and 8.0-8.1 deg. FOV. You could see so much of birdlife, that is, different species and their movements, in one view. But I felt its 6x was inadequate for detail of the birds. Since then I have been hoping for such a view at 7x from some model of good optical quality. I would also, as you might remember, like a binocular to be smaller!"

Testing and returning: "Where I am it is nearly impossible to look for binoculars, getting one (from abroad) is a long process, returning is complicated if possible at all, and selling here is uncertain (finding takers for a model, even if the unit is in perfect order), and will be at a much lower price. (I have gone through that n times!)"

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Ok, got it...returns sound like a major hassle and I can't blame you for being careful to avoid them.