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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Announcing the S.A.L.T. (Southland Alternative Lens Test)

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Evin Grant

Evin Grant

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I'm pleased to announce the S.A.L.T. to be held at Keslow camera sometime around NAB. Details are still being worked out but here's the basic details...

Location:
Keslow Camera, Culver City

Contributers: (Alphabetical)
Brook Willard
David Mullen ASC
Evin Grant
Matthew Duclos
Matt Urhy
More TBA.

Purpose: testing new glass :matrix:
I'm beginning the process of contacting all of the various new lens manufactures about providing samples for the test. It will be held as close to NAB as schedules allow so that manufacturers from foreign countries can participate without making two trips. If you have access to any of these new lenses please drop me a PM or e-mail. All equipment will be insured and can be shipped if necessary. Keslow Camera will provide reference lenses from Cooke, Zeiss and Angenieux, as well as a lens projector and a 1080P theater for subjective evaluations.

The purpose of this test is to produce a fair, concise but detailed impression of both the technical and aesthetic qualities of the image as well as the mechanics of the individual barrels. If the lenses provided are prototypes this will be taken into consideration and evaluated as such.

To the lens makers...
Keslow Camera is an unbiased location for such a test (they do not sell anything) and will provide both a controlled and outdoor environment to test in. All lens representatives are welcome to accompany their optics, and if you feel the test does not due justice to your product it will not be published. I want this to be "no risk" so as to encourage as many players as possible, however published test will be honest and unedited. All parties will sign NDA's as necessary for the test to proceed. The end result will be much more exposure of your product to your key market, Red owners :weight_lift:


This will not be an "open" test, in my experience it's just too hard to get real work done with too many cooks in the kitchen. I have invited a few more people I think will be instrumental in producing a definitive test, some names you may know, others you don't but they will all be top industry professionals. If you are not able to bring new glass to the test or are not contacted by me directly please do not ask to be involved.

I will update this thread with info as it becomes available or otherwise out of NDA.
 
If it's possible I would love if you had a lens technician that actually could disassemble the lenses? I know this might not be feasible but that's, of course, the only way of seeing how they're internally.

I've found myself buying new lenses that seemed GREAT in the beginning (on the charts and in the projector) and then by time they failed on me. As you open them up, you notice the flaws in their design and although mine are corrected now, they still cost me a lot of money in service. This should preferably be considered as well (in times like this), with so many new lenses being announced.

Edit: I am aware of that the lenses you're testing will have more TLC to them then the manufactured real life ones.
 
weirdcrew said:
I've found myself buying new lenses that seemed GREAT in the beginning (on the charts and in the projector) and then by time they failed on me. As you open them up, you notice the flaws in their design and although mine are corrected now, they still cost me a lot of money in service.
Click to expand...

Hi Fredrik,

Do you mind to elaborate?

Hans
 
weirdcrew said:
If it's possible I would love if you had a lens technician that actually could disassemble the lenses? I know this might not be feasible but that's, of course, the only way of seeing how they're internally.

I've found myself buying new lenses that seemed GREAT in the beginning (on the charts and in the projector) and then by time they failed on me. As you open them up, you notice the flaws in their design and although mine are corrected now, they still cost me a lot of money in service. This should preferably be considered as well (in times like this), with so many new lenses being announced.

Edit: I am aware of that the lenses you're testing will have more TLC to them then the manufactured real life ones.
Click to expand...

I don't think that would be a very likely course. Taking apart a lens that someone has never seen before takes many hours. And even more hours to put back together (properly).

I can understand your concern. Opening a lens would reveal its build quality, grade of materials used, complexity in regards to reliability, and many other important factors. But it would take far too much time.

That sort of in depth analysis will come in time.
 
weirdcrew said:
As you open them up, you notice the flaws in their design and although mine are corrected now, they still cost me a lot of money in service.
Click to expand...

Matthew Duclos said:
I can understand your concern. Opening a lens would reveal its build quality, grade of materials used, complexity in regards to reliability, and many other important factors. But it would take far too much time.

That sort of in depth analysis will come in time.
Click to expand...

Both quotes speak for themselves.
 
Matthew Duclos said:
I don't think that would be a very likely course. Taking apart a lens that someone has never seen before takes many hours. And even more hours to put back together (properly).

I can understand your concern. Opening a lens would reveal its build quality, grade of materials used, complexity in regards to reliability, and many other important factors. But it would take far too much time.

That sort of in depth analysis will come in time.
Click to expand...

I think, weirdcrew mean about detailed inspection of lens without take to pieces of optical block.
Yes, to Take to pieces of optical block on optical components can be complex procedure and ask of detailed adjusting of position of every component at assembling and ask of special optical devices for this.

But, weirdcrew have good questions, because, the many manufacturers of lens to save money on parts of body of lens and on parts of focusing mechanism.
That's why, the lens can a lost of optical characteristics after a some time use because, the parts of body and focusing mechanism can have surface deterioration and additional gaps.

The many prime lenses have single body of optical block and optical block move inside of main body of lens at focusing.
The idea of inspect of parts of body and parts of focusing and aperture control mechanism can be good.

The many information about real optical quality of lens can give of MTF.
But, to need have special, expensive, equipments for measuring of MTF.
 
Thanks!

Thanks!

Thanks for putting this test together- I'm eagerly looking forward to reading about the results, and seeing the images. :)
 
Olex Kalynychenko said:
I think, weirdcrew mean about detailed inspection of lens without take to pieces of optical block.
Click to expand...

Actually I didn't discover my problems until I did so. So yes it's a pain in the.... but it would be valuable considering all these new lenses are indeed manufactured differently then the old school way.
 
I am very much looking forward to these tests.

At this moment, my next intended lens purchases are the Optimo DP 16-42 and the RED primes. Any more reasons for or against these planned purchases of mine will be welcomed! :)

I'd like to see the RED lenses make it for this test, if possible.
 
A Note on Testing

A Note on Testing

Carrying out valid tests on lenses is a complicated and controversial matter.
Most of the testing methods used in the rental world and in most service facilities have varying degrees of inherent subjectivity. The people best qualified to interpret the images produced by test equipment such as autocollimators, linear collimators and lens projectors are people who examine and service a lot of lenses. They know from experience what "works".

Yet even the judgment of experienced craftspeople can vary. And the technicians themselves sometimes find it difficult to put into words how they interpret a test image, and to what degree they are mentally compensating for the influences and defects of the test itself. All test equipment introduces artifacts of its own. Lens projectors are especially prone to problems. Many systems are "one off" custom jobs of unkown characterstics. Even some professionally built units by famous makers have really bad defects. Example: Richter Cine Equipment, makers of the old industry war-horse autocollimator made a projector that places the test reticle way out of the plane of focus of its condenser optics, resulting in massive format coverage problems. Nearly all lenses seem to "vignette" on a Richter projector, but it's the projector, not the lens. They also suffer from centering problems due to an imprecise back-focus adjustment mechanism, making them useless in testing zoom tracking. Did I mention the hot spot in the center of the field ?

Panavision and Zeiss attempted to introduce the world to the routine use of MTF (modulation transfer function) machines in lens evaluation and service.
Prior to that time, MTF was used strictly as a scientific and design tool. It is a system that creates an objective, numerical evaluation of a lens' ability to reproduce contrast at a given spatial frequency (resolution standard) and light bandwidth (color). But MTF is a multi-parameter system that must be applied properly. Most technicians and cinematographers do not have the training to appropriately set up and interpret MTF testing. Nor access to the $ 150K + instrumentation and computer software required. Zeiss did however produce a simplified machine intended for service use.

My point is this: Any such public test should be set up with a well thought-out protocol created by a knowledgeable and disinterested third party. It should use the best equipment available, strive for fairness, and thoroughly document both the testing methods and results. It should take place at the most neutral facility possible. I'm not certain a rental house (any rental house) is the best choice. Rental houses do sell something: equipment rental ! But I understand there are issues of practicality.

I'd like to see participation or oversight by someone from SMPTE, the ASC and or SPIE (international optical engineeing society).

I'm hardly a disinterested third party (due to involvement with the Luma Tech Inc. "Illumina S35 primes"), but may I suggest some things I'd like to see included in the test:

-Use of Century/Clairmont lens projector. It's the best commercially available unit. Large interchangeable condenser optics, not a converted slide projector.

-Accurate T-Stop testing via newly calibrated T-stop machine/photometer

-Testng on Zeiss MTF machine if available, at uniform stops and spacial frequency (40-50 cycles).

-Live test on strongly back-lit subject (flair test), Lit by professional DP, shot on RED and rendered by skilled work flow specialist. Lock down shot.

Respectfully,
Charles
 
Hi Charles,

Evin and I had a brief conversation yesterday about some of these points. I think you'll be satisfied with the quality and impartiality of our test. We're especially interested in seeing the new crop of lenses in direct comparison to S4's and Zeiss UP / MP.

I'll look into what kind of lens projector they have at Keslow.

Will we see the Luma Tech lenses there ?

Matt Uhry
www.mattuhry.com
 
SirGear said:
The people best qualified to interpret the images produced by test equipment such as autocollimators, linear collimators and lens projectors are people who examine and service a lot of lenses. They know from experience what "works".
Click to expand...

I wonder where we could find someone who spends every day examining and servicing motion picture lenses... I'm sure if we look hard enough... ;)
 
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