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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 :)

Red Zoom Lens

Hans von Sonntag said:
All of B4 HD-ENG lenses I've been working with show these chromatic aberations, some more (wide angle zooms), some less - greenish and magenta, even stopped down.

Pretty annoying if you pay 20k or more for a lens. One big reason to avoid the B4 route on RED.

Hans

Edit: Never saw these things on 35mm. Was blind in these days probably. Does anyone know wether this is a "digital" problem? Zeiss DigiPrimes were fine, even shot wide open (2/3 needs to be shot wide open).
Click to expand...

Those "chromatic abberations" you see in most B4 ENG lenses are due to the 3CCD design. I´m not sure exactly what causes this but the component colors are a little of from each other in the focal plane, its said to cause this magenta-green problem. Zeiss made their digi-lenses with this in mind so they are as a result of that free from this phenomen.

Check it out on their homepage

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

Roll down to
"4 the camera interface"

I dont know if for the same reason, they would be lesser suited for the RED camera or not.

Johlan
 
Good finding!

The abberations I was refering to were the ones Gavin Greenwalt found on RED-Footage. This is a non-3CCD camera. I'm sure the 3CCD system with the beam splitter does not make optics better and even more difficult for lens builders to calculate abberation-(almost)free lenses.

Still I don't know by now wether this is a "digital" phenomenon on not. Anynone saw this on 35mm footage? I never came across this on 35mm. Is film more forgiving? And digital more prone to this? Will opticts that serve well on 35mm show with RED these awful abberations?

Hans
 
Graeme Nattress said:
I found that stopping down really killed the issue. Some lenses needed more stopping down than others though.

The same sort of thing happened in the stills world, where they found that the precision and low noise of digital showed up things which they'd not seen before in the lenses.

I don't buy that it's the bayer pattern that causes the green / purple though, as that, you'd expect if it were bayer, would produce problems the size of 1 pixel, and the problems are much greater than that. It's also in the raw data before demosaic, so it's not the demosaic algorithm (we tried lots, just to be sure). The green stuff is the opossite of the purple stuff, and that's been well known in digital for a long while. There are many theories to the cause, but no definitive answers as far as I can see.

http://web.canon.jp/imaging/eosd/eos1dsm3/eos1dsm3_sample-e.html shows the exact same issue quite clearly.....

Graeme
Click to expand...

You are correct that its not the Bayer pattern causing problems. The Canon image you linked to clearly shows longitudinal chromatic aberration. More precisely, its the secondary spectrum thats showing. A well-designed apochromat or superachromat will not have that. There also appears to be some artifacts from a poorly manufactured aspheric surface.

Its my personal belief that lenses will have to get far better in the near future to catch up with advances in camera and projection technology. As a lens designer, I'm prepared to do something about it.

Brian
 
I think a few of you mis understood my post. I wasn't blaming the issue on the Bayer system, merely pointing out the added green resolution of the system was responsible for the tint of the aberrations posted here earlier. if this were not the case, and these were more standard chromatic aberrations you would see corresponding (yet opposite) offsets in the other colors.

_mike
 
Stephen wrote:Can anybody tell me how many iris blades the Red Zoom has, and are the edges straight or curved when stopped down?
Click to expand...

18-50 has 7 blades and mild curve

50-150 has 9 blades and mild curve

300 has 9 and a mild curve
 
Mike, the green is balanced by purple. It's a different kind of chromatic aberation than normal. I don't think it's bayer pattern influenced in it's colours because the direction of the effect changes, whereas bayer effects have constant direction.

Graeme
 
Wouldn't they always appear to radiate from the center out?
 
Yes, they radiate, whereas bayer artfact stuff is constant across the image.

Graeme
 
brickwall said:
You are correct that its not the Bayer pattern causing problems. The Canon image you linked to clearly shows longitudinal chromatic aberration. More precisely, its the secondary spectrum thats showing. A well-designed apochromat or superachromat will not have that. There also appears to be some artifacts from a poorly manufactured aspheric surface.

Its my personal belief that lenses will have to get far better in the near future to catch up with advances in camera and projection technology. As a lens designer, I'm prepared to do something about it.

Brian
Click to expand...

Hi Brian,

I'm interested in hearing about what your prepared to do about it.

thanks,

Chuck
 
I guess I don't see it that often because I exclusively use primes (and not all that fast ones at that) in my 35mm still photography. If that abberation tends to happen at wide open on fast zoom glass I wouldn't see it very often.
 
chuck colburn said:
Hi Brian,

I'm interested in hearing about what your prepared to do about it.

thanks,

Chuck
Click to expand...

Hi Chuck:
Early in my career I kept wondering whether there was anything really new to do in lens design. Experience has taught me that there is alot of room for improvement in photographic/cinematographic lens design. Yes, I am working on a specific project, but all I can say right now is stay tuned.
 
The 18-50mm Red Zoom seems to be performing very well according to Evin; but having ordered a set of Red Primes with my camera, I am wondering when we will hear any updates from Red on their development.

I went for Red lenses because they are matched to the camera sensor but it was a difficult choice to make between going for the Red primes or the Red Zoom; but in the end 5 Primes from 15mm-85mm was just too good an opportunity to miss for under $20k. Although I think I may well buy a Red Zoom at a later date.
 
i'd just like to see a thorough lens test, evaluation and comparison of the red with other lenses.

Thats all.

Show the red v. cooke, v zeiss primes, v nikon - i'm sure people want to see these evaluations, and my hopes are that people are doing those tests right now. My hopes take into account that such acts would be generous and detract from actually getting out there and shooting!

I hope this will be conducted at the LART
 
Cooke S4 & Zeiss ultra & master primes have been out for awhile ... i don't see any Cooke vs. Zeiss test out there ???
i have seen some Cooke test and some Zeiss test but not together ...
i don't think there will be night & day differences between any of them ...
sometimes that 10% better cost 60% more ..for some it is worth the extra cost - others not worth it ...
 
Although this is known here... "The Prime set is delayed until March 2008. The 18-85mm is now scheduled for Summer 2008."

This is new and per Jim..."The 50-150mm zoom will deliver in small quantities 1st of November, larger quantities after that." I asked when this might deliver two or three days ago along w/ "when is the RED grip going to be available" to no avail here... thats fine, just glad to have some info. Thought I would share w/ the class. Also, great to have an idea on the red grip release and price... very happy guy here.
 
50 - 150mm zoom availability

50 - 150mm zoom availability

Andrew Benz said:
This is new and per Jim..."The 50-150mm zoom will deliver in small quantities 1st of November, larger quantities after that."
Click to expand...

sorry, andrew, can you help me out? did jim post this onn reduser? i can't seem to find it in any of his posts.....
 
garth hagey said:
sorry, andrew, can you help me out? did jim post this onn reduser? i can't seem to find it in any of his posts.....
Click to expand...

No worries Garth, here is the full meal deal quote from c##.com...

[/QUOTE]We can certainly deliver a RAW port... we just don't have an order for one. And I continue to "not recommend" it. Our image is now so clean that you have to wonder why anyone would want to record 335MB/sec. if they don't have to. We'll sell you one, but be warned. You can use a Codex box to record to or other options. We haven't spent too much time thinking about all the other options because there is no demand. And we still have our hands full getting all the features enabled.

We are delivering the camera body, rail system, batteries and charger, 18-50mm zoom, 300mm, CF cards and some mics. extras now. The 50-150mm zoom will deliver in small quantities 1st of November, larger quantities after that. The Prime set is delayed until March 2008. The 18-85mm is now scheduled for Summer 2008.

Hope that helps,

Jim[/QUOTE]


My apologies to Jim and Stephen Williams if this is not allowed, but seeing were are in a period of "glasnost" and the cold war seems to be thawing...
I hope this helps.

Cheers--- Andrew
 
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