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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 :)

The Scarlet Lens Dilemma

Zach Nelson said:
How can the focus fall on 3 different layers? Sounds like a very complicated lens design with dichroics. Wouldn't that separation happen in the camera and not inside the lens? Ouch.
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Hi,

Video lenses are designed that way, it was easier in to do that in the 'tube' days.

Stephen
 
KETCH ROSSI said:
Welcome to REDUSER Hogs,

there is definitely great glass for the 2/3 cameras, such as the ARRI/ZEISS DIGI PRIMES, fantastic glass, and truly at par with UP and Cooke S4.

Zooms to my likings are lees available in such format.

But after seen the clip from Jarred of the Lizard I'm exited to see what RED comes out with as far as the Mini Primes.

I mostly shoot and Love PRIMES, and stay away from zooms, but must say that RED's 18-85 made me think very differently about zooms.

Also remember that you can mount just about any adaptor and make use of any lens mount and lens type with any of the Brains.

Personally If I ended up with few 2/3 Scarlets will be the Fixed lens for Documenting and behind the scene footage, as well as Still for Continuity and scouting, but I will ultimately go with FF Scarlet and Epic as they become available, think that I'm also a Photographer and like to replace my Still cameras s well.



ciao
Click to expand...
Yes the ARRI/ZEISS DIGI PRIMES are very nice to work with but...
The ARRI/ZEISS DIGI PRIMES are purpose built for the 2/3” CCD and beam splitting prism optical system found in current digital cinematography cameras. So if you would have problems with 2/3 HD ENG glass you would experience the same with the ARRI/ZEISS DIGI PRIMES.
 
Zach Nelson said:
How can the focus fall on 3 different layers? Sounds like a very complicated lens design with dichroics. Wouldn't that separation happen in the camera and not inside the lens? Ouch.
Click to expand...

According to Zeiss:

"This color dividing prism separates the light into its green, red and blue parts, before it reaches the image plane and the CCD-Chip respectively. The distance of the CCD-Chips to the entrance surface of the prism is standardized. It varies according to the used detector size and prism. For the 2/3-inch CCD-Chip HDTV prism the blue channel position lies 5 um behind the green channel position and the red channel 10 um behind the green channel position. To correct the lens for such a longitudinal color contribution, glasses with an anomalous dispersion and other high index glasses are necessary."

Source:
http://www.zeiss.de/C12567A8003B8B6F/EmbedTitelIntern/DigiPrime-Artikel-Gaengler2002/$File/spie2002.pdf

The paper referenced at the end of the Zeiss article has moved, and can now be found here:
http://tech.ebu.ch/docs/tech/tech3294.pdf

As for what the lenses would look like on a Bayer sensor, I wouldn't hazard a guess, and would want to see it for myself.
 
block of glass

block of glass

Stephen Strangways said:
As for what the lenses would look like on a Bayer sensor, I wouldn't hazard a guess, and would want to see it for myself.
Click to expand...

To use lenses corrected for the prism on Scarlet you would need to put a block of glass of the right type in front of the sensor, even then if they stager the thickness for each color, you would not get sharp focus.

This is like the problem with Bolex RX lenses, although you might have better luck with the Bolex RX lenses if you put the prism from an old Bolex RX between the lens mount and the sensor.

==

If I had the money I would go with the S35 sensor rather than the so called 2/3" (11mm diagonal) since the larger the lens and the sensor the better the overall image quality and the wider the f/ stop range you can use. On a 2/3" camera you should not stop down past f/8 since the resolution will fall off, but on S35 you can go maybe to f/12.5 or so.

You can see the relation ship of the Scarlet 2/3" sensor active area to Super16 film, and how the Super16 lenses look in that small sensor area at these links,

http://reduser.net/forum/showthread.php?t=28486&page=5

http://reduser.net/forum/showthread.php?p=402805#post402805


You can see how S35 size RED ONE compares to 35mm Anamorphic film at this link, its a side by side of 35mm "6K" master positive scan done on an ARRI scanner and RED "4K" in another of my posts, "Yojimbo vs. RED ONE..." 09-03-2008, 05:23 PM,

http://www.reduser.net/forum/showthread.php?t=18391&page=4

You need to be logged in to see the thumnails in those posts, and to click on the thumbnails to see the images (and crops) at 1K size...

==

The advantage of the C mount Scarlet is that it would be compact and light weight since the C mount lenses are small. But for follow focus small machine vision megapixel lenses are of limited use since they are not marked and may have some backlash in their mounts. The Sensor in Scarlet should be maybe 3x as sharp as film, so any small mis-focus will be visable in the end results, maybe.

Larger lens mounts for S35 sensors will make follow focus easer, probably.
 
Negative spherical aberration

Negative spherical aberration

Stephen Strangways said:
With Bolex RX lenses, the issue is spherical aberration:
Click to expand...

Any glass plate or prism with flat sides will introduce negative spherical aberration, so lenses for the RX bolex, or 3-chip video cameras that use a prism must have positive spherical aberration to compensate for the glass between the sensor and the rear element of the lens.

So if you use lenses made for a 3-chip camera on a single sensor camera you will get blur when the lens is wide open, they will be under-corrected for spherical aberration if desigined for the prism's negative aberration.

You can in part fix this by putting a block of the right kind of glass with the right thickness behind the lens between it and the sensor.
 
Red's B4 to PL adapter has optical correction and I am sure the B4 mount for Scarlet/Epic will have optical correction to match the single focal plane Bayer sensor.
 
How?

How?

David Rasberry said:
I am sure the B4 mount for Scarlet/Epic will have optical correction to match the single focal plane Bayer sensor.
Click to expand...

How can they correct Longitudinal chromatic aberration without curved surfaces, and if they use curved surfaces then what happens to the image size and distortion?

It seems in many of these issues, that products are made that "sort of work" but do not give faultless results, that is the people who purchase these things won't notice that the resolution is lower that it should be or there is a slight color fringe?
 
David Rasberry said:
Red's B4 to PL adapter has optical correction and I am sure the B4 mount for Scarlet/Epic will have optical correction to match the single focal plane Bayer sensor.
Click to expand...

Definitely not. Most mounts are hollow. And a piece of glass designed to correct aberrations from one lens aren't going to be right for another, even if such a correction were possible.

If you want to use B4 glass from the broadcast world on a 2/3 scarlet, you're probably going to be getting less than your full 3k ( x 78% bayer blah blah blah) sharpness.
 
The abakus adapter (which is the same as Red's B4 adapter afaik) does two things:

Firstly, it increases the image circle to cover S-16, and secondly it corrects the light paths so that all of the wavelengths focus on the same plane. I'm not an optical engineer, so I don't know the ins and outs of it, but it works very well. I can tell you that there is some minor stop loss (about 1/3 iirc) and it does involve glass!

Regarding the original post, there are plenty of 2/3" coverage c-mount lenses, so they are an option, but they're a pita to change on set, what with all that screwing involved! That's why older c-mount 16mm cameras usually have a 2 or 3 lens turret. Bloody cheap glass though.

PL-mount super-16 Zeiss lenses are still pretty cheap at the moment (but get them whilst they're hot, cause that won't last long once these babies start shipping).

As far as not making decisions until the camera ships, well... At the moment 16mm glass is dirt cheap as there's very little demand for it. If I was buying a 2/3" Scarlet (and I just might, at that price!), I'd get me a set of 16mm lenses pretty damn quick...

Cheers,
Dom.
 
J. Bernard Vallon said:
Definitely not. Most mounts are hollow. And a piece of glass designed to correct aberrations from one lens aren't going to be right for another, even if such a correction were possible.

If you want to use B4 glass from the broadcast world on a 2/3 scarlet, you're probably going to be getting less than your full 3k ( x 78% bayer blah blah blah) sharpness.
Click to expand...


The B4 HD mount prism refraction index is standardized for all HD cameras. An optically corrected mount or adapter designed for RED or Scarlet will work just fine for any B4 lens and eliminate the chroma and focal aberrations. You get the full performance of the lens. B4 lens stops are already calibrated to include the prism losses.

http://www.abakus.co.uk/Adapters2.pdf
 
J. Bernard Vallon said:
Didnt Olympus make a SLR system designed around a 3/4" sensor? Those might be perfect.
Click to expand...

Its the 4/3rds format. Olympus makes a superb series of premium F2 and F2.8 constant speed zooms that would cover 3k format on an S35 Scarlet or Epic or on a RED 1 if a mount was made available. The standard covers a 21mm image circle. These are telecentric lenses designed specifically for digital sensors.
 
Hey guys, been following this thread best as I can, but i'm looking at the floor beneath my feet and discovered parts of my brain oozing around. Could you guys prescribe me a good read that explains in full detail lenses and the effect they have on motion picture. I have a fairly good understanding of DOF and how to use it artistically, I shoot using a Canon EOS 10D with a few different primes and zooms for leisure. However, I'm a bit thrown off sometimes by a lot of the terminology associated with film and what it's direct relation is to the lenses used. I'm new to the world of Film and i'm trying to best absorb as much as I can before I make my decision to purchase a new camera.


Thanks much,
Zas from STERiO
 
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