Rifle Scopes Then I saw CA, now I'm a believer...

[ForgeValley]

To all you guys who have complained about chromatic aberration, I apologize to you.

See, in my heart, I laughed at you and thought my eyes were superior to yours. I own a k624 and scoffed at all the complaints of CA, because I never saw it. Surely all you CA complainers were just whiny little bit**s.

Well, I stand corrected. Today I looked through a new scope at the snow covered landscape and thought I was tripping on LSD.. the colors would have been amazing if they weren't in a $3200 scope.

Anyway, no longer will I feel smugly superior, I have joined the ranks of CA true believers.

And yes, for all you CA apologists, I DO think it would have made me miss a target.

All kidding aside, I won't tell you what scope it was. My experience with the K624 leads me to believe that CA can show up on a scope by scope basis. I looked at that same scene through the k624, no CA. But I will post a picture.

 

[just browsing]

Welcome to the dark side.

 

[918v]

Purple haze all in my brain...

 

[KZP]

Whew, looks more like CA from a $320 scope. Is there something wrong with it?

 

[doctordoctor]

That's pretty bad

 

[Kickin45]

Wow, that’s some of the worst I’ve seen. Great shade of purple though ?

 

[StealthOwl]

Steiner?

 

[Vodoun daVinci]

Holy shit...I have a Vortex Crossfire II 6-24X50 scope that cost me $250 and it has none of that. Some CA at 24X but it's about 10% of that ...noticeable but not all that bad, $3200 and that much CA?

Get a rope....WTF?

VooDoo

 

[koshkin]

I wouldn't be too quick to evaluate the amount of CA based on that photo. You can induce a lot of CA that is not visible to your eye under normal conditions by how you align the camera to the scope.

I do not doubt the OP's words, but you can not compare what you see with your eye through your scope with a picture taken with a camera under uncontrolled conditions.

ILya

 

[ForgeValley]

I wouldn't be too quick to evaluate the amount of CA based on that photo. You can induce a lot of CA that is not visible to your eye under normal conditions by how you align the camera to the scope.

I do not doubt the OP's words, but you can not compare what you see with your eye through your scope with a picture taken with a camera under uncontrolled conditions.

ILya

Trust me, I have no dog in this fight, I didn't even believe CA was much of a thing before this scope.

The CA was worse with my eye. The picture actually kind of lessened it.

 

[patriot07]

I wouldn't be too quick to evaluate the amount of CA based on that photo. You can induce a lot of CA that is not visible to your eye under normal conditions by how you align the camera to the scope.

I do not doubt the OP's words, but you can not compare what you see with your eye through your scope with a picture taken with a camera under uncontrolled conditions.

ILya

This is worth noting. My T5Xi had hardly any CA if your pupil was perfectly centered on the optical axis. Anytime I got off center at all, it would get bad, and getting really off center would make it really bad. You can do the same thing with a phone - make the CA look way worse with the camera positioning than it really is when viewed through the scope normally.

My SWFA HD 5-20 has a little bit when you get really off axis, but almost none the rest of the time. I could take 2 pictures through the same scope and make it seem much worse or much better than it is depending on which one I show you.

JMHO

 

[koshkin]

Trust me, I have no dog in this fight, I didn't even believe CA was much of a thing before this scope.

The CA was worse with my eye. The picture actually kind of lessened it.

I am not arguing with that at all. The only point I am making is that judging the amount of CA by looking at a through the scope a picture is not a good way to go.

Also, if the scope was not set-up for your eye correctly, the amount of CA you see can be notably higher than it would be otherwise.

ILya

 

[mdmp5]

That’s what you get for buying a counter sniper scope

 

[5RWill]

Yup...it's annoying AF. It does make me laugh because there are people that dislike people that dislike CA i guess they just attached part of their soul to their optic idk.. My point of contention has always been it's not that big of a deal until a certain price point. Past a certain point i expect little to none...

Without knowing what manufacturer it is they obviously use the tremor 3..so there's that. Sample size is also a factor sometimes even at that price point.

 

[Blackfoot 7]

I looked through an S&B that looked like that. Just saying high-end optics aren't immune to it, so I guess there are some variances that might be due to manufacturing processes.

 

[ForgeValley]

I am not arguing with that at all. The only point I am making is that judging the amount of CA by looking at a through the scope a picture is not a good way to go.

Also, if the scope was not set-up for your eye correctly, the amount of CA you see can be notably higher than it would be otherwise.

ILya

So what is your take on CA being variable within the same scope line? Do variances in the coating process cause it to be better in some, worse in others? As I mentioned, I have an early k624, from what I can tell there were a lot of complaints about that scope and CA, but when I looked at that same scene, I got none in the Kahles... And I tried to induce it. Moved my eye around, messed with the parallax, looked at the edges of the lense. No CA.

 

[koshkin]

So what is your take on CA being variable within the same scope line? Do variances in the coating process cause it to be better in some, worse in others? As I mentioned, I have an early k624, from what I can tell there were a lot of complaints about that scope and CA, but when I looked at that same scene, I got none in the Kahles... And I tried to induce it. Moved my eye around, messed with the parallax, looked at the edges of the lense. No CA.

CA is not caused by coatings. There can be a fair amount of sample variation even with fairly high end scopes. Most of that variation is due to assembly differences and some component variance. Early K624i scopes varied a fair bit from what I saw and CA was not the only optical issue with them. I have seen some with severs CA and some that just weren't sharp at higher magnifications. I do not think I ever ran into one that did not have any optical issues. Perhaps, you've got that one.

ILya

 

[LAW-DOG]

I agree with koshkin on sample variance due to components & assembly. Another problem is also glass quality, the higher the abbe number the less ca you will have. I wish rifle scope companies would be more like telescope companies because they will say what glass exactly they use like ohara fpl53 which has a 95 abbe, or Hoya fcd10 with 90 abbe, & Chinese chengdu have fk61 with 81.5 abbe or their higher end fk71 with 90 abbe. APM telescopes quit using chengdu fk61 in their low end Ed scopes & now use ohara fpl51 even though they both have 81.5 abbe rating the sample variation in Japanese ohara glass was better than Chinese chengdu cdgm glass

 

[eklarsen]

Might be complicated by that snipers nest you have there, shooting through the windows and all that perfectly clear glass.

 

[LAW-DOG]

Ca doesn’t bother me I have a Chinese bushnell ffp mrad spotter & it works great for me it has some ca but people who are bothered by it might need a higher end scope with perfect glass, that’s all I was saying

 

[koshkin]

I agree with koshkin on sample variance due to components & assembly. Another problem is also glass quality, the higher the abbe number the less ca you will have. I wish rifle scope companies would be more like telescope companies because they will say what glass exactly they use like ohara fpl53 which has a 95 abbe, or Hoya fcd10 with 90 abbe, & Chinese chengdu have fk61 with 81.5 abbe or their higher end fk71 with 90 abbe. APM telescopes quit using chengdu fk61 in their low end Ed scopes & now use ohara fpl51 even though they both have 81.5 abbe rating the sample variation in Japanese ohara glass was better than Chinese chengdu cdgm glass

This would not work at all for riflescopes. Astronomical telescopes are an entirely different animal and while the diameter of th eoptical elements is larger, there are a lot fewer of them. Sort of an apples to oranges comparison.

These days, pretty much everyone has access to high quality glass if they are so inclined and since the size of the optical elements is rather moderate, it is more a matter of what you do with it rather than what material you use. Some designs are more challenging than others, but by and large looking for difference in raw materials is a waste of time.

Another issue to consider is that since you are looking at very different things with a riflescope than you do with a celestial observation instrument, the design optimization is frequently a little different since our perception makes a difference.

ILya

 

[koshkin]

Ca doesn’t bother me I have a Chinese bushnell ffp mrad spotter & it works great for me it has some ca but people who are bothered by it might need a higher end scope with perfect glass, that’s all I was saying

That, I fully agree with. It is very personal.

ILya

 

[LAW-DOG]

That, I fully agree with. It is very personal.

ILya

That, I fully agree with. It is very personal.

ILya

That makes makes sense about the rifle scope vs telescope glass. It makes a bigger difference in telescopes because of higher mag & larger objectives vs rifle scopes with smaller objectives & lower mag. I’ve just always wondered if a rifle scope would look much better fluorite or fpl53 vs what they are using now

 

[koshkin]

That makes makes sense about the rifle scope vs telescope glass. It makes a bigger difference in telescopes because of higher mag & larger objectives vs rifle scopes with smaller objectives & lower mag. I’ve just always wondered if a rifle scope would look much better fluorite or fpl53 vs what they are using now

72mm Hensoldt has a fluorite crystal lens in the objective. However, that was designed before comparatively easy availability of fluoride doped glass. With that scope, since it has a fairly large objective and short overall length, there was a good reason to use fluorite crystal, but getting it built so it survives recoil was an engineering challenge.

I have no idea which exact ED glass different companies use, but I know that some designs out there use very exotic compositions. Still, fundamentally, it does not matter since everyone has access to everything.

ILya

 

[LAW-DOG]

72mm Hensoldt has a fluorite crystal lens in the objective. However, that was designed before comparatively easy availability of fluoride doped glass. With that scope, since it has a fairly large objective and short overall length, there was a good reason to use fluorite crystal, but getting it built so it survives recoil was an engineering challenge.

I have no idea which exact ED glass different companies use, but I know that some designs out there use very exotic compositions. Still, fundamentally, it does not matter since everyone has access to everything.

ILya

I agree it must not matter too much since less expensive scopes are looking very good now. My cousins Nikon fx1000 looks great for $$ & I have a vortex pst gen 2 that also looks very nice

 

[ForgeValley]

Might be complicated by that snipers nest you have there, shooting through the windows and all that perfectly clear glass.

Window is open. Give me some credit.

 

[Glassaholic]

I've said this for a while now, for those who don't see CA, don't go looking for it because once you find it it's hard to ignore just as Cav found out here. I have also noticed CA is most prevalent when I am shooting in winter time and there is snow on the ground, much like the OP's situation above. CA happens because glass elements in scopes direct light and different colors (ever seen what a prism does to light) can sometimes be off axis, so if the lens elements are not designed or positioned just right, you begin to get color fringing like what is seen in Cav's original post above, sometimes this fringing can be harsh but thin and sometimes it can look like a ghost image and sometimes it can bleed. The OP asked the question of whether this can be related to sample variance, where one scope doesn't have it and another does and while that is certainly possible, more often it is just a product of the design, that being said, some manufacturers have been known to "fix" this issue in later iterations of the same scope, so while early models may suffer from this aberration, later models may fair better. I wish manufacturers would do better at identifying "fixes" much like firmware upgrades, but I understand why they do not - if they admitted that certain scopes had issues then everyone would send there scopes in to be fixed regardless of whether they thought anything was wrong or not.

 

[LAW-DOG]

Out of all the optics I’ve seen I think only the Kowa 88m fluorite spotting scope didn’t have ca that I could see. The Zeiss SF & Swarovski sv binoculars are great at handling ca even at the edge where ca is usually the worst, but some of the birdforum people will say there is ca they can’t stand but I barely notice it in those or my Zeiss conquest hd binoculars which cost a lot less but do have more ca than the alphas. In rifle scopes the nf beast/atacr & sb pm ii are the best i think but you will have to pay for that quality & engineering to to get the best ca handling optics. It sucks that an expensive optic has ca, most will have some, so sell it get another that you can live with or it will drive you crazy

 

[Glassaholic]

Out of all the optics I’ve seen I think only the Kowa 88m fluorite spotting scope didn’t have ca that I could see. The Zeiss SF & Swarovski sv binoculars are great at handling ca even at the edge where ca is usually the worst, but some of the birdforum people will say there is ca they can’t stand but I barely notice it in those or my Zeiss conquest hd binoculars which cost a lot less but do have more ca than the alphas. In rifle scopes the nf beast/atacr & sb pm ii are the best i think but you will have to pay for that quality & engineering to to get the best ca handling optics. It sucks that an expensive optic has ca, most will have some, so sell it get another that you can live with or it will drive you crazy

Minox ZP5 and and Tangent Theta are the best on the market as of today in regard to overall control of CA, my Minox ZP5 has bested all of my Schmidt & Bender's in this regard, but I've only had the PM II 3-20x50, PM II Ultra Short 3-20x50 and PM II Ultra Short 5-20x50 so cannot comment on their legendary 5-25x56.

With regard to a birding optic, you want something that you can see every little detail of a birds feather, etc. and I can see how even slight CA might bother them, for long range shooting, CA can be annoying but shouldn't be an issue especially with steel, maybe if you had a target with a bunch of black dots on white background (anyone remember the old Snipers Hide Dot Drill target...) it might become an issue but for the most part even my "cheaper" scopes that have CA are not an issue with me hitting the target, again... an annoyance, but not a serious issue. That being said, I personally have an expectation regarding the overall IQ of a scope if I'm paying over $2k for it and part of that equation is CA, but similar to reticle preference so is CA with different shooters. Some see it, some don't, some see it and aren't bothered by it while others see it and are bothered by it; I fall into the camp of being bothered by it (in $2k+ scopes) but that's me...

 

[Sniperstud]

Clever title OP. "Then I saw CA, now I'm a believer..."


...there's not a trace, of doubt in my mind.
~The Monkeys

…the CA never bothered me anyway!
~Queen Elsa

 

[ForgeValley]

Clever title OP. "Then I saw CA, now I'm a believer..."


...there's not a trace, of doubt in my mind.
~The Monkeys

…the CA never bothered me anyway!
~Queen Elsa

Finally, someone got it.

 

[Sniperstud]

Finally, someone got it.

My wife says I'm an encyclopedia of useless information. Every now and then, it comes in handy.