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F23 Questions


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#1 Matt Gorrie

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Posted 04 December 2007 - 07:40 AM

I'm shooting a short with the F23 this weekend and due to scheduling conflicts and what not I wont get a chance to go over the camera beforehand or do any testing. This will be the first time I've shot with this camera.

I have a few questions which I hope some of my learned colleagues here may be able to help me out with.

For starters I was going to use one of Steve Shaw's (Digital Praxis) log curves with the camera instead of the standard Sony S-log curve. With regards to this does anyone who has used the camera think there will be a problem using the "Moni Gamma Enable" function which applies a fixed gamma (R709) to the monitor output for viewing "corrected" images on set?

Also, when shooting in log mode, should I set my zebra's to something other than the usual 65-70% for Caucasian skin tones, or would I be better off just using my light meter and monitor/wfm?

I am planning to shoot 4:2:2 for this project due to budget constraints and because some of the shots will be high speed. I'm guessing that as I'm not doing any green screen or comp work the hit from dropping down from 4:4:4 will be negligible, any comments?

With regards to color correction, I see in the manual the user has the option to use the optical filter wheel to set the camera to 5600K or to set it electronically, why would one use the electronic method?

Can someone explain to me the difference between S25PsF and 25PsF and so on for the other standard shooting speeds? Does the S in front of the frame rate have something to do with selectable frame rates, and how does this impact on shooting higher speed footage?

Also does anyone know if variable speed footage can be mixed on the same tape and if I need to change the settings on the F23 and the SRW-1 when adjusting the speed?

Finally, on a more mechanical note... any suggestions for a home made shoulder pad for these things?

Wish I had some time to test these ideas out for myself beforehand!

Regards

Matt
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#2 Shaun Joye

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Posted 04 December 2007 - 09:50 AM

The electronic 5600k is used when you either don't have the light to use the filter or you have the color correction filter wheel set to ND. The ND on the wheel lets you go in smaller increments by combining it with the regular ND wheel.

As for s23.98 and so on. S does refer to selectable framerates. For slow motion your're going to want to shoot s59.94. Which will allow you to go from 1-60fps. It will be laid down with 23.98 timecode regardless of what framerate you're shooting so the deck will actually play it back at whatever framerate the deck is set to. This is true variable framerate so in that respect its more like film. There won't be any problem in having slow motion and regular speed on the same tape. This is all with the deck actually mounted on the camera. With the srw1 detached the functionality is much less straight forward.

If you're not doing effects 4:2:2 vs 4:4:4 is not going to make any visible difference.
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#3 Mitch Gross

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Posted 04 December 2007 - 10:01 AM

My experience is from bench testing, not on set.

I think that the Praxis curves are great and viewing in 709 is a safe, solid move.

Set zebras as normal.

In 4:2:2 it will behave much like an F900R (but better), so you should be fine.

All electronic sensors are generally blue-starved, which means they are nominally daylight-balanced. They have to be electronically balanced to tungsten, which is why you'll always see noise in the blues first. So electronically shifting the balance to daylight just plays to the strengths of the sensors, making a cleaner picture. That and you gain some sensitivity.

Don't have an answer on the frame rate.

I would never mix variable speed on the same tape. Not only is it torture for the deck, but torture for the post guys as well, who would have to sit there and monitor all the downloading. Always use a separate tape for off-speed work.

Homemade shoulderpad: A thick neoprene computer mousepad or keyboard wrist rest works wonders. Costs pennies.
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#4 Michael Nash

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Posted 04 December 2007 - 04:30 PM

I would never mix variable speed on the same tape. Not only is it torture for the deck, but torture for the post guys as well, who would have to sit there and monitor all the downloading. Always use a separate tape for off-speed work.


I don't understand why this should be necessary with the F23. Unlike off-speed shooting with the Varicam where the clips have to be logged and converted in post, the F23 records off-speed and ramps as one-to-one progressive frames. What you end up with on tape is just like off-speed film that's been telecined at 24fps, and you certainly don't need a separate tape for all slow motion takes during telecine.
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#5 Mitch Gross

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Posted 04 December 2007 - 05:03 PM

I guess in the end you're right. I just always trained to split out off speed shots, even to the extent of changing mags when shooting film. It was always a question of making things easier for editorial.
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#6 Michael Nash

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Posted 04 December 2007 - 05:36 PM

I just always trained to split out off speed shots, even to the extent of changing mags when shooting film.


Does this extend to P2 cards as well? (just kidding :P )

I honestly didn't know if there would be any hidden gotchas with timecode or anything else, since I've never worked with a deck that actually changes speed. As long as all the material is 24fps time base it seems like it should be okay. Different recording formats (like 60i and 24P) should never be mixed on the same tape.

In any case, with any format it's always good to also note the fps on the slate when shooting off-peed, usually with a finger pointing at the number, so that post knows what's going on with those shots.
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#7 Stephen Williams

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Posted 04 December 2007 - 05:41 PM

I guess in the end you're right. I just always trained to split out off speed shots, even to the extent of changing mags when shooting film. It was always a question of making things easier for editorial.


Hi Mitch,

I know there are issues playing back HDCAM SR tapes with different recording settings. I have been asked to use different tapes by the post house.

Stephen
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#8 Matt Gorrie

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Posted 04 December 2007 - 06:34 PM

Thanks Shaun, I thought that was the case regarding the S for selectable frame rates... We're in PAL land and not going to do a film out or anything like that so we'll be shooting at 25PsF and for high speed, we'll just ramp it up to S50P.

Mitch, thanks for your answers too (at least you've bench tested the camera!). It will be nice to use the optical ND's in 1 stop increments, so using the Electronic 5600K option sounds like a good idea.

I will keep in mind the notion of not mixing variable speed shots on the same tape, but we could get stuck if our stock runs low. A colleague of mine was recently at a Post house where they were having all sorts of trouble locking their deck up to variable speed stuff shot with the F23. They said the material was going from 59.94 to 60 and all over the place and they couldn't get it to digitise. Also they had problems grading the material that was captured with the S-log. Apparently they said that there wasn't enough chroma information in the image to bring it back to a natural look without introducing a lot of noise. Though they were trying to grade in Shake or After Effects, not a true grading suite. A guy from Sony came out and told them they should have shot 709 linear... don't know why, if they intended on grading it?

Thanks for the tip on the homemade shoulder pad too, I'll try and whip one up tonight.

Matt
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#9 Felipe Perez-Burchard

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Posted 31 July 2008 - 12:19 PM

I can't totally speak for the F23, as I've yet to use it (very soon I think), but on the Genesis (witch uses the same SRW-1 deck), the main reason for switching tapes when doing high-speed work is because you have to switch to 4:2:2 -- not a problem for Matt since the whole thing is 4:2:2, but in general, if the 23.98PsF material is being shot at 4:4:4, the trouble is the Editorial Deck won't do an automatic switch, and somebody would HAVE to be there... if that material is shot on another tape, it simplifies the workflow and I think its better practise... but it technical terms I guess not necessary.
With solid state media or clip based recording (RED, P2, SxS) every shot carries all the necessary info and there is no linear deck involved, so mix frame rates and formats as much as you want.... Timecode is also much easier to deal with.

Hope it helps.
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