Saturday, October 10, 2015

Every little bit helps (bitrate info concerning the Sedna hack and stopmotion)

For my own edification, here's info on the hack I installed in my GH2. The important thing to note in each block is the bitrate - that's the amount of information captured by the sensor, which equates to greater detail resolution in the video.

Sedna A - Max Detail Q20 version, including the Pasadena Pulse audio hack

SDXC card - Sandisk 64Gig, Class 10, write speed 95MB/s (the bulletproof card)

Shot done in HBR mode (high bit rate):
FPS:                            29.97 (standard in HBR 1020 AVCHD)
Shutter Speed:            1/30 second  -   nice smooth panning - tested @ 1/25 and got jitter
Profile:                        Smooth, flat (everything set to - 2)
Bitrate on playback:   150.54 mb/s

Shot done in 24P mode:
FPS:                            24 (standard in 24p 1020 AVCHD)
Shutter Speed:            1/25 second   -  nice smooth panning
Profile:                        Smooth, flat (everything set to - 2)
Bitrate on playback:   160.97 mb/s
I had to laugh to see that the bitrate is actually higher in 24p mode than in HBR (high bit rate)! Those are really astonishing bit rates - pre-hack I was getting rates of 114.26 mb/s (it looked really good even then!) But here's the really crazy thing... I just checked the data on a couple of the clips shot on the old G1 in stopmotion, using still pictures assembled into a video file. Those stills of course are much bigger than 1920 x 1080. Here's the info:

Shot on the G1 in stopmotion:
Uncompressed full size video files:    Size: 2963 x 1240
Bitrate on playback:                             1,216.94 mb/s (!!!!)

Uncompressed HD video files:          Size: 1920 x 803
Bitrate on playback:                             376.72 mb/s (!!!) 

Wow!!! Even after reducing the size to HD, the stopmotion files are still more than double the bitrate of the Sedna files!! And this is on the G1 - the first Micro Four Thirds camera, @ only 12MP. It will be even better with the GH2, a 16MP camera.

shutter speed for 24p video - 1/25 of a second!!

And while I'm documenting things I learn so I don't forget them..

The standard procedure is to always shoot video with your shutter speed double the framerate. Ie - for 24 fps, shutter speed would be 1/50 of a second. Or that's as close as you can get anyway - on a PAL camera it would be exact because of the 25 fps framerate. But it actually works better to use a much lower shutter speed, which increases brightness considerably and gives more motion blur. And by lower I mean 1/25 of a second. Sounds crazy, and you'll get a lot of extremely pissed off shouting from people who learned the standard programming and have never tried anything different.

I first heard this on the Personal Views website, where people discuss hacking the GH2 and other Panasonic cameras - it's to combat the excessive strobing (judder, shudder or what have you) that you can get when panning rapidly using a high bitrate hacked camera - objects moving sideways tend to show up as double or even triple images and move in a jerky fashion. The standard way to deal with this in film and video in The Biz is to always pan very slowly - they even have a formula to figure it out (and you know how much I love formulas, right? Pfft!)

Because of the increased motion blur it actually creates a much more filmic look, at least I think. Though that might just be my initial impression - frequently when you first discover something really cool like this it delights you and then after you come down from that and see it with a more sober eye you realize it's gimmicky and crude - time will tell. Anyway, now I've got the info documented here (and this is exactly the kind of technical stuff that tends to evaporate from my brain quickly).

Megapixel lens ratings - 2MP = 1080 HD

Just went through a little learning curve and I want to document it for future reference. For the first time I ran across something called the megapixel rating for lenses. I didn't really know exactly what a megapixel is, but I do know that my G1 has 12 of them and the GH2 has 16. So just now I was on the verge of buying what looked like a really decent 6.5mm wide angle when I notice it's rated for only 2 MP. Wait, what? Seriously!!?? I mean, isn't that like - totally 10 years ago or something? Who has a 2 MP camera?

A little digging turns up that while many cameras have high MP ratings for still photos, 1080p HD is only just about 2 MP. Ok, actually it's 2.07, but apparently a 2MP lens is good enough for shooting HD video at full 1080p. Though I wonder if a hacked GH2 might be trying to capture more detail than a 2MP lens can resolve? Would using it basically negate the hack? Like putting a low flow shower head on a high pressure hose?

Possibly, to some extent. I don't know tech stuff (love that line from the Terminator - use it every chance I get). But then I have some 1/2" format CCTV lenses that resolve only a small image circle in the center of the G1's sensor, and need to be severely cropped, which reduces the resolution to probably around 1MP. I'm not a pixel peeper or a perfection junkie, I believe as long as it works then it's fine. Hell, I love a lot of old films shot on 16mm film handheld with bad exposure and all that stuff - it can give a film a visceral punch in the gut kind of feel as opposed to a careful, overproduced and over intellectualized feel. Screw it, I'm gonna get it.

No good for stopmotion - the really wide lenses capture stuff that's all around you and almost behind you - you'd need a wraparound set including a sky or ceiling and to have the camera jammed way back into it so you don't end up seeing the basement walls over the edges, and a set like that would make it hard to reach in and animate, unless of course you're building a massive set that the animator can walk around on like a Laika production. But anyway, it would be good for some live action video stuff.

Info:
"In a megapixel (MP) camera such as the GoPro Hero line, the focal plane spot size of the lens should be comparable or smaller than the pixel size on the sensor. So if you are capturing high MP media you should use a lens that will resolve the pixels for the resolution you are capturing. MegaPixel ratings of a lens relates directly to the image sharpness, the ability to resolve pixels at a particular resolution. Using a lower MP lens than the MP rating of the mode you're shooting in will still work, though the media may be a little fuzzy (less sharp).

For GoPro Hero 4 & 3 video modes, here are the pixel measurements:

4K = 3840x2160 pixels 8.3MP (16:9)
4K Cin = 4096x2160 pixels 8.9MP (17:9)
2.7K = 2716x1524 pixels 4.1MP (16:9)
2.7K Cin = 2716x1440 pixels 3.9MP (17:9)
1440p = 1920x1440 pixels 2.8MP (4:3)
1080p = 1920x1080 pixels 2.1MP (16:9)
960p = 1280x960 pixels 1.2MP (4:3)
720p = 1280x720 pixels 0.9MP (16:9)
WVGA = 848x480 pixels 0.4MP (16:9)

For GoPro Hero 4 & 3 photo modes, here are the pixel measurements:

12MP Wide: 4000x3000 pixels
11MP Wide: 3840x2880 pixels (11.1MP)
8MP Medium: 3200x2400 pixels (7.7MP)
7MP Wide: 3000x2250 pixels (6.8MP)
7MP Medium: 3000x2250 pixels (6.8MP)
5MP Wide: 2592x1944 pixels
5MP Medium: 2592x1944 pixels

To figure out the MP of a photo or video resolution, you would multiply the pixels by each other. For instance, shooting a video in 1080p means you'll use 2,073,600 effective pixels (1920 x 1080 = 2,073,600). That 2,073,600 pixels is 2.07MP, or "mega pixel". So that means that if you plan to mostly shoot in 1080p (like we do) you'll simply need a 2MP or higher lens. The higher the MP rating of a lens the sharper the captured media will be, assuming you're capturing at a high MP that you'll be able to notice any difference. Using a 12MP lens (such as the stock one) to capture 1080p (2MP) content is theoretically not that much better than using a 2MP lens. There are other factors which affect image quality, such as the diameter of the outer glass element, anti-reflective coatings and of course the quality of the optics used (i.e. glass vs plastic)."

Tuesday, October 06, 2015

Nice demo on camera movement


Explains what effect various camera moves can have on the story or the viewer's perception of what's happening. You need to know why you're moving the camera.

Sunday, October 04, 2015

Got a GH2 and learning editing - keyframing brightness filter


I haven't made any direct progress yet on the stopmo flick, still haven't got the power fixed. But I did buy a couple of cameras and start to learn Final Cut Pro. In the spirit of journaling - largely to preserve the info here in case I need it later, here's the quick rundown.

First I decided to get another camera. Not for doing the stopmotion - the G1 is plenty good enough for that, but to document the process, to shoot stills (with the G1 in shot) and video and maybe even some time lapse. So I needed something capable of HD video, and I thought it would be wise to get another micro 4/3s camera so I could use the lenses I already have. Checked eBay and immediately found a Panasonic Lumix GF3 going for the ridiculous price of $58!! - they're usually more like $400 to $600 body only, even used. So I snatched it up, got a couple spare batteries , and then made the disappointing discovery that it doesn't do time lapse and has no socket where you can plug in a remote shutter release. Well crap! In fact, a little more digging turns up that it was aimed at people used to a camera phone or point and shoot who wanted to step up to M4/3s. So made to be used mainly in full auto mode, though it does allow manual control.

I played with it for a while, and cooked up a crazy plan to devise some kind of electronic shutter release using a linear actuator, something I've seen the Mythbusters use a lot for pushing buttons. Researched that (ok, I begged on SMA and Thomas Nichol was kind enough to talk me through the whole thing) and bought the stuff I need to rig it together, including a beginner's soldering kit for electronics.

Meanwhile I had also bought a 7" monitor since the camera's rear screen doesn't flip out allowing you to see it when shooting selfies. And it turns out it will work with a monitor - sort of, that is until you start recording, at which point the signal shuts off and the monitor goes black.

That was the straw that broke the camel's back, and I ordered a Panasonic GH2 - a filmmaker's wet dream said to capture video as good as $5,000 cameras and nearly as good as the $10,000 ones. That's if you use a hacked GH2 - this Russian guy named Vitaliy Kiselev found a way to get into the coding and trick it out so people could start creating patches to upgrade various parameters of its performance.

The GH2s tend to go for around $600 - $800 body only, but I found one for $330. Started researching on how to hack it, downloaded all the stuff I need and when the camera came in I started getting familiar with all the menus and features, and suddenly realized it must already be hacked, because the ISO goes all the way up to 12800! That's definitely not factory. No idea which hack it has, but the amount of detail and clarity is astonishing. And it should get even better when my new SDXC card comes in - the write speed of the card determines the data rate while filming.

Anyway, aside from that, I've been recording some video every day and editing it into little movies - stupid ones at this point, littered with bad cuts and bad shots and every error imaginable, but this is how you learn. By the time I get to work on the stopmo flick I plan to have reached a point of competency with editing and getting the right kind of shots to allow for good editing and good storytelling.

Last night I was testing various lenses for low light performance while walking through the house, some dark rooms some lit, and outside a bit. And I figured out how to add a brightness filter and keyframe it to bring light up smoothly in the dark areas and back down in the light ones. Really sweet!

Tuesday, September 01, 2015

Brush brush brush..


Major unearthing done, and now it's down to the delicate work with tiny brushes, like any excavation job.

I'm going to finish this film


Suddenly decided last night that I cannot let this film die. It's so close to completion - a few more months can see it all the way through. As you can see, the set literally needs to be excavated before I can even get within 2 feet of it! So much stuff piled around it and on it. Let the digging commence.