Tagged with system - Personal View Talks https://personal-view.com/talks/discussions/tagged/system/feed.rss Sat, 23 Nov 24 13:04:09 +0000 Tagged with system - Personal View Talks en-CA Improve DFD contrast based auto focus for video. https://personal-view.com/talks/discussion/16596/improve-dfd-contrast-based-auto-focus-for-video. Wed, 15 Mar 2017 09:21:43 +0000 cas1 16596@/talks/discussions Dear Panasonic,

I love to see a better video auto focus system. DFD has already removed the first wrong direction start of the focus pull, but I like to address the second wrong direction autofocus pull, the "focus confirmation" rack at the end of the auto focus pull.

I'm not an engineer but I like to understand what is happening what, how, where, when and why.

At this moment the Auto Focus system for video looks the same as for stills. And for stills it works fast and well, accept in continuous high when it has a hard time keeping up with fast action. For video (akin to a very high number of stills) the AF is way to slow, and the focus confirmation pull is very distracting and jarring.

If DFD is able to measure the blur amount, and therefore can measure how far the subject is, the I think a reprogramming of the focus system can help to get rid of that jarring focus confirmation refocus.

I can think of this focusing system:

Focus pull situation:

1) DFD measures the amount of blurr, 2) compares it to the current focus distance, 3) estimates subject distance, 4) smoothly starts racking focus, 5) measures amount of blur half way racking focus, 6) checks the blur shift amount of the first and second measurement, outputs second focus target distance, 7) at the last part of the focus rack the focus speed eases off to arrive at the second estimated focus distance.

Continuous AF situations:

1) DFD measures the amount of blurr, 2) compares it to the current focus distance, 3) estimates subject distance, 4) smoothly starts racking focus, 5) measures amount of blur half way racking focus, 6) checks the blur shift amount and compares it to the first measurement, calculates subject movement, 7) rack focus to second focus target distance, 8) checks the blur shift amount and compares it to the previous measurement, calculates subject movement, 9) repeat 7 and 8 until no blur.

10) If subject leaves the frame maintain the current focus distance for x time before starting with 1 on the new subject in the assigned focus area.

Maybe DFD blur measurements are hard & slow, so having measurements while the camera is auto racking focus is harder to do, but I prefer a slower focus much over racking past the focus and racking back in video.

As a compromise DFD could be used to make a 1 time focus distance estimate, the focus racks smoothly (s curve) to the estimated distance, and stops (without racking past the estimate focus distance AND racking back). This would be good enough for a G85, and the more processing heavy higher DFD sample rate for the high end GH5. I must admit this all hinges on DFD accuracy in measuring the blur and estimating the subject distance.

What do you people think? Love to learn how the current contrast and DFD actually works. Love to hear your suggestions of how to improve AF.

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ROWA Wireless microphone system https://personal-view.com/talks/discussion/2607/rowa-wireless-microphone-system Sat, 17 Mar 2012 23:15:38 +0000 Vitaliy_Kiselev 2607@/talks/discussions image

  • 1.0" LCD display screen
  • Operating Frequency: 2.4~2.483GHz
  • Battery display, Lock display, mode display, Autoscan manual, channel display and Mic plus
  • RF output power: 50mW
  • Apply to multiple channel operation or long distance transmission
  • Powered by 1 x 3.7V / 710mAh lithium battery (Transmitter and receiver)

image

Price: $177.10

http://www.dealextreme.com/p/1-0-lcd-2-4ghz-50mw-stereo-wireless-microphone-system-transmitter-receiver-set-for-camera-122179

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Aputure Amaran HR672W High CRI95 LED OR Yongnuo YN900 LED or Yongnuo YN600? https://personal-view.com/talks/discussion/12939/aputure-amaran-hr672w-high-cri95-led-or-yongnuo-yn900-led-or-yongnuo-yn600 Wed, 06 May 2015 04:47:18 +0000 club_irate 12939@/talks/discussions I am a film maker. Planning on an indie film on a GH4 soon.

Which would you guys recommend, Aputure Amaran HR672W High CRI95 LED OR Yongnuo YN900 LED or Yongnuo YN600?

Is the Yongnou 900 better to buy in a fixed 5500k version (since i get all 900 bulbs to be usable together) or should i rather opt for the fixed 5500k YN600 Led.

Should i go for the Bi color models available in both these brands or the fixed 5500k ones are logically a better option. (Need suggestions, please dont reply saying depends on your needs). Planning on buying 2 of the ones that are suggested.

Also, i am aware the Yongnou are brighter but just wanted an expert opinion based on experience from fellow members. Is the Fan sound issue on the Yongnou's too much of a bother?

Any other LED suggestions are also welcome.

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My New Upgradeable GH2 Cage From Berkey System https://personal-view.com/talks/discussion/3502/my-new-upgradeable-gh2-cage-from-berkey-system Fri, 08 Jun 2012 01:04:40 +0000 tvpglabs 3502@/talks/discussions What do you guys think? I have a detailed write up on how it came to be and more pics on my blog: http://tvpglabs.com/2012/06/08/my-new-upgradeable-gh2-cage-from-berkey-system/

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Extend physical (not focal) length of lens? https://personal-view.com/talks/discussion/2650/extend-physical-not-focal-length-of-lens Thu, 22 Mar 2012 00:30:57 +0000 shane 2650@/talks/discussions I buckled down and bought the Voigtlander 25mm f.095 and I love it. But now it's time to put a follow focus on it. As anyone who owns this lens will know, the focus ring has old-school ridges that make it tricky to put a focus gear on, but right underneath it is a "smooth" area that I am convinced could be made to turn with my iDC System Zero follow focus (if not by itself, then with a standard office ziptie or something similar).

The problem is, the shape of this device puts the rubber about a millimeter shy of where it needs to be. It's so close, but it doesn't quite touch:

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If I could find a way to add even 1/8 of an inch to the lens, I think that it could make contact and possibly work. But my problem is that all adapters tend to do something. I want one that does not do anything. Since it's a manual lens to begin with, I won't be losing any functionality.

Does anyone know of anything like this, or another workaround?

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Anyone used a Lockit Buddy? https://personal-view.com/talks/discussion/2581/anyone-used-a-lockit-buddy Wed, 14 Mar 2012 22:14:08 +0000 B3Guy 2581@/talks/discussions Hey, everyone! The rental house where I am interning just picked up a "Lockit Buddy", and I was just wondering if anyone else is using these or is aware of their capabilities. Its basically a small box that takes in timecode and sends that to your camera's audio track, essentially enabling proper dual-system timecode synched audio on DSLR type cameras that otherwise would not have timecode. OF course you must edit in a software that supports audio timecode, but the site lists Avid and FCP both as software that have this ability. I'll be testing this nifty little thing out in the near future, so I'll re port back when I've used it ia bit more, but I just thought it sounded like something very useful.

http://www.lockitbuddy.com/website/index.html

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How long will my relation with panny last? https://personal-view.com/talks/discussion/603/how-long-will-my-relation-with-panny-last Fri, 05 Aug 2011 20:23:58 +0000 luax 603@/talks/discussions I found myself breaking my head over what road to go when it comes to buying into a (new) lens system. 
As a PAL native and I felt a little 'put off/betrayed' by panasonic because of the PAL related issues when it comes to the our beloved gh2.
It raised pherhaps completely unnecessary questions like: Will I stick with lumix for the next couple of years? If not? Is it wise to infest a lot of money into a M43 system? 
Since I feel that panasonic abandoned me and my PAL pals a little, will I stay faithful to them?
So my question is, what would be a good way to go lensewise that does well on the GH2 but could also soften divorce procedure when going into a potential new marriage in the future?

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Risk of owning mirrorless-system lenses https://personal-view.com/talks/discussion/271/risk-of-owning-mirrorless-system-lenses Thu, 23 Jun 2011 13:42:56 +0000 stoney 271@/talks/discussions
Oly is about to release new bodies with incredibly fast AF. Faster than GH2!!! Just a month ago I was complaining about Oly's slow shutter lag. But only if newly designed Oly m43 lenses like 12/2.0 and 45/1.8 are used. I wouldn't buy new Oly body since I can't get such fast AF from Panny m43 lenses I own. Resale value of older Oly m43 lenses are expected to nosedive.

I just canceled PL 25 preorder. I heard 14/2.5 price dropped a lot in Asia. It dropped to $340 in the States. Maybe going below $300 soon.]]>