Dale Mccready
Forum Replies Created
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when you go from 180 degrees to 250 or so, you are widening the shutter (in physical terms on a film camera, electronically it is a gate circuit) and so are letting more light through to the film/sensor, exposing for longer. So you would close the iris a little in this case. Going from 180 and tightening or closing the shutter to 90 degrees you would need to open up the iris. rememener that 180 degrees and 24FPS is 1/48th of a second, closing to 90 degrees becomes 1/96th. (I’m used to using 172.8 degrees, so someone correct me if thats wrong). So a shorter exposure, requiring more light.
As to the flicker, we don’t often shoot for NTSC directly here, and if we are shooting for the US, such as for Xena or Hercules (I’m from New Zealand) we shot at 24.
But the math for the flicker isn’t terribly difficult, check out the red Samuelson’s camera manual. It has the equations in it.
With the Varicam you have the fortunate ability of being able to see the flicker on a monitor, so you’ll be able to find a flicker free window by adjusting the shutter as you change frame rates. The recent shoot at 18FPS I did created flicker and so I changed the shutter down to 131.0 degrees, which made it disappear. No thats a great feature of digital photgraphy!
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I’ve also been turning the shutter off when shooting at 50FPS lately, as it saves lighting up a stop, or opening the lens a stop, and in theory should provide the same motion blur as footage shot at 180degrees and 25FPS.
Weirdly, I found that (again perceptions based on previous viewer experience) where I liked the look, people were disappointed that it didn’t look as detailed as slow-motion that they had seen on film. I guess having something move in slow motion is interesting enough that people want to be able to see it more clearly, and so now I shoot with a more traditional 180 degree shutter and 50FPS, and I open up the lens to compensate. This gives a crisper, more detailed look.
I like the motion blurred look though at 50FPS, and opening the shutter completely is something that a film camera can’t do at all, so it’s nice to provide a new look.
As Leo recommends though…test, test, test. Find the look that you prefer, everyone has different opinions (as we have seen earlier on the forum) and you’ll more thoroughly understand the tool in the process.
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haha. a last thought. I think I’m eating my own tail now anyway.
It’s interesting to me that film and television is holding on to these low frame rates. There are a lot of logistical reasons, from my point of view the amount of light it takes to shoot high frame rates becomes restrictive. But it’s interesting to me that interactive media such as gaming is where the high frames are really demanded.
Perhaps this is a key thing. That passive media up to this point is comfortable living with it’s older system and low frame rate, and maybe just having a larger TV won’t change this.
But what about a real pradigm shift? If you were able to immerse yourself in your media in the way that gaming does today, then I imagine you’ll want all the frames you can get because it’s about believable immersion. Perhaps when a change of this type comes along to replace our films and television?
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Hi Herb,
That project sounds great, and I’ll keep do some tests of 50 interlaced to 25 to have a look (I’m in PAL land downunder).
Unfortunately for your DP, they’ll have to live with the flickery eyepiece for the time being. It’s the progressive nature of the Varicam, that you are seeing only 24/25/30 HZ replayed to you progressively. There is no interlacing between the camera head and the eyepiece monitor so that persistence of vision thing turns up again and strobing is noticed. In a film camera eyepiece it is also 24FPS progressively, but with a blurred shutter look so it’s softer and easier to deal with.
On my recent drama shoot, after a day of shooting neither the operator or I noticed it anymore, and once you know it’s normal or okay, it can quickly be forgotten about and bigger problems come up. The nice thing about the Varicam while shooting is that you see what you get with frame rates, shutter angles and lighing power supply flicker, and I wouldn’t trade that now that I’ve become used to it.
Dale
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Wow,
I didn’t realise that I was open to personal attack just for writing my opinion down. I don’t smoke anything thank you very much and have instead been shooting for the last 13 years. Before that I was an editor. I shoot film & tape, and have successfully shot with the Varicam on many occassions and frame rates spending upon the needs of the project, and funnily my last one was at 18FPS to give a slightly antique feel (but some was at 60 to capture more detail).
If you know me then you can make statements as to my character and whether or not I am on drugs, but otherwise a rational discussion of the thread is more useful. You can take exception to my viewpoint and that is fine, I agree that the more detailed and higher resolution, temporally, in colour space, and lines per image something captured is, the more information you have. That is a given. Obvious really.
A 35mm film frame holds vaguely 12megapixels of detail and is analog in it’s colour and luminance range, but if I can’t tweak a camera to do/be that, but I can change one factor to make it comparable to what an audience perceives as filmic, then perhaps a similar frame rate, with its associated loss in temporal quality is an option.
If a director wanted a 1970’s feel that reflected a person’s memories of childhood I might suggest shooting on 8mm too. Maybe at 18FPS with a reversal stock that only has 5 stops of contast range too! But I’d probably suggest shooting 16mm to have more quality and flexiblity. As you say, artifacts can be introduced.
As a great English focus puller once told me dryly…
“whatever’s right” 🙂
Dale McCready
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Hey there,
My experience has been that clients prefer 24FPS for it’s look when dealing with drama, and I agree that higher frame rates provide greater quality, but we are stuck with the systems that have been developed and my point is that people are now responding to this. Their perception is that a flickery image is filmic because that is what they’ve become accustomed to. Yes of course the ‘film’ look is due to many factors. As a a DP I’d be the first to tell you that good lighting, production design, art direction, costume, make up, colour-correction, print and negative film stocks, lens and filter choices, and the concentrated attention of evryone involved creates the production value and finished feel of a film. No one factor can mimic this.
The choice between shooting and editing 60FPS or 24FPS must of course consider all the factors in a project, the target market and delivery system, and the desired affect on your audience.
The showscan system could well have taken off and now what we would associate with quality could well have become 60FPS, But it didn’t. The traditional development of 24FPS (with a second showing of each frame in projection making 48Hz) in the early days of film was an economical/logistical choice, but has led us to where we are now.
Interesting what was previously posted about 60FPS becoming an interlaced 30FPS, thats a great way of capturing more detail for each field. Can you tell us what result this has with motion? what does it look like? Ultra smooth motion I would imagine. Was the Varicam used shooting with it’s shutter at 180degrees and 60FPS? Did the DP have to then light up to make this decreased exposure time per frame or was the ‘open’ or 360 degree shutter setting used?
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Absolutely true. If you are wanting a filmic look then 60 FPS is not the way to go.
My previous post does not refer to it being retimed to look like 24FPS. IF 60 FPS is retimed it will be slow motion. The only way around that is to drop frames at intervals (like every second one) to create a more normal 24/25/30 frames, but because of the short interval of exposure it will not look like normal shooting and more like shooting 24FPS with a narrowed shutter angle.
To answer redflag, if you have shot at 60FPS and want to use it in a 30FPS timeline, remember that a second is a second no matter how many frames you stick into it. I believe that if you don’t retime/convert the footage FCP will just squeeze the footage into your timeline as is….
….I just did a test of this (60FPS into a 30FPS timeline without frame rate conversion) and yes, it requires some rendering but it just drops every other frame, and looks stuttery because there isn’t enough motion blur between each frame left over. Equivalent to having shot at 30FPS with a 90 degree shutter setting.
It is one of the interesting things that I believe has emerged about human perception over the last few years, especially as it pertains to film. When HD was being developed there was a lot of talk about using cameras wih very high frame rates such as 60FPS because it would give smoother motion, and more realistic portrayal of reality (since we see well more than 24 FPS ourselves). But this idea got thrown out very quickly as people associated high frame rates too much with reality and quickly came to associate those images with news or documentary information.
When watching film and drama, the visual cue of the subtle flicker of 24FPS signals to the viewer that they are watching fiction, and so they can suspend their disbelief and relax into the story being told. People enjoy the artificiality of film and television, and this is where motion, grain, unrealistic colours, and even black & white (or especially B&W) give the viewer a different world to enjoy, unlike their own, everyday one.
I enjoy the fact that in this area the ‘lesser quality’ option wins out here, and that in the future we may have 32bit Log 4:4:4 4K images streaming across our internet connections, but they will probably only be 24FPS.
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If you choose to shoot at 60FPS there are no dummy frames at all so you wouldn’t see any stuttering of the image if it is not retimed. so it can be used from then on as it is, or if you convert it via FCP or the frame rate converter it will stretch out to 2+ seconds duration for every second shot.
Some people prefer to shoot at 60 FPS to give themselves more detail/smoother motion. Also the footage can be retimed at a later date in most retiming applications as there are no dummy frames to be identified and removed which otherwise requires the use of the frame rate converter or FCP’s software converter.
The photographic effect of shooting at 60FPS and not converting it into slow motion is a temporal oversampling. Normal films shoot at 24FPS and play back generally at 48Hz when projected. This is around the minimum frequency to provide the illusion of motion in a series of still images (which film is) and is called persistence of vision. Playing back a 60FPS movie at 60FPS exceeds this benchmark and would give the illusion of very smooth, detailed and sharp images. Sharp especially because there is less perceptible motion blur per frame shot. (things have less time to move between frames leading to less blur).
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Hi there,
The camera head shoots variable frame rates, but what the site is referring to is the tape system. The recorder always runs at 60FPS on the Varicam and uses a memory buffer while shooting to place frames onto the tape consistently at this rate, no matter what shooting rate you choose.
When shooting 25FPS for example, the buffer creates duplicate or dummy frames and places them onto the tape. So 25FPS is 25 real frames and 35 dummies. The user bits code on the tape when recording ‘flags’ these frames with a 1 or a 0 depending upon whether the frame is a real one or a dummy.
The frame rate converter, or non-linear editing system recognises these flags when capturing, and can discard the dummy frames and lay the real frames out in a new time-base, such as 24, 25, or 30 FPS. When capturing material that was shot at your capture frame rate no other conversion is necessary.
When shooting off speed material, when your shooting frame rate differs from your base frame rate or delivery frame rate such as 25FPS, a conversion is necessary where the frame rate converter or FCP software plugin will retime the flagged footage. If for example your frame rate 50 FPS there are 50 real frames shot and 10 dummy frames added to make the 60 recording format. When converting back to 25FPS, the dummy frames will be discarded and the 50 frames left will be stretched out to the playback speed of 25FPS, doubling the duration of the original footage and appearing as slow motion.
Any ‘over-cranked’ or ‘under-cranked’ footage refers to any footage over or under your base frame rate. Under being (in the case of a 25FPS delivery frame rate) anything between 4 and 24FPS, over being anything between 26 and 60 FPS.
An interesting factoid about the Varicam and ‘under-cranked’ footage, is that the dummy frames give the very same appearance as running a telecine slowly, or ‘step-printing’. So it is possible to get two looks out of one piece of footage, one before, and one after retiming/conversion.
Hope that helps
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I’m just finishing off post on a shoot that I DP’d with two Varicams and we used Steadicam extensively. I’m a Steadicam Owner/Operator and don’t see this camera being particularly heavy when you compare it to most other cameras that I’ve hauled around. If the film is a continuous shot then yeah, trim as much weight off as you can, but as to the image quality, especially outside with trees, the varicam is probably your best bet. The cine gamma FILM REC function and exposing it at it’s rated ASA will give you a lot of leeway between sun and shade. Even more interestingly I did a lot of live exposure changes on our shoot from shade to sun as the camera pivoted around, and really I often needn’t have. I’ve found in post that the lattitude of the Varicam is so good outside that even 2 stops over in sun holds very well and can be pushed back down easily, so in the future I will be more likely to expose the camera in between a sunlit and shade lit setting and compensate in post to improve the timing.