HD100 to 35mm Transfer - any experiences?

[Alexei Berteig]

I'm looking for anyone who has experience transferring HD100 footage to film. I have checked out the scene files and recipies posted elsewhere on this forum, but so far I haven't read that anyone has tested any of these scene files through to the transfer to film stage.

I will be dealing with extremely high-contrast subject matter; I'm hoping to completely diguise the fact that this was shot on anything other than film negative. Depth-of-field is not an issue, however; we don't want shallow depth of field. What we _do_ want for this short narrative film project is a final print on 35 mm that will compare with other shorts shot on film neg in the international festival circuit.

I would be interested in hearing from any of you that have transferred other flavors of dv, hdv, digibeta etc. to film and have any experiences that I could, even tangentally, bring to bear on my preparations for my upcoming shoot.

P.S. This forum is big, so there may be threads I've missed. Feel free to redirect me.

[Daniel Weber]

Do a search for posts by and about Andrew Young. He did a film out of the project that he shot in Madagascar last year.

Dan Weber

[Tim Dashwood]

Hi Alexei,

We have discussed this topic many times, and there are a few opinions with regards to black levels, detail, knee, etc.
The real experts in this area (with experience outputting HD100 source to 35mm film) are Andrew Young of Duart and James Tocher of Digital Film Group. They are both members here, so try searching their posts for thoughts on the subject.
Stephen Noe also did a film out in January, but most of the source was from m2t supplied by various members of the forum, so there were many unknown factors and settings.

http://www.dvinfo.net/conf/showthread.php?t=54171

http://www.dvinfo.net/conf/showthread.php?t=57634

http://www.dvinfo.net/conf/showthread.php?t=58710

http://www.dvinfo.net/conf/showthread.php?t=65469

http://www.dvinfo.net/conf/showthread.php?t=66526

[Alexei Berteig]

Thanks, I'll check out those posts.

[Andrew Young]

Hi Alexei,

As Tim mentioned, I have been involved in several HD100 filmouts, including my own material and that of 4 other DPs. DuArt has also done filmouts from just about every format imaginable and I have seen most of them. The HD100 holds up very well, particularly at this price point. But be sure to turn detail way down, otherwise the images have a tendency to look electronic. So far, none of the footage we have filmed out has strayed far from camera default settings. I intend to test Tim's and Paolo's settings, as well as others, but I'm afraid I've got too much on my plate to promise when. Will post the results when I have them.

In the meantime, keep detail way down (you can always add it in post), do not use black compress, do not use the filmout gamma setting, and mind your exposure - you can not dig very deep into an HDV image. And forgive me for stating the obvious, but don't shoot in 30p unless you intend to overcrank.

[Alexei Berteig]

Your responses are greatly appreciated. I just got back from Shanghai where I've been doing the prep for the filming.

Yes, I know that the bandwidth is precious, but we also have some really extreme lighting conditions. Just want to check quickly: if, for film transfer, I have to err on the side of underexposure or over exposure, which way would you go?

Also, in the world of video, normal black level is 7.5 IRE, but I'm considering setting "master black" to minus one or minus two so that I can get an extra stop of dynamic range. Would you recommend sticking with 7.5 IRE rather than try and get 0 IRE? Why or why not?

[Andrew Young]

Originally Posted by Alexei Berteig

Just want to check quickly: if, for film transfer, I have to err on the side of underexposure or over exposure, which way would you go?

Hi Alexei. Well, either will result in clipping at that end, but it is better to be a little under than a little over. Underexposure, however, is not a good thing in a compressed format. When you reach into the shadows to find detail, you will also find noise and artifacts. Good exposure is really important with this format.

Originally Posted by Alexei Berteig

Also, in the world of video, normal black level is 7.5 IRE, but I'm considering setting "master black" to minus one or minus two so that I can get an extra stop of dynamic range. Would you recommend sticking with 7.5 IRE rather than try and get 0 IRE? Why or why not?

It sounds like you are little confused here between setup and black level. Setup only effects what goes out of the camera's analogue output and not what goes onto tape. The JVC defaults are correct for the US, but check with your local post facility if you are using analogue outs to record your image.

Black level does affect what gets recorded and is an important setting. As I have not yet tested the results of lowering master black in a filmout, I would consult with Tim Dashwood or Paolo Ciccone - they have played around much more with this. Just be sure that you do not crush your blacks in any way. That should be done in post. Good luck.

[Alexei Berteig]

Originally Posted by Andrew Young

Good exposure is really important with this format.

Yeah, definitely. It's going to be a challenge because we're shooting in an area the size of four football fields, huge areas have gotta be lit, and sooner or later I'm going to be behind the camera staring down the barrel of one of the 15 HMIs we're pulling out for this gig. I've managed to communicate to the Chinese grips that we're bringing the highs down and the shadows up to manually compress the light values in our scene. Great in theory, but God, what a headache in our huge outdoor location.

Originally Posted by Andrew Young

It sounds like you are little confused here between setup and black level.

I'm talking about 0 IRE versus 7.5 IRE, which on the JVC, if I'm not mistaken, is controlled by MENU->CAMERA PROCESS->BLACK LEVEL. According to Paulo's tests using histograms from shots off a color chart, BLACK LEVEL -2 yields information in the absolute darkest areas, although it cannot be seen on a tv monitor unless it is calibrated to represent 0 IRE as 7.5 IRE. I can't comment on what the same functionality is called on other cameras - the Canon XL2, for example, has "Setup" and "Master Pedestal."

Originally Posted by Andrew Young

Setup only effects what goes out of the camera's analogue output and not what goes onto tape.

Really??? Setup level is adjustable on the HD-100? What the heck? If you can actually do that, please tell me how; I'd love to be able to record black at 0 IRE and see it represented at 7.5 IRE on a monitor.

In the meantime, we are recording on tape. I'm only talking about what's being recorded on tape when you set MASTER BLACK to -1 or -2. From what you've said, it sounds like using the default of MB=0 is safe. If I use MB -1 or MB -2 I'll of course tell the editor to reset black to 7.5 IRE in post.

Originally Posted by Andrew Young

Just be sure that you do not crush your blacks in any way. That should be done in post. Good luck.

By "crush your blacks" are you talking about the BLACK COMPRESS function or a negative Gamma setting? I'm not planning on using either. I have heard this term used a lot - differently, I might add, by various people - and I just want to make sure I know what you mean by "crush the blacks" so that I don't do it.

Thanks again.

I'm gonna go with MASTER BLACK -2 and adjust blacks back up to 7.5 IRE in post.

[John Jackman]

BTW, I have just received a filmout test from DuArt using HD100 footage that we will have screened in front of a group of DPs next week. There will be an article in an upcoming issue of DV Magazine.

Andy can respond for himself, but what he means by "crushed blacks" is allowing dark areas of the picture to hit 0 IRE (or 7.5 IRE with setup). There should only be a small number of regions that actually kiss the "solid black"; that's because those areas will have NO detail preserved digitally.

Using a negative black setting makes it MORE likely you will have problem with this, use black stretch of +1 instead. And make sure to toss some light into those dark areas!

[Chad Terpstra]

Originally Posted by Alexei Berteig

I'm gonna go with MASTER BLACK -2 and adjust blacks back up to 7.5 IRE in post.

Definitely don't do that. You've got it the wrong way around. Once the black level is set that low, there's very little chance of bringing it back up in post. Trust me, if you under-expose at all you'll see a lot of artifacts appear once you try bring it up.

However, if you shoot for a little bit more milky blacks (MB 0), possibly with black stretch depending on how contrasty your scene is, you can easily bring it back in line in post to where it looks nice (back down to 0 or 7.5 IRE). The goal is to capture as much detail as possible so that you have choices later on and more wiggle-room for error in exposure.

[Alexei Berteig]

Very good info. Thanks guys.

[Andrew Young]

Hi Alexei,

Maybe I misunderstood you, but there still seems to be some confusion.

Originally Posted by Alexei Berteig

I'm talking about 0 IRE versus 7.5 IRE, which on the JVC, if I'm not mistaken, is controlled by MENU->CAMERA PROCESS->BLACK LEVEL.

On the JVC HD100, SET UP is an option on the Video Format menu. It gives you two options: 0% and 7.5%. As far as I can tell, this option should only affect the analogue output of NTSC material, not what is recorded to tape. The correct setting would be 7.5% for US and 0% for Japan. Since blacks are recorded as 0% on digital formats, this setting would have greatest consequences in NTSC monitoring, unless your master is going through an NTSC analogue stage.

The menu item that you are speaking of above would either be MASTER BLACK (aka Pedestal) or BLACK which contains the steatch & compress options.

Originally Posted by Alexei Berteig

Really??? Setup level is adjustable on the HD-100? What the heck? If you can actually do that, please tell me how;

You can do it under the video format menu as outlined above.

Originally Posted by Alexei Berteig

I'd love to be able to record black at 0 IRE and see it represented at 7.5 IRE on a monitor.

A factory default HD100U does this right now when working in NTSC over analogue. If your not working in NTSC or analogue, I'm not sure why you would want to do this.

(The HD100 manual claims that setup can be added to 1394 output, but I see no difference in black level when doing this).

Originally Posted by Alexei Berteig

In the meantime, we are recording on tape. I'm only talking about what's being recorded on tape when you set MASTER BLACK to -1 or -2. From what you've said, it sounds like using the default of MB=0 is safe. If I use MB -1 or MB -2 I'll of course tell the editor to reset black to 7.5 IRE in post.

There are recipes that call for a Master Black of less than 0 but I would not use one unless I had a waveform monitor on set or was able to do a test output of the results, preferably both. I'm not sure what you mean by having the editor reset black to 7.5 in post. If you are working in a digital environment, why would you do that?

Originally Posted by Alexei Berteig

By "crush your blacks" are you talking about the BLACK COMPRESS function or a negative Gamma setting? I'm not planning on using either. I have heard this term used a lot - differently, I might add, by various people - and I just want to make sure I know what you mean by "crush the blacks" so that I don't do it.

To me, "Crushing the Blacks" means loosing information in the darker part of a scene. It is a contasty look that many people like, including myself, but doing it in camera causes information to be lost that can never be retrieved. Anything that causes blacks to clip or shadow tones to be pushed together, would be crushing the blacks, and that could include lowering the cameras master black setting or using black compress. I and many others advocate preserving as much information as possible for color correction at the mastering stage, whether you are planning for a filmout or not. There, it is easy to create a crushed look and you have complete control over what information gets lost.

If you're hooked up to a waveform and you have a cap on your lens, black should ideally be close to zero.

Again, sorry if I am misunderstanding what you are talking about.

[Alexei Berteig]

Thanks Andy.

As to changing "setup:" There were situations where I wanted to use a black level of 0 IRE (master black -2) but in order to see on the monitor what is actually being recorded to tape, you need to change the setup on your analog outs, or get a monitor that is manually adjusted to represent 0 IRE as 7.5 IRE. From tests that others have done (Paulo Ciccone) I can see that setting your master black (pedestal) at -2 (theoretically 0 IRE) doesn't actually cut information out of the picture: the information is still being recorded but you can't see it on a regular monitor because everything less than 7.5 IRE is represented on the monitor as black. In other words, detail in the shadows is making its way onto the tape but you can't see on the monitor. Solution: adjust the setup output from the analog outs on the camera.

However, I'm a little less excited than before because setting Master black at -2. It may not (contrary to what I'd previously thought) give you an extra "stop" of contrast range. The difference between 7.5 IRE and 100 IRE is supposed to be something in the neighborhood of 8 or 9 stops (10 bits downsampled to 8), and I thought setting master black at -2 gives an extra stop at the bottom. Maybe not; it seems to only distributes the data differently across the 8 bits availabel for each color channel.

However, as others have pointed out elsewhere in this forum (too tired to find the thread at the moment) the darker areas are represented by less bandwidth on the tape. Signal between 90 IRE and 100 IRE uses almost a third of the datastream, 80 IRE to 90 IRE uses 20%, etc...so that by the time you get under 30 IRE and you only have about 10% of the data stream left over to record a third of the light values in your scene. The top four stops, therefore, aren't going to show any serious banding or compression breakdown, but in shadows it could be a serious problem. Therefore, it's not a good idea to record critical info at the sub-7.5 IRE range; there's not enough bandwidth there in the compression scheme to handle it.

Upshot: I'm going to play it safe: master black = 0, black stretch 1, sharpness = off, etc...more or less Paulo's TCV3.

This forum is really super cool. There's nobody in Beijing that I can talk about this stuff with. I feel so darn....(sniff)...connected.

[Paolo Ciccone]

Originally Posted by Alexei Berteig

This forum is really super cool. There's nobody in Beijing that I can talk about this stuff with. I feel so darn....(sniff)...connected.

Alexei, this is pretty new stuff for lot of people, at least at this level.
It's great that we can all share information from both sides of Great Firewall of China :)

[Steve Mullen]

Originally Posted by John Jackman

And make sure to toss some light into those dark areas!

That depends. It is very common for blacks below 3IRE-5IRE to be clamped to full black which totally eliminates noise. So if you have an area you can't light correctly -- it is better to remove all stray illumination and let the area go inky black.

If you add a little bit of light to an area -- the system won't clamp the level to 0IRE and you'll see noise in this area.

If one can't light a huge area -- I would light pockets and let the other areas go fully black.