Topics

Bigger is better and VistaVision

Art Adams
 

It is shot with a field of view equivalent to a 50mm in Academy 35mm film. This is obvious, despite the visual cues that make people think this is a wide shot.

I'm curious how you know this. It makes sense, but that would mean this shot was taken with a 100mm lens. It feels wider than that, but it could just be that I'm being thrown off by depth cues. Omar Sharif appears to be right next to O'Toole, and yet he's considerably smaller. Then again, I think they're on horses at this point...
 
Addfitionally Peter O’Tool carries much brighter make up and he is lit with Brutes. What you confuses you most is that you can see the “bounce from below” board in his eyes. This gives a bit of dimensionality

Yes, it's beautiful. I love light from below on faces.

--
Art Adams
Director of Photography
San Francisco Bay Area

Paul Curtis
 

I agree with Argyris and using that sphere would be super helpful.

Or is there any value in also doing this virtually?

Set up a CG scene, using different virtual film backs and virtual lenses and compare. That way you can have a control test using 'perfect' optics. Then i'm pretty sure we're talking about the fact that when comparing small backs to large backs you're really comparing the optics of one lens to another.

Or does everyone think that technically it would be identical and that would be a pointless sidetrack?

cheers
Paul

Paul Curtis, VFX & Post | Canterbury, UK

Argyris_Theos_cml
 

Or does everyone think that technically it would be identical and that would be a pointless sidetrack?

I do.
However I would like to remind you that even in the 1960's every DP would run his own lens tests that would include depth of field as no two lenses were equal at the time, even if they were both e.g. Cooke Series II 25's

So unexpected things can happen with vintage and intermediate glass.
That would include geometry of course.
Best

Argyris Theos, gsc
DoP, Athens Greece,
theos@...
+306944725315
Skype Argyris.Theos
www.vimeo.com/argyristheos
via iPhone

Argyris_Theos_cml
 

I'm curious how you know this

I know it and you also know it because that's what we do for a living.
You just need to accept it.

Argyris Theos, gsc
DoP, Athens Greece,
theos@...
+306944725315
Skype Argyris.Theos
www.vimeo.com/argyristheos
via iPhone

Art Adams
 

I found this online while doing a search for large format vs. 35mm comparisons:

https://wolfcrow.com/blog/why-does-the-revenant-look-so-3d-and-life-like-what-makes-the-65mm-format-special/

This somewhat illustrates the difference in perceived depth between large format and S35.

This video does a great job of showing how 70mm film represents depth in a unique way to 35mm/S35. In spite of the low video quality, the large format sense of depth and resolution still holds up:


A direct comparison of 70mm cropped IMAX vs. 35mm anamorphic capture:


And, lastly, the highest resolution selection of clips from Lawrence of Arabia that I could find on the Internet:


Even highly compressed on Vimeo, the large format film difference is obvious. I see no reason why this effect won't be the same in large format digital.

The same look in digital, shot recently by Panavision:


I'm fascinated that Panavision, a company that hopes to make its living by bringing back large format cinematography, doesn't appear to have any kind of direct comparison of looks between S35, full frame anamorphic, 70mm spherical and 70mm anamorphic beyond some crappy images of people sitting in chairs in front of strands of holiday lights. They just expect that the people who control the check books will see the difference without having any point of reference. That's a pretty serious mistake.

If only cinematographers can see the difference—and if only -some- cinematographers can see the difference without a direct comparison, as appears to be the case—then WHERE IS THAT DIRECT COMPARISON that teaches potential clients to see the large format look that they are trying to sell?

They've got some very nice DXL demo footage. That's great, but every new camera has great demo footage behind it. Large format digital is a significant step, but the differences are not completely obvious until people are shown what to look for. That's the piece that's missing.

We shouldn't be having this discussion. It should be enough to post a link to a Panavision web page that definitively settles the matter. The problem is... that page doesn't exist.

--
Art Adams
Director of Photography
San Francisco Bay Area

Paul Curtis
 

On 4 Dec 2017, at 16:06, Art Adams <art.cml.only@...> wrote:
I found this online while doing a search for large format vs. 35mm comparisons:

Not sure about this. He's demonstrating the same sensor size and moving a scene around to mimic is, so of course there's compressed perspective.

Also the Revenant example, in that trailer: are all the shots Alexa 64, wasn't there quite a bit of normal Alexa in there too?

But isn't the question:

Given the same scene. If you had a theoretical sensor B that was double sensor A size, then if you put a 50mm lens on A and a 100mm on B then the image (perspective and so on) would be *identical*. It's very easy to show this in 3D/Nuke/whatever.

The difference is that in the real world that 100mm and the 50mm are different lenses, with different apertures, speeds, corrections and distortions. It also means that you can achieve a shallower DOF if you want to because it's a damn sight easier to make a 100mm f2 that performs really well than a 50mm f1.4 with the same kind of correction and overall performance.

Or a more extreme example a 25mm f1 is more difficult to find than a 50mm f1.4

Ergo, you can use 'better, faster' lenses on a bigger sensor and the only difference in look are the lenses choices.

Or am i missing the point?

cheers
Paul

Paul Curtis, VFX Post | Canterbury, UK



Stuart Brereton
 


On Dec 4, 2017, at 8:06 AM, Art Adams <art.cml.only@...> wrote:

I found this online while doing a search for large format vs. 35mm comparisons:


He’s a little vague on how he created this 70mm image. I’m not convinced that ‘stitching’ 2 shots together is the same as shooting with a larger format. My own very simple test suggests it’s not..


A direct comparison of 70mm cropped IMAX vs. 35mm anamorphic capture:


It’s not really a useful comparison unless the subject matter is identical.


I'm fascinated that Panavision, a company that hopes to make its living by bringing back large format cinematography, doesn't appear to have any kind of direct comparison of looks between S35, full frame anamorphic, 70mm spherical and 70mm anamorphic beyond some crappy images of people sitting in chairs in front of strands of holiday lights. 

We shouldn't be having this discussion. It should be enough to post a link to a Panavision web page that definitively settles the matter. The problem is... that page doesn't exist.

Perhaps they are worried that the differences are not sufficiently mind-blowing to live up to the hype. :)

Stuart Brereton
DP, LA

Scott Dorsey
 

On a big screen, the difference in resolution changes everything, to the
point where any other subtle lens issues are likely swamped.

On a small screen, likely there is little difference.

It's true that it's easier to make low distortion wide lenses with a larger
sensor, but that's just an implementation issue.

--scott

Scott Dorsey
Kludge Audio
Williamsburg, VA

Mark Warmington
 

This is an interesting thread. 

Regarding The Revenant, I was under the impression that it was shot on a mix of the Alexa 65 and "regular" 35mm Alexa. I saw the film in the cinema and there certainly weren't moments that stood out as having been shot on different formats (which I appreciate would have been an odd thing to aim to do). The reason that a lot of that movie had a 3D like dimensionality I feel was more down to the fact that it was all shoot on extremely wide lenses, especially the close ups of people. 

I was also interested to read that Roger Deakins tested the Alexa 65 during the pre production for Blade Runner 2049, but rejected it in favour of his tried and tested Alexa and Master Prime combo. He said he preferred the slight grain inherent with the SXT and felt the 65 was too clean. Obviously the Alexa still makes clean enough images though - Blade Runner had a pristine look about it. 

--
Best,
Mark

DOP • LONDON 
www.markwarmington.com
+44(0)7793942273

Sent from my iPhone 

On 4 Dec 2017, at 16:06, Art Adams <art.cml.only@...> wrote:

I found this online while doing a search for large format vs. 35mm comparisons:

https://wolfcrow.com/blog/why-does-the-revenant-look-so-3d-and-life-like-what-makes-the-65mm-format-special/

This somewhat illustrates the difference in perceived depth between large format and S35.

This video does a great job of showing how 70mm film represents depth in a unique way to 35mm/S35. In spite of the low video quality, the large format sense of depth and resolution still holds up:


A direct comparison of 70mm cropped IMAX vs. 35mm anamorphic capture:


And, lastly, the highest resolution selection of clips from Lawrence of Arabia that I could find on the Internet:


Even highly compressed on Vimeo, the large format film difference is obvious. I see no reason why this effect won't be the same in large format digital.

The same look in digital, shot recently by Panavision:


I'm fascinated that Panavision, a company that hopes to make its living by bringing back large format cinematography, doesn't appear to have any kind of direct comparison of looks between S35, full frame anamorphic, 70mm spherical and 70mm anamorphic beyond some crappy images of people sitting in chairs in front of strands of holiday lights. They just expect that the people who control the check books will see the difference without having any point of reference. That's a pretty serious mistake.

If only cinematographers can see the difference—and if only -some- cinematographers can see the difference without a direct comparison, as appears to be the case—then WHERE IS THAT DIRECT COMPARISON that teaches potential clients to see the large format look that they are trying to sell?

They've got some very nice DXL demo footage. That's great, but every new camera has great demo footage behind it. Large format digital is a significant step, but the differences are not completely obvious until people are shown what to look for. That's the piece that's missing.

We shouldn't be having this discussion. It should be enough to post a link to a Panavision web page that definitively settles the matter. The problem is... that page doesn't exist.

--
Art Adams
Director of Photography
San Francisco Bay Area

Michael Nagel
 

"would be *identical*. It's very easy to show this in 3D/Nuke/whatever."

it will be in Nuke, but that's a theoretical example, will not translate to real world very well in most scenarios


the main differences between large format 70mm/65mm/VV captures and S35 (or smaller) capture of the same scene with the same intended FOV are (assuming in both cases we do use lens sets that fully cover the image plane):

> sharpness
> contrast
> uniformity
> CA
> light falloff
> DOF
> resolution

on the smaller image plane u need to compensate by using shorter focal lengths in order to match the FOV of the larger sensor. this alone will introduce the above mentioned deviations. there is no perfect lens, but for sure not when going shorter and shorter in focal length. the FOV will match but the IQ will not, especially the more u deviate from the center.

so technically we have the same FOV, but the image quality of both shots will differ.

but, u gotta keep in mind, that some will have trouble finding a good/great lens set for their large format plane capture. Nowadays Panavision and Arri offer high-end, high-quality, for rent options, but in the case where one shoots with a self-put together set of Leica's and Hasselblad (former still glass) on that large 70mm/65mm/VV plane and we compare that to shooting with a very, very good, matched set of lenses on S35, most of the points above will be negligible, but not the last one: resolution.

since u capture much more data on the large plane, that will always play a factor when downscaling to final delivery format (if we are assuming that final delivery is smaller than capture). u will get a benefit in sharpness, contrast, noise and perceived DR when downscaling from the larger capture. That can/will also make the image appear to have more depth, or slightly more "three dimensional".

Best way to test this is to use Alexa XT and Alexa 65. Both use the exact same sensor, just in a larger plane. And that is currently still the best digital sensor on the planet. Shoot the Alexa XT with Master Primes and the Alexa 65 with PV70 or the Arri set. The larger the screen on which this test is being viewed, the more the differences will be obvious. Pretty much everything I've seen so far from the Alexa 65 looks just absolutely stunning.

RED 8K VV and 8K Helium are not good options (for this test), different sensors, both with different issues altogether. Both with 8K resolution would eliminate the resolution factor, but the smaller pixel pitch in the S35 Helium sensor now amplifies lens design problems: CA etc etc etc

and obviously diffraction will kick in sooner on Helium, but if delivery is 4K - so much smaller than capture that it is rather negligible. Viewed at 8K, it will be there.
- Mike Nagel
Director, Producer, Cinematographer



From: Paul Curtis <paul@...>
To: cml-general@groups.io
Sent: Monday, December 4, 2017 2:15 PM
Subject: Re: [cml-general] Bigger is better and VistaVision

On 4 Dec 2017, at 16:06, Art Adams <art.cml.only@...> wrote:
I found this online while doing a search for large format vs. 35mm comparisons:

Not sure about this. He's demonstrating the same sensor size and moving a scene around to mimic is, so of course there's compressed perspective.

Also the Revenant example, in that trailer: are all the shots Alexa 64, wasn't there quite a bit of normal Alexa in there too?

But isn't the question:

Given the same scene. If you had a theoretical sensor B that was double sensor A size, then if you put a 50mm lens on A and a 100mm on B then the image (perspective and so on) would be *identical*. It's very easy to show this in 3D/Nuke/whatever.

The difference is that in the real world that 100mm and the 50mm are different lenses, with different apertures, speeds, corrections and distortions. It also means that you can achieve a shallower DOF if you want to because it's a damn sight easier to make a 100mm f2 that performs really well than a 50mm f1.4 with the same kind of correction and overall performance.

Or a more extreme example a 25mm f1 is more difficult to find than a 50mm f1.4

Ergo, you can use 'better, faster' lenses on a bigger sensor and the only difference in look are the lenses choices.

Or am i missing the point?

cheers
Paul

Paul Curtis, VFX Post | Canterbury, UK





Michael Brennan
 


On 5 Dec 2017, at 3:06 am, Art Adams <art.cml.only@...> wrote:

We shouldn't be having this discussion. It should be enough to post a link to a Panavision web page that definitively settles the matter.

My experience with manufacturers and vendors is they are not impartial enough to be be relied upon.


A quote from this forum years ago regarding the Frazier lens, 
“If the depth of field thing is true, Panavision needs to do a crash course with its employees. It does seem most of them are tired of the depth of field questions and don't believe it themselves.”

The Wiki entry says “The Frazier lens provides an appearance of a massive depth of field...”

That word, appearance!

Anyone spot the grammatical optical illusion in this post:)

Mjb

Art Adams
 


My experience with manufacturers and vendors is they are not impartial enough to be be relied upon.
 
That's why I like pictures, with lots of documentation. Give me enough information and I can make up my own. That's how one knows whether a manufacturer is confident in their own products: they put them out there and let them stand on their own.

There are some things I just assume manufacturers lie about, like ISO, because it's so easy to fudge the numbers using that standard and everyone wants to sell a faster camera. Images, though... they're pretty hard to argue with, if you know the condition under which they were taken.

--
Art Adams
Director of Photography
San Francisco Bay Area

Jordan Cushing
 

Thanks for clarifying your misunderstandings about the Panavision post Art. I have been meaning to post to ask you to clarify because I wasn’t seeing it as you were and couldn’t figure out why.

I think Paul’s suggestion of a virtual comparison will produce no difference because, theoretically at least, there should be no difference.

I’ve been a fan of 3D since adolescence (wave 2 or 3? ‘Metalstorm’ etc) and endeavor to see as much native 3D as I can. Generally, it’s accepted that wider lenses produce “rounder” images. It’s counterintuitive to me that roundness is seen as a function of the longer lenses used for larger format photography. I think that’s a red herring. If a test is to be made using a sphere with a grid on it, can I suggest that there be a gridded background as well, and that a matching primes set also be used alongside a zoom?  Combined, these would give a clearer picture of how much more, if any, the wider front element of a zoom sees “behind” the sphere. Occlusion plays a big part of our depth perception after all. My hypothesis is that this difference (which supposes wide format lenses are generally physically larger with bigger front elements), plus the potential shallower depth of field, are probably the main contributors to any sense of additional depth in wide screen formats. 

If I were to generalise, the flatter geometry of longer lenses reduces the sense of dimension to me. However, the ability to be closer to the subject without adding as much geometric distortion is an advantage. The intimacy of having the camera close is perceptible to the audience, and we all may be more inclined to exploit that with wide screen formats if we don’t have to trade away selective focus and also accept distorted faces to do so. This is where the potential lies for
me, rather than in the sweeping vistas, which of course benefit from the increased resolution. This discussion has inspired me to consider larger formats for a project I have on the horizon that’s set in a tiny barbershop.

Art writes:
“...then WHERE IS THAT DIRECT COMPARISON that teaches potential clients to see the large format look that they are trying to sell?”
I know you’re not this naive Art and I share your surprise, but why produce proof when it is evident on its face that 8K is better than 4K and mine is bigger than yours. If we’ve learned anything since 2007, it should be that.

--
Jordan Cushing
DOP
London Milan

Stuart Brereton
 

On Dec 6, 2017, at 1:38 AM, Jordan Cushing via Groups.Io <jordancushing@...> wrote:

If I were to generalise, the flatter geometry of longer lenses reduces the sense of dimension to me. However, the ability to be closer to the subject without adding as much geometric distortion is an advantage.
This is an interesting, and integral part of this discussion. Is the flatter geometry of a ‘long’ lens intrinsic to the lens itself, or is it dependent on the size of the sensor/negative that it is exposing? A 50mm lens on s35 is short telephoto, with a mild compression of depth. A 50mm lens on a 6x7 camera is very wide, and displays all the exaggerated depth and slight distortion that you would expect from a wide lens. If the way that any given lens stretches or compresses depth is dependent on the format you are shooting, then there is nothing to be gained from shooting longer lens/larger format, at least in terms of geometric distortion.

Stuart Brereton
DP, LA

Art Adams
 

Hi all-

Panavision reached out to me and has provided me with a lot of amazing material. I've learned a lot, and I hope to have a PVC article up by the end of the week.

Short story: 8K mades a big difference. Large sensors make a big difference. Evidence is forthcoming.

--
Art Adams
Director of Photography
San Francisco Bay Area

Stuart Brereton
 

On Dec 6, 2017, at 8:39 PM, Art Adams <art.cml.only@...> wrote:

Panavision reached out to me and has provided me with a lot of amazing material. I've learned a lot, and I hope to have a PVC article up by the end of the week.

Short story: 8K mades a big difference. Large sensors make a big difference. Evidence is forthcoming.
Hi Art,

Any chance you could share the material here, rather than editorialized in an article?

Stuart Brereton
DP, LA

Mark Kenfield
 

On Wed, Dec 6, 2017 at 09:37 pm, Stuart Brereton wrote:
Hi Art,

Any chance you could share the material here, rather than editorialized in an article?

Stuart Brereton

+1

 

Though still looking forward to your article Art!

 

Cheers,

 

Mark Kenfield

Cinematographer

Melbourne

Art Adams
 

The material itself is incomplete without additional explanation, so it's going to have to be editorialized. Panavision is being generous about letting me access it early, before they release it themselves, and some of it they are holding back for their own presentations. I'm free to write about what I've learned, but some of the graphics and images they've shown me are theirs to release when they wish. (I don't think you'll have to wait too long, and it'll be worth it.)

I also make a small amount of money by publishing to PVC, which makes it worthwhile to put in the hours necessary to present this material decently and avoid egregious mistakes. (Hopefully.)

Not sure it'll go up tomorrow, but Friday at the latest.

--
Art Adams
Director of Photography
San Francisco Bay Area

Stuart Brereton
 

On Dec 6, 2017, at 10:30 PM, Art Adams <art.cml.only@...> wrote:

I also make a small amount of money by publishing to PVC, which makes it worthwhile to put in the hours necessary to present this material decently and avoid egregious mistakes. (Hopefully.)
I certainly understand the desire to make a few $$ from your efforts, but as this discussion originated and developed right here on CML, it would have been nice to see this information made available to CML members, so we could draw our own conclusions.

Stuart Brereton
DP, LA

Jordan Cushing
 

Is the flatter geometry of a ‘long’ lens intrinsic to the lens itself, or is it dependent on the size of the sensor/negative that it is exposing”
That is certainly part of the question, and I do realise I’ve contradicted myself. On paper (which is all I have to hand) there should be no difference. That said, I have seen an 8mm that’s “flatter” than its 10mm brother, so the execution can’t be ignored. I still think if there’s anything in it, it must be down to the physical dimensions of the lens. I am prepared to be wrong on all counts! 
I am curious to see any tests that come out of this discussion and still inspired to have a look at widescreen for an intimate setting.

Art, I look forward to your article and hope you share with the OP (Tom Gleeson?) whatever materials you got, if I recall this question was posed because he was writing an article also...
--
Jordan Cushing
DOP
London Milan

Art Adams
 

Ah, I didn't catch that Tom was writing an article as well! That message seems a lifetime ago. Tom, email me off-list if you'd like. I can't automatically share anything I've been given, but I'm happy to inquire and/or put you in touch with someone who might be able to help you directly.

art@...

--
Art Adams
Director of Photography
San Francisco Bay Area

Thomas Gleeson
 

On 7 Dec 2017, at 6:48 pm, Jordan Cushing via Groups.Io <jordancushing@...> wrote:
Art, I look forward to your article and hope you share with the OP (Tom Gleeson?) whatever materials you got, if I recall this question was posed because he was writing an article also…

Art,

That is excellent news. Unfortunately here in Australia we do not have the same access as yourself in California so I look forward to the PVC article. Having said that Panavision and Arriflex are helping so everybody is on the same page. I assume Panavision will also give the ACS the same access to material? Its always a plus that multiple people make an effort on these issues as it involves so much work that has to come out of leisure time after work and family.

We still plan on tests in the coming weeks which may now may include the Arri65 but its hard to design these tests without a clear understanding of the issues.

Tom Gleeson
Sydney DOP

Adam Wilt
 

I’ve been shooting a few tests these past few days in an attempt to dissect the “large format look”, using a full-frame Sony A7ii, a Super35mm-ish A6300, and a micro-four-thirds GH5 (half the size of full frame). Just simple tabletop setups, varying one thing at a time to see what happens:
Or, to skip the intro stuff and just see results:
Comments and critiques welcome, here or in the PVC comments section.

Adam Wilt
technical services: consulting / coding / camerawork
Vancouver WA USA (no, not that Vancouver, the other one)

Michael Brennan
 

Wilt, thanks for the test. 
Do you have specs regarding the diameter of the front element on these lenses?

Mike Brennan
DP
Melbourne

On 11 Dec 2017, at 5:50 pm, Adam Wilt <adam@...> wrote:

I’ve been shooting a few tests these past few days in an attempt to dissect the “large format look”, using a full-frame Sony A7ii, a Super35mm-ish A6300, and a micro-four-thirds GH5 (half the size of full frame). Just simple tabletop setups, varying one thing at a time to see what happens:
Or, to skip the intro stuff and just see results:
Comments and critiques welcome, here or in the PVC comments section.

Adam Wilt
technical services: consulting / coding / camerawork
Vancouver WA USA (no, not that Vancouver, the other one)

Jordan Cushing
 

Nice article and good range of trying to isolate the variables. Motion might reveal some differences which may be far more subtle as stills but by and large your observations seem reasonable and well supported by the photos.
I would really like to see what the background looks like in focus for the "look-around" test, particularly with foreground objects that are similar in size to the front element.  I'm nearly ready to discard that as a possible contributing factor, particularly with subjects that aren't very, very near the lens.

 ... like a Sony F55 for S35mm and a Venice for full frame, and a case full of matched Zeiss primes for each. All I can say is: if you pay for the rentals and insurance, I’ll happily test ’em.
I'd also like to see the same sorts of tests performed with top end lenses and imagers, let's hope that's forthcoming!

Looking forward to more food for thought from Australia and San Francisco.
--
Jordan Cushing
DOP
London Milan

Richard Bradbury
 

Just a small point to add to the discussion of large formats.

I have a large format stills camera (i.e. 5x4” negative size), where a 150mm lens has the same field of view as a 28mm would have on a super 35mm movie camera. Large format lenses are relatively simple - at infinity the lens sits its own focal length from the film plane. This isn’t possible with reflex viewing systems on small format cameras (lens and mirror would interfere). Retrofocus wide angle lenses were developed to allow a lens to sit a greater distance from the film plane than its focal length (along with the reverse in the case of telephoto lenses). However retrofocus designs are known to introduce geometrical distortion into the optical path.

Could it be that the longer focal lengths of wide angle large format lenses, with standard (non-retrofocus) designs, create images with less geometrical distortion and it is this that we are responding to as more “natural”, or “rounder”?

Richard Bradbury
Focus Puller
London, UK


On 11 Dec 2017, at 06:50, Adam Wilt <adam@...> wrote:

an attempt to dissect the “large format look”

Scott Dorsey
 

That's a lens issue, not necessarily a format issue.

You can get a 10mm Angenieux or Switar and have that retrofocal design
experience if you'd like. The distortion _is_ different than with
conventional lenses.

But most large format still camera lenses are conventional lenses.... most
of the classic ones are just tessar or cooke triplet designs. Nothing fancy
at all, which is what's nice about them.

When I shoot with a 4X5 camera, I get the narrow depth of field and maybe I
get a different blur than I would get with a smaller format camera and lens,
but mostly I just get crazy amounts of resolution. I honestly do think that
all of the main difference has to do with resolution AND with minimizing
artifacts.

If I watch a 16mm film I can tell it's 16mm just from the size of the dust
specks and scratches... they look very different than 35mm or 70mm marks.
Likewise I suspect a lot of the digital artifacts from dematrixing are clearly
different and very visible with the larger format digital systems. That's
a good thing, but that's still less significant than the higher resolution.
--scott

Scott Dorsey
Kludge Audio
Williamsburg, VA.

Art Adams
 

Every image with more resolution looks "rounder" to me. I think that's because depth cues, like highlights/shading, are smoother.

My article should show up sometime today. It has some interesting images as well.

Nicely done, Adam. Thanks.

--
Art Adams
Director of Photography
San Francisco Bay Area

Adam Wilt
 
Edited

On Mon, Dec 11, 2017 at 12:37 am, Michael Brennan wrote:
Do you have specs regarding the diameter of the front element on these lenses?
Sony FE 28-70mm:  about 33mm
Nikon 50mm: about 36mm
Sigma 50mm: about 58mm

On the GH5, the Nokton 25mm's front is about 40mm across. Sorry I didn't put that in the article; I'll update it.

Adam Wilt / technical services / Vancouver WA

Adam Wilt
 

On Mon, Dec 11, 2017 at 01:08 am, Jordan Cushing wrote:
I would really like to see what the background looks like in focus for the "look-around" test, particularly with foreground objects that are similar in size to the front element.
That chai tin is 73mm across, so I figured it's roughly as much bigger than my front elements as a human head is bigger than the front of a long Optimo or RED 18-85 or the like.

I can shoot another series with a smaller round subject. For the background, it's hard to shoot wide-aperture tabletop and getting any background in focus! Do you want something closer to the lens, or just another shot focused on background instead of foreground?

Adam Wilt / technical services / Vancouver WA / not used to adding his SIG in the web interface!

Thomas Gleeson
 

On 11 Dec 2017, at 8:08 pm, Jordan Cushing via Groups.Io <jordancushing@...> wrote: I'd also like to see the same sorts of tests performed with top end lenses and imagers, let's hope that's forthcoming!
Looking forward to more food for thought from Australia and San Francisco.
Thanks Art for the fabulous article which is in line with my thinking although it is a developing story. I am setting up tests now with a Red Monstro VistaVision camera and we should have a set of Leica Thalia lenses although I am considering using a Zeiss CZ.2 28-80 so I can match focal lengths. Plan is to shoot everything on the same camera windowing the sensor to create different sizes. This should remove variables caused by glass, cameras and even subtle variations in the cameras position. At this stage our tests should mirror what Art has done although I plan to shoot a human subject in a “normal” environment.

Sorry Jordan the one test we probably wont do is the roundness test unless I can source a large diameter full frame zoom lens and I will admit that I am sceptical its a factor at normal working distances?

Tom Gleeson
Sydney DOP

Thomas Gleeson
 

Apologies in my last post I have mixed Art Adam with Adam Wilt. I should have said thankyou Adam for your PVC article and I look forward to Art Adam’s contribution.

Tom "dazed and confused” Gleeson
Sydney DOP

Adam Wilt
 

Apologies in my last post I have mixed Art Adam with Adam Wilt.
No worries. That happens so often we're thinking about incorporating as a composite person: Art Adams Wilt.

Adam "I'm not Art Adams and I don't play him on TV" Wilt
technical services / Vancouver WA USA

Jordan Cushing
 

Adam, I was thinking whether you'd see a difference with the background in focus: how much is obscured by the out of focus foreground. I could do this myself but all of my stills lenses are basically the same size (which has never been an issue til now).
Good to know the chai can may be about right for a head. That information, in conjunction with Tom's comment about "normal working distances" got me thinking about what our subjects tend to be.  Sure they're mostly human heads, so about 20-25cm across, but they're not balloons, their roundness is revealed by the curves of cheeks and chins, how far back the ears sit and noses protrude. So, the scale of volume cues on a face is much smaller than for a ball or a tin, and we know them far more intimately. Moreover, we routinely include objects that are nearer and further from the camera that aren't the subject, all of which contribute to the depth of the image. Doesn't change my impressions thus far, just reminding myself to look a little more closely at the entire frame.
--
Jordan Cushing
DOP
London Milan

gleurquin@...
 

As shown by Adam’s and Stuart's tests, the lenses and the sensor/negative sizes don't change the way the space is translated.
Or let’s say that I do not see the differences others seem to notice.

A way to confirm that the focal length does not interfere with perspective (= geometry) is a long shot / short lens test, magnifying and cropping a wide shot to match the FoV of a long shot, both from the same PoV. Another way to do it is the dolly zoom (actually, shooting with different focal lengths a subject framed the same way as someone suggested is just a dolly zoom with a lot of images missing), or more precisely a dolly move shot with a short lens, post-processed (magnified/cropped) to achieve the same framing on the subject. That demonstrates well the difference between relative magnification due to the PoV and uniform magnification due to the zoom lens.
Another option is to dig into conic projection and perspective laws (how a given 3D object-space is translated onto a flat surface, the respective positions and relative sizes of the images of the objects distributed in the 3D space).
So, very strong evidences exist that there is no relation between the space geometry and the lens (not speaking of aberrations or trivial ‘signatures’ of optical designs, of course).
‘Long’ or ‘short’ is all relative to the size of the sensor/film, and speaking of the ‘flatness’ of a 100mm (or whatever number associated with ‘long’) doesn’t make sense. The flatness is a matter of relative magnifications due to the distance. That’s how it works : the ratio of magnifications of two objects one meter one from the other is 1/2 if the PoV is one meter away (assuming alignment), 1/21 20 meters away, and so on. The ratio decreases when the distance increase. Visually, the far space is flatter because his depth is translated by smaller and smaller differences of magnifications. The very bizarre thing with the overall magnification due to a long lens is that it shows the ‘far space close’. Acting as a developer, it reveals the geometry of the far space magnified as would be a close space. The effect of the lens in that case is to make the geometry noticeable, not to create it.

Another intriguing idea is the ‘roundness’ (and other terms referring to, IMHO, subjective appreciations, feelings).
And as far as the front lens is supposed play a role (unlikely, but the definition of ‘roundness’ would help) is it possible to elaborate a little bit?
The way I understand it, a wide front lens collects more light than a small one, so it contributes to achieve a wide stop.
A large front lens does not mean that the camera ‘sees’ from everywhere on the whole surface. That would mean a bunch of PoV, hence no image.
Whatever the diameter, the PoV is punctual at the entrance pupil. What is not seen from that point is... not seen.
Disclaimer, what is said here is just speculative common sense, I am not a lens designer nor a physicist..

The flaw in Art’s article IMHO is that it states at the beginning what he is planning to demonstrate at the end.
So the demo is rather rhetoric.

Thanks for the nice tread.
Hope we will soon have the opportunity to see a (big) formats well protocoled comparison tests on a big screen.



Regards,
have a nice day,

Georges Leurquin
Brussels
Belgium

Art Adams
 


So, very strong evidences exist that there is no relation between the space geometry and the lens (not speaking of aberrations or trivial ‘signatures’ of optical designs, of course).

Are you saying there’s no difference between a closeup shot on a 25mm lens vs. a 50mm lens, with the subject the same size in each frame?
 
The flaw in Art’s article IMHO is that it states at the beginning what he is planning to demonstrate at the end.
 
How is this a flaw?

--
Art Adams
Director of Photography
San Francisco Bay Area

Scott Dorsey
 

Are you saying there???s no difference between a closeup shot on a 25mm lens
vs. a 50mm lens, with the subject the same size in each frame?
If the lenses are perfect and at the same f/stop this is the case.

In the real world, lenses are not perfect. The question is what imperfections
are doing what.
--scott

Scott Dorsey
Kludge Audio
Williamsburg, VA.

Art Adams
 

In the real world, lenses are not perfect. The question is what imperfections are doing what.

Exactly. So in the real world, a closeup shot on a 25mm lens is not going to look the same as that shot on a 50mm lens, because it’s easier to minimize distortions in a 50mm lens.

It seems reasonable to me to assume that shooting through a less-than-perfect 25mm lens on an S35 sensor will look different to shooting through a more perfect 50mm lens on a 70mm sensor. 

--
Art Adams
Director of Photography
San Francisco Bay Area

Scott Dorsey
 


In the real world, lenses are not perfect. The question is what
imperfections are doing what.

Exactly. So in the real world, a closeup shot on a 25mm lens is not going
to look the same as that shot on a 50mm lens, because it???s easier to
minimize distortions in a 50mm lens.
Not necessarily. If you design a 50mm lens to cover 35mm and you design
a 25mm lens to cover 16mm, most distortion problems scale the same way.
Not all of them, but barrel does. Coma may not.

It seems reasonable to me to assume that shooting through a
less-than-perfect 25mm lens on an S35 sensor will look different to
shooting through a more perfect 50mm lens on a 70mm sensor.
Well, if this is the case, to my mind the solution is better lenses and
stopping down more.

The problem, though, is that the resolution difference is just so dramatic
on a big screen that it swamps any other differences.
--scott

Scott Dorsey
Kludge Audio
Williamsburg, VA.

Adam Wilt
 

On Tue, Dec 12, 2017 at 08:59 am, Art Adams wrote:
So in the real world, a closeup shot on a 25mm lens is not going to look the same as that shot on a 50mm lens, because it’s easier to minimize distortions in a 50mm lens. It seems reasonable to me to assume that shooting through a less-than-perfect 25mm lens on an S35 sensor will look different to shooting through a more perfect 50mm lens on a 70mm sensor. 
For a given format size with its edge-to-edge coverage requirements, sure. But we're talking about lenses built for different formats: a 25mm for Super35mm is facing the exact same distortion challenges as the 50mm designed for 70mm (I'm making the simplifying assumption that the 70mm image is exactly twice the size of the S35mm image). Granted, tolerances on the S35mm lens are tighter, as they scale with size, but I'm hard pressed to believe that a Zeiss or PV cine lens built for S35mm is substantially and noticeably "less perfect" than their correspondingly larger lens built for 70mm (if they are that much worse, I'm really peeved about how much we spent on a set of UltraPrimes a few years ago... and gobsmacked at how good my sub-$1000 MFT-format Veydras are, given how imperfect they must be!).

Likewise, the "shorter lens is a retrofocal design" argument, while perfectly valid within any particular format with a fixed flange-back and mirror-clearance requirement (on reflex cameras), ignores the fact that a smaller format with a shorter flange depth and proportionally downsized clearance requirements can use a similarly downsized lens with no changes to its "retrofocality". And even allowing for a more complex retrofocus design, we're talking about mild retro in these focal lengths; it's not like we're using a 10mm on S35mm. In my experience, mild retrofocal designs these days are pretty darned good, certainly good enough that no visually significant flaws occur in their images.

In any case, we're really grasping at straws if we're having to resort to these arguments!

Jordan Cushing
 

On Tue, Dec 12, 2017 at 04:42 am, <gleurquin@...> wrote:
Whatever the diameter, the PoV is punctual at the entrance pupil.
Absolutely right.  When you hope something may be a factor...
I have been struggling with this because "look around" seems to mesh with my own experience shooting with large zooms near subjects compared with their corresponding primes. We can sometimes see more  or less of the background behind a subject with a zoom (with a big front element) and a prime of matching focal length (with a much smaller front element). I am reasonably confident now that the reasons are in the details of optical design, (about which I evidently know very little) and unconnected to physical dimensions of said lenses (as has been postulated by others and entertained by me). I do know that as the elements move within a zoom, the entrance pupil typically moves as well, and I think the disparity between the entrance pupils of two "matching" focal lengths would have an observable influence on perspective. I'm guessing that's because, however minutely, we are in effect altering the camera to subject distance? You can see something like this in action simply zooming in and out on most zooms and observing changes in parallax for near subjects. This is exacerbated by close focusing too, pushing the entrance pupil far back on some zooms. Optics experts, enlighten me please. 

I thought this might be a clue to the question of perspective rendering across formats too... Could there, for example, be a big difference in entrance pupils between an S4 25mm and a S7 50mm? A quick look at the Cooke website reveals that Entrance Pupils are engraved on the lenses. Most clever. I could not find them on the website however... Disappointing. For an extreme and inexact comparison, the entrance pupil on the 45-250 Arri Allura at 80mm is -101.5 mm, whereas for a 75mm Master Prime it's 154.6 mm. So that's a significant shift of nearly 11 inches.  Enough to really change the vantage point and parallax for near subjects, which reassuringly confirms something about my experience, without any regard for the size of the front element. However, for primes alone, ( where unfortunately I can mostly find stills data with the exception of the Master Primes), they tend to be grouped much more closely, even when doubling the focal lengths.  So it seems to be an unlikely candidate for creating meaningful changes in "roundness" and geometry rendering across imagers.  Any other theories out there, or just hopes?    

Tom Gleeson, do watch out for that Zeiss CZ.2 28-80 at close range...
 
--
Jordan Cushing
DOP
London Milan

gleurquin@...
 


Le 12 déc. 2017 à 17:08, Art Adams <art.cml.only@...> a écrit :

So, very strong evidences exist that there is no relation between the space geometry and the lens (not speaking of aberrations or trivial ‘signatures’ of optical designs, of course).
Are you saying there’s no difference between a closeup shot on a 25mm lens vs. a 50mm lens, with the subject the same size in each frame? 

No, hopefully not :) 
I was saying that, everything else being equal, the focal length determines the overall magnification, which determines the FoV (or AoV, synonym right?). Which in turn determines the DoF (I just add it now). And saying too that the position of the PoV determines the perspective (in a given space). 
So using a 25mm and a 50mm to shoot a subject the same size in each frame implies to move the camera. 
The main difference between the two frames comes from that move, which changes relative magnifications (FG -the subject supposedly- vs BG)
When I said that there is no relation between space geometry and focal length, I forgot to add ‘everything else equal’, which means that you just change the focal parameter.
In that case, space geometry doesn’t change at all.
  
The flaw in Art’s article IMHO is that it states at the beginning what he is planning to demonstrate at the end. 
How is this a flaw?

Ok you’re right, let's put that differently.
What you are planning to demonstrate seem to me mostly made of perceptions.
The demo here looks more like an attempt to prove that those perceptions are facts objectively visible in the images.
I just don’t see that.. 
  
Georges Leurquin
Brussels
Belgium

gleurquin@...
 


Le 12 déc. 2017 à 17:35, Scott Dorsey <kludge@...> a écrit :
Are you saying there???s no difference between a closeup shot on a 25mm lens
vs. a 50mm lens, with the subject the same size in each frame?
If the lenses are perfect and at the same f/stop this is the case.
In the real world, lenses are not perfect. The question is what imperfections
are doing what.
--scott

Hello Scott,
I answered Art's message before seeing yours…

I would agree with you if the space framed was a flat surface.
If the space is 3D, there will be obvious differences between a subject framed identically with a 25mm and then with a 50mm. 
To keep that same size, the distance from the PoV to the subject will be multiplied or divided by two (one focal being half -or twice- the other).
So the space geometry (the depth here) change will be significant (proportionally to the move). 
And you are right, differences might appear too because of lenses characteristics and that’s actually why we test them...
But as far as I know, that’s not really the point of this tread.

Best regards,
have a nice evening (well, is it really the evening where you are? :))

Georges Leurquin
Brussels
Belgium

Scott Dorsey
 

I would agree with you if the space framed was a flat surface.
If the space is 3D, there will be obvious differences between a subject =
framed identically with a 25mm and then with a 50mm.
Not at all. Take one picture with a 25mm lens. Take another picture with
a 50mm lens with the camera in the same place. Then, crop the images so
the frame lines are in the same place. They will look the same, IF the lenses
are perfect and they are at the same f/stop. You will have to crop in much
more with the photo taken with the 25mm.

To keep that same size, the distance from the PoV to the subject will be =
multiplied or divided by two (one focal being half -or twice- the =
other).
No, we're not talking about changing the distance to the subject, we're talking
about changing the size of the negative.

So a 25mm lens on a 16mm frame will give you about the same field of view as
a 40mm lens on a 35mm frame. The perspective will be the same, because the
_perspective is not a function of the focal length but a function of the
angle of view_.
--scott

Scott Dorsey
Cine-Skopar fan

gleurquin@...
 


Le 13 déc. 2017 à 02:23, Scott Dorsey <kludge@...> a écrit :

I would agree with you if the space framed was a flat surface.
If the space is 3D, there will be obvious differences between a subject =
framed identically with a 25mm and then with a 50mm.
Not at all. Take one picture with a 25mm lens. Take another picture with
a 50mm lens with the camera in the same place. Then, crop the images so
the frame lines are in the same place. To keep that same size, the distance from the PoV to the subject will be =

Oh ok, you are right, I did not understand it was shot at the same place and cropped to match.
Yes, in that case, no difference.

So a 25mm lens on a 16mm frame will give you about the same field of view as
a 40mm lens on a 35mm frame. The perspective will be the same, because the
_perspective is not a function of the focal length but a function of the
angle of view.

I agree too.
The general formulation would be that the perspective depends on the PoV, but in his particular example, it means the same thing.

Sorry for the confusion.

Still further in the night than before :)
Best,
Georges Leurquin
Brussels
Belgium



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