What is meant by a '3D quality' in reference to some lenses?

[James B.]

Read this interesting comparison of Leica Summilux C vs Cooke S4

http://www.hurlbutvisuals.com/blog/2014/03/why-do-we-want-flat-glass/

But I am confused by this description. Is '3D quality' something that is subjective, or is it something that can be measured like local or micro-contrast?

And is it actually the increased 'local contrast' exhibited by a lens that gives it a '3d quality'?
I have some Zeiss ZE glass and a quick google search both on Reduser and elsewhere will turn up many threads where people talk about this '3d quality'.

But what is it?

 

[Steve Das]

Looks like Cooke wins out over Leica in this pretty much.

There is that micro-contrast quality of lenses but in this test
seems like 3D is more referred to in terms the geometric perspective
that is popping the foreground/people forward while the background
and the depth of field falls off into total softness.

 

[Phil Holland]

While a useful comparison this isn't exactly groundbreaking news. This does exemplify why it's extremely important to test lenses yourselves for whatever type of production you're shooting.

More or less this shows the difference between spherical and aspherical design and the effect each has on the image. For some curvature of field/distortion isn't exactly desirable, however, in this test Shane finds it produces the look that suits his and his director's preference.

I'm pretty familiar with both of these sets of primes. One thing I can say is while the 21mm was tested with a cowboy frame if you attempt to shoot a medium or close up with the 21mm Leica Summilux-C you will see distinct advantages to the flatter draw of the lens.

That's not to detract from the Cooke S4s and the Cooke Look, port of which is this particular level of distortion. Some prefer it. Some don't. The Cookes have shot plenty of gorgeous films over the years.

Lens character and technical performance is a very heavy conversation for most DPs. Many of the top tier guys find a set of primes (or two) they enjoy shooting with and stick with that for a long time. The only thing that is important from a shooter's perspective is to understand a lens's strengths and weaknesses to get the image you want from them.

One fun thing I'm not such a big fan of is breathing while focusing, the zooming effect you get when pulling focus. Some lenses have minimal breathing, some have none, most exhibit it in some way or form. One of the reasons I didn't go with the Zeiss Ultra Primes for my personal lens set was exactly this. For instance the Ultra Prime 32mm T1.9 breathes like a pig, however the Zeiss T1.3 32mm Master Prime does not. It's a more "wrangled" design that for me is pleasing to shoot with - which is important for a lot of folks at this particular focal length.

I often think to Kubrick and how he was trying to create moving paintings with much of his work. If all the paintings on the big screen looked the same it would be boring indeed.

These last couple of years with all the time I've spent with various primes and zooms, literally all of them that are available, I've more or less come to the conclusion that there is no "best lens". Only the best lens suited for your project and budget. While there is such a thing as the "technical best lens" that doesn't always mean it's the best choice for a given story, look, or feel.

Shocked to see that Panavision Primos were brought up in a somewhat negative way here. Those are some of the prettiest lenses around in my opinion. But to each their own

Shane's a good and hard working guy with a great eye for lighting and framing. Glad he put this together.