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DI or not to DI: HD to 35mm


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#1 Sarmed Mirza

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Posted 23 July 2010 - 06:12 AM

Hi guys,
This is a very useful forum and I am learning a lot from it. I hope I can find some useful info here which can help me plan my next movie. I am planning to shoot a feature using EX1/EX3 + Letus setup and working out the best workflow for post.

So I shoot the movie using EX1/EX3, I edit it in FCP. Then :
1. What is best output for me to give to the lab
2. If I do colour correct post will it come out any different when a 35mm print is made? Or should I get, lets say, different sections of the movie of 10-30 sec duration each section up to total of 5 minutes to see how the result will be for any tweaks before getting the whole movie converted.
3. Will this mean that I will not need a DI or does a DI serve other purposes as well? I want to save money by skipping the DI stage basically.
4. EX1/EX3 footage: Do I lose quality/resolution (from 1920x1080) at any stage in the post affecting the quality of the final print. Any potholes I should look out for?

Thank you for any replies in advance guys :)
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#2 Brian Drysdale

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Posted 23 July 2010 - 06:48 AM

If you're only making a small number of 35mm prints you could check out using a Cinevator. You don't need a DI using this.

http://www.cinevatio...=Cinevator&id=8
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#3 John Sprung

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Posted 23 July 2010 - 04:05 PM

You might just film out individual frames from each setup, and project them a slides to check timing before outputting the whole show.





-- J.S.
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#4 Phil Rhodes

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Posted 23 July 2010 - 04:25 PM

One addendum to this.

There's a lot of use of the word "need" in situations like this - as in, you "need" to have it graded in a calibrated facility, you "need" to look at it on a certain type of display, etc. These requirements are often designed to cater for the needs of extremely well-funded, highly visible and very exacting productions. What they need may not reflect what you need.

Be careful of being told what you need to do (ask here if unsure). After all, I suspect the post house involved has the ability to receive a file from you, and the ability to shoot files out to film; if your original looks right, it would in some ways be their job to ensure that the result is somewhere in a watchable range, simply as part of the service. You won't get the ability to tweak or adjust, perhaps, but it really depends what your priorities are.

I don't wish to encourage you to be in any way slapdash or to imply that your production is unworthy of precision, but it's often possible to do these things much cheaper in a way that results in something that's quite watchable. Perhaps not exactly the way it looked on your Mac, but perfectly technically acceptable and entirely watchable.


Of course I'm assuming here that your EX-shot production is not a multimillion dollar feature film; perhaps you are making Public Enemies II, in which case this will not apply.

P
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#5 Stuart Brereton

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Posted 23 July 2010 - 11:33 PM

3. Will this mean that I will not need a DI or does a DI serve other purposes as well? I want to save money by skipping the DI stage basically.



A DI, or Digital Intermediate, is a post production stage which is necessary when scanning film to digital files for color correction (and other processes) before outputting back to film for release.

Material which is electronically originated does not go through this process - the 'Intermediate' stage is unnecessary.

DI has become a common, but inaccurate term for digital color correction. I think that it is important to use the correct terms for the processes involved. It's already hard enough to get producers to understand the post processes, without us further muddying the waters by using inaccurate terminology.
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#6 Sarmed Mirza

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Posted 25 July 2010 - 07:35 AM

Thanks for the replies guys. A producer friend who is getting his movie through DI process by sitting through the colour correction process himself, is also going to find out the process and cost of reverse telecine and if there would be any huge changes in the look of the film if we do not include colour correction as part of the reverse. I am also going to speak to a few more production houses about the cost as well as the test 5 minute footage cost etc. And of course I will share on this forum any thing I learn from this research.

Of course I would want my movie to look superb, however this particular production is light years away from something like Inception. Hence I am flexible when it comes to the final output. That is why we are making this movie now so we can learn from the mistakes here and on our bigger budget production we would know before hand the reverse telecine cost and the result it would buy us.

Also totally agree with the terminology comment. DI is a muddled term because it can have different processes depending on which boxes are ticked so I will also just talk about the stages with their names. This forum, I am hoping, would keep me right too.

Thank you very much again for the hospitality. I am feeling much better now that I have a place where I can get some independent information.
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#7 Sarmed Mirza

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Posted 25 July 2010 - 10:12 AM

Hi guys
Looking at another aspect of EX3, I was wondering if its 4:2:0 colour sampling would have any effect on quality? I don't intend to do any chroma work but if I did would it matter a lot.

Will I get the full resolution of 1920 x 1080 shooting at 24p in EX3 at all stages?

Sorry if this is slightly out of the topic range. I can re-post it to another area but my context is really all to do with the 35 mm conversion so it's important I know all aspects before buying one, and I am coming very close. I want to come up with a setup using a Letus adapter and Nikkor or similar lenses for the EX3.
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#8 Adrian Sierkowski

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Posted 25 July 2010 - 11:15 AM

You'll be recording 1080 full @ 24p.. but when you put that lens adapter in front you won't really be resolving 1080. That's ok, though as I find the diffusion from a lens adapter alright in terms of softening the HD sharpness (often oversharpness) but it will also reduce your contrast a bit, and cause light halation. Furthermore, if you're even considering a film out, it might make sense to first put the right money into the right lense.. eg. not stills lenses, which while optically find for motion picture work, are a mechanical nightmare!
As for the 4:2:0 of the XDCams, no it's not full chroma resolution, but it works well enough. The biggest limiting factor I find is the 8-bit signal which is 256 possible values per pixel (v say 1024 for a 10bit). This means that it'll record nice and fine, but you can't push it around too much in post. Try to nail as much in camera as you can. Personally, I shoot the XDCam very flat knowing I can add contrast in later on if needed. Make sure you white balance properly and get out of any "fix it in post" mindset you might have.
Now, that all being said, yes you can go out to film, it'll also put out the full 1080, assuming you editing and captured and recorded @ 1080, and it'll look very nice on film. This will be kinda of expensive and it might make more sense to go out to an IN (internegetive) and then strike prints from that, if you'd doing a limited number of them. I would try to do a color correction in a nice facility, or at least on Apple Color in a proper viewing environment, preferably on a calibrated (in some form) monitor (e.g. one you can adjust bars to!).
If you're going to do a Letus, there is a relay lens system which mounts to the EX3, which I find easier than working with it on the EX1 (i sold my letus as it annoyed me to no end.)

One last thing too, when you come to export your movie, I'd recommend something like ProResHQ. Yes, I know it's more information than is in the EX clips themselves, but it's universal enough to work at most places native, and it's fast enough to be pulled off of a hard drive in real time for a layout to tape, if you wanted to go that route-- which is another option, XDCam--ProRes-->HDCam (or HDCamSR)-->Tape to Tape Color Correction-->HDCam (or SR) and ProRes recaptures, from which you can make your DVDs/BRDs and any Tape Dubs you might need.
Hope this helped.

I would also get the price on a DCP, for digital cinema distro.
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#9 Sarmed Mirza

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Posted 26 July 2010 - 10:05 AM

Thanks for the detailed reply. Yes, the relay sounds a better option quality wise, however a price hike has to be considered. I am looking into different lenses such as Nikkor etc, bearing in mind that I don't want a lens which I have to focus on a separate camera before mounting on the EX everytime.

I will discuss what you have said about the codec options with my online editor and assess hardware requirements as well. Plus now when I meet the lab guys I can discuss this in detail keeping in mind the the forum comments.

Thanks ever so much.
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#10 Adrian Sierkowski

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Posted 26 July 2010 - 10:09 AM

You'd always be focusing the lens on the EX camera.... well, to be more succinct, you'd focus the lens on the end of the letus, leaving the lens on the EX (unless you're on a relay) untouched and focused on the ground-glass within the Letus. You'd never pull a lens off, throw it on say a Nikon camera, focus on that, then put it back on... It wouldn't be in focus anymore.
And basically any stills lens is mechanically a nightmare to work on a film camera.
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#11 Robert Houllahan

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Posted 26 July 2010 - 10:13 AM

If I were shooting a film on a EX series sony camera I would put the money into recording the SDI feed on a AJA Ki or similar instead of wasting time with a DOF adapter. You could record to 4:2:2 10bit ProRes with the AJA and if you are going to go to all the trouble and expense of a 35mm film print it would be worth it in the end.

As for whether to do a DI or not I would say that even reality Tv gets a color correction pass to fix color balance issues. If you skip color correction on a projector there is no guarantee about what your film will look like after it is shot out to film. You could shoot and pray and then have a color timer time the print after the master negative has been shot.

-Rob-
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#12 Sarmed Mirza

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Posted 27 July 2010 - 10:17 AM

I would definitely do colour correction but I mean if I do it in FCP on the digital footage, would I need to go through another colour correction stage during conversion to 35mm? I have seen some very good results on FCP using magic bullet plugin. If I can do it in post in FCP and the 35mm result is 10% within what I see during post I think would be quite happy.

And thanks for the AJA tip. Looking into it :)
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