[donyjunk]

Maybe I've been lucky in not doing a lot of photos of high contrast subjects at wide aperatures in "normal" shooting. Having just gotten a FA43 off eBay I just wanted to put it through its paces to see if anything was off, and I did a quicky focus test on an old hard drive set a f1.9 of course to maximize effect of missed focus. Spot focusing on lettering in the middle of the label, taken at an angle (LED desk lamp directly above the drive, me off about 45 degrees to the side and above).

Focus was pretty much dead on, but wow, at f1.9 the CA was crazy strong, all the lettering to one side of the focus point green tinged, other side purple tinged.
Was worried that something was wrong with the lens. Then I broke out my F 50mm f1.7 ... same issue wide open. FA 50mm f1.4. Same issue wide open.
Also some review sites note the FA43 has pretty strong CA, so I assume my copy is not unusual, the CA inherent in the design?

Setting K-1 in camera Lateral CA correction toggle on/off made no difference. Reading around suggestions it only works on DA and DFA lenses? If that's really the case setting ineffectiveness would make sense.
Is there a way to create a customized correction table or mapping the settings from a lens's closest kin that does have CA adjustments? Obviously the fix would be incomplete/partial, but better than none. Or is the only hope in trying to remove/reduce it in post processing?

Maybe I've been lucky in not doing a lot of photos of high contrast subjects at wide aperatures in "normal" shooting. Having just gotten a FA43 off eBay I just wanted to put it through its paces to see if anything was off, and I did a quicky focus test on an old hard drive set a f1.9 of course to maximize effect of missed focus. Spot focusing on lettering in the middle of the label, taken at an angle (LED desk lamp directly above the drive, me off about 45 degrees to the side and above).

Focus was pretty much dead on, but wow, at f1.9 the CA was crazy strong, all the lettering to one side of the focus point green tinged, other side purple tinged.
Was worried that something was wrong with the lens. Then I broke out my F 50mm f1.7 ... same issue wide open. FA 50mm f1.4. Same issue wide open.
Also some review sites note the FA43 has pretty strong CA, so I assume my copy is not unusual, the CA inherent in the design?

Setting K-1 in camera Lateral CA correction toggle on/off made no difference. Reading around suggestions it only works on DA and DFA lenses? If that's really the case setting ineffectiveness would make sense.
Is there a way to create a customized correction table or mapping the settings from a lens's closest kin that does have CA adjustments? Obviously the fix would be incomplete/partial, but better than none. Or is the only hope in trying to remove/reduce it in post processing?

I remember this: If I take my watchmaker magnifying glass and put a light on above me and study a text on a white surface I get the same. Colours to the right and left of the symbols and some above. If you look very close you will notice it is actually the colours of the rainbow, not just purple and green. I think it would be wise to try out the same again but with indirect lighting of the subject. I do not think it is in your camera but in the way you tried out your lens. And let me guess, you never noticed it before with both the 50mm's.

[house]

Maybe I've been lucky in not doing a lot of photos of high contrast subjects at wide aperatures in "normal" shooting. Having just gotten a FA43 off eBay I just wanted to put it through its paces to see if anything was off, and I did a quicky focus test on an old hard drive set a f1.9 of course to maximize effect of missed focus. Spot focusing on lettering in the middle of the label, taken at an angle (LED desk lamp directly above the drive, me off about 45 degrees to the side and above).

Focus was pretty much dead on, but wow, at f1.9 the CA was crazy strong, all the lettering to one side of the focus point green tinged, other side purple tinged.
Was worried that something was wrong with the lens. Then I broke out my F 50mm f1.7 ... same issue wide open. FA 50mm f1.4. Same issue wide open.
Also some review sites note the FA43 has pretty strong CA, so I assume my copy is not unusual, the CA inherent in the design?

Setting K-1 in camera Lateral CA correction toggle on/off made no difference. Reading around suggestions it only works on DA and DFA lenses? If that's really the case setting ineffectiveness would make sense.
Is there a way to create a customized correction table or mapping the settings from a lens's closest kin that does have CA adjustments? Obviously the fix would be incomplete/partial, but better than none. Or is the only hope in trying to remove/reduce it in post processing?

The green / magenta fringe at either side of the focal plane is longitudinal CA. You can't really correct for that.

[Adam]

Maybe I've been lucky in not doing a lot of photos of high contrast subjects at wide aperatures in "normal" shooting. Having just gotten a FA43 off eBay I just wanted to put it through its paces to see if anything was off, and I did a quicky focus test on an old hard drive set a f1.9 of course to maximize effect of missed focus. Spot focusing on lettering in the middle of the label, taken at an angle (LED desk lamp directly above the drive, me off about 45 degrees to the side and above).

Focus was pretty much dead on, but wow, at f1.9 the CA was crazy strong, all the lettering to one side of the focus point green tinged, other side purple tinged.
Was worried that something was wrong with the lens. Then I broke out my F 50mm f1.7 ... same issue wide open. FA 50mm f1.4. Same issue wide open.
Also some review sites note the FA43 has pretty strong CA, so I assume my copy is not unusual, the CA inherent in the design?

Setting K-1 in camera Lateral CA correction toggle on/off made no difference. Reading around suggestions it only works on DA and DFA lenses? If that's really the case setting ineffectiveness would make sense.
Is there a way to create a customized correction table or mapping the settings from a lens's closest kin that does have CA adjustments? Obviously the fix would be incomplete/partial, but better than none. Or is the only hope in trying to remove/reduce it in post processing?

The in-camera corrections are not designed to fully eliminate fringing. This requires heavy computation and can be done in post if needed.

Adam
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[Serkevan]

Green/magenta happens in slightly out of focus areas and it's called spherochromatism or Longitudinal CA (green in foreground IIRC), the famous "purple fringing" happens in the focus plane. Correcting for spherochromatism on fast lenses is challenging and you would negatively impact the bokeh. It's also difficult to remove in post. You will have to live with it, more or less...

[ffking]

and you would negatively impact the bokeh

I'm really glad to hear you say that - too often criticisms of equipment are made as if it could have been done if the company had wanted to/ had the competence to rather than the truth - usually - that design is a series of trade-offs: you might not like the decisions the designer made, but you'd have to forgo some good quality in the product to correct for what you don't like. And the more that conformity is pushed on designers by reviewers* and others who suggest that it's possible to have everything, the fewer interesting products we'll have,as they'll all tend to a generic norm.

*btw, I'm sure that some reviewers are useful in pushing for higher standards, but they need to be aware of what's possible physically.

[Serkevan]

I'm really glad to hear you say that - too often criticisms of equipment are made as if it could have been done if the company had wanted to/ had the competence to rather than the truth - usually - that design is a series of trade-offs: you might not like the decisions the designer made, but you'd have to forgo some good quality in the product to correct for what you don't like. And the more that conformity is pushed on designers by reviewers* and others who suggest that it's possible to have everything, the fewer interesting products we'll have,as they'll all tend to a generic norm.

*btw, I'm sure that some reviewers are useful in pushing for higher standards, but they need to be aware of what's possible physically.

Well, it might be possible to correct for it while keeping good bokeh, but that would most likely mean a ridiculously heavy lens (even the "super-fifty" recent examples suffer from this aberration) and no one wants to but a 3000€ 50/1.4 lens just to get rid of something that isn't a problem in most cases.

[ffking]

Well, it might be possible to correct for it while keeping good bokeh, but that would most likely mean a ridiculously heavy lens (even the "super-fifty" recent examples suffer from this aberration) and no one wants to but a 3000€ 50/1.4 lens just to get rid of something that isn't a problem in most cases.

well, yes, that's another design choice

[Serkevan]

Absolutely, and one that I'm glad isn't taken

[rawr]

Worth noting that whatever RAW or general JPEG image processor you use will likely have a big effect on how CA, fringing etc looks in your images.

Lightroom and DxO PhotoLab, for instance, have specific correction modules for many Pentax lenses (including the FA 43) that give you a good degree of control over fringing problems.

Even lenses that are 10 times worse CA producers (eg K 300 f4) can be tamed to an almost acceptable degree through decent software correction.

[Rondec]

You need a good post processing program. Lightroom will work and honestly Rawtherapee has a very nice feature to eliminate this sort of fringing.

It doesn't always work though. Which is to say, you can eliminate the fringing, but sometimes it leaves behind a gray colored line where the fringing was. But that is a worst case scenario. Then you just have to go black and white, I am afraid.

[house]

Well, it might be possible to correct for it while keeping good bokeh, but that would most likely mean a ridiculously heavy lens (even the "super-fifty" recent examples suffer from this aberration) and no one wants to but a 3000€ 50/1.4 lens just to get rid of something that isn't a problem in most cases.

Judging by recent lenses by various brands you can get very far towards eliminating aberrations, keeping the size below monumental and having smooth bokeh.

[Wheatfield]

Try this if you use Photoshop:

How to Correct Purple Fringing in Photoshop

It works equally well for green fringing.

[donyjunk]

OK, thanks folks for all the advice. I was most concerned over whether or not the new lens was a bad copy but seems like it's not unusual, and then it's just a matter of how to deal with the artifact.

I guess in some cases where the CA is most obviously only in a near B/W area you can maybe do a local desaturation.
Maybe in the more complex cases I'll look into the more advanced correction methodologies.

[Serkevan]

Judging by recent lenses by various brands you can get very far towards eliminating aberrations, keeping the size below monumental and having smooth bokeh.

I meant for longitudinal chromatic aberrations, not lateral. Lateral isn't a huge problem anyway, the one-click correction on Lightroom does a more than decent job without any visible impact for most applications.