GH4 4K Panasonic video camera, official topic

Sangye

Shot an interview today on a fairly high-budget international doc project. Main camera was a C500, with a 70-200. 2nd camera was my GH4, with a Rokinon 85mm Cine + Speedbooster.

The GH4 really held its own. The C500 might be the best camera at the moment for documentary filmmaking, but the GH4 compliments it beautifully. It's the ideal B-camera for these kinds of shoots, and an ideal A-camera for many other kinds of shoots.

Can't share any footage, but here's a still that I did a quick and dirty color grade on.

The GH4 was set to Cine-D, -2, -5, -5, -2, 0, iDyn-High, +2 shadows / -2 highlights, to get as close to C-Log as possible. I was worried that I may have gone too flat, but it really grades nicely in my opinion.

markr041

Trying out another lens on the GH4, in 4K:

rNeil

@Sangye

Interesting, noting you used iDynamic. Not been willing to try those mish-up settings out, as letting the cam's engineers do something I don't understand that can change on the fly isn't comforting to my brain. However, that is a nice looking grade you've got there. What do you think iDynamic gets that is past what other settings you control allow? Very curious. Nice look there.

Neil

Sangye

Thanks @rNeil.

I've had good luck with iDynamic on the GH4. I would never use it on the GH2, because it seemed wildly unpredictable. But on the GH4, it consistently boosts dynamic range, and I feel that it lends a smoother roll-off on the highlights. This is all very subjective, and like you, I don't understand how it works or how it differs at the functional level from other in-camera settings that one might tweak. What I do know is that Cine-D with -5 contrast, and a -5 highlights / +5 shadows curve in-camera, looks "dead" and is difficult to grade... whereas pulling those settings a little back but applying iDynamic creates more useable dynamic range for post-production, without looking "dead".

rNeil

@Sangye

Interesting, thanks for the post ...

dracore

I'm using the 20/1.7 with the camera set to Aperture priority. Even though I have aperture value fixed and set, I notice that when I point the camera at different lighting conditions, the lens aperture to continually changes automatically. Also sometimes focus is automatically engaged. All of this happens just by pointing the camera at different light sources - my finger is not on the trigger button at all. This behavior happens regardless of what focus method I am using.

I have never seen this behavior on the GH2. What is this function for on the GH4?

Vesku

@markr041

Trying out another lens on the GH4, in 4K: (35-100mm)

Sorry. The famous micro jittering is strong in this one. Thanks for sharing. This is a good warning example. DO NOT USE THAT LENS HANDHELD.

Panasonic has a big issue with POWER OIS jittering. I just wonder when customers figures that in large scale.

AronJAnderson

I just tried out a new lens also.

Vesku

@AronJAnderson

Hi Aron

What do you think about that lens OIS for handheld video shooting? New version of the lens is very bad handheld.

AronJAnderson

@vesku not sure yet. I still need to do some shooting with it.

brudney

@Vesku I personally never experienced any kind of micro jitter using 14-140 v1 w/GH2. Seems like OIS may be better than POIS for video.

brianl

Jitters should be solvable with calm hands and different rig.

Vesku

@brianl

Jitters should be solvable with calm hands and different rig.

What is the meaning of OIS then? Big enough rig calms any lens and post stab too.

Vitaliy_Kiselev

With all OIS issues discussion go to appropriate topic, please.

driftwood

Good article on crop factors that has probably been covered before here.

http://gh4crew.co.uk/?p=460

Sangye

@driftwood - A lot of the talk about crop factors amounts to inane comparisons between different sensor formats, but I did not realize how small the active part of the sensor is when shooting 4K. This puts the GH4 in an awkward position for lens choices, as you're losing 25% of the image circle that MFT lenses are optimized for.

I don't use MFT lenses, but instead use a Nikon-MFT Speedbooster, primarily with my Sigma 18-35mm, a few vintage Nikon AI-s primes, and Rokinon Cine primes. My Sigma 18-35 is FF-equivalent, then, to 32-62mm on full frame, whereas on my GH2 it was FF-equivalent to 25.5-50mm, which was just shy of vignetting. Switching to the BMCC Speedbooster would sit somewhere in between, at 29-56mm (very close to what this lens is optimized for, on standard APS-C sensors).

In light of this information, I am very tempted to sell my 0.71x MFT Speedbooster, and pick up the 0.64x BMCC variant for my GH4. But then, there are rumors of a GH4 specific variant of the Speedbooster. Should I hold out for that, and what kind of focal reduction factor should we expect from it, given that the 4K mode on the GH4 uses a smaller active imaging sensor than the BMCC? Is there a thread where this is being discussed?

mo7ies

From what I heard, BMPCC speedbooster is designed exclusively for that camera and will not fit others, even though they are M43 mount as well.

There is some conflicting info on this, so I suppose it's good to proceed with caution... Personally I don't have a speedbooster to check this out, although I do have both cameras - BMPCC and GH4.

RRRoger

The problem with the BMPCC SpeedBooster is that it fits too deep in the GH4 mount. I believe that it is the mechanical shutter that hits it. I would wait for the GH4 specific model to come out or just pick up a cheap knockoff.

_gl

From what I read, BMPCC SB hitting the shutter is the first issue. If you're brave you can switch to electronic shutter and it will just fit (and pray you never change it back accidentally). But it's supposed to vignette anyway as the image circle is designed for the smaller BMPCC sensor. Not sure how that affects the smaller GH4 4K mode though (do a Google).

Sangye

@mo7ies, @RRRoger, @_gl, to be clear I am talking about the BMCC speedbooster, not BMPCC!

_gl

Sorry misread. Seems to be the same shutter issue and wide corners, eg.

"Summary: The BMCC speedbooster has a wider FOV and puts slightly more light onto the sensor at the expense of having to turn "electronic shutter" and "silent mode" on. Also, the BMCC protrudes a bit and causes slight scratches on the inside of the camera - no serious damage. Very noticeable corner softness in my comparison - whether it was from the BMCC speedbooster or the lens is not completely sure, but if I had to guess I'd say it's from the BMCC speedbooster as I wasn't even using the full lens.

Update: I have noticed some undesirable green light leak like spots at times - very rare, only happened when I was pointing it in a very specific way at the direction of a light source... occurred between 2 different lenses. My guess is this is just a factor of the extra glass (all speedboosters), you see this kind of stuff with UV filters and such some times. Also was able to make a band of light streak across the image

The bottom left corner softness of the BMCC bothers me. Mind you though the text in general is not as legible on the BMCC, but the MFT text is larger.

Corrections: Mentioned 2 options to reframe/match the composition - zoom and move forward, can also move subject closer though"

(do more Googling to confirm).

Sangye

@_gl yeah that's consistent with what the designer of the Speedbooster said over on EOSHD. Sharpness issues come from the different filter stack thickness between Panasonic MFT cameras, and the BMCC. Each Speedbooster has to be optimized for the filter stack thickness of the receiving camera, otherwise there are IQ issues. Alright, I guess I'll suffer this crop factor until there is a GH4 specific variant, preferably with the ULTRA specs :)

Vitaliy_Kiselev

@Sangye

Check topic title, use Speedboster topic for all this talks.

anti12

GH4 Firmware 2.0: http://panasonic.jp/support/global/cs/dsc/download/fts/dl/gh4.html

OBgene

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