zeiss victory II and chromatic aberration?

[Anders Bræstrup]

I have read some articels that emphasises the fact that the Victory's shows a lot af chromatic aberration when looking at high contrast objects under bright light conditions! BVD is the only place it is not mentioned. I have not looked through many binoculars and I wonder how big this problem is - how annoyed I will be looking at the visible prism effect when watching birds? Some of you tell that every roof-prism binoculars suffers from chromatic aberration - but is the Victory's worse at that point?

Anders

[CJW]

Hi Anders and welcome to Bird Forum from all the Moderators and Admin.Staff.

I can't understand where these comments about chromatic aberration come from, but they're complete rubbish. I have a pair of 10x42 V2s and they are wonderful - certainly as good, if not better, than the Leica Trinovids and Swarovski ELs.

Chris

[william j clive]

Hi Anders and welcome to Bird Forum from all the Moderators and Admin.Staff.

I can't understand where these comments about chromatic aberration come from, but they're complete rubbish. I have a pair of 10x42 V2s and they are wonderful - certainly as good, if not better, than the Leica Trinovids and Swarovski ELs.

Chris

I must be lucky, I cant see CA either, in any optic that I have ever tried, and I have even tried specifically looking for it! Does that make me the perfect customer? All the optic firms should be fighting for my custom!

Clive

[Grousemore]

Hi Anders,seems that the Victory 2's are the BF Moderators' binocular of choice!
I have a pair of 8x40 V2's and having used them extensively in Florida under the brightest conditions,can reiterate Chris's findings of no discernible CA.
I bought them after testing alongside Swaro 8.5x42 and Leica Ultravid 8x42 and to my eyes they were the best.

[gorank]

It has been suggested that som people are more sensitive to CA. I didnt see/react to CA until I started digiscoping with a non-ED scope and a bad camera...and saw the photos...then i started to look for it in my binos...and found it there as well...

CA is more visible in certain circumstances...and if you know how to stress the binos..CA is much easier to detect..

Another possible cause is individual variations within the same product. Has anyone tested 5 different VII:s and checked the differences ??

I also wonder if the use of eye glasses could have a negative influence on CA ???
Especially glasses with plastic lenses would not be optimal i think..

[Leif]

It has been suggested that som people are more sensitive to CA. I didnt see/react to CA until I started digiscoping with a non-ED scope and a bad camera...and saw the photos...then i started to look for it in my binos...and found it there as well...

CA is more visible in certain circumstances...and if you know how to stress the binos..CA is much easier to detect..

Another possible cause is individual variations within the same product. Has anyone tested 5 different VII:s and checked the differences ??

I also wonder if the use of eye glasses could have a negative influence on CA ???
Especially glasses with plastic lenses would not be optimal i think..

Unfortunately I see CA, and some others do, but most people do not. In any case, the VII are no worse and no better than competing products with respect to CA. If it is any consolation I saw huge amounts through the Leica 8x42 Ultravid but most people say they see none. I beleive that it is psychological i.e. it is there, but for most people the brain filters it out. (I am told that we do not see directly, but rather we see a model of reality constructed in the brain from the senses. That's why optical illusions work!)

Also correct eye placement does help otherwise you see what is called horizontal and/or vertical CA. So make sure you adjust the intra-ocular distance correctly.

[william j clive]

I also wonder if the use of eye glasses could have a negative influence on CA ???
Especially glasses with plastic lenses would not be optimal i think..


I wear specs with plastic lenses - I see no CA. I do think that I am very lucky in this respect. There is much discussion on this and other forums with regard to CA. It must be a real pain if you can see it.

Clive

[scampo]

I think everyone can see it, Leif, in the right conditions. If we view a central backlit object, then look at objects in the top and bottom peripheries, objects in those areas will exhibit fringing - one periphery blueish, the other reddish.

[henry link]

That kind of off axis CA unfortunately doesn't originate in the objective, but in the eyepiece. It may be improved in the new Zeiss bins but not as a result of Fluorite being used in the objective.

[Leif]

I think everyone can see it, Leif, in the right conditions. If we view a central backlit object, then look at objects in the top and bottom peripheries, objects in those areas will exhibit fringing - one periphery blueish, the other reddish.

What I see in most roof prism bins is purple fringing (the purplies) and it increases with distance from the field centre, but is sometimes evident even near the field centre. I also see the more traditional fringing (yellow one side, red the other) esp. when watching a swan on a lake. I know you don't see it Steve, so count yourself lucky. Just don't start looking for it. It really peeves me something rotten. Grrrr.

[CDK]

CA is most noticeable when someone reads about it in a magazine, or word of mouth. At this years birdfair, I wanted to view one particular model and was disappointed to say the least, as I could clearly see a yellow fringe on the side of a post. I was not the only one, but then I see other people comments, and I read that they were the best binoculars ever. I am sure that we do see things, but can convince ourselves that a specific model / manufacturer, does not have any CA. I suppose it can depend on ones bias.

[scampo]

I think you're right, CDK - and I'm coming to think it's mainly to do with prevailing lighting conditions.

[zuiko]

Count me as one of the people who can see chromatic aberration readily.

My older Zeiss 8x56's have blue/red type fringing but quite small amounts on centre.

In the newer binoculars I see purple/green fringing. Even on the Zeiss 10x42 FL dark tree branches against bright cloud background made purple fringes easily visible.

The Ultravid 10x42 has a similar amount and it all depends on what is being observed. I find it easy to detect when there is strong contrast & usually with a white source as it is the white light which refracts into all the separate colours and therefore is more likely to show CA.

It's present in all binoculars to a greater or lesser degree.

[ceasar]

If you look hard enough you will find it. I don't think it is something you want to get into the habit of seeing. I even saw it in the new lens I received after cataract surgery when I looked out of the far corners of my eye. It is gone now.

In any optic, if it is readily obvious, it is a problem. If you have to look for it it isn't a problem. Don't lose any sleep over it.

Bob

[zuiko]

If you look hard enough you will find it. I don't think it is something you want to get into the habit of seeing. I even saw it in the new lens I received after cataract surgery when I looked out of the far corners of my eye. It is gone now.

In any optic, if it is readily obvious, it is a problem. If you have to look for it it isn't a problem. Don't lose any sleep over it.

Bob

Hi Bob,

Yes it doesn't bother me in general. When out in nature it's certainly not a problem either.

Like you point out, it's in the nature of optical instruments and with both the Zeiss and Ultravid, the amount is so small even at the edges that it doesn't detract at all in normal viewing.

[gorank]

Count me as one of the people who can see chromatic aberration readily.

My older Zeiss 8x56's have blue/red type fringing but quite small amounts on centre.

In the newer binoculars I see purple/green fringing. Even on the Zeiss 10x42 FL dark tree branches against bright cloud background made purple fringes easily visible.

The Ultravid 10x42 has a similar amount and it all depends on what is being observed. I find it easy to detect when there is strong contrast & usually with a white source as it is the white light which refracts into all the separate colours and therefore is more likely to show CA.

It's present in all binoculars to a greater or lesser degree.

be sure to adjust the "inter-pupilary distance" correct, the precise alignment of the eye is important to mimimize CA, even with the Zeiss FL:s

[henry link]

As gorank says exactly centered pupil placement is needed to avoid LATERAL chromatic aberration. Lateral CA orignates primarily in the eyepiece and needs to be differentiated from longitudinal CA that originates in the objective. I'm convinced that most of the time when people complain about CA in binoculars they are talking about lateral because there is far more of it in binocular images than longitudinal. Lateral CA is almost absent on-axis unless the pupil is decentered (which unfortunately happens frequently in binoculars when hand holding or looking at close objects) but it increases as you look farther off-axis toward the field edge. The color of the fringes at the edge of an object will be different on the side of the object that faces the field edge compared to the side that faces the center, perhaps yellow or red in one direction and purple or green in the other. It is usually most obvious at the edges of wide field eyepieces, especially when combined with low focal ratio objectives like the ones in binoculars. You can see it on-axis simply by moving your eyes up and down a little to decenter your pupils. If you concentrate on the top edge of an object it should appear as one color when the pupil is down and a different color when the pupil is up. In the Zeiss 8x42 FL the color changes from yellow to magenta.

Longitudinal CA from the objective is constant over the entire field (although it will combine with lateral toward the field edge or with decentered pupils) and the fringes have only one obvious color in all directions, usually purple. Conventional binocular objectives have very large amounts of longitudinal CA, but at the low magnifications used in binoculars it is all but invisible as a color fringe. It grows worse with higher magnification, essentially because it is being magnified along with the objects it effects, which makes it very obvious at high magnifications in achromatic telescopes. Lateral CA on the other hand doesn't change with magnification. The Flouride glass in the Zeiss FL really only addresses longtudinal CA, and it is very effective. I've boosted the magnification of the 8x42 FL to beyond 60x and seen remarkably little longitudinal CA compared to other binoculars boosted to the same magnification. The color fringes from longitudinal CA in the FL are about 20-25% of the width of the color fringes in binoculars using achromatic objectives, but lateral CA in the FL eyepiece is not much different from other good binoculars with eyepieces of similar field widths. The visible benefit of the FL objective's lower longtudinal CA at 8x appears to me to be confined to a small but worthwhile improvement in contrast and sharpness across the center 1/3 of the field. Farther off-axis lateral CA, field curvature and astigmatism compromise the image quality and make the improvement invisible.

[Hogjaws]

Victory II's

Going along with what henry link stated above about CA and eye alignment, under challenging light conditions, I find my 10X40 VII's have very little CA in the middle 20-25% of the view with proper eye alignment. With proper eye alignment in VII binos, CA in the center sweet spot is probably less than what I have observed in 10X42 SLCs (in their center). However, moving out of the sweet spot, the CA increases fairly dramatically, and is on par with the Pentax DCF SP line. Also, when I do not properly align my eyes with the eyepiece, the CA increases dramatically across the full view. Under challenging light conditions, the VIIs require more work and are not as pleasing for wildlife observation as the best top line binos.

I have never looked through the VII 8X40's, but I would suspect their CA would be reduced from that in the 10X due to lower magnification.

Some general VII observations: I like them very much, their view in mid to low light conditions is on par with any other top end water proof bino. They have excellent contrast, the apparent depth of field is better than the B&L Elites, but not as good as Nikon or Swarovski SLC or ELs. Also the VII's have good ergonomics. I do not mind hauling them around the deserts or California mountains. They were also less expensive than event the Nikon LX's.

So, the VIIs are very good in some conditions, but are eclipsed by other binos in full light conditions. I decided that most wildlife is crepuscular or hides in the shade, except for primarily sea birds.

Just my 2 cents.

Hogjaws

[zuiko]

As gorank says exactly centered pupil placement is needed to avoid LATERAL chromatic aberration. Lateral CA orignates primarily in the eyepiece and needs to be differentiated from longitudinal CA that originates in the objective. I'm convinced that most of the time when people complain about CA in binoculars they are talking about lateral because there is far more of it in binocular images than longitudinal. Lateral CA is almost absent on-axis unless the pupil is decentered (which unfortunately happens frequently in binoculars when hand holding or looking at close objects) but it increases as you look farther off-axis toward the field edge. The color of the fringes at the edge of an object will be different on the side of the object that faces the field edge compared to the side that faces the center, perhaps yellow or red in one direction and purple or green in the other. It is usually most obvious at the edges of wide field eyepieces, especially when combined with low focal ratio objectives like the ones in binoculars. You can see it on-axis simply by moving your eyes up and down a little to decenter your pupils. If you concentrate on the top edge of an object it should appear as one color when the pupil is down and a different color when the pupil is up. In the Zeiss 8x42 FL the color changes from yellow to magenta.

Longitudinal CA from the objective is constant over the entire field (although it will combine with lateral toward the field edge or with decentered pupils) and the fringes have only one obvious color in all directions, usually purple. Conventional binocular objectives have very large amounts of longitudinal CA, but at the low magnifications used in binoculars it is all but invisible as a color fringe. It grows worse with higher magnification, essentially because it is being magnified along with the objects it effects, which makes it very obvious at high magnifications in achromatic telescopes. Lateral CA on the other hand doesn't change with magnification. The Flouride glass in the Zeiss FL really only addresses longtudinal CA, and it is very effective. I've boosted the magnification of the 8x42 FL to beyond 60x and seen remarkably little longitudinal CA compared to other binoculars boosted to the same magnification. The color fringes from longitudinal CA in the FL are about 20-25% of the width of the color fringes in binoculars using achromatic objectives, but lateral CA in the FL eyepiece is not much different from other good binoculars with eyepieces of similar field widths. The visible benefit of the FL objective's lower longtudinal CA at 8x appears to me to be confined to a small but worthwhile improvement in contrast and sharpness across the center 1/3 of the field. Farther off-axis lateral CA, field curvature and astigmatism compromise the image quality and make the improvement invisible.

Henry,

Thank you for this information. I've tested my Ultravid with various IPDs as well as decentring the exit pupils in relation to my eyes at correct IPD and it is remarkable how intolerant the binoculars are to being misplaced.

I think my previous experience with 8x56's spoiled me for this.

When the IPD is correct and well centred then CA is well within tolerable limits.

What is frustrating compared to older models is that neither the FL nor Ultravid have IPD scales to set IPD repeatably. I leave my bins on a preset and I guess one could make a mark on the hinge for this but I find it odd that the manufacturers don't mark it anymore.

[henry link]

Zuiko,

I'm not surprised to hear that you've been spoiled by your 8x56. I've had the same experience with large exit pupil binoculars. A 7mm exit pupil bin will be effectively stopped down by the constriction of the eye's entrance pupil to f/10 to f/15 in daylight, while a 10x42 will be effectively operating at around f/5 to f/8 under the same conditions. Those higher effective focal ratios reduce longitudinal CA (and spherical aberration) and have the happy side effect of reducing the eyepiece's lateral CA at the same time. You're absolutely right about the unfortunate disappearance of IPD scales. They were very useful things even when they were inaccurate.

Henry

[Joejack]

Hello all, I don't post here very often but decided to add to the mix :). As for CA, I have always noticed it in every pair of binoculars I have seen. Last year I saved up and wanted a really good pair of binos and decided to look through a few. I tried the swarovski EL and some of the zeiss (don't remember which ones but they didn't have the FL) at a local shop. I looked at a flourescent sign at night (talk about contrast) and saw CA badly in all of them. It was then that I opted for a pair of 8x42 FL's sight unseen (with a 30-day return policy from the store of course) and still cannot see any CA in them. I do however get a "sense" of a slight greenish hue when I am scanning rapidly or shaking slightly. "Sense" is the best description I can come up with as the CA vanishes when I focus attention on one spot or get relatively still.

I have often wondered if the difference in spectral sensitivity between some people could be the source of some of the CA or at least exagerate it. For example, some people can see farther into the blue and red than others while everyone sees all of the green and yellow section. I have been told that some of the colors can be corrected for in an achromatic objective at the slight expense of others, so is it possible that the manufacturers would correct for the most common colors and be happy that the majority of people will be taken care of or am I full of crap :) Just my two cents.


By the way, Leif is right, if you are blessed enough to not notice CA don't go looking for it!

-joejack

[hg1]

Hello all, I don't post here very often but decided to add to the mix :). As for CA, I have always noticed it in every pair of binoculars I have seen. Last year I saved up and wanted a really good pair of binos and decided to look through a few. I tried the swarovski EL and some of the zeiss (don't remember which ones but they didn't have the FL) at a local shop. I looked at a flourescent sign at night (talk about contrast) and saw CA badly in all of them. It was then that I opted for a pair of 8x42 FL's sight unseen (with a 30-day return policy from the store of course) and still cannot see any CA in them. I do however get a "sense" of a slight greenish hue when I am scanning rapidly or shaking slightly. "Sense" is the best description I can come up with as the CA vanishes when I focus attention on one spot or get relatively still.

I have often wondered if the difference in spectral sensitivity between some people could be the source of some of the CA or at least exagerate it. For example, some people can see farther into the blue and red than others while everyone sees all of the green and yellow section. I have been told that some of the colors can be corrected for in an achromatic objective at the slight expense of others, so is it possible that the manufacturers would correct for the most common colors and be happy that the majority of people will be taken care of or am I full of crap :) Just my two cents.


By the way, Leif is right, if you are blessed enough to not notice CA don't go looking for it!

-joejack


Despite trying on numerous occasions with lots of diferent bins I have NEVER been able to see CA. I am very slightly red-green color blind. I wonder if this sort of individual variability has something to do with the inability of some people to detect CA?

[Joejack]

hg1,

Good question. I'm curious if it is possible to test individual variation for spectral sensitivity or red-green blindness, etc. by taking a picture and have people who do and don't see CA look at the picture and see if they detect any fringing. Wouldn't it show the same thing theoretically? This assumes the camera is held so that lateral CA is eliminated.

-joejack

[Kevin Purcell]

Very old thread but ...

I'm red-green colorblind (deuteranomalous) so my green receptor is moved towards the red.

And yes I do see CA.

I didn't used to see it but now I can see it with some effort (and distinguish the types) ... it is a learning thing (so as people recommend unless you want to learn to see it don't try ;) )

A good way to see lateral CA is to view a well lit while rectangular target (say 10 to 20% of the field ... signs make good CA targets). Keep the target centered and move your eye off center from the EP. If you go one way you will see purple fringing on one side and yellow on the other. If you move your eye back across center and to the opposite the color fringes will change places.

Good EP design can help reduce this (you see some bins using LaK ... Lanthanum crown in the EP to try to reduce lateral).

Along with using ED glass in the objective.

Recently set Bushnell EX 8x36 back for terrible CA ... much worse than similar bins. I guess I'm getting more and more picky!