2016-04-18

continuous Multicam recording

I know, I have too many cameras.
What do you say. It's a hobby of mine.
But every now and then I actually use all of them... at the same time.
Lectures and events have a tendency of ending up as multicam events that need more then 20 or 40 minutes per camera and should have their highest possible quality because they simply can't be repeated. 


Surprisingly I got my hands on a used Ninja 2 on eBay.
Now I have completed my setup!
(inserts manic laughter here) 

Center

One GH4R with no internal recording limit can be powered by an Atomos Power Station and record in 4:2:2 onto a Ninja Assassin in UHD for the wide shot that also gives crispy sharp, post-stabilized, post-panned FullHD medium shots as a crop. It doesn't move or refocus and thus needs little monitoring.(for Wifi monitoring I would have to switch from 10bit down to 8bit and I won't do that)
An internal MPEG backup recording is running.
Zoom H6 does the sound as 6 wav including - 4dB  backup against clipping channels ,if not all channels are uses and has its line out run into the Ninja Assassin too. Channel 1+2  are the Mid/Side microphone because that gives perfect Mono down mix and can not have any stereo cancellations like the shotguns 3+4. 5+6 is a Rode VideoLink digital wireless channel to a Lavalier. 

Remote Right

One Blackmagic Pocket Cinema Camera on the far right. Powered from a Lanparte V-mount plate. An Atomos H2S converts the HDMI to SDI.
An internal ProRes LT backup recording is running.
It provides FullHD Closeups from the right .
The SDI cable runs to left side. 

Left

There am I with an Atomos Samurai Blade, monitoring and recording it and giving instructions via PMR radio to match my own framing.
Myself I am with another Blackmagic Pocket Cinema Camera, another Lanparte battery plate and the Ninja 2 for matching Closeups from the left side. Monitor is not as good and I have no scopes but I have my eyes and the screen of the camera.
Now we have wide shots from dead centered with any crop we desire and Closeups for dialogues from left and right.
Wenever something important is obscured from one side, we have 2 different angles to choose from.

Advantages

  • Each recording has a backup. 
  • I can see what the opposite camera is doing including focus peaking and give instructions
  • HDD (Fullhd)  and SSD (UHD) drives last forever 
  • so do the batteries 
  • audio from 3 locations +lav in case a chair chair squeaks and for a wide applause with no single shouts standing out
  • all recordings are in 10bit (or raw)  -  no banding when I pull the midtones up of down in post or pull up the shadows 
  • all recordings are in ProRes (or raw) - fine noise floor for NeatVideo to work with and no MPEG artifacts 
  • Editing off the 3 SATA drives directly with no need to copy anything

2016-04-11

GH4 und Lumix Club - Wie kriegt man die 100GB?


Mit dem V2.5 Firmware Upgrade für die GH4/GH4R soll man 100GB freien Speichersplatz bei Google Drive bekommen.
Kommt aus dieser Presse-Meldung:

http://www.presseportal.de/pm/14151/3293032
und wird auch so fleißig überall abgedruckt.

...bis man mal versucht das so zu machen.

Zitat:
"*Nutzer müssen sich zunächst im LUMIX CLUB (http://lumixclub.panasonic.net/ger/c/) registrieren, um dort den Speicherplatz für Google Drive zu erhalten und bis 30. September 2016 den Account Service aktivieren.
Eine Kurzanleitung zur LUMIX Club Registrierung ist verfügbar unter ftp://ftp.panasonic.com/camera/howto/compact_cameras_how_to_create_a_lumix_club_account_howto.html"



  1. Im Lumix Club findet sich kein "Google Drive"

  2. Einen "Account Service" gibt es dort gar nicht

  3. Auch die angegebene Kurzanleitung schwiegt sich zum "Account Service" und zu Google Drive aus.

  4. dafür aber das schon vor Jahren in Google+ aufgelöste Google Picasa
-> Der Lumix Club zeigt auf der Startseite dem Nutzer 3 Wartungsmeldungen aus dem Jahre 2014 

  5. Wird die Englische Sprach-Variante benutzt, kann für Support-Anfragen "Deutschland" nicht als Land ausgewählt werden

  6. Support-Anfragen sind auf ein Feld von nur einer Zeile und 20 Zeichen Breite beschränkt.


Wie zum Henker soll  man das machen?

2016-04-09

Film making power box MK II

As many of you know, amateur film making is a hobby of mine.
One particular topic I started to adress was having all these different battery types and their chargers for all the cameras, hdmi recorders, monitors, lights, ...
A while ago, I made a charging box. A euro-sized box with a 19" power socket strip and 2 velcro strips to hold all my chargers in place.

charging box MK II


I upgraded my charging box to twice as many power sockets.
Also there are 4 rows of velcro, to hold twice as many chargers.

I'm still waiting for a universal charger with 2x2A and independently interchangeable plates for NP-F, GH4, AA/AAA and BMPCC batteries. That one will take up additional space and an additional power socket and I was already running out of both.

proper labeling



All NP-F batteries are now labeled with their size on side add front and all chargers with their maximum current and battery type.

There is enough confusion and chaos as it is.
Simple, ubiquitous tasks like Batteries and charging should not be a part of that.
1 standard, stackable Euro-sized box, 1 power cable, 1 switch and it even has sockets to spare.
All my chargers are attached with Velcro also can be removed to use them elsewhere and exchanged for different ones.

Each camera has its box and you can see the size of the batteries just by looking into the box (front) or when it is mounted in some device (side).

Lanparte VBP- 01





Why this emphasizis on NP-F? Because that's my ONE battery standard that can power everything now.

Two Lanparte V-mount plates arrived.
With 2xNP-F to V-mount adaptors I can now power everything(5V accessories, 7.4V cameras and recorders and 12V accessories and 12-15V cameras) , from one type of battery and from mains power while charging these batteries in the Lanparte without taking them off.
AND I have the option of renting huge, expensive V-mount batteries without even having to rent an expensive charger for very, very long sessions.
(The charging and mains power is the huge advantage of the more expensive Lanparte plates.)


Future project:
Add a step-up converter into the dual NP-F to V-mount adaptors, so they also work with only 1 battery. Meaning I can replace batteries on the go. Downside is: I will loose the ability to charge the NP-F.

WARNING
The ground level on left and right side of the Lanparte is different. Some people have burned their BMPCC and BMCC HDMI ports by powering an Hdmi recorder and the camera from the same plate while they are creating a ground loop via the HDMI cable.
I GUESS using the same side (you have 12V on both sides) SHOULD be safe. 

Also the HDMI splitter in the Lanparte is incompatible with the signal a BMPCC outputs. I already knew this. 

Links

  • HDMI port on my Pocket melted!!
    http://www.bmcuser.com/showthread.php?10743-HDMI-port-on-my-Pocket-melted!!

  • Issue analysis and recommendations by David Green
    • only fiddle with the HDMI/SDI cables when both devices are OFF (the SDI/HDMI standard specifies insufficient ESD-protection against static discharge)
    • Connect HDMI/SDI first, THEN connect power
    • Make sure you are discharged when handling HDMI/SDI/SATA
    • The TRS(German: Klinke) Audio connection is safe against any ground loops.
    • These steps are against static discharge as well as against a discharge caused by different, floating ground levels on the regulators that power monitor and camera
    • Note: using 2 regulators that have a different ground level that is not isolated from each other, is a receipt for desaster.
    • Powering all devices from the same (e.g. D-Tap) output is safe because they all share the same ground level.
  • another thread about this issue
  • thread with an opned BMCC. SDI GND is connected to Power-GND.
    • analysis: source should be floating GND-levels on the different regulators in the plate to drift and thus build up a voltage different (that the ESD-protection can't handle when connecting HDMI after both devices are already under power)

+

2016-04-08

should I get a laser cutter?

Today the Kickstarter campaign for Mr. Beam II started.

Version I was a kit for 500-600eur.
That's the price of the very common Chinese laser cutter. They take a lot of reworking to make them safe and reliable and the kit takes assembly.
So it's okay and I considered and finally declined it.

The price point

Version II comes fully assembled for 1400eur on Kickstarter and +40% later.
That's a lot of money.

Why shell out so much when you can upgrade a 600eur one?

Why get a personal one when you can travel to the nearest FabLab for such a seldomly done thing? (Same thing with a lathe when I have a 4 axis mill. )

What to use it for?

Let's see...
I have a large and a portable CNC milling machine and a super reliable 3D printer.

Plywood constructions
Any (ugly) plywood T-Slot cases I can do on a mill just as well. More noise but no fumes and no 4mm depth limit.

Labels, front plates and stamps
Engraving I can do on mills as well and I'm not even limited to flat objects but can make use of the rotational axis as well.
Stamps are easier to on a laser but that's a very seldom use.
Front plates need  deep cuts in addition to labels.
Quite frankly I usually include the label, logo or QR code as an embossed part of the complex design itself instead of labeling things afterwards.

T-Shirts
Vinyl cutting I can do without heating and burning the material by mounting a knife in the CNC.

In addition to that I can do all kinds of complex, non flat shapes on the 3D printer.

Conclusion

I'll rather design a mount for the 4th milling axis with a vector knife in the spindle mount = vinyl and stamp vector cutting.
... and get a second 3D printer because the first one is running near 24/7 when I'm building another Robot Arm or other machine with lots of parts.
The large CNC mill was just as expensive then the - 40% Kickstarter laser and is much more versatile. But also louder and makes more of a mess.

2016-03-30

MyPrivateDisplay

I just installed a privacy screen protector on my phone.
Since I travel a LOT, I wanted people left and right of me to not be able to see the screen.

protection


Aparently it only limits the viewing angle left and right.
So in landscape mode, it does nothin at all.

colors

Colors still less saturated and highlights are clipping. Not very good.
It's like watching an overexposed photo of your screen.

touch

Tough screen working...so far.

2016-03-22

Building a "uStepper Robot Arm rev. 2" during EasterHegg

 

The Plan (tm)

During EasterHegg in Salzburg, I want to build a "uStepper Robot Arm rev. 2".
(Sorry, Thingiverse doesn't offer a nice iFrame-Embedding as YouMagine does.)

I want to build it, as it is.  Using their assembly instructions from GitHub. Then check it out and install improvements.
Planned improvements are:
  • mounting holes for optical homing switches on the gears
  • reduce the number of different bolt sizes and ball bearings
  • Replace the uStepper with NEMA17 steppers controlled by a chain of L6470 (e.G. SparkFun AutoDriver boards) due to simpler synchronisation of multiple axes
    • 3xAutoDriver - Stepper Motor Driver (Watterott: 2x 38eur , Sparkfun 34USD) 3A, 8-45V
      • 15x 2 pin screw-on terminals with 3.1mm pitch (3xpower, 3xGND, 6xstepper coild, 3xE-Stop) "Schraubklemmen 2.54mm Pitch (2 Pin)"
      • 5-6x 2x5 2.54mm headers  (Comms-In + Comms-Out) "Wannen-Stiftleiste gerade 10 polig RM2,54"
      • 5-6x 2x3 2.54mm headers  (Meta-In + Meta-out)
        "Wannen-Stiftleiste gerade 6 polig RM2,54"
      • 2x cable for  2x5 2.54mm headers on both sides (SPI between boards)
      • 1x cable for  2x5 2.54mm headers on one sides (SPI to Arduino)
      • 3x cable for  2x3 2.54mm headers on one sides (Meta to Arduino)
    • 3xNEMA17  (Watterott: 2x16eur) 0.33A, 12V
    • any power supply 1A, 12V for testing (final power supply will be 38-40V)
  • Change the joins with to not only be press-fit into the aluminium tubes but to have a bolt running across it (into the tube, through the join and out the tube on the other side) to allow for pulling small loads upwards.
  • Change the effector mount to use a standard ISO-9409-1-50-4-6 (=4xM6 on a 50mm circle)
  • Have a hole in the center of the mount to allow for cables
 

Preparation

I know the uStepper Robot Arm is still a Work In Progress.
I hope to get the original CAD files just in time for Easterhegg, so I can design my improvements.
I did get most of the parts from their BoM:

http://www.thingiverse.com/thing:1398215#comment-834544

bearings

5x 608Z
  • standard skateboard-bearings.
  • for 8mm shafts
  • Z=closed on one side.
  • ZZ=closed on both sides or 608 = open will work too.
5x 625Z
  • for 5mm shafts(I'm missing these)
10x 624Z
  • for 4mm shafts
(I did an order of all standard bearings 3mm-8mm a while back. So I *hope* my stock has these covered.)

Nuts

20x M3
7x M4
1x M5
2x M8
(done)

Bolts

The BoM didn't specify the type of head or material for any bolts.
So I tried to stay with hexagonal headed and PH2 ones and tried to stay away from sink-hole bolts.

1x M8x40
  •  used in Fig.10 - use hexagonal head, so you can have the bolt from below and nut on top. Other flat heads mean the nut has to be at the bottom and can fall out on disassembly.
1x M8x70
  • used as main axis for the large gears
1x M5x40
  • 1x used in Fig.48
4x M4x20
  • 2x used in Fig.55
  • 1x used in Fig.56
  • 1x used in Fig.57
1x M4x30
  •  1x used in Fig.55
1x M4x35
  • 1x used in Fig.63
1x M4x55  substituted  M4x60 as 55mm was not avaliable.
  • 1x used in Fig.65
15x M3x8 substituted M3x10 counter sunk head
  • use 4x (M3x10) in Fig.29 
  • use 4x (M3x10) in Fig.31
  • use 4x (M3x10) in Fig.33
  • TODO: where to the other 3 go?
2x M3x10 substituted M3x10 
  • 2x used in Fig.25 - longer is okay. Any flat head type.
4x M3x12 substituted M3x16
  • 4x used in Fig.9 - must be 11-13mm, head must have at most 5mm diameter
7x M3x20
  • 5x used in Fig.3 - any flat head. steel brass or aluminium but even plastic bolts are okay.
  • 2x used in Fig.21 - indended maximum head diameter 5mm but larger ones work if the head is at most 3mm in height 
4x M3x30
  • 4x used in Fig.44

Washers

5x M8 OD=15,8mm
4x M5 OD=9,8mm
2x M4 OD=8.8mm
I didn't find ANY of these sizes. So I hope grabbing large and small washers for M4,M5 and M8 from my stock will do.

Spacers

1x 14m  (update: inner diameter just wider then M8 threads)
1x 7mm  (update: inner diameter just wider then M4 threads)
Didn't find any because the BoM doesn't specify what kind of spacers they talk about.
I can't find them on the image nor the instructions.

Update: found them. Fig.36 has a typo and speaks of "space" instead of "spacers". Aparently they must have an inner diameter to fit an M8 and M4 bolt loosely.

tubes

The instructions don't specify if they talk about the outher or inner diamter
and what wall thickness is expected. (Clearly as seen in figure 20 and 22, inner AND outher diameter are important.)

1x 15x300 I got 1m of 16x1mm, it seems to be a snug fit in Gears_main_arm_15mm.stl, large_joins.stl fits but is a bit loose
1x 15x220
2x 6x240  I got 1m of 6x1mm
1x 6x252

...as you can see. The pure number of DIFFERENT bolt sizes is staggering.


Progress

Done:
  • sourcing all nuts and bolts (some bolts replaced by longer versions)
  • cutting tubes to length
  • assembled the first parts. List of suggestions for improvements is growing... 
  • Written the source code that will rund this arm using G-Code to control L6470 chips.
  • Assembled the original design as far as I can without the 625Z bearings.
  • I forked the project on github to post an improved version of the parts and the manual
  •  
     
Doing :
  • Waiting for the electronics
  • manual is coming along nicely...
  • starting to design improved parts...
Notes about assembly instructions
  • name inner+outher diameter of tubes
  • name head-type of bolts
    • M8x40 is for Fig. 10, any flat head. Steel brass or aluminium
    • M3x20 is for Fig.3 and ??? any flat head. steel brass or aluminium but even plastic bolts are okay.
    • ...
  • name where longer versions of bolts are acceptable and up to what length
  • name and show all dimensions for spacers (one is for M8, the other for M5)
  • Fig.1: a 608 (no covers) would do just as well  as a 608z(cover on one side) or 608zz (covers on both sized)
  • Fig.2: prepare how? What am I supposed to do in this step? 
  • Fig.3: no comment
  • Fig.4 use M3x20. 
  • Fig.5: no comment
  • Fig.6: use a sturdy table to help press-fit the 608Z or 608ZZ skateboard bearing
  • Fig.7: "prepare" means "insert M3 nuts"
  • Fig.8:  this is "side2.stl", not "side1.stl"
  • Fig.9: use M3x12 (at most 13mm) to mount the sides to the base?
  • Fig.10: use M8x40mm
    • M8 x 40mm
  • Fig.11: add an M8 washer of 9-12mm (if not included as a feature of base.stl)
  • Fig.12: use M3x8mm(M3x10 works too) to mount the small gear to the motor-shaft
  • Fig.13: 
    • M3x10 is too short for the  NEMA17 motor but the M3x8 are the only ones we have >12pcs of ??? (same for Fig.29+31. Question asked here)
    • you may want to do this before Fig.12 because the mounted motor determines where on the shaft the gear has to be
  • Fig.14: no comment
  • Fig.15: no comment
  • Fig.16: no comment
  • Fig.17: use a sturdy table to help press-fit the 608Z or 608ZZ skateboard bearing
  • Fig.18: no comment
  • Fig.19 
    • Is this large_joint.stl ? 
    • The "main arm" the short 15mm pipe
  • Fig.20: use glue and/or a drill and an additional M3x20 with a self-locking M3 nut 
  • Fig.21: use M3x20mm
  • Fig.22: no comment
  • Fig.23: use a sturdy table to help press-fit the 608Z or 608ZZ skateboard bearing
  • Fig.24 TODO: I seem to be missing 624Z or 624ZZ bearings
  • Fig.25: use M3x10mm 
  • Fig.26: no comment
  • Fig.27: TODO: what size of washers?
  • Fig.28:
    • use M3x8mm(M3x10 works too)
    • don't forget about the M3 nut (hole is slightly larger then M3)
    • use the thinner one of the 2 small gears
  • Fig.29: use 4x M3x10mm, make use of the recess for the bolt-heads
  • Fig.30: 
    • use M3x8mm(M3x10 works too) to mount the small gear to the motor-shaft
    • use the wider one of the 2 small gears
  • Fig.31: use 4x M3x10mm, make use of the recess for the bolt-heads
  • Fig.32: this is needed because you can't reach all 4 motor-bolts with the main gear on
  • Fig.33: use 4x M3x10mm, make use of the recess for the bolt-heads
  • Fig.34: no comment 
  • Fig.35: no comment 
  •  
  • Fig.36 
    • "space" should be "spacer"
    • Spacer is 14mm long and fits around an M8 bolt
  • Fig.38 one washer between gear and side plate is plenty
  • ...
  • Fig.44: 
    • use 4x M3x30mm, bolt heat must be <4mm in diameter
    • bracket_part1.stl
    • bracket_part2.stl
  • Fig.45: nothing to do here
  • Fig.46: nothing to do here
  • Fig.47 see comment for Fig.48
  • Fig.48 why M5? It's the only 5mm bolt in the entire construction and introduces an entirely new type of ball bearing. M4 would have worked just the same. 
  • Fig.49 one washer on the bearing, the other where the bolt exits
  • Fig.50 one washer where the bolt exits
  • Fig.51 this should be a nylon locking nut or else it will shake loose. 
  • Fig.52: nothing to do here
  • Fig.53: nothing to do here
  • Fig.54: nothing to do here 
  • Fig.55 
    • use 1x M4x30 on the secondary arm joint 
    • use 2x M4x20 on the 2 rods that connect to the triangle
    • TODO: Where to put what rod-length and what side to mount to (inside/outside)
  • Fig.56
    • use 1x M4x20 on the rod that connect to the triangle
  • Fig.57: use  1x M4x20
  • Fig.58: nothing to do her
  • Fig.59: nothing to do here
  • Fig.60: no comment
  • Fig.61: nothing to do here 
  • Fig.63: use M4x35
  • Fig.64
  • Fig.65: use M4x55 (or longer) 
  • Fig.66: finished! (with the mechanical hardware)
Notes about improvements:
  • holes for bolts should have a camfer to make inserting bolts easier by having them self-align. 
    • the holes for the 608 bearings work surprisingly well without them but it would still be a good idea since not every printer produces dimensionally accurate results.
  • labeling the holes with the bolt-sizes costs nothing in 3d printing.
  • use less different bolt sizes
  • name bolt sizes in assembly steps
  • all parts are very low resolution. Lots of clearly visible polygon-edges.
  • Gears are a highly simplified design. They however do have only little backlash.
  • ...
  • base.stl
    • M3 bolt-holes too small. 3.1mm would be better. 
    • M3 nut-holes could use a camfer (any stray sterand of filament makes this harder).
    • my bolts have a 6mm wide head. The hole is 5mm. Wider heads should be supported.
    • Make M8 hole smaller to allow for M8 washer of 9-12mm to sit on bottom 608/608Z/608ZZ bearing OR include that washer as a feature of the base.stl design
  • Gears_bottom_edited_plus10.stl
    •  M3 bolt-holes too small. 3.2mm would be better (slightly larger then the hole in the side that holds the nut). 
    • nuts are inserted too deep. You can't align them after having them fall down the shaft to meet the bolt.
  • side_plate1.stl
    • is a very tight fit into base.stl
    • a tapper on the nuts that slide into base.stl coult also help.
    • holes for M3 nuts should be hexagonal and closed on one side to prevent the tiny bolt from slipping out. (This isn't laser-cutting.)
    • move the bolt that doesn't go through the bottom gear further outwards, so it can be removed without having to disassemble the bottom gear.
  • Gears_main_arm_15mm.stl
    • camfer for 3mm bolts needed. Any stray strand of filament makes this harder then it needs to be 
    • label the gear "main gear"
  • Gears_second_arm.stl
    • no tapper for M5 nuts
    • mirror the small gear to have the bolt on the inside of the machine (accessible from above). That way it won't interfere with a longer bolt in the side_plates and the side plate can be made stronger by not having the access tunnes for this bolt.
  • second_gear_arm.stl
    • no hexagonal holes for the M3 nuts. They may shake loose.
  • link.stl
    • M4 hole is too tight 
    • large hole needs camfer. Hard to inser.
    • A flat instead of round end should make push-fitting the rod with force easier
  • triangle.stl
    • M3 holes definately need a camfer
    • convert to use M4 and get rid of the 625Z bearing size in favor of only using 624Z
  • end_part3.stl
    • integrate the M4 spacer into this part
  • bracket_part1.stl
    • wider brace to allow for 16mm aluminium rods 
    • convert to use M4 and get rid of the 625Z bearing size in favor of only using 624Z
  • bracket_part2.stl
    • should have a slightly wider holt then bracket_part1.stl , so the bolt fastens properly in the plastic
    • should allow for wider bolt-heads
    • wider brace to allow for 16mm aluminium rods 
    • convert to use M4 and get rid of the 625Z bearing size in favor of only using 624Z

Software

I'm planning to use this trivial Arduino G-Code parser, throw out the Bresenham line algorithm (since we need not generate step+dir pulses ourself) to instead feed tool-coordinates into the L6470 Autodriver boards.

Result

Links

2016-01-26

recording and matching V-Log on the GH4 camera externally

The few things I blog here are mostly about making things.
However I DO have another hobby. Cinematography. Especially the technical aspects.
Currently I do use 2 Blackmagic Pocket Cinema Cameras and I have waited patiently for years to get a good deal on a non-EU GH4 or GH4R to combine 2 FullHD closeups (left and right interview subject/dialog participant/stage side) with a DCI 4K or UHD wide shot that acts as both wide and semi-wide by taking FullHD crops in post.

 Motivation

I'm finally going to get a GH4R with an external recorder.
Recording much on Blackmagic Pocket cameras, V-Log looks nice.
However there are some reports of issues it has. Many with 8bit 4:2:0 internal recording and sounding like they may go away with 10bit 4:2:2 recording.

Status: I did receive the GH4R and Ninja Assasin. However the Power Station is going to run late.
I'm not entirely disapointed about that, given the bug of the current Power Station mentioned below.

Reading material on V-Log

This is the text-list I have come up with so far to get a grip on this topic:

Very interesting read on VLog vs. Cinelike-D vs. Natural on the FH4 when using 10bit external recording and 8bit internal recording on the #GH4.

Linked to from this discussion:
http://www.eoshd.com/comments/topic/9431-v-log-l-captured-in-8-bit-vs-10-bit/

after reding this in-depth anylysis of the color-spaces:
http://forum.slashcam.de/gh4-aces-unterstutzung-vt127380.html
(better LUTs then the ones from Panasonic at the bottom of the thread.)

Some practical analysis of V-Log in 10bit here:
http://www.provideocoalition.com/v-log-l-on-the-gh4-don-t-panic

conclusions about V-Log

Record V-Log externally as compressing this huge dynamic range into 8 bit 4:2:0 MPEG leaves you with banding and green+magenta noise.
Maybe overexpose slightly when using V-Log to reduce noise in the shadows.
(8-bit ProRes seems to work well but...file size doesn't matter when recording to a hard disk/SSD-drive. anyway ) 
  • whenever possible but only recorded externally
  • priority on high dynamic range (e.g. lights at night)
  • high contrast situations (e.g. film noir)

For scenes with low dynamic range but important skin tones, "Natural" or "Cinelike-D"  seem to be called for.
  • when priority is on subtle skin tones 
  • when subtle gradients in the midtones are important (deep blue sky, rolling but bright fog)
  • hazy footage where focusing gets difficult (unless I can focus with a LUT and peaking on the recorder)
  • when recording internally

power everything

The Atomos Ninja Assasin for external recording comes with an Atomos Power station.
Aparently the Assasin drains batteries like crazy (not as crazy as the Blackmagic Pocket). So Atomos hands out larger batteries for the early adopters and makes a limited time deal for Power Stations to the later crowd.
It already includes the adapter to also power the GH4.

HOWEVER, numerous reports state that the Power Station has a few flaws in it's current firmware or hardware.
  • Same battery in Power Station lasts just half as long as directly plugged into the Ninja Assasin/Shogun 
  • Full Batteries in Power Station suddenly reported as empty
The voltage detection seems to be confused with the large power draw of the Shogun. It works fine with a small camera. My guess is that due to the power draw the voltage drops and thus the batteries are reported as empty way ahead of time.

matching cameras

Obviously I want to match the GH4 to the two BMPCC.
I found the color chart automatic matching in Davincy Resolve to be a great starting point.
However it does not match gain (white level 786 vs 1024), gamma (grey at 130 vs 250) and olive/green seems to be rendered differently (despite nothing non-green having any color cast at all).

The perfect way to go seems to be ACES "Academy Color Encoding System".
Yes, that's the Academy as in Academy Awards = Orcars.
Yes, Resolve V12 can convert footage into the camer-neutral XYZ color space using an IDT=input device transform.
Yes, there are IDTs for GH4 in V-Log and BMPCC in ProRes (Cinema DNG does not need an IDT as it contains all that transform information).
No, Resolve can not import IDTs and is limited to the few it has.
Choosing BMDFilm for the flat BMPCC and Sony SLog for the Panasonic V-Log gets you close.
However not as close as the color-chart.

Since I can't do this properly yet, I'll use it as a simply starting point whenever I can't have a color chart before/after the shot.