Yannick Khong: "The Problem with modern Optics"

[stenrasmussen]

Can you spot which is the Nikkor 50mm f/1.4 AF-D and which is the Sigma 50mm f/1.4 Art?  Someone was helpful enough to make this gif.

While it is certainly subtle, the Sigma's dynamic range in light is compressed compared to the Nikkor.  My best attempt at using my musician lingo to describe the difference in the two.  That is what makes the Art images I've seen feel a bit dull.  Over all the seem contrasty, the tonal difference feel squished.

The Sigma is the wider one..?

[Tristin]

Sten, I don't want to give away the answer yet so others can try and see if they can tell.  There are some clear indicators in the image that distinguish which is which though   

One thing I should point out though is that the Sigma Art lenses proved to be a bit wider than the nikkors with both the 35mm and 50mm.  The person who made this gif aligned/cropped the images so the perspective is not exactly the same which effects how wide the background looks.

[jhinkey]

You might be interested in this:

The problem with modern optics
http://yannickkhong.com/blog/2016/2/23/the-problem-with-modern-optics

Thoughts on the right kind of cameras and lenses
http://yannickkhong.com/blog/2016/01/31/right-gear

rgds,
Andy

PS: might contribute to the current Otus debate

I may be in the minority, but I thought the article was terrible.  Full of apples vs. oranges examples that serve to "prove" his point(s).  Everything is so subjective that is seems to be a great morass of text that really can't support any solid conclusions IMHO.

Give me some true side-by-side apples vs. apples comparisons with same camera, photographer, subject, lighting, distance to subject, etc. etc. and then it would be useful.

[Bjørn Rørslett]

On a purely scientific basis, I tend to agree. However, that is not the point. We need to learn to understand that lenses are not objective in the way they capture our images.

[Tristin]

Give me some true side-by-side apples vs. apples comparisons with same camera, photographer, subject, lighting, distance to subject, etc. etc. and then it would be useful.

Perhaps you missed the link at the bottom of the previous page in this thread, he has provided just what you ask for.

[Akira]

Sten, I don't want to give away the answer yet so others can try and see if they can tell.  There are some clear indicators in the image that distinguish which is which though   

One thing I should point out though is that the Sigma Art lenses proved to be a bit wider than the nikkors with both the 35mm and 50mm.  The person who made this gif aligned/cropped the images so the perspective is not exactly the same which effects how wide the background looks.

Well, you GAVE the answer!    The IF and RF design shortens its focal length when focused closer, which is common phenomena.

[Airy]

The contributed GIF is interesting indeed. If it can demonstrate something, it will probably be that the lens brand, cost, or generation hardly matter.

I do not expect to see a lot from compressed files, but I nevertheless tried very hard to see differences *suggested*. So yes, on the picture with the wider angle, one may see *traces* of something looking like compression (whites becoming gray-ish?), given that the rest of the picture is exposed the same way in both versions. The nuance is such faint that it is not only close to irrelevant, but could be "suggested".

Worse, lenses being passive and linear devices (WRT light intensity), I do not expect them to perform any "compression" owing to glass quality or number of elements. When a compression algorithm has been at work for producing the final image, I won't point my finger at the lens anyway.

This is not to negate that lenses have their own character, as often convincingly demonstrated here, not even needing A/B comparisons. While I definitely had sympathy for the thesis exposed in the first page of the present thread, I get more and more convinced, now that we are on page 8, that it has no merits.

[Tristin]

Things like the highlights being grey are exactly what I mean by the range of light being compressed.  Of course, whether one feels it is a significant difference is another matter.

[Airy]

Significance is of course a matter of perception, hence personal. But then, establishing a causality link is more questionable, and not a matter of perception.

[pluton]

I'm not seeing much difference between them, contrast-wise.  Note: I'm viewing on a 13" laptop, so my observation may be of reduced value.

[Jan Anne]

I'm not seeing much difference between them, contrast-wise.  Note: I'm viewing on a 13" laptop, so my observation may be of reduced value.

Same here...

[Frank Fremerey]

Can you spot which is the Nikkor 50mm f/1.4 AF-D and which is the Sigma 50mm f/1.4 Art?  Someone was helpful enough to make this gif.
While it is certainly subtle, the Sigma's dynamic range in light is compressed compared to the Nikkor.  My best attempt at using my musician lingo to describe the difference in the two.  That is what makes the Art images I've seen feel a bit dull.  Over all the seem contrasty, the tonal difference feel squished.

As far as I know the Sigma is pretty well corrected (staight lines are straight) while the Nikkor (I had it for many years) bends the lines quite significantly.

The Sigma is also made to produce more contrast, while the Nikkor is on the soft side at least wide open, so judging from the lines on the throat and the geometrical distortion I'd say the softer one with the bended lines is the Nikkor.

It is very interesting that the foreground is matched to well, esp the white balance. The color of these lenses should be different.

I guess though that the white balance is corrected in post. Very possibly on the gray card below the head.

I further guess the f-stop used in this example is 5.6 or 4, an area where the difference between these lenses is very small anyway.

If I want to shoot at 4.0 or 5.6 or 8.0 I get a better corrected lens of the 2.8 or 2.0 opening.

1.4 lenses I buy because I want to shoot them at 1.4!

[simsurace]

Things like the highlights being grey are exactly what I mean by the range of light being compressed.  Of course, whether one feels it is a significant difference is another matter.

Don't you think that the differences are so small that they can easily be corrected for during RAW conversion? It seems that moving the sliders by a few percent would already make for a bigger change than what we see here.

[Chip Chipowski]

I have a tough time narrowing down exactly what qualities I like from a lens.  I agree with those who are skeptical about YK's fundamental "thesis."  It is hard for me to see or describe any major differences in the examples he posted.  Yet I like the look produced many of the lenses he discusses, like the 35mm f/2.  Even if that lens actually does not have any special 3D magic, I like it just as much as the large, modern Sigma for my photography. So I would rather use the smaller, cheaper lens, because the "improvements" of the modern lens don't matter much to me. 

[Tristin]

Don't you think that the differences are so small that they can easily be corrected for during RAW conversion? It seems that moving the sliders by a few percent would already make for a bigger change than what we see here.

The same can be said for many properties of a lens.   A softer lens can be sharpened more, a lens with CA can have the CA corrected, a lens with distortion can have the distortion corrected.  Where you draw the line and what qualities you prioritize are up to you.

I personally would choose a lens with more pleasing rendering of the range of light and tones than one that is sharper.  Reason being, outside of really large prints, the fine detail where the sharpness really shows is lost anyhow.  The way the light/tone renders is not.  Correcting for the squashed light range the Sigma exhibits above is not as simple as bringing your whites and hilights up and all is well.  Anytime you push and pull on an image's exposure, you get closer to running into artifacts.  I'd rather the lens give me an image that needs less to look good off the bat, so that I have more latitude to shape it.  I have no doubts that most find this negligible, but it is something to be aware of.