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Author Topic: Expert Opinion needed , Sigma ART , micro-contrast and depth rendition Previous  (Read 6825 times)

yair

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Dear All,

I seek an advice from an expert on this subject.

i have being reading this blog :

http://yannickkhong.com/blog/

http://yannickkhong.com/blog/2016/2/12/extra-credits-applying-the-micro-contrast-test-onto-an-otus-lens

After i saw this YouTube channel

https://www.youtube.com/playlist?list=PLbUhhy2IMh89QSP5dpDiibNwf6q49qHcX

( Try to over look this guy crazy attitude , and stick to the content , i at start thought he is crazy , he is not)

Than i started examining those claims myself , and i must say i find them very real.

I shoot with D810 / Sigma ART lens (20,35,50) for a while now and i really feel those guys claims that those lens lack micro-contrast and have bad depth rendition are true.

Plus recently i bought a Nikon 24-70 2.8 G , and every shoot i take looks less sharp than my sigma ART yet it is full of life and 3D pop and beautiful colors.

I can't get My Sigma ART pictures to look this way, honestly no even close.

What do you feel about their claims on the Zeiss Milvus line ? Are the older designs better in that aspect ?

I use both LR and Capture One , and my WB is correct on all cases.

Do you agree with them ? Am i missing something ?

I am heavily invested in the ART series and before selling it i want to be sure.

Thanks in Advance ,

Yair
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dwswager

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I can't answer you directly with respect to the Sigma Art lenses.  However, I switched from Canon to Nikon a long time ago specifically because I preferred the rendition of Nikon lenses.

While we all want sharpness and preservation of as much detail as possible, this is only one aspect of a len's rendering of the image.  We are currently in the period of "psychotic sharpness" that reminds me of the "over saturated" Fuji Velvia period.  An image is meant to invoke thought and emotion.  Some of my favorite photographs are not favorites because I notice how sharp they are!
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John Koerner

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It's funny, I have just purchased all 3 elder, classic, all-manual Nikon lenses (50mm, 35mm, and 28mm) for the specific purpose of using on a reverse-ring for macro studio photography.

They all have 52mm front filter elements, which is the most common reverse-ring size also.

Even though these timeless Nikon lenses got rave reviews, I couldn't help imagining a Zeiss Otus reverse-mounted for macro.

I was actually going to post a thread about this topic, asking if anyone had ever tried it (and if it was even possible) ... but nevermind, since micro-detail is what I am after :)
« Last Edit: February 16, 2016, 10:59:59 am by John Koerner »
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Colorado David

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I liked Fuji Velvia.  So did a lot of other photographers. Of course, at the time, there were discussions about how images shot with Velvia weren't real photography. ;)

Ghibby

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I disagree that the Sigma ART series lack micro contrast.  They may not have quite as much of it as some of the other lenses mentioned but still have plenty to give images the 3d feel and pop you talk about.  I think that some of the look that we crave on older lens designs stems from the fact that they are not as highly corrected as their modern counterparts with regard to optical aberrations, and I mean all optical aberrations from simple spherical to more complex primary and secondary LOCA.

Different processing of images can help to bring out micro contrast that is present in the images. The clarity slider in LR and the far superior controls for clarity available in Capture one will help bring back a lot of this pop. 

I am using the 35 and 50 art on a Canon EOS 5Ds and personally love the rendering of these lenses, especially the 50 which is capable of slicing the scene into regions of depth very effectively. It may not quite rival the Zeiss lenses, certainly the 3D feel from the 100mm Makro Planar is astonishing but the Sigmas are pretty good IMO. 

Perhaps best to shoot a few comparable lenses of the same focal lenght side by side before ditching your investment in Sigma Art. Process the images in a way that suits the rendering of each lens rather than just using identical settings, then decide what to do.  I think when it comes to comparing things like this that the technical and more scientific approach is helpful to a point, but taking a more creative and looser approach to just using them creatively and working with each lens in a more targeted way is the best way to decide for yourself.  Yannicks info is interesting but not exactly the last word on the subject. 

Ben
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NancyP

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Well, I haven't used the Zeiss 35, but I do like the Sigma Art 35.
I would be very curious to compare output of the Sigma Art 20 (I don't have it) with the Zeiss 21 (which I do have) at same aperture.

Some of the old manual film era lenses are quite nice and have good rendition, even if not as sharp as modern computer-design lenses. There is always a trade-off in optical design, no such thing as a perfect lens, the designer chooses resolution and aberration characteristics. The old double Gauss design fast normal lenses (50-60mm f/1.2 to f/1.8) have whopping aberrations wide open that give them a different look than the premium 50s of today.
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dwswager

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I liked Fuji Velvia.  So did a lot of other photographers. Of course, at the time, there were discussions about how images shot with Velvia weren't real photography. ;)

I liked and shot Velvia a lot. It was a specialty product, but people used it to try to make uninteresting photos interesting by cranking the saturation levels.    I actually used Kodacrhome and Astia for accuracy.

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yair

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Thank you everybody for the relevant response.

 I do have the sigma 20 mm 1.4 art and I don't have the Zeiss 21 mm  2.8

And would love to see a comparison between them.

Thank you

Yair
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Bart_van_der_Wolf

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Dear All,

I seek an advice from an expert on this subject.

i have being reading this blog :

http://yannickkhong.com/blog/

http://yannickkhong.com/blog/2016/2/12/extra-credits-applying-the-micro-contrast-test-onto-an-otus-lens

After i saw this YouTube channel

https://www.youtube.com/playlist?list=PLbUhhy2IMh89QSP5dpDiibNwf6q49qHcX

( Try to over look this guy crazy attitude , and stick to the content , i at start thought he is crazy , he is not)

Than i started examining those claims myself , and i must say i find them very real.

Hi Yair,

Although his examples do show a difference in rendering, I think his analysis of the cause is a bit crazy. Also comparisons between lenses with significantly different widest apertures is meaningless for analysis of the root cause.

It's obvious that, even with good coating, each lens element of group will introduce some loss of definition due to impurities and glare. Uncoated air to lens surfaces lose as much as 2.5% of the incident light at each surface, and that will bounce around inside the optical system, lens element edges, and inside of the lens barrel. Coating will reduce that to a fraction of a percent per surface, but many surfaces do add up to a still significant glare contribution. Glare will lower the contrast of a lens.

The lower contrast is compensated by a more accurate rendering and possibly higher MTF in other parts of the lens response, without or with reduced other aberrations like chromatic or spherical aberrations that affect resolution. That doesn't mean there are fewer tones, it's just that their contrast is lower.

The solution is to use properly/better dimensioned lens hoods (may be difficult with a Zoom lens), and compensate the remainder in postprocessing. To me, Topaz Labs Clarity seems like the perfect tool for that job.

Cheers,
Bart
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== If you do what you did, you'll get what you got. ==

John Koerner

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Thank you everybody for the relevant response.

 I do have the sigma 20 mm 1.4 art and I don't have the Zeiss 21 mm  2.8

And would love to see a comparison between them.

Thank you

Yair

DxO Mark Comparison

Doesn't look like much of a contest, really.
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NancyP

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Sigma Art 20 may well be sharper by DXO (18, vs Zeiss 21mm at 15), but we were talking about the overall rendering, and also about characteristics across the field of view. DXO numbers are limited in their specificity. Also, the overall lens score is heavily biased by the maximum aperture. So I am hoping for a comparison IN ACTUAL USE by a user who has worked with both lenses. My interest is somewhat hypothetical at this point, since the camera I use (6D) is clearly outresolved by the Zeiss lens IRL, and I enjoy the images I get from the Zeiss 21 (and don't miss AF). I also confess that I can enjoy output from technically inferior legacy lenses, eg, AIS Nikkor 105 f/2.5, AIS Nikkor 50 f/1.2. The Nikkor 50 f/1.2 is actually a pretty good landscape lens at f/2.8 to f/8, and is fairly light (half the weight of the Sigma Art 50) so it fits into a multi-lens kit.
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dwswager

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... So I am hoping for a comparison IN ACTUAL USE by a user who has worked with both lenses.

That is the point!  Lab measurements are all fine and dandy, but what most people really care about is how a lens renders an image overall.  I think people get too wrapped up in this measurement or that.

There is another recent thread discussing the $3000, used, Nikon Noct.  The reason it is $3000 used is how it renders.  There are lenses that measure much better in this specification and that, but no other lens in its focal length renders with such ethereal quality while still being accurate like the Noct.
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John Koerner

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The Nikkor 50 f/1.2 is actually a pretty good landscape lens at f/2.8 to f/8, and is fairly light (half the weight of the Sigma Art 50) so it fits into a multi-lens kit.

It is actually sharper than all of the newer/AF 50mm lenses and, importanly, it also has a reverse-ring-friendly front filter size of 52 mm if one wants to reverse the lens and get 1:1 macro shots (even greater if extension tubes).

More importantly still, since the aperture is manual, this too can be adjusted in reverse-mode.

It is, by far, the most versatile of the 50mm options IMO.
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NancyP

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If I am hiking a cumulative 1000 ft elevation in a day hike, I will be much happier with the 400 gram AIS Nikkor 50 1.2 than with the 850 gram Sigma Art 50!
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kers

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http://yannickkhong.com/blog/2016/2/12/extra-credits-applying-the-micro-contrast-test-onto-an-otus-lens
hello yair,

Must say the quoted 'test' is not much of a test at all. If i test my lenses from time to time i have learned it needs to be done very carefully and repeatedly and then still be careful not to jump to fast conclusions. Not a simple shot from the hip in the local store between coffee and lunch with a smiling girl.

For the youtube man i also find his statement not very trustworthy; a simple change in raw conversion or slightly different sharpness setting may change the situation from A to B.
In his second video about microcontrast the snow is al lot more blue on the Zeiss than on the Canon lens... so could we change the subject to Zeiss lenses produce bluer whites? Yes! look here!...



If a lens is actually sharper it produces more detail and colour gradients... a more delicate toned image that may look less contrasty from a distance because of being more delicate and detailed.
What is called microcontrast here -i think -should be called contrast between objects. It is not micro at all.

Microcontrast to me is contrast between pixels as seen at 100% on screen, not between objects in a 5 % enlarged image.
At any given enlargement of the image you need to adjust the addition of sharpness and contrast to make it come out best; but that is post production, done in software.
At 100% on screen a not so sharp lens will be muddy and a sharp lens will show detail; in other words ... micro contrast.

Then i do have the 50mm sigma Art lens and think it is very, very good. i like the rendering very much and the contrast. Coatings and sharpness is better than the 1.8 and 1.4 AFS nikkors.
It produces very natural looking images with lots of detail, even @ F1.4 ( A shame Nikon did not make a very good 50mm lens)

That said, I do think the coatings and lens design in general are of influence on the perceived contrast. All lenses have their own specific rendering.
The 58mm Nikkor lens is a good example of that. Very strong colours (very good coatings, probably nanocoating on more lens surfaces), in this case combined with a remarkable small depth of field.
It is not very sharp wide open...so @ 1.4 when viewed  100% on screen it will have less microcontrast then the sigma 50 ART.
If we downscale the images to 50% ( 3500pixel) the sharpness problem of the Nikkor has gone, and it will produce probably more contrasty images than the Sigma does.
In the end the photographer has its own taste and sensitivity of what is better looking.

The photographs i have seen made with the 20mm Sigma did not appeal  to me- very sharp yes, but to my eyes not a very nice rendering. (Also strong field curvature)
I got the 24mm 1.8 Nikkor and like its rendering and colours very much.

« Last Edit: February 17, 2016, 07:03:18 pm by kers »
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ErikKaffehr

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Hi,

My take is that good lenses are pretty good when stopped down.

In bokeh kind shots there can be a lot of difference as correction of spherical aberration can play nasty surprises in out of focus areas. I did not made a lot of comparisons but I would say I see little difference between say my Planar 120/4 macro on the Hasselblad and my Minolta 100/2.8 MD Macro on the Alpha 99, nor did I see a lot of difference between the Planar 120/4, the Minolta 100/2.8 and the Sony 70-400/4-5.6 G when shooting all three on the Sony A99.

I am pretty sure the new Sigma Art series lenses are great. The Nikkors are said to be designed for good bokeh. Nanocoatings probably also help.

I don't think lenses have a lot of colour. I have not seen that in my comparisons and white balance probably takes care of most differences between lenses. Also, I would say that colour is mostly decided by the camera profile in the raw developer. Or decided by the camera's JPEG processing if you shoot JPEG.

Web size images say little about a lens. A small issue is that almost all lenses vignette. A program like Lightroom may be set to apply lens corrections automatically. So, a Canon lens may have vignetting corrected automatically. Put a Zeiss lens on the same camera and it may have no automatic lens corrections, so Lightroom may not correct vignetting.

But, most images look a bit better with some vignetting.

Best regards
Erik

Best regards
Erik

hello yair,

Must say the quoted 'test' is not much of a test at all. If i test my lenses from time to time i have learned it needs to be done very carefully and repeatedly and then still be careful not to jump to fast conclusions. Not a simple shot from the hip in the local store between coffee and lunch with a smiling girl.

For the youtube man i also find his statement not very trustworthy; a simple change in raw conversion or slightly different sharpness setting may change the situation from A to B.
In his second video about microcontrast the snow is al lot more blue on the Zeiss than on the Canon lens... so could we change the subject to Zeiss lenses produce bluer whites? Yes! look here!...



If a lens is actually sharper it produces more detail and colour gradients... a more delicate toned image that may look less contrasty from a distance because of being more delicate and detailed.
What is called microcontrast here -i think -should be called contrast between objects. It is not micro at all.

Microcontrast to me is contrast between pixels as seen at 100% on screen, not between objects in a 5 % enlarged image.
At any given enlargement of the image you need to adjust the addition of sharpness and contrast to make it come out best; but that is post production, done in software.
At 100% on screen a not so sharp lens will be muddy and a sharp lens will show detail; in other words ... micro contrast.

Then i do have the 50mm sigma Art lens and think it is very, very good. i like the rendering very much and the contrast. Coatings and sharpness is better than the 1.8 and 1.4 AFS nikkors.
It produces very natural looking images with lots of detail, even @ F1.4 ( A shame Nikon did not make a very good 50mm lens)

That said, I do think the coatings and lens design in general are of influence on the perceived contrast. All lenses have their own specific rendering.
The 58mm Nikkor lens is a good example of that. Very strong colours (very good coatings, probably nanocoating on more lens surfaces), in this case combined with a remarkable small depth of field.
It is not very sharp wide open...so @ 1.4 when viewed  100% on screen it will have less microcontrast then the sigma 50 ART.
If we downscale the images to 50% ( 3500pixel) the sharpness problem of the Nikkor has gone, and it will produce probably more contrasty images than the Sigma does.
In the end the photographer has its own taste and sensitivity of what is better looking.

The photographs i have seen made with the 20mm Sigma did not appeal  to me- very sharp yes, but to my eyes not a very nice rendering. (Also strong field curvature)
I got the 24mm 1.8 Nikkor and like its rendering and colours very much.
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Erik Kaffehr
 

yair

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The photographs i have seen made with the 20mm Sigma did not appeal  to me- very sharp yes, but to my eyes not a very nice rendering. (Also strong field curvature)
I got the 24mm 1.8 Nikkor and like its rendering and colours very much.

Thank you for the response, i am learning.The 24 1.8 G looks like a great buy :)
 
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yair

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Hi Yair,

The solution is to use properly/better dimensioned lens hoods (may be difficult with a Zoom lens), and compensate the remainder in postprocessing. To me, Topaz Labs Clarity seems like the perfect tool for that job.

Cheers,
Bart

Thanks Bart , i downloaded a trail of the Topaz Labs Clarity, you are right! it really is the tool i needed , Thanks a lot!
Yair
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RobertJ

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Regarding this test: http://yannickkhong.com/blog/2016/2/12/extra-credits-applying-the-micro-contrast-test-onto-an-otus-lens

He's confusing a lack of microcontrast with the Otus' superior background blur.  Where the Nikon is harsh, the Otus is smooth, pleasing, and superior in every way.
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