who said f2.8 for the zoom lens

Jarred Land said:
its important as well to choose a zoom lense that has constant exposure throughout the zoom range.. or else you will need to rack your iris during a zoom.
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Been there.... not fun.
 
TimurCivan said:
Is the F2.8 Fstop an attmept to control the Cost of lenses? just curious, as i used some cookes on a project and they were all T1.3, as well as being horrendously expensive. Perhaps the slight loss in Apeture size permits high quality optics at lower cost. Is this the general thinking behind this move?
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T2.8 for a 35mm zoom of that range is pretty fast, a really fast zoom of that range would be around T2.2 you can find shorter zooms around T2 but certainly not T1.3

You'll find that faster primes are available as well as faster zooms for 16mm or 2/3" sensors. Perhaps the Cooke lens you recall is either a smaller format zoom lens or a prime.
 
Jannard said:
We designed the 18-85mm f2.8 zoom to be an "easy buy" for many who are stepping up to this large format. It is compact and high quality. Many major films have been shot with the Cooke 18-100 T3 zoom lens. So we are not far off. And our zoom is about half the length and weight.
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Anyone know the size and weight of the Cooke 18-100 T3?
 
ZaneIsNumber1 said:
Anyone know the size and weight of the Cooke 18-100 T3?
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13" long (32cm approx.), 12'lbs in weight (6Kilos) 150mm in diameter (max.) About $40K to buy.
 
ZaneIsNumber1 said:
Thanks,

Half the size, half the weight, quarter the price...

But I wonder how good...
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Sounds doable, all you really need is a couple of experienced optical experts and the infrastructure to test and manufacture lenses. I'd say given the background of their mother company they are already more than halfway there. I wonder who is the individual/team doing the optical design is... Wonder where he/she/they came from.
 
Jannard said:
The RED ONE is a very unusual camera. The sensor size and resolution is at minimum comparable to 35mm film. You start off by down-rezzing to 4k. Many industry experts have told us that the maximum they can measure with film is 3.2k.
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I know the sensor size is over 4k but as you are using a Bayer arangement to sense colour won't actual imaging resolution be slightly lower than that. Probably making it pretty much equivalent to 35mm film res. I am not trying to knock the resolution, I am very happy with 35mm res, I just though it was worth establishing the difference between number of pixels and actual resolution imageable.

Of course if I have got the wrong end of the stick please put me straight.

Martin
 
Muttondraw said:
I know the sensor size is over 4k but as you are using a Bayer arangement to sense colour won't actual imaging resolution be slightly lower than that. Probably making it pretty much equivalent to 35mm film res. I am not trying to knock the resolution, I am very happy with 35mm res, I just though it was worth establishing the difference between number of pixels and actual resolution imageable.

Of course if I have got the wrong end of the stick please put me straight.

Martin
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That's why RED ONE actually has a 4.9k sensor, which will eventually will pull out circa 4.5k REAL resolution :)
 
It's been pointed out by Graeme that a bayer demosiac should yield at least 70% of the sensor resolution in the output image.

Shooting with a 4.5K sensor should result in at least a 3.2K image, hopefully better. Hence Jim's argument about 35mm being only 3.2K.
 
Jannard said:
The RED ONE is a very unusual camera. The sensor size and resolution is at minimum comparable to 35mm film. You start off by down-rezzing to 4k.
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This has me a bit confused actually. I thought Red was only down-rezzing (from 4.9K) in the prototype.

Given the 4K mode that will be offered to users is RAW, how can it be down-rezzed?
 
david farland said:
at 2540p you can on crop, not downrezzing about it!
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Hmmm... Don't know. I had assumed that 2540p (full active sensor array) to 4K was a downrez and not a crop. Much like 4K to 2K scaled is a downrez. The literature speaks of shooting full S35mm @ 4K. If a crop as you suggest, then at 2540p would you not be shooting off the lens, so to speak?

Can anyone confirm? 2540p to 4K - a downrez or a crop????
:huh:
 
4.9K --crop--> 4.5K (look around in viewfinder) --crop--> 4K

As correctly indicated by others no resampling / resizing in RAW recording mode (only cropping). RGB recording modes have some resizing options (2K, 1080p, 720p)

2K in RAW would be cropping (or windowing the sensor is what basically happens).
 
Muttondraw said:
I know the sensor size is over 4k but as you are using a Bayer arangement to sense colour won't actual imaging resolution be slightly lower than that. Probably making it pretty much equivalent to 35mm film res. I am not trying to knock the resolution, I am very happy with 35mm res, I just though it was worth establishing the difference between number of pixels and actual resolution imageable.

Of course if I have got the wrong end of the stick please put me straight.
Martin
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In a Bayer patterned sensor, each pixels is biassed to either Red, Green or Blue. Just because the pixels are biassed to one color or another, does not mean that pixel doesn't know the wavelength of light (color) that's striking the photon receptors.

Most people I've found that complain about Bayer patterned sensors "not being full resolution" don't understand that just because a pixel has a bias, it doesn't mean the pixel stops doing it's job.

We use very sophisticated algorithms to maintain maximum resolution and sensitivity. It wouldn't surprise me if the folks at Red do something similar.

I.
 
Illya Friedman said:
In a Bayer patterned sensor, each pixels is biassed to either Red, Green or Blue. Just because the pixels are biassed to one color or another, does not mean that pixel doesn't know the wavelength of light (color) that's striking the photon receptors.

Most people I've found that complain about Bayer patterned sensors "not being full resolution" don't understand that just because a pixel has a bias, it doesn't mean the pixel stops doing it's job.

We use very sophisticated algorithms to maintain maximum resolution and sensitivity. It wouldn't surprise me if the folks at Red do something similar.
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Interesting, but are you saying you can image at the full sensor pixel resolution without any artifacting relating to the reduced frequency colour sampling, or that you maximise resolution achievable? I would have assumed the latter, that is certainly what happens with still cameras using Bayer pattern sensors.

I would like to underline the point that I am not complaining about this issue though, I just thought it was worthwhile pointing out that there is a difference between the number of pixel you count on a sensor and the actual resolution you can achieve from that sensor if you are using the Bayer approach, rather than using something like the Foveon sensor. In the particular case of the Red camera with an active pixel area of 4520 x 2540 I would assume they are probably going to achieve 3k to 3.5k resolution. Maybe Graeme would contribute to this thread, I am sure he could put some more accurate figures to this,

As soon as a comparison is made to imaged resolution then we have to be comparing to the imaging resolution achievable by the sensor.

Martin
 
It's pointless to compare bayer to foveon when foveon's have neither the resolution nor the fps needed for a digital cinema camera. And although foveon cameras never seem to come with an OLPF, they certainly do need a hefty dose of anti-alias filtering as you can see from the severe aliassing artifacts in any foveon image. And 3 chip systems don't work with the size of sensor we're using, so they're out of the running too.

Say you're shooting 4k raw. You're recording 4096x2304 pixels. And that's the resolution of the final RGB image also. What the measured resolution will be is something smaller due to the optical low pass filtering which is necessary to avoid nasty aliassing artifacts occuring. It's that filter that puts an upper limit on the measured resolution, and the bayer demosaicing algorithms can get as close as you want to that, given enough render time :-) Practical algorithms can get very close though.

I state that the figure is > 70% which I think is accurate enough, because one of the nice things about a good demosaic algorithm is that it doesn't look uprezzed and artifacty the way it would look if you took a 30% smaller image of "full resolution" and blew it up to 100%. A good demosaic can look rather nice and smooth, and film-like in a good way, as the images we showed at IBC demonstrated.

Graeme
 
Graeme_Nattress said:
I state that the figure is > 70% which I think is accurate enough, because one of the nice things about a good demosaic algorithm is that it doesn't look uprezzed and artifacty the way it would look if you took a 30% smaller image of "full resolution" and blew it up to 100%. A good demosaic can look rather nice and smooth, and film-like in a good way, as the images we showed at IBC demonstrated.
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Thanks for that Graeme. I saw the footage at IBC and it looked stunning

So going back to the original point. Assuming the > 70% figure. Would it be fair to say that the maximum resolution you could capture using the 4K on the RED one would probably be about equivalent to the top end of what you could get off a 4K scan of 35mm film in ideal circumstances (assuming Jims figure of 3.2K for 35mm)

Would there be much of an issue upon the use of a B4 lens for 1080p, assuming the lens is only going to be able to use 1080 x 1920 pixels, or are the effects of the mosaic going to be swamped by the anti alias filter again. Would there be a significant resolution advantage in using S16 lenses at 2K instead and then downrezzing to 1920?

Martin
 
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