Tagged with speed - Personal View Talks

Fine Tweaks in GH2 Operations

kholi — Sun, 04 Dec 2011 21:30:02 +0000

Not sure where to put this, sorry VK if it's in the wrong place.

I'm back using the GH2 and now with the hack. Been great. Still love whipping out the Epic and rolling but right now the hacked GH2 is allowing us to move super fast and deliver a format that people can wrangle all on their own. Quite impressed with the quality coming out of the camera in low lit (working with 3-4K lighting packages sort of low lit) situations.

Curious, though, about at least two things:

1. Any way to open up the picture profile (film mode_) manipulation? I'm sure this one has been talked about plenty, seems like it would be top lister. If so, what was the progress on it? I've done a search but not come up with an answer.

2. What's the possibility of opening up the shutter speeds to go from 1/40 to say 1/42, or especially 1/48? Being locked into 1/40 or 1/50, I automatically gravitate toward 1/40. On Canons, I shoot at 1/45. Obviously, neither 1/40(45) or 1/50 equal 180 degrees @ 24 frames, opting for a slower angle over the hair faster one looks better to my eye.

What are complications with doing so? Is it a hardware lock and not a software lock?

The second one would be a major deal to me, as it would further help correct how the camera renders motion.

Thanks for all the hardwork. I get paid next week, so my small contribution is finally going in.

FF on Panasonic lenses with variable focus speed/change ratio

janis — Fri, 27 Jul 2012 05:57:12 +0000

I just got my first FF and found out something that didn't bother me before. On Panasonic standard lenses focus distance change varies with the speed the focus ring is moved. So there is no point in putting some marks on FF and then trying to create repeatable focus movement. I have seen some references to this problem but is there some workaround?

GH2 - Motion Fluidity (360º shutter) test on slow shutter speeds.

duartix — Fri, 24 Feb 2012 23:26:23 +0000

Having spent some time developing a settings package for timelapses, and having noticed how most of the times motion doesn't seem 100% FLUID at 2fps, I have found the urge and need to test it on 1080p modes in order to see which setting better fits this particular kind of footage.

For that I focused the camera on a strong light, started recording and then I quickly panned the camera horizontally on the tripod while varying the shutter speed. Then I looked at consecutive frames and measured the light interruption (measures.jpg) and computed the fluidity normalizing it as a percentage of the average segment length.

The results are in the attachment (MotionFlow.zip) which is also shown as a screenshot (MotionFlow.PNG). They are approximations as the values can have some variation, but will clearly show you which are the good ones and the others to avoid at all cost.

The resulting videos can also be downloaded (they are very small) from here: http://www.mediafire.com/?ezz6zroqcronq28,ova2axx3qjev573,ca6o3g4cjhx46lc

As you can see, HBR 25p easily beats all other 1080p modes with no less than 5 100% FLUID motion shutter speeds, 4 of them very useful indeed. Now it's time to perform some tests to see (subjectively of course) how much we can notice it and how high can we tolerate the interruption before the motion flow stops looking natural.

(EDIT) The ideal patch GOPs should be useful in this thread. Here they are:

SS - Frequency of new frames - Ideal patch GOP

24p & 25p HBR

1/2s - 1/13 - GOP13

1/2.5 - 1/10 - GOP10

1/3.2 - 1/8 - GOP8

1/4 - 1/7 - GOP7

1/5 - 1/5 - GOP5

1/6 - 1/4 - GOP4

1/8 - 1/4 - GOP4

1/10 - 1/3 - GOP3

1/13 - 1/2 - GOP2

1/15 - 1/2 - GOP2

1/20 - 1/2 - GOP2

SS - Frequency of new frames - Ideal patch GOP

30p HBR

1/2s - 1/16 - GOP16

1/2.5 - 1/12 - GOP12

1/3.2 - 1/10 - GOP10

1/4 - 1/8 - GOP8

1/5 - 1/6 - GOP6

1/6 - 1/5 - GOP5

1/8 - 1/4 - GOP4

1/10 - 1/3 - GOP3

1/13 - 1/3 - GOP3

1/15 - 1/2 - GOP2

1/20 - 1/2 - GOP2

Speeding up your SD card (the unexpected way)

duartix — Sat, 28 Jan 2012 21:42:01 +0000

Short story: My SD Card got a speed upgrade from stock and it cost me NOTHING!

Long story:

Bought a Samsung SD 16gb Plus Class 10 (this kind: http://www.amazon.co.uk/Samsung-16GB-Class-Extreme-Speed/dp/B00569J5JC/ref=sr_1_5?ie=UTF8&qid=1327802435&sr=8-5)

First thing I did was format it at 32K and 64K clusters for optimal speed and benchmark it. Speed gains from 64K were marginal, and IIRC the camera didn't like them and defaulted to 32K if I formatted in camera.

Benchmarked the card at almost ~15MB with 16MB files and ~13MB with 8MB files. "Nice!" - I thought, 15MBs is better than Class 10 and since it's 120Mbps it will hold some pretty aggressive patches for a card that costs 20€.

But one day as I was moving FW from my laptop to the card I noticed the transfer speed was way below 10MBs! :( This started a heavy series of benchmarks that were all flawed (basically the problem was that the internal SD reader on the laptop is speed limited) but that had an unexpected development in my struggle to get the benchmark back to the speed I knew it was capable of. In that series of events I used some SSD reasoning "It's flash memory, I should try a Full Format not a Quick Format."

When I returned home and benchmarked the card on the external reader where I originally got almost 15MBs, this is what I got:

I don't know if this will transport to other brands, but I know I'll be doing this every now and then....

How To Improve Image Quality From Soft Lenses

apefos — Wed, 11 Jan 2012 13:52:05 +0000

The challenge: to use the lenses wide open to get the most shallow dof in GH2. But this makes the image soft because almost all lenses are soft wide open. So what is the solution? Watch the video tutorial on vimeo

Your favorite shutter speed (SS)?

stoney — Tue, 24 May 2011 16:12:42 +0000

At 1080p24, I used to like 50 SS but had to switch to 60 SS for fluorescent lighting. At 60 SS, it seemed a tad bit fast, but fast SS actually helps apps like Twixtor and Timewarp. So 60 has become my favorite for 24p.

At 720p60, I use 125/250/500 SS depending on how fast subjects move. Faster subject, faster SS. Basically... there seems enough motion blur in shorter duration when moving faster which negates some of increase in motion strobe. In other words... my favorite SS varies.