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S2 Chromatic Aberration - how big an issue is it?

Mark, LR3 cannot deal with it at all- in my experience. Peter
LR3 does not remove it completely, but using the Chromatic Aberration sliders under the Lens Correction pane does help.

Thank you for the link to the Puts article NotXorc. That is an interesting read. In fact, he says the same thing as Peter - "...none of the raw developers can handle this effect..."
 

NotXorc

New member
Thank you for the link to the Puts article NotXorc. That is an interesting read. In fact, he says the same thing as Peter - "...none of the raw developers can handle this effect..."
You're very welcome. Thank you for providing your opinion, based on extended use. It is a fine paradox – on one hand you acknowledge the deficiencies (lens, software, or maybe a combination), but you are still so unreserved in your support. :confused: Is there a 'killer app' which makes it right for your subject matter or shooting style?
 

brianc1959

New member
Although he has not posted here to my knowledge, it seems that Erwin Puts has been mulling CA in the S2 system very recently too.

http://www.imx.nl/photo/optics/optics/chromatic.html
Thank you for the link. I had no idea the 70mm lens had such poor axial color correction. Best to not use it wide open in bright sunlight to avoid poisoning by the uncorrected deep violet light.

Even more interesting is that the 180 APO is *not* apochromatic! - unless the chromatic focal shift curve bends back to the zero line somewhere in the near-IR. But this seems doubtful because surely Leica would be bragging about it? And I thought Leica didn't abuse optical terminology the way some other manufacturers do! What are we designers and manufacturers of *real* apochromats (and superachromats for that matter) supposed to call our lenses?
 

fotografz

Well-known member
Absolutely, in a heartbeat. And, without hesitation this time. (I struggled with the decision first time around.) The S2 suits me perfectly.
Good for you Mark. And I mean that.

I think the S2 system is a lightening rod for critique for a few major reasons:

The manner that Leica has touted its lens making ability as super-superior with no need for any assistance from software .... (calling it a waste of time and money, for example). IMO, this is sort of turning a blind eye to the digital age that Leica is trying to be major player in now. It's a stubborn retro mindset that is partially the cause of the second reason below ...

The staggering pricing that even locked out many of those used to Leica's jaw-dropping prices.

This camera will remain on my radar because it would also suit me well, and suit the shift in the type of work that has taken place for me in the past two years.

If (in my example) Hasselblad had not advanced toward better fulfilling my needs with the H4D, and the economy had recovered better than it has (if at all), the S2 would have been more of a contender ... despite the critiques, most of which I think I could over-come with more experience with the camera ... and those that I couldn't overcome, I could live with because of the other unique attributes.

However, Hasselblad DID waste time and money in improving its computer based corrections, and the lenses I already paid for got even better. These improvements did not cost me one single penny extra ... meanwhile, the new camera itself cost $8K less than a basic S2 body.

So, it isn't just the previous investment in a MFD system that keeps me here, it's also that the company keeps investing in improving what I already bought from them. I don't have to deal with the shortcomings because they did.

-Marc
 

markowich

New member
Good for you Mark. And I mean that.

I think the S2 system is a lightening rod for critique for a few major reasons:

The manner that Leica has touted its lens making ability as super-superior with no need for any assistance from software .... (calling it a waste of time and money, for example). IMO, this is sort of turning a blind eye to the digital age that Leica is trying to be major player in now. It's a stubborn retro mindset that is partially the cause of the second reason below ...

The staggering pricing that even locked out many of those used to Leica's jaw-dropping prices.

This camera will remain on my radar because it would also suit me well, and suit the shift in the type of work that has taken place for me in the past two years.

If (in my example) Hasselblad had not advanced toward better fulfilling my needs with the H4D, and the economy had recovered better than it has (if at all), the S2 would have been more of a contender ... despite the critiques, most of which I think I could over-come with more experience with the camera ... and those that I couldn't overcome, I could live with because of the other unique attributes.

However, Hasselblad DID waste time and money in improving its computer based corrections, and the lenses I already paid for got even better. These improvements did not cost me one single penny extra ... meanwhile, the new camera itself cost $8K less than a basic S2 body.

So, it isn't just the previous investment in a MFD system that keeps me here, it's also that the company keeps investing in improving what I already bought from them. I don't have to deal with the shortcomings because they did.

-Marc
marc,
you hit the point precisely. the disturbing issue is leica's arrogance: best optics, no software correction needed, the other MF companies are far behind, they do ugly software corrections.....etc....etc...and fanboy reports to follow, confirming the leica advertisement campaign without or after only very limited testing. then when the serious tests start, all turns around and the truth is revealed in no time. suddenly the campaign shifts from 'best MF system around' to 'most ergonomic and rugged almost-MF system around'.
benchmark comparisms shift from Hasselblad and Phaseone to canon/nikon.
i do believe that the leica engineers are serious and hardworking people but the still need a lot of help in the software domain. surely phase could have done it and adobe is apparently not interested in doing something specific for leica.
peter
p
 

brianc1959

New member
marc,
you hit the point precisely. the disturbing issue is leica's arrogance: best optics, no software correction needed, the other MF companies are far behind, they do ugly software corrections.....etc....etc...and fanboy reports to follow, confirming the leica advertisement campaign without or after only very limited testing. then when the serious tests start, all turns around and the truth is revealed in no time. suddenly the campaign shifts from 'best MF system around' to 'most ergonomic and rugged almost-MF system around'.
benchmark comparisms shift from Hasselblad and Phaseone to canon/nikon.
i do believe that the leica engineers are serious and hardworking people but the still need a lot of help in the software domain. surely phase could have done it and adobe is apparently not interested in doing something specific for leica.
peter
p
Bear in mind that the aberration discussed here - longitudinal chromatic aberration - cannot really be corrected in software. Its something that has to be fully corrected in the lens itself.
 

thomas

New member
Bear in mind that the aberration discussed here - longitudinal chromatic aberration - cannot really be corrected in software. Its something that has to be fully corrected in the lens itself.
however dedicated tools in a raw software (e.g. C1) do a great job. From a practical standpoint it simply works!
The S2 shows CA, purple fringing and moiré ... under certain circumstances.
So a software fix would make things easier. And, by the way, as it safes time (compared to a removal in Photoshop) it also safes money ;-)
 

NotXorc

New member
Ahh, the plot thickens.
We have a new lens to CA-critique: the Summarit-S 35/2.5 is now in the wild, as reported by David Farkas.

http://dfarkas.blogspot.com/2010/07/testing-leica-summarit-s-35mm-f25-asph.html

Regarding the 35, he says, ". . . the fringe is quickly fixed with a -15 red/cyan correction in Lightroom’s Lens Correction palette, along with Leica’s recommended setting of Defringe to “All Edges.” I’d expect the forthcoming profiles from Adobe and Leica to include this correction automatically as a lens profile."

This recommendation sounds similar to Mark Gowin's advice in this thread regarding the 70mm.

Looks like I am becoming this thread's link jockey. Someone stop me before I am, you know . . . :deadhorse:
 

narikin

New member
I shoot near wide open a lot - so lots of CA and fringing. Purple fringing is easier to fix, CA is very difficult. OOF objects have broad green bands one side of them, red the other.

what is the point of a beautiful f2.5 lens if you cant use it below f4.0 on a sunny day?
 

Jack

Sr. Administrator
Staff member
Looks like I am becoming this thread's link jockey. Someone stop me before I am, you know . . . :deadhorse:
No worries, we like the external references :D
~~~

Newsflash for Leica, from Jack's "Binniss" and Marketing 101 class:

1) Arrogance does not sell well internationally, and this is especially true in the US market.

2) If you're going to make something new, don't reinvent the wheel. Instead use an existing lensmount and corresponding IC. (And at this point, I sincerely don't care whether they chose Hassy H or Mamiya M, one of the two current top sellers.) Even if you think the price to do so is too high, you've immediately expanded your potential lens market by some significant factor, and moreover, allowed your tweener, hybrid camera body concept to become a viable back-up or second to another working brand -- so have additionally expanded its potential market! (I submit this may be one reason why the Leica M remains so successful aside from its shortcomings...)

2a) Corolarry food for thought: IF Leica had opted for say the Mamiya lensmount, I personally would probably already own at least an S2 body. And if the 70 and 35 were good, I would likely own them as well. You see, I could justify the cost and the shortcomings as long as it added flexibility to my total MF system.

3) History shows over and over again that totally closed technical systems rarely survive.

Okay, maybe that's all too logical.
 

David K

Workshop Member
No worries, we like the external references :D
~~~

Newsflash for Leica, from Jack's "Binniss" and Marketing 101 class:

1) Arrogance does not sell well internationally, and this is especially true in the US market.
Unless you're selling women's handbags, e.g Hermes' Birkin Bag... up to $10k and a long waiting period for delivery. Even heard they were screening potential buyers to make sure they were of the right "sort" :)
 

markowich

New member
Unless you're selling women's handbags, e.g Hermes' Birkin Bag... up to $10k and a long waiting period for delivery. Even heard they were screening potential buyers to make sure they were of the right "sort" :)
then let us hope that leica is not after the hermes-type clients only.
peter
 

brianc1959

New member
I shoot near wide open a lot - so lots of CA and fringing. Purple fringing is easier to fix, CA is very difficult. OOF objects have broad green bands one side of them, red the other.

what is the point of a beautiful f2.5 lens if you cant use it below f4.0 on a sunny day?
Purple fringing is a form of chromatic aberration, and it can't be fixed in software - only masked by some sort of localized desaturation technique.
 

Jack

Sr. Administrator
Staff member
Purple fringing is a form of chromatic aberration, and it can't be fixed in software - only masked by some sort of localized desaturation technique.
Let's clarify this a bit further:

1) CA is a LENS aberration caused by an inability to bring all three primary colors (or secondary colors) of the visible light spectrum into precisely the same focus point on the imaging medium. Moreover, the effect is usually spread laterally, and software is exceptionally good at being able to re-align the three separate visible primary color channels and bring them into one common point -- and why it is thus "relatively easy to correct for."

2) Purple fringing is primarily a lens aberration, however it is accentuated by a digital SENSOR's excessive UV and IR sensitivity. It is [usually axial and] caused by the lens' inability to bring the short UV and long IR bands outside the visible spectrum to the same focus point as above. The distinction is that these bands are outside normal visible spectrum and it's virtually impossible to correct for them in lens design as the spread of wavelengths is far wider than the total visible spectrum to begin with. Thus, internal camera IR/UV cut filtration is probably the best approach to attenuate these; external filtration probably the second best approach. IOW, if a camera exhibits this trait, the lens is probably not the place to place the blame, rather the design of the sensor's filtration is the more relevant culprit.

3) Sensor bloom is, or rather can be, another form of fringing and can be perceived as green, red, cyan or magenta (purple) depending on the sensor design. It is caused primarily by a pixel getting over-saturated and bleeding off to adjacent pixels. The resultant aberration can vary from spots to ghosting to streaks to edge fringing. Moreover, it's primarily a CCD issue as most CMOS sensors have anti-blooming gates by design. Though many CCD's do use anti-blooming gates in their design, the attenuation isn't as efficient as with CMOS, thus we tend to see it more commonly in cameras using CCDs. Fortunately, good software will attenuate this anomaly too, the key being its ability to isolate it before the desaturation process as a global desaturation is not a viable method.

Edit: The above explanations are simplified in the interest of keeping them easy to understand. Here is a good source for those that want to investigate optical issues in more depth: http://toothwalker.org/optics/chromatic.html
 

David K

Workshop Member
Let's clarify this a bit further:

1) CA is a LENS aberration caused by an inability to bring all three primary colors (or secondary colors) of the visible light spectrum into precisely the same focus point on the imaging medium. Moreover, the effect is usually spread laterally, and software is exceptionally good at being able to re-align the three separate visible primary color channels and bring them into one common point -- and why it is thus "relatively easy to correct for."

2) Purple fringing is primarily a lens aberration, however it is accentuated by a digital SENSOR's excessive UV and IR sensitivity. It is caused by the lens' inability to bring the short UV and long IR bands outside the visible spectrum to the same focus point as above. The distinction is that these bands are outside normal visible spectrum and it's virtually impossible to correct for them in lens design as the spread of wavelengths is far wider than the total visible spectrum to begin with. Thus, internal camera IR/UV cut filtration is probably the best approach to attenuate these; external filtration probably the second best approach. IOW, if a camera exhibits this trait, the lens is probably not the place to place the blame, rather the design of the sensor's filtration is the more relevant culprit.

3) Sensor bloom is, or rather can be, another form of fringing and can be perceived as green, red, cyan or magenta (purple) depending on the sensor design. It is caused primarily by a pixel getting over-saturated and bleeding off to adjacent pixels. The resultant aberration can vary from spots to ghosting to streaks to edge fringing. Moreover, it's primarily a CCD issue as most CMOS sensors have anti-blooming gates by design. Though many CCD's do use anti-blooming gates in their design, the attenuation isn't as efficient as with CMOS, thus we tend to see it more commonly in cameras using CCDs. Fortunately, good software will attenuate this anomaly too, the key being its ability to isolate it before the desaturation process as a global desaturation is not a viable method.
Jack, thanks for this explanation, I actually think I'm beginning to understand it now.
 

brianc1959

New member
Let's clarify this a bit further:
2) Purple fringing is primarily a lens aberration, however it is accentuated by a digital SENSOR's excessive UV and IR sensitivity. It is caused by the lens' inability to bring the short UV and long IR bands outside the visible spectrum to the same focus point as above. The distinction is that these bands are outside normal visible spectrum and it's virtually impossible to correct for them in lens design as the spread of wavelengths is far wider than the total visible spectrum to begin with. Thus, internal camera IR/UV cut filtration is probably the best approach to attenuate these; external filtration probably the second best approach. IOW, if a camera exhibits this trait, the lens is probably not the place to place the blame, rather the design of the sensor's filtration is the more relevant culprit.
I've wondered about this for quite a few years now. I suspect that its not true UV (<400nm) and IR (>700nm) light that causes alot of the problems, but rather plain old visible light at the violet and red extremes of the waveband. For instance, most lenses are pretty terrible from 400nm to 435nm, but that is definitely visible light, and alot of it will leak through the Bayer array. Similarly with light from 660nm to 700nm. Some true IR might be getting through since there is typically alot of it in the scene and sensors are very sensitive to it. I doubt that true UV is playing much of a role in the purple fringing phenemenon.

BTW, if you're interested in a true medium format UV-VIS-IR apochromat with zero focus shift from 330nm out to 1100nm I'm planning to show one at Photokina. It will be 120mm f/4.5, Copal-0 mounted, 100mm image circle, and will have a manually adjustable floating element for infinity down to 1:1.
 

Steen

Senior Subscriber Member
(...) BTW, if you're interested in a true medium format UV-VIS-IR apochromat with zero focus shift from 330nm out to 1100nm I'm planning to show one at Photokina. It will be 120mm f/4.5, Copal-0 mounted, 100mm image circle, and will have a manually adjustable floating element for infinity down to 1:1.
On behalf of Coastal Optics / Jenoptic - or on behalf of Caldwell Photographic Inc ?
 
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