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Comparing results is always possible fortunately but my 6-bit coded Summicron 35/2 asph v1 and 7art 35/2 look so close that i did not have the courage to do side by side comparos so far. Couple of test pics with the 7art 35/2 on the Digital CL below, most if not all at f/2. This great litle lens works fine on my M240 and Sony A7s mod as well but i prefer the handling of the Summicron 35/2 asph v1 on those bodies, also its smoother OoF rendition to be honest. Now in spite of their different prices, both lenses look very close actually. Same for the CV 35/2 BTW. Great to find lenses that good at affordable prices nowadays. 
https://lctphot.smugmug.com/Diverse/7-artisans-352-on-Leica-digital-CL/n-nJBCXF

 

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  • 6 months later...
On 6/9/2019 at 6:46 AM, loughtonsmith said:

I get the same color cast with my M-P240, but only with my CV 21/4.0.  The CV 35/1.4 and my old Elmarit 90/2.8 don’t have any color cast at all.  

 

From the reading I’ve done on really wide lenses, the color cast is expected and correctable.  I haven’t read about anyone having an issue with the 7artisans lens (regarding color)...just some critiques on bokeh, etc.

I have the same issue with this CV 21/4 - how do you correct it in Lightroom ? I tried so far to put the purple value between -30 to 70%.

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On 6/9/2019 at 5:46 AM, loughtonsmith said:

I get the same color cast with my M-P240, but only with my CV 21/4.0.  The CV 35/1.4 and my old Elmarit 90/2.8 don’t have any color cast at all.  

 

From the reading I’ve done on really wide lenses, the color cast is expected and correctable.  I haven’t read about anyone having an issue with the 7artisans lens (regarding color)...just some critiques on bokeh, etc.

The colour cast generally arises from non-Leica lenses and others (e.g. 'old' Leica ones) which do not have a their profile recorded on the camera. Other users report trying profiles of different Leica lenses with a non-Leica lens to try and reduce or eliminate the shift, a process of trial and error and possibly searching for others' experience in the Forum.

Lens colour shifts would also be symmetrical, i.e. the same in all 4 corners, not like the sample the OP submitted.

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37 minutes ago, Richardgb said:

The colour cast generally arises from non-Leica lenses and others (e.g. 'old' Leica ones) which do not have a their profile recorded on the camera. Other users report trying profiles of different Leica lenses with a non-Leica lens to try and reduce or eliminate the shift, a process of trial and error and possibly searching for others' experience in the Forum.

Lens colour shifts would also be symmetrical, i.e. the same in all 4 corners, not like the sample the OP submitted.

Leica lenses can display color shifts as well, especially wides and super wides, and 6-bit coding cannot always fix the issue. Also there is not necessarily symetry in those color shifts. True for my Leica 21/2.8 asph for example but i have less problems with later Leica lenses like 21/3.4 asph admittedly. Now this is true also for non Leica lenses like the CV 21/3.5 compared to the CV 21/4.

Edited by lct
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3 hours ago, Richardgb said:

Lens colour shifts would also be symmetrical, i.e. the same in all 4 corners, not like the sample the OP submitted.

Not always true - which is why this effect is sometimes called "the Italian Flag Syndrome" - red/magenta on one side, and blue/green on the other.

The M8, with external greenish anti-infrared filters, produced symmetrical green/cyan stains in all four corners with wider lenses. That was one issue.

But on the larger-sensor cameras (M9/240) there is this additional two-color issue, which occurs for a different optical reason - and even without using IR filters. Although the core problem is still shallow angles of incidence with certain lenses that sit close to the sensor.

This shot was made with a coded Leitz/Leica 21mm Elmarit-M on the M9 (1/2010) - with early firmware where Leica had not yet adequately "tuned" the corrections for this legacy lens. The white (or pink, or blue-green) snow is especially revealing of the problem.

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The current theory is that this is caused by the essential asymmetry of the basic Bayer-color-filter quartet, and angular leakage (or "crosstalk") of green light from green-filtered pixels (the most numerous and brightest) onto the silicon of neighboring red pixels in one direction and blue pixels in the other.

Leica has been reworking the layers of their sensors, in the M(240) - and yet again for the M10 - to reduce such directional spill. With steeper microlenses, and thinner internal layering of the silicon to block the leakage. But it is still not perfect.

https://leicarumors.com/2012/09/19/the-24mp-max-sensor-inside-the-new-leica-m-is-mabe-by-cmosis.aspx/

BTW, it is not totally a Leica problem - the effect was noted, and got its name from, Kodak's first 24x36 sensor in the DCS Pro 14n (2003). It is just 'worse" with short-focus rangefinder lenses.

https://www.dpreview.com/forums/post/37257846

 

Edited by adan
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I went from an M8  to an M240 (M-P) and was horrified to find the Italian flag on any of my lenses from 28mm and wider.  WTF.

Another droob with Leica..have to manually focus, no live-view, no macro, parallax errors, work the files, crap flash synchro, very expensive...and now some weird edge colours.

Just damn lucky i love you guys (and the system)...and Flat Field Correction...🤔

😂😂

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Well, it's interesting....

The picture below was made with an un-IDed, uncoded (and uncodable) 1976 28mm Elmarit v.2 on an M10.

Now, this version 2 was the one introduced for the M5 metering, and has the longest back-focus of any M-28 (except maybe the tiny Summaron) - Leica rather overcooked the retrofocus design (and dialed it back a bit with subsequent versions) to be sure of clearing the M5/CL metering arms.

Nevertheless, some combination of the lens design and the additional M10 sensor revision completely eliminate any color vignetting at 28mm, even without a profile. No Italian Flag or other color shifts at all.

That feature, plus a generally lower contrast (but high saturation) has made this 28 my new "best-friend-forever" for digital, even though it is a bit weak at f/2.8.

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I have the 7A 35mm f2, 50mm f1.1 and the 28mm f1.4 and used them with M240 and M10 cameras. The 35 and the 50 came from the factory with six bit coding, the 28mm did not. Only the 50mm gives me odd color casts on the edges, and then only in certain situations. I really notice it when I photographed a snow scene. The other two lenses work just fine and the 50 is terrific for low light work or wide aperture portraiture.

I think that 7Artisans does not six bit code any of their Leica M mount lenses anymore.

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17 hours ago, lct said:

Leica lenses can display color shifts as well, especially wides and super wides, and 6-bit coding cannot always fix the issue. Also there is not necessarily symetry in those color shifts. True for my Leica 21/2.8 asph for example but i have less problems with later Leica lenses like 21/3.4 asph admittedly. Now this is true also for non Leica lenses like the CV 21/3.5 compared to the CV 21/4.

 

15 hours ago, adan said:

Not always true - which is why this effect is sometimes called "the Italian Flag Syndrome" - red/magenta on one side, and blue/green on the other.

The M8, with external greenish anti-infrared filters, produced symmetrical green/cyan stains in all four corners with wider lenses. That was one issue.

But on the larger-sensor cameras (M9/240) there is this additional two-color issue, which occurs for a different optical reason - and even without using IR filters. Although the core problem is still shallow angles of incidence with certain lenses that sit close to the sensor.

This shot was made with a coded Leitz/Leica 21mm Elmarit-M on the M9 (1/2010) - with early firmware where Leica had not yet adequately "tuned" the corrections for this legacy lens. The white (or pink, or blue-green) snow is especially revealing of the problem.

The current theory is that this is caused by the essential asymmetry of the basic Bayer-color-filter quartet, and angular leakage (or "crosstalk") of green light from green-filtered pixels (the most numerous and brightest) onto the silicon of neighboring red pixels in one direction and blue pixels in the other.

Leica has been reworking the layers of their sensors, in the M(240) - and yet again for the M10 - to reduce such directional spill. With steeper microlenses, and thinner internal layering of the silicon to block the leakage. But it is still not perfect.

https://leicarumors.com/2012/09/19/the-24mp-max-sensor-inside-the-new-leica-m-is-mabe-by-cmosis.aspx/

BTW, it is not totally a Leica problem - the effect was noted, and got its name from, Kodak's first 24x36 sensor in the DCS Pro 14n (2003). It is just 'worse" with short-focus rangefinder lenses.

https://www.dpreview.com/forums/post/37257846

 

Hmm, I stand corrected - thanks🤔

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Amazing I never really noticed this phenomenon until reading through this thread; after looking through some images, I found an example as can be seen on the far right:

This was taken with version 1 of the CV 15/4.5 Super-Wide Heliar with a LTM adapter I had 6-bit coded as the f/4 WATE.

Edited by cobbu2
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  • 2 weeks later...
On 6/11/2019 at 7:50 PM, Fredrik_Jalhed said:

No, no more colorcast.. I really wasn't excepcting this from 7artisans, though I know its a Chinese brand.. 

Is the first time I see such a purple/magenta cast with a 7Artisans lens on a M240.
I don't have this lens, but saw many pictures taken with them and never seen such a mess.
Al people I saw is very happy with these lenses. 

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On 1/2/2020 at 4:15 AM, cobbu2 said:

This was taken with version 1 of the CV 15/4.5 Super-Wide Heliar with a LTM adapter I had 6-bit coded as the f/4 WATE.

Allan, the purple/magenta cast with the CV 15/4.5 versions 1 and 2 is notorious on the M240 and maybe also on the M10.
The only version of this lens with the problem solved is version 3, the most recent.

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5 hours ago, epand56 said:

Allan, the purple/magenta cast with the CV 15/4.5 versions 1 and 2 is notorious on the M240 and maybe also on the M10.
The only version of this lens with the problem solved is version 3, the most recent.

Interesting, thanks. I think a big reason I never noticed it in the past was that I used this lens almost exclusively on the M8; the M8's sensor would crop out the area of discoloration. Since the M240 is full frame, it would make sense that the issue only now becomes noticeable.

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Am 2.1.2020 um 04:15 schrieb cobbu2:

...I had 6-bit coded as the f/4 WATE.

Try another coding - e.g. 21mm Elmarit (non asph). The WATE has a completely different lens design which is not much prone to produce the magenta shifts. So there is less correction of this issue for the WATE. It may not go away completely with another correction for you 1. version Super Heliar, but may get less obtrusive. 

 

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