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Panasonic GH4 for true video observing

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#1 mpgxsvcd

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Posted 22 April 2014 - 01:00 PM

I just got the Panasonic GH4 yesterday. It will do high quality 4k video at 30 FPS up to ISO 6400. Sadly it only goes to ½ a second exposures(2 frames per second) in video mode.

It should be really nice for objects in our Solar system though. The 4K @ 30 FPS will be great for the moon. It also has 1080p @ 96 FPS for those nights when seeing is not so great. For planetary it also has the 4.9x crop zoom mode at 30 FPS.

I haven’t tried a dark frame with it yet. It is so new that no program except for the one it comes with has support for the RAW files that it produces.

Our local club is observing this weekend so hopefully I will get a chance to test it out.

#2 chasing photons

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Posted 22 April 2014 - 02:56 PM

Congratulations on your new GH4! We will be anxiously awaiting reports of its capabilities for near real time viewing. Does the remote app currently support the GH4?

#3 ippiu

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Posted 22 April 2014 - 03:33 PM

Only 1/2 second in video mode?? Not so wonderful!

I would have preferred at least 12.800 or 25.600 iso in video mode and up to 8-12 sec...

#4 ccs_hello

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Posted 22 April 2014 - 06:42 PM

Travis,

What do you mean on "(up to) ½ a second exposures on video mode"?
E.g., if in 30p format, will it generate the entire 30 frames but only 2 different images within that 1-second window, or there will only be 2 frames generated, even the setting is 30p?


Or ... "video" you meant LiveView?

Clear Skies!

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#5 jdbastro

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Posted 23 April 2014 - 12:00 AM

Travis,

What do you mean on "(up to) ½ a second exposures on video mode"?
E.g., if in 30p format, will it generate the entire 30 frames but only 2 different images within that 1-second window, or there will only be 2 frames generated, even the setting is 30p?


Or ... "video" you meant LiveView?

Clear Skies!

ccs_hello


He means that the longest shutter speed selectable in manual movie mode (aka video mode) is 0.5 seconds. Which actually is pretty good. It's the same as the GH3. And twice as long as the max shutter speed on the Sony A7, which maxes out at 0.25 sec. So an 0.5 sec shutter speed means effectively 2 unique frames per second in video mode on the GH4 (and GH3). Those 2 unique frames get packed into a 30p video stream. Regarding 'live view', before (and during) a video recording session, one can 'preview' the scene at 2 fps (if shutter speed is set to 0.5 sec) either on the OLED screen, viewfinder, or on an external HD monitor connected to the HDMI out port on the camera.

Travis, Hurry up already and start using your GH4 so the rest of us can find out how much better it is than a GH3. You lucky dog!!

#6 mpgxsvcd

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Posted 24 April 2014 - 09:18 AM

We will have clear skies tomorrow and Saturday night. I will do a semi dark site tomorrow and my back yard on Saturday. It isn’t modified so don’t expect great Ha performance.

However, I did discover a few new things. It can do a lossless 2.6x zoom during video with the 1080p @ 60 FPS setting and 200 mb/sec all Intra frame compression. The GH3 could only do 1080p @ 30 FPS and 50 mb/sec IPB.

The GH4 has gamma curves and a new Cin-D profile that can get you closer to the RAW sensor capture than typical color profiles would. With it you can compress the dynamic range of the scene to fit into the 8 bits that the H.264 4:2:0 codec can store.

It can also output 10 bit 4:2:2 1080p @ 60 FPS lossless video via HDMI. That truly is closer to RAW video whereas the color profiles just mimic it.

With the app you can now start and stop the video function remotely. You can also start and stop in bulb mode up to 60 minutes. However, it doesn’t have the nifty live time feature that my Olympus E-PM2 has.

I didn’t really buy the GH4 as an AP camera. My modified E-PM2 will be better for it. However, I like the completely wireless interaction with it. I just need to go out and buy another iPad to use with it. My wife ran over my son’s iPad yesterday so all I have is my phone for the remote live view now.

The real strength of the GH4 is as an everyday camera. It is relatively light but every bit as good as any A-PSC camera out there. It you can’t take great pictures with the GH4 buying a different camera isn’t going to help you.

jdbastro's explanation is correct for how the video mode functions. I use live view and stills mode more for AP though.

#7 mpgxsvcd

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Posted 28 April 2014 - 07:45 AM

As always. If you get fancy new equipment the skies will darken and laugh at you. The prediction for clear skies didn't pan out.

I didn't get a chance to observe at all this weekend and now we have the threat of severe storms every night this week.

Hopefully it will clear up again next week. Living in the south is not good for AP.

#8 chasing photons

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Posted 28 April 2014 - 09:54 AM

Living in the south is not good for AP.



Maybe the southeast isn't good, but the southwest is the astronomer's paradise. I can't wait to move to the high desert of New Mexico. Better luck next week.






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