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07-30-2011, 07:35 AM   #1
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Sigma 24mm f2.8 Super-Wide II (Manual Focus)

On APS-C: (K10D)










On film (K1000). Both pictures are slightly straightened and cropped.







10-29-2012, 06:16 AM   #2
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10-29-2012, 08:18 AM   #3
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it is interesting that in both these images I perceive that there is a substantial lateral CA. I have questioned this before, as I have a Sigma Mini Wide II 28mm which i find the lateral CA is not acceptable without using an image editor that has geometric rescaling of the color layers as the correction method, but when I question this regarding the 24mm people say it does not exist. Any chance of posting a 100% resolution clip out of the corner or side to see better.
10-29-2012, 10:59 AM   #4
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Lateral CA? Not sure what you mean, where do you see it? My main gripe with this lens is that it makes everything really blue, and it flares very easily.

10-29-2012, 11:49 AM   #5
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lateral CA is the separation of colors, due to the difference in magnification of each color, it is manifested by shadings that are red-purple on one side of a subject and green-blue on the other side, it radiates out from the middle of the image.

it is best seen on the second photo, look at the person on the led ft hand side of the photo, with the yellow coat/smock.

there is a red outline on the upper left side of the person and a green outline on the right.
10-29-2012, 12:10 PM   #6
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I'm struggling to see it, but if you say so... Much less of a problem than the blue cast and the flare IMHO.
10-29-2012, 01:36 PM   #7
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It is there in most photos, the problem seeing it is because the photos are downsized by about 5:1 for posting. Look at the original images and you will see about 5-6 pixels of a color halo or band around each edge.

10-29-2012, 05:20 PM   #8
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Lightroom 4 gets rid of that quite nicely with zero effort (single checkbox -- I have it enabled by default). It noticeably sharpens images from lenses that suffer from bad lateral CA. That's what is nice about the advancing technology -- it is making these old lenses better than they have a right to be.
11-05-2012, 03:35 AM   #9
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Full size shot with Sigma 24mm Superwide II on Sony NEX3:



Note red CA in reeds:



Removed in LR3 without severely affecting image sharpness (I have a preset for this):


Last edited by ihasa; 11-05-2012 at 03:42 AM.
11-05-2012, 03:45 AM   #10
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Extreme border crops (after PP):





11-05-2012, 03:51 AM   #11
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Same again with the CA left in:





11-05-2012, 03:54 AM   #12
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Another sample shot on Sony NEX3:

10-07-2013, 08:04 PM   #13
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These are with the AF version, but same optics from what I know.




08-29-2017, 08:57 AM   #14
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Whatever I did, I could not like this lens. Below are three photos, with two before-after comparisons, for you to see what this lens can, and cannot, do.
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