Jump to content


Photo

First time red advice


  • Please log in to reply
6 replies to this topic

#1 christina alexandra voros

christina alexandra voros

    New

  • Basic Members
  • Pip
  • 4 posts
  • Cinematographer

Posted 16 May 2009 - 07:02 AM

So I'm shooting a short on the RED. With a budget/schedule that isn't going to allow us time/money for tests - which makes me awfully nervous.

Looking for general and trouble shooting advice for a first time user. My AC is familiar with the set up and workflow of the camera, but from a creative angle I'm trying to research some obvious pitfalls. So a few general questions...

What is the best set up to allow me the most versatility in post re: color correction?

Looking to shoot some sequences at 60fps - Ive read this can only be done in 2k - though someone has mentioned the option of 3k - haven't heard much about this - any advice?

We'll be working with shift tilt lenses in a certain sequence meant to replicate heaven - aiming for diving-bell-type gauzy whites, searching focus, and blooming highlights - how much of this should we aim to be achieving in camera rather than setting a look in post?

IR filter? half the film is daylight exteriors - do i need one?

thanks so much for your help,

cheers,
cv
  • 0

#2 John Sprung

John Sprung
  • Sustaining Members
  • 4635 posts
  • Other

Posted 16 May 2009 - 11:51 AM

> What is the best set up to allow me the most versatility in post re: color correction?

Not to worry, this isn't like a tape camera where you have to tie your hands on the set. Just record RedCode36, versatility in post is what the Red was designed for.

> Looking to shoot some sequences at 60fps - Ive read this can only be done in 2k - though someone has mentioned the option of 3k -

2K is visibly lower resolution, you might be better off going with the highest rate that the current build supports in 3K.

> We'll be working with shift tilt lenses in a certain sequence meant to replicate heaven - aiming for diving-bell-type gauzy whites, searching focus, and blooming highlights - how much of this should we aim to be achieving in camera rather than setting a look in post?

Do the focus and gauzy stuff in camera, mostly hold the highlights and adjust them to your taste in post.

> IR filter? half the film is daylight exteriors - do i need one?

IR is mainly an issue if you need to use large amounts of ND. The new ND's made for Red contain the IR cut you need.




Here's the current version of my collection of notes on the Red:

1. The camera takes a long time to boot up, about 1.5 - 2 minutes. That wouldn’t be so bad if it didn’t have to be re-booted every time you change batteries. One solution is an offboard hot-swap box, they’re commercially available now, both for block and V-lock batteries. One ASC member who shot with it (3-08) says that the solution is big batteries. You can boot in the morning and swap batteries at lunch, making it much less of a problem, provided that you live on the dolly all day. Unfortunately, there’s no way to view and start setting up until after the camera has booted, unlike the Arri D-21 and Dalsa, which have mirror shutter viewfinders.

2. Batteries from vendors other than Red will work, but the Red can’t give you an indication of how much life they have left. You have to go by a meter on the battery.

3. The connectors on the camera are non-standard fragile mini-BNC and mini-XLR. It needs a breakout box or a bunch of pigtails. Breakout boxes are readily available as aftermarket accessories. Hot Swap could also be built into a breakout box.

4. There’s no focal plane mark on the early production bodies, and the hook for the 1st AC’s tape is an option that’s out of stock (3-08). See the attached photo for where the plane mark should be. Later production units will have the “Phi” mark. See the attached .JPG image for where it should be.

5. With CF cards, you get 4 minutes on an 8 Gig card. When 16 Gig cards become available, they’ll be good for 8 minutes. (1-09, they’re available) There’s a hard drive, but it’s reported to have reliability problems in handheld use. The motion of the camera can be more than the head arm can stand. The same ASC member confirms the hard drive motion issue. The drives are not RAID protected, and have had non-motion-related failures. They should be backed up frequently, don’t put too many eggs in that basket.

With either cards or drives, you need some kind of backup station. The best solution at the moment seems to be a Mac computer with card readers feeding a big RAID array plus some SATA shuttle drives and LTO tapes. You need an assistant full time to watch every take as it backs up, just in case something disastrous happened. So, it’s a full time job. (2-09)

6. You can’t mix different frame rates or mix 2K and 4K on the same card now. Test to see if this has been fixed.

7. For video tap use, it can output only one format at a time. That means that the on camera LCD viewfinder screen and an offboard monitor of a different format can’t be used simultaneously. This is supposed to be fixed soon (3-08).

8. The run-stop button is close to the user-assignable buttons, and it’s easy to accidentally press the wrong one.

9. The data LCD is on the back of the body rather than the operator’s side, which is inconvenient in tight locations.

10. There have been a few total failures of the camera reported, so it would be wise to have at least one spare body on the truck. The bigger the show, the more spares you should carry.

11. “Codec Error” – very seldom, the camera shuts down with this error message. You lose the take, and have to re-boot, but the camera isn’t totally dead.

12. Overheating used to be a problem, and may still be if you shoot a lot of long takes in a very hot environment. A white barney is the wrong idea, because the problem is getting rid of heat that the camera generates internally, not heat from outside. It needs shade and air flow, not insulation.

13. The “black sun” issue: This is reported to have been fixed, but on early cameras, the sensor would shut down individual pixels that were severely overloaded. This was discovered in day exteriors in which the sun appeared as a small black circle. More recent reports (5-08) say it’s not completely fixed; you can still get “black sun” by opening up too much. It’s a fairly easy post fix, but alas not a freebie.

14. The rolling shutter issue is a big one. It’s generic to all CMOS cameras. The term is also a little misleading, because there’s no pulldown, and therefore no need to actually shut anything.

Suppose we have a film camera running 24 fps with a 180 degree shutter, and a CMOS camera shooting 24p with a 1/48 second exposure time. Any point in the aperture of the film camera sees image light for 180 degrees, and darkness for 180 degrees. Any one pixel on the CMOS chip is sensitive to light and accumulating charge for the equivalent of the same 180 degrees, and then it's read out and inactive for the rest of the cycle. Those are the similarities.

The big difference is that the edge of the shutter blade on the film camera spends maybe 45 to 60 degrees passing over the aperture, while the CMOS camera is designed for a continuous uniform flow of data from the chip, so the readout "edge" takes the whole 360 degrees to sweep over the whole image and start over. Therefore, worst case, the top and bottom of the film frame are 60 degrees apart in time, while the top and bottom of the CMOS image are nearly 360 degrees apart, six times as long. This can introduce some subtle distortions. Things that move horizontally rapidly get a kind of leaning effect, for instance car wheels become a little bit oval. Hand held stuff gets a strange rubbery look, sometimes called the “jell-o-vision effect”. High vibration situations such as vehicle mounts on rough roads or high speeds can get even more rubbery looking.

Those distortions are mostly subtle. The big problem happens if we have a very brief bright flash of light, one that goes on and off very quickly rather than fading up and down.

Do a bunch of flashes at random, and there's some chance that you'll catch the film shutter edge during its rapid pass over the aperture. But mostly they'll either hit when the shutter is open, and go on the film, or hit when the shutter is closed, and go into the viewfinder. (That's something to watch out for when you operate -- If you see the flash in the finder, you *didn't* get it on the film, and vice versa.)

On the CMOS camera the "start" and "stop/readout" edges are always in the frame somewhere. So, no matter when the flash happens, you're going to catch the "shutter" edges. To fix that, you'd have to sync both the beginning and end of the flash to the camera, with the flash starting when the readout edge is at the top of the frame, and ending when the turn-on edge is at the bottom of the frame. In this example, the flash would have to have a duration of 90 degrees or 1/96 second.

Another difference is that the CMOS "edges" are absolutely horizontal and pixel-boundary sharp. The film shutter being between the lens and the film casts a soft-edged shadow, and is only horizontal at the middle of the frame, sweeping across the rest of the frame at an angle. (Or it's vertical at the middle in cameras with the shutter under rather than alongside the gate).

Another approach would be to read the CMOS out faster, and pause between frames, which would be more film-like. But to get the same time difference as a film camera, you'd have to read the chip six times faster, which would be equivalent to being able to shoot 144 frames per second in continuous rolling mode. That's not cheap or easy, which is why it doesn't happen in real world cameras.

15. Counterintuitive “ASA” settings: (5-08) There’s one report that you get better shoulder handling/highlight detail at the expense of more noise in the shadows by going to a *higher* ASA setting on the Red, and vice versa. This should be easy to test if we ever use the camera, and should be tested. The ASA setting on the camera isn’t at all like loading a film stock of a particular ASA. You could think of it as if it were the ASA setting on a light meter instead.

16. Early firmware didn’t do 16:9, only 2:1. On such cameras, it’s necessary to frame for cropping in post. More recently (10-08) with Build 17, they’ve added a mode called “4K HD” which does true 16:9, using most but not all of the chip. It’s really quad-HD, 3840 x 2160 photosites. Reports are that this works very well, and because the scaling involved to HD is exactly 2:1 rather than a long decimal fraction, the render times are about 40% faster, and the images are sharper. This mode only works with 16 gig cards or larger.

For us in TV, this is the best mode for most purposes. The only exception would be for higher frame rates, only available with smaller active areas. 3K mode is acceptable, but the 2K mode doesn’t have adequate resolution. (2-09)

17. You can’t pre-slate an MOS like you can with film. The slate would be stored as its own separate clip.

18. Neutral Density/Infrared Issue: The camera is sensitive to infrared in addition to visible light. Conventional ND filters are neutral across the visible spectrum, but pass a great deal of IR. Use enough ND (roughly 0.9 or more), and the ratio of IR to visible light gets high enough to cause visible and unpredictable results, primarily color shifts in specific objects. (6-08) Formatt Filters now make IR and ND filters specifically to solve this problem. (10-08) Add Tiffen to the list of IR compatible filter makers.

19. The savings are illusory: The camera body may be only $17,500, but it’s like a Barbie doll. The rest of the stuff you need pushes the total price up into the same region as some conventional 2/3” cameras.

20. Offline editing: The broadcast quality output from the camera is in the form of compressed raw Bayer images in their proprietary .R3D file format. Red started out working with Apple to build some compatibility into Final Cut Pro. With FCP, you can edit immediately using Red-generated proxies, but at less than full HD resolution. For better resolution, or to use Avid, the raw Red files have to be rendered, which takes a lot of computer time. Full 4K to HD at full quality prior to Build 17 took 25 hours to render one hour of material. One workaround is to work at lower resolution offline, and render only the selects for online. But even working with Build 17, it still takes 15 times run time to render. This isn’t just a matter of building an extra day into the schedule, it’s also a facility scheduling bottleneck. (1-09): Some facilities can now render multiple takes simultaneously, thus reducing the overall time to get dailies out.

Red has recently released a software development kit, which will allow other vendors to work with the same inside information that Apple has had.

21. “Sub-Prime” Lenses: The introduction of thousands of new PL mount cameras has generated an unexpected demand for lenses. One major rental house restricts their best glass to customers who rent their cameras, so as not to have bodies left on the shelf for lack of lenses. They’re keeping older lenses in their rental inventory just to serve the Red market.

22. Dropped Frame Counter: The camera sometimes doesn’t get all the frames recorded. When this happens, a little red square appears in the finder giving the number of frames missing. It seems not to happen often, but when it does, you need to shoot another take. (12-08)

23. Firmware: It’s recommended to always have a copy of the firmware build you’re using on a card so it can be re-installed in the field. (1-09)

24. Green Screen/Blue Screen: Green screen works well, except with tungsten balanced light. Ideally, work with HMI’s at 5600K. If you have to go tungsten, hang at least an 80D filter. Forget about blue screen. The Bayer sensor has only half as much blue resolution as green, and the blue channel is the noisiest on any CMOS or CCD camera. (1-09)

25. Test end to end with the firmware build you’ll use, and don’t change builds during a shoot. New builds sometimes “break” post production software (17 did this). (1-09)

26. Avoid “Max” mode unless the camera says to use it. (It’s for extremely complex and difficult to compress images.) It makes everything downstream go much slower. (2-09)

27. There are reports from a major video facility of blocky artifacts in the blacks, traced to problems in the Red post software. Going to .DPX files doesn’t have that problem. (2-09)

28. For accurate time code, a Lockit or equivalent outboard box is recommended.

29. Color decisions should be set in the metadata for automatic transfer. .RSX files created on set will override the camera’s color metadata.

30. Color gamut of the camera is limited, especially for saturated blues and violets. The green primary is also quite yellowish. So, if you need to distinguish between fairly saturated colors, test first. If your colors are subtle, there’s nothing to worry about here. (2-09)

31. The meaning of “K”: When Red refers to “4K”, they’re counting the photosites across their Bayer masked chip. That’s not the way the rest of the industry uses the term. “4K” as used elsewhere refers to pixels. Each pixel is a complete three color RGB data set for a single location in the grid. Red counts one color per location, not three. So, it’s apples and oranges.




-- J.S.
  • 0

#3 christina alexandra voros

christina alexandra voros

    New

  • Basic Members
  • Pip
  • 4 posts
  • Cinematographer

Posted 17 May 2009 - 08:50 AM

Hey John -

this is amazing. Thank you so very much!
  • 0

#4 Mike Washlesky

Mike Washlesky
  • Basic Members
  • PipPipPip
  • 194 posts
  • Cinematographer
  • Austin,TX

Posted 17 May 2009 - 09:32 AM

John, awesome info man.
  • 0

#5 Matthew Rogers

Matthew Rogers
  • Basic Members
  • PipPipPip
  • 175 posts
  • Cinematographer
  • Knoxville, TN

Posted 17 May 2009 - 04:47 PM

Let me correct some of John's notes as they are out of date.

1. The camera now shows an image about 10-15 seconds into booting. You can't change the shutter or record, but there is an image for monitoring.

6. You can mix resolutions AND framerates as long as the project is left in one base setting (aka, either 23.98, 24, 25, or 29.97). If you switch the base framerate setting, you will not be able to record until you erase the media to the new base setting. This is not an issue for probably 99% of projects (I've only ever shot 23.98 base on mine.)

7. You can now run the RED LCD, RED EVF, and a HD-SDI monitor or an HDMI monitor (I think you can run HD-SDI and HDMI both at the same time.)

9. I don't know why it matters if you can see the back LCD when you've got the EVF or RED LCD on the camera. It shows exactly the same info as the back monitor.

11. I personally, have not seen the codec error since last August. They've pretty much totally eliminated it.

24. I don't know why you've had issues with Tungsten and green screen, but I've done a couple of shoots like that and it works great. Tungsten on the background and daylight on talent works nicely and gives clean keys. Blue screen also works fine if it's lit with daylight on background and talent.

30. It has a limited color space on the HD-SDI monitor out, but I've never had any of those things transfer over when I actually look at it in RedCine or in Color off the RAW file. The color space you monitor in also makes a difference. I found on the render out that it looks best if the gamma is set to Rec709 and color space to RedSpace.

I find it's best to monitor on set in Rec709. If you monitor in RedSpace, you probably will underexpose a little too much and get a noisier image in post. It's also nice to set the "RAW" view mode to one of the user buttons so you can quickly see if something is clipping in the actual raw, or just in the colorspace you are monitoring in.

Matthew
  • 0

#6 John Sprung

John Sprung
  • Sustaining Members
  • 4635 posts
  • Other

Posted 18 May 2009 - 02:54 PM

Let me correct some of John's notes as they are out of date.


Yeah, that thing's a lot like my garage. I should go through it and clean it up a lot. Does anybody else have any suggestions on what to throw out, what to keep, and what to add? (I mean for the Red camera notes, not the garage.... ;-) )





-- J.S.
  • 0

#7 Alex Wuijts

Alex Wuijts
  • Basic Members
  • PipPipPip
  • 181 posts
  • Cinematographer

Posted 24 May 2009 - 04:13 AM

Yeah, that thing's a lot like my garage. I should go through it and clean it up a lot. Does anybody else have any suggestions on what to throw out, what to keep, and what to add? (I mean for the Red camera notes, not the garage.... ;-) )





-- J.S.


Sometimes the camera won't boot (build 17) when you have the viewfinder and LCD screen plugged in because it lacks the necessary voltage. The little screen in the back will just show the message "booting...". Unplugging the LCD screen before startup is the solution.
  • 0


Rig Wheels Passport

CineLab

The Slider

rebotnix Technologies

Ritter Battery

Tai Audio

Willys Widgets

Gamma Ray Digital Inc

Visual Products

Metropolis Post

Media Blackout - Custom Cables and AKS

CineTape

Opal

Broadcast Solutions Inc

Abel Cine

Glidecam

Aerial Filmworks

FJS International, LLC

Technodolly

Wooden Camera

Paralinx LLC

Glidecam

Opal

Metropolis Post

CineLab

FJS International, LLC

The Slider

Abel Cine

Wooden Camera

Paralinx LLC

CineTape

Rig Wheels Passport

Willys Widgets

Ritter Battery

Broadcast Solutions Inc

Media Blackout - Custom Cables and AKS

Gamma Ray Digital Inc

Technodolly

rebotnix Technologies

Aerial Filmworks

Tai Audio

Visual Products