Help with Sigma 56mm

Dch

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Nov 20, 2013
Messages
71
Hi,
i just received a sigma 56mm 1.4; i had high hopes for it and did a quick test against my Oly 45mm 1.8
Upon opening the shots in C1, first thing i noticed is the lack of correction for the Sigma, showing some pinchcushion distrotion; i just fixed it manually, although it was already a nuisance.
Then i immediately noticed some strange coloring on the Sigma samples, even without zooming in; i have no idea if it's some reflection from the camera's sensor or what.
These are two samples, small 100% crops, both at f/2.8, same WB and no adjustments:
Oly:

Olympus_45.jpg
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Sigma:

Sigma_56.jpg
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What the hell is going on here? I checked the newspaper and there is no trace of that stuff.
I can see how much sharper the Sigma is, and it's nice to use, brighter and so on: but this is so off...
Thnak you for all the suggestions,
D.
 

mawz

Mu-43 Veteran
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Mar 2, 2013
Messages
243
That's colour moire

You're getting it because of the extra resolution of the Sigma combined with the regular texture pattern in the newspaper halftones.
 

Dch

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Ok, but i do get it in the f/1.4 shots of the Sigma and not in the f/2.8 of the Oly...
Yet indeed it is stronger the more the Sigma is stopped down; i suppose it is also because of the distance difference: right for the moiré in the Sigma to show and not for the Oly.
Still, i've never seen such moiré in years of shooting with several bodies and lenses; granted, i do not shoot newspapers on the wall often ;-)
 

RAH

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There's something very strange about the original post - if you are a subscribing member, it shows the camera and lens info below a posted picture. Under BOTH images, it says it was taken with the Oly 45mm lens. @Dch , are you sure about these images? Here is a screen snapshot of what a subscriber sees, with the oddity circled:
m43_forum_snap1.png
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Dch

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Messages
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There's something very strange about the original post - if you are a subscribing member, it shows the camera and lens info below a posted picture. Under BOTH images, it says it was taken with the Oly 45mm lens. @Dch , are you sure about these images?
Yes, sorry for the mess: i stacked both captures in PS to crop them the same and the base layer was the Oly...
 

mawz

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Messages
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Ok, but i do get it in the f/1.4 shots of the Sigma and not in the f/2.8 of the Oly...
Yet indeed it is stronger the more the Sigma is stopped down; i suppose it is also because of the distance difference: right for the moiré in the Sigma to show and not for the Oly.
Still, i've never seen such moiré in years of shooting with several bodies and lenses; granted, i do not shoot newspapers on the wall often ;-)


It's tied partially to the resolution of the lens and partially to the frequency of the detail.


The combination of the two produces the moire.
 

Brownie

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Hi,
i just received a sigma 56mm 1.4; i had high hopes for it and did a quick test against my Oly 45mm 1.8
Upon opening the shots in C1, first thing i noticed is the lack of correction for the Sigma, showing some pinchcushion distrotion; i just fixed it manually, although it was already a nuisance.
Then i immediately noticed some strange coloring on the Sigma samples, even without zooming in; i have no idea if it's some reflection from the camera's sensor or what.
These are two samples, small 100% crops, both at f/2.8, same WB and no adjustments:
Oly:

View attachment 893190

Sigma:

View attachment 893191

What the hell is going on here? I checked the newspaper and there is no trace of that stuff.
I can see how much sharper the Sigma is, and it's nice to use, brighter and so on: but this is so off...
Thnak you for all the suggestions,
D.
Have you tried any other subject matter?
 

RAH

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Have you tried any other subject matter?
All kidding aside, @Dch , I don't think that a newspaper is a good subject for testing a lens. All those dots in the printing probably cause a lot of trouble. Even some higher-quality images (magazine printing, etc) would be better, I should think. Any brick walls around your neighborhood? Cereal boxes? Etc...
 

Dch

Mu-43 Regular
Joined
Nov 20, 2013
Messages
71
Have you tried any other subject matter?
Indeed ;-)
I was just reviewing several snapshots taken this afternoon with both lenses: Sigma, even wide open, is very, very impressive.
What i'm not so sure about is overall rendition: the Oly, while not as sharp, seems less contrasty (in a good way) and more pleasing. But overall, an impressive lens; i'll take more pictures tomorrow and see if i actually like it enough.

I don't see the Sigma 56mm listed here: https://support.captureone.com/hc/e...t-in-Capture-One#h_01F509T6WENGMHNCR6M0AJH2M6

So apparently that's a problem of Capture One. I know that at least DxO PhotoLab does have lens corrections available for the Sigma 56mm.
One more reason to try PhotoLab (or the RAW equivalent, can't remember the name); i just hate to add steps in the workflow, though...
 

Dch

Mu-43 Regular
Joined
Nov 20, 2013
Messages
71
Other than the colors I like the Sigma better in your OP, but then I'm a contrasty kind of guy. The Oly looks flat and dull in a direct comparison.
I find it easier for portraits if the lens is not extremely sharp and also contrasty; OTOH i had and used the Oly for years and i'm quite used to it: i'll have to try the Sigma more.
It definitely feels much more substantial and robust, and the manual focus is miles ahead of the tiny 45 1.8; if i had an M1 ii (trying to get one used, but...) it would probably be a great match!
 

WT21

Mu-43 Legend
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Feb 19, 2010
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Are you using an EM5 original? One reason I didn't keep that camera long is I don't feel it got along with non-Oly lenses. A lot of magenta colors and pf out the wazoo. I'm on Panasonic now, and the S56 sings. I think the newer Olys also control for purple a bit more with at least Panny lenses. Or it could be color moire. I don't know much about that, TBH.
 
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RAH

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Rich
Are you using an EM5 original?
It appears that he is. Below is a forum snapshot of an image I posted earlier that I had taken with my E-M5.3. It shows the "MarkIII" info as well as the model.
m43_forum_snap2.png
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Dch

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Nov 20, 2013
Messages
71
Are you using an EM5 original? One reason I didn't keep that camera long is I don't feel it got along with non-Oly lenses. A lot of magenta colors and pf out the wazoo. I'm on Panasonic now, and the S56 sings. I think the newer Olys also control for purple a bit more with at least Panny lenses. Or it could be color moire. I don't know much about that, TBH.
Indeed i am. I will try it on the GX80 i also have and see if it works better.
 

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