View Full Version : For those shooting Slomo @ 60fps
John Allardice January 9th, 2006, 07:43 PM Currently shooting some tests for an elements shoot I've got tomorrow and discovered something interesting... the 180 degree shutter setting when you're shooting at 24pn refers to the recording speed, not the shooting speed.
In other words, the 60p frames dont have a shutter speed of 1/120th, but in fact 1/48th. This is why any slomo we've seen so far has a little of that 'slurry' video feel. After I set the electronic shutter to 120th, bingo, perfect film style 60fps slow motion.
Cant actually post any stuff yet, 'work for hire' an all that, but hopefully later.
John
Rob McCardle January 9th, 2006, 08:36 PM Top tip, John.
Any "noise" for you ? Or have gone with Barry's recommended -5 setting ?
thanks in advance. Rob
Steven Thomas January 9th, 2006, 10:28 PM Here's a link to a recent example demonstrating under and overcranking using HVX200 720/30p timeline:
http://www.onetensix.com/hvx200/
The car goes by 4 times
Here's what I dissected from the Janglish
1. 30FPS (match timeline)
2. 12FPS (2.5 times faster) fast-mo
3. 60FPS (1/2 time as fast ) slow-mo
4. I believe it was a combo of 12FPS>60FPS>12FPS
In that order.
Steven Thomas January 9th, 2006, 10:39 PM Please experiment with the different gama modes.
Compare noise levels for HD NORM, CINE-LIKE_D, and CINE-LIKE_V.
I'm hearing that the CINE modes can increase the noise levels.
It would be interesting to see the differences.
Thanks,Steve
Barry Green January 9th, 2006, 10:48 PM A few things affect noise, and changing some settings can lower the noise noticeably.
1) Detail Coring -- crank that up higher to minimize noise. It works in conjunction with detail level -- the higher the detail level, the more effect coring will have; the lower the detail level the less effect coring will have.
2) Choose your gamma curve -- cine-like-D is the noisiest. It gives you the widest dynamic range, but the tradeoff is boosted noise. Black press is a pretty clean gamma.
3) Choose your color matrix -- the cine-like matrix really makes colors pop, but again, it increases the noise some. Choose the normal matrix for lower noise.
4) Detail level -- the higher the detail level, the more "sharpening" or "edge enhancement" will occur; and this includes enhancing the edges around any noise in the image. So a lower detail level will clean up the signal and make the image smoother and any noise less apparent.
Finally, there's the light level overall -- if there's adequate level for exposure somewhere on the CCD, then the shadows will stay clean and sharp. If there's not enough light for proper exposure, noise appears to increase picture-wide.
And, of course, gain -- gain = noise, the more gain, the more noise. Stick to 0dB whenever possible.
Steven Thomas January 9th, 2006, 11:04 PM Thanks Barry. Nice summary of parameters that will affect the noise level.
Steve
Rob McCardle January 10th, 2006, 12:12 AM Yes - I'll say, excellent summary.
Great, Barry.
Thanks.
John Allardice January 10th, 2006, 02:05 AM I've only been working in Cine-like-V for the moment, so I can't compare any other modes.
As far as noise is concerned, I know you some of guys have been scared by the stills that have been published, even I'd been starting to gravitate towards the Xl-H1 after some of the stuff I've seen...but after these tests, I'm happy. I'd say its extremely film-like in nature...it definitely has more of a 'grain' feel, than a 'video noise' feel. And this is from 25 years of shooting anything from super-8 to 3/4" to 35mm to genesis.
I'd put it at better than super16 but worse than 35......as sort of 23mm, if you will.
As far as Latitiude is concerned, it's definitely better than any chip based solution I've used before, bar the Viper or Genesis. The Genesis has about 12-13 stops of latitude..this is around 8.
I know this is expanding beyond the realm of this paricular thread, but I'm just gonna keep typing for informations sake.
The equivalent ASA for the HVX is about 350 at 0 gain, (Barry, would you concur?)I haven't gone above 0 gain, If you have, why did you bother buying this camera.... :)
I wouldnt be happy shooting interiors without a couple of CTB'd 2Ks or a 1.5K HMI.
It's probably fairly well suited to the sorta modern style of 'high-key, no fill' stuff, as long as you keep your kickers down to a only 2-3 stops above the key.
The glass is good, really good, the finder and the LCD however, don't do it justice, you'll want a decent sized monitor on set...AND/OR A FOCUS PULLER. It's amazinghow in focus something can look on a 3.5" lcd and still be competely out of focus ona 20" monitor
Resist the temptation to go with 'long shutter' stuff to keep you light levels up. This camera really does benefit from some proper lighting.
Major Impression....this isn't for corporate, event, or reality stuff...its for shorts, local spots, low-budget features...In short it's a tool for fiction work. This is the system ( if you cant stretch to 35mm) to shoot that movie that you wanna send to sundance, or that spec spot that you're gonna send to Smugger or Anonymous.
and lastly.....
I'm dying to see this thing with a cinemek G35 in front of it.
John
Cassidy Bisher January 10th, 2006, 10:56 AM In other words, the 60p frames dont have a shutter speed of 1/120th, but in fact 1/48th. This is why any slomo we've seen so far has a little of that 'slurry' video feel. After I set the electronic shutter to 120th, bingo, perfect film style 60fps slow motion.
Can you set it higher than 1/120th?
Mike Marriage January 10th, 2006, 11:33 AM Finally, there's the light level overall -- if there's adequate level for exposure somewhere on the CCD, then the shadows will stay clean and sharp. If there's not enough light for proper exposure, noise appears to increase picture-wide.
That's interesting Barry. Does it mean the DSP is doing some sort of "auto-gain" to bring the levels up to what IT thinks is correct.
I am preping a film-noir style feature (loads of dark shadowy scenes) and was considering the HVX. However, it sounds like it may not be ideal for this type of shoot. What do you think?
I am also thinking about the Sony HDW-750P, the HD100 and the XLH1. The Sony is the obvious choice, but I am going for quite a gitty look, so it may be overkill and would mean using higher spec steadicam, grip etc.
Barry Green January 10th, 2006, 10:46 PM It should do very well for film noir. Film noir isn't all dark, there's always proper exposure somewhere in the frame.
If you go about underexposing the video, it'll be grainy -- just like film would. If you properly expose it, it'll be much cleaner.
As far as the "auto gain" comment -- Adam Wilt made some fascinating observations about that, as referencing not the HVX but basically all CCD cameras. I'm on the road now, don't have that e-mail in front of me, but maybe when I get back I can dig it up and post some of the ideas he listed. In short, all these cameras perform some sort of dynamic allocation based on the presence of and amount of highlights etc. in the scene.
As for shutter speed, yes you can set it to as high as 1/2000th. But the 180-degree shutter does work film-style; set the shutter on 180 degrees (you MUST be in "FILM CAM" mode to do this) and then as you change frame rates to a faster frame rate, you'll see the exposure getting darker and darker. Like a film camera would.
As far as an overall ISO level, that will be answered tomorrow when we know definitively. However, keep in mind that the ISO level is not a fixed number -- it changes (or appears to change) based on where in the exposure curve you are. It could be due to CCDs reacting differently to the amount of light present or, more likely, due to the actual t-stops of the lens not matching the displayed f-stop. On the JVC HD100 I was able to rate it at 100 ISO at f/1.4, and as fast as 400 at f/11. On the DVX it rates at 320 ISO at f/2.8, and 800 at f/16. So there is not one set, fixed ISO value that you can reliably declare, as it effectively changes based on what f-stop you're currently at.
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