A SWANSONG FOR THE "BIG" URSA

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robert Hart

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A SWANSONG FOR THE "BIG" URSA

PostTue Oct 15, 2019 7:22 pm

Alas it has gone to the good Lord above or to 'im down below, crossed the rainbow bridge or whatever happens to video cameras when their essence of being leaves this mortal coil.

This was its last hurrah before it was put away for the winter and failed to rise after its long slumber. It was good while it lasted, faithful colours, good sound via mike inputs, nice rolloff of whites into highlight overexposure when it could not be avoided and an image straight out of the camera that I preferred over the later URSA Mini 4.6K, which has a bit of a videoish look to me but that is just me.



Now it is back to the SI2K, having to mess with separate audio mixers, dealing with a codec and LUTs which DaVinci Resolve does not support and generally trying to hot it up a bit to approach modern expectations to get it up to where I was with it in 2014.

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rick.lang

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Re: A SWANSONG FOR THE "BIG" URSA

PostWed Oct 16, 2019 5:43 am

Nice thoughtful post, Robert. Now get yourself a BMPCC4K and enjoy shooting once again.


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robert Hart

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Re: A SWANSONG FOR THE "BIG" URSA

PostWed Oct 16, 2019 8:27 am

I neglected to mention that the lower clip of Araluen Botanic Park was shot on the SI2K, fitted with a BMPCC Metabones Speedbooster, the faux-ALEXA trick of a contrast filter back near the sensor and connected to SD302 mixer with Sony mikes.

It was a struggle and grunt carting it around semi-agile with just the side-finder and "mouse" blind-controller buttons.

I do have Blackmagic to thank for building the original pocket cinema camera which prompted the development of the Caldwell optics and Metabones Speedbooster to suit it. 35mm-style images on the SI2K and modern solid state drives really extended to the utility of the SI2K camera.

Likewise in a reversed sort of way was the 0.71x speedbooster mod to the "big" URSA. That was inspired directly by an experiment in the RED DSMC2 camp which sought to emulate on smaller sensors the image of the then larger Dragon sensor.

It was very simple to execute by comparison because of the generous workspace of the original BM camera body/turret design which required nothing to be interfered with.

I'd better start buying into lotto. There may be the day when my cargo plane shall come home and bring a good thing for the people but in the meantime, needs versus wants are the imperative.

Besides, it is pre-ordained that the Hart breed shall never prosper at games of chance, but like the lemmings from the cliffs, it does not stop us from trying.

The modern pocket 4K cam looks interesting but I miss the decent and robust audio coupling and camera bodies that are less likely to come apart if you do a geriatric totter and accidentally sit on them.
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rick.lang

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Re: A SWANSONG FOR THE "BIG" URSA

PostWed Oct 16, 2019 1:33 pm

Fair enough, sir. Since it appears you’re over six years old, I’ll have to respect that choice.

The left side of the BMPCC4K where you would want to add perhaps three or four cables is certainly designed for the fingers of a six year old to be able to insert and remove cables and is the biggest operational challenge of the camera. I still love it though!


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robert Hart

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Re: A SWANSONG FOR THE "BIG" URSA

PostWed Oct 16, 2019 6:26 pm

Rick Lang.

Am definitely over six years old. Maybe in six years time if geriatric dementia sets in, I may relive the experience. It would be nice to be six again with the knowledge I have but things do not work that way, except in the movies of course.

There was a damaged-in-transit pocket 4K on the eBay which looked interesting but the asking price was too much for something which might have totally destroyed innards. I had entertained the notion of transferring the guts into the big URSA body and getting some of the utility of that big body back.

The "big" URSA is basically what the next generation of the SI2K ( SI4K ) could have been which is probably why I went for it.
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Iain Philpott

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Re: A SWANSONG FOR THE "BIG" URSA

PostMon Oct 21, 2019 5:44 pm

Sorry to hear of your loss. Touchwood my 'big' Ursa v2 is still going strong. I am fortunate to also have a UMP and Pocket 4K. However I agree with you. I shot most of last week - camera of choice, the 'big' Ursa. If you have sufficient light and you nail the exposure (I rate the camera at 400 not 800) it is a really beautiful image. Very filmic. With used prices stiffening for good condition ones I have a feeling that the big Ursa will end up with a cult following amongst those that know! The downside of course is when they break is the fault simple enough that it can be repaired?????? I'd love to see an independent repairer step forward.
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robert Hart

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Re: A SWANSONG FOR THE "BIG" URSA

PostMon Oct 21, 2019 8:48 pm

With this one, the info is that a mother board replacement is worth $3509inc GST including labour. The sensor and its two PCBs plus Peltier heat exchanger is not available for replacement. It looks like the sensor and/or its associated PCBs have gone west.

I suggest that my following comment is tested by enquiry with more competent folk than I. When I first began to dismantle the camera I found that the turret came out cleanly. An extruded piece of the conductive heatsink paste had gone into the fan which is low and at the rear. I had never heard a fan running.

The turret and the thermal pickup for the liquid cooling system are both secured so should not move relative to each other. My suspicions lie with the thermal compound. It does set hard. My thought is that it may have disbonded due to shocks experienced in transport and thermal conductivity may have been reduced enough to cause the sensor to fail in overtemperature.

The original 4K sensor in the big URSA does not seem to have been disclosed by BM to humble peasants but is widely suspected of having been the Cmosis CMV12000. This sensor was apparently not tolerant of high operating temperatures or high temperatures in storage. - Comment from another forum.

QUOTE:
"When you read PAGE 13 of the Datsheet " ABSOLUTE MAXIMUM RATINGS " , you see that Maximum Junction Temperature is 70 C ( which is not that high .. ) . And you read that Maximum STORAGE Temperature is 40 C... It means you should not forget your Camera inside your Car , under the Australian Sun ... Even here , we had up to 45 C. in the Shadow .. last July ( which I suffered from .. I prefer Rain .... ) .. which could be Harmful for the Sensor ..

Continuous Power Dissipation 4200 Milliwatts .. It's very important to have a Radiator Behind , and a perfect Thermal Contact ..

Also Relative Humidity MINIMUM 30 PerCent .. that means no storage in a Completely Dry Environment ... It begins to get Complicated."

END OF QUOTE:

If the big URSA sensor is the CMV12000, then it seems that every sensor's days are numbered unless meticulous care is taken to avoid the sensor experiencing overtemperature. If the camera is to be stored, it may be prudent not to use sachets of dessicant silicagel if the camera is in a box in a refridgerated ( heat pump ) airconditioned environment which tends towards dryness.

Knowing what I know now, I would seriously consider pre-emptively maintaining the thermal bond of the firm-setting heatsink paste by adding a non-hardening white thermal paste to whichever surfaces disbond when the turret is extracted from the body. - A caution - The people who know best at Blackmagic or New Magic in Australia or offshore service centres and dealers should be consulted first. Often, human interference will introduce a fault where before there was none.

The thermal bond between the Xilinx processors and their heatsink consists of a soft pad which is fixed by adhesive on both surfaces. When I dismounted the motherboard, these bonds were very secure.

If BM were to sell a retrofit kit for the big URSA consisting of the current pocket 4K sensor, a motherboard and sub-board to run the big display and sub board for the sound, I could live without the duplicate control panels. I would still be in pigheaven. Alas this is the stuff pipedreams are made of.

I am now back on the SI2K, which has been "Alexarised" with a speedbooster, plain IR filter and a small panel of Formatt Hitech NC8 filter as close to the sensor as I dare place it. Formatt Hitech had the good generosity of sending me some small laser cut pieces to experiment with. They will get my business in the future.

I had a 0.71x speedbooster on the "big" URSA which placed it comparable to the Mini 4.6K in sensitivity and fields of view. Now all that work has been a waste of time and it is probably fit only for cruel children to burn ants with on the cement path under sunlight.

Apparently, the unloved AJA Cion, used the same sensor and performed similarly to the "big" URSA. I don't see too many of those on the used market. It would be interesting to know how long their sensors lasted. I heard indirectly that Peltier heat exchangers for computer CPUs had been a R & D dead-end for one outfit which was trying to master the application of them. I wonder how well BM got the tech sorted or if they found cooler running sensors for the later cameras instead.
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Leon Benzakein

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Re: A SWANSONG FOR THE "BIG" URSA

PostTue Oct 22, 2019 1:43 pm

Good heavens, it is a pleasure to read something written by an adult with know how.

May I be so bold as to ask what you refer to when talking about "the SI2K"?
Television: Lighting/Cameraman, O.B. Camera Operator, Experience in EFP, EPG and ENG , Grip, Lamp Operator
Film: Grip, Lamp Operator
Theater: Lighting Designer, Light board Operator, Stage Electrician, Stage Management
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rick.lang

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Re: A SWANSONG FOR THE "BIG" URSA

PostTue Oct 22, 2019 1:59 pm

Rick Lang
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robert Hart

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Re: A SWANSONG FOR THE "BIG" URSA

PostTue Oct 22, 2019 4:52 pm

The Silicon Imaging SI2K had its genesis in a discussion page on the dvinfo.net forum when folk were despairing about the big players in the videocamera business holding back innovation.

An idea was floated about the possibility of gutting out a Kransnogorsk K3 16mm film camera body, adding a Super16mm sensor by Altasens of about the same dynamic range of the "big" URSA.

A small PC would be built into the mag space to do the recording. Then a bunch of different entities decided, yes we can do this and the first disruptor of the status quo was born.

It was soon to be followed by Jim Jannard who also floated his notion of the RED camera also on dvinfo.net and built up a development team.

The most notable success of the SI2K system was in the filming of "Slumdog Millionaire" in which over half of the imagery was shot with it.

The system consisted of a camera head, referred to as the Mini, which held the respective applicable codec and operating system licences within its internal memory.

The recording choices were to use a suitable laptop or a PC running Windows XP, or a Windows XPe based purposed recorder which was built as a camera body by P+S Technik in Germany into which the Mini head docked in the front and the recording media docked into the rear.

The computer hardware within was adapted from and built to the standard of available split motherboard and backpane computers which were of critical reliability for use in systems like rail traffic control.

Unlike the "big" URSA, the P+S Technik camera/recorder unit was modular. The computer guts would slide out on a small tray after four screws were unfastened.

It was however hell expensive compared to Blackmagic's current offerings. That's what comes when ex-ARRI engineers get to play with their CAD programs and computerised milling machines. Even the fillet radii of mounts were tightly measured.

The bodies and the "Mini" camera head enclosure were computer milled out of aluminium. The thing was meant to be reliable and robust to ARRI standards. There was even an optical viewfinder for the B4 ENG lenses and the digital cine lenses which were emerging from Fujinon and Optika-Elite.

With the emergent disruption of the RED One, the SI2K likely holds a record for the most rapidly depreciated camera system as everyone wanted 35mm sized sensors. RED adopters had been building and buying groundglass-based image relay systems for 1/3" and 2/3" camera for nearly ten years.

Some P+S Technik Pro35s were fitted to the SI2K for "the 35mm film look" but not widely adopted. I tinkered with a Letus Extreme adapter which was kindly donated to me by the Le brothers and got it up to practical 2K resolution on the SI2K and well into HD resolution on the Sony PW-EX1. It was a one-off Some sods burged the house and pinched it a year ago.

Cinevate's Dennis Woods, developed a varifocal relay lens and Brevis 35mm ground-based adaptor specifically for the SI2K, which also realised that performance. I still have the prototype here.

P+S Technik had a go at a 35mm sized sensor camera of HD resolution to be upgraded to 2K with their PSCam but it did not go far. The RED had the 35mm game sown up and along came the ARRI Alexa with its better than 2K origination.

In the meantime after my "big" URSA quietly said its prayers and martyred itself over winter, I have resumed my attempts to tweak the SI2K which I had put aside.

SI2K NO OPLF PLUS NC8 PLUS SPEEDBOOSTER REDUCED.jpg
SI2K NO OPLF PLUS NC8 PLUS SPEEDBOOSTER REDUCED.jpg (194.76 KiB) Viewed 2242 times


I had found the perfect replacement in the "big" URSA. It had about the same real-world dynamic range as the SI2K, the bonus of global shutter and that huge screen, a blessing for the folk who need close-up glasses.

It was like stepping into a new pair of already fitting comfortable shoes then having the soles fall off less than half-worn. That was a rug pull which has left me a bit cross but thems the breaks when you buy used.

The "big" URSA shares some attributes with the SI2K by the turret choices being removable from the front of the body and interchangeable along with a B4 lens mount adaptor for the URSA 4K Mini which was fully compatable with the "big" URSA.

Then there was the highly anticipated aborted fetus of a 4.6K turret upgrade option. That notion of course fell over on its bum for stated technical reasons but perhaps because it would have been a financial dead-end. It would have been nice to have but I am not overwrought about it.

Unlike the SI2K and offerings from the big three who have fought back in more recent years, the guts of the Blackmagic cams are unitary not modular, to be entirely replaced not repaired.

They are a bit like our aged pensioners under the current administration, intended to work until they drop before they will ever draw a pension, then die and get buried out of the way before they get too old and become an incubus upon the millennials.
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robert Hart

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Re: A SWANSONG FOR THE "BIG" URSA

PostTue Oct 22, 2019 5:12 pm

The crew who made the film critically acclaimed but not widely exhibited "Bellflower" went a step further with the SI2K. They made a groundglass relay device for large format plate camera sized images to be aquired by one of Ari Presler's early SI2K Mini camera heads recording into a laptop computer.

BELLFLOWER'S COATWOLF CAMERA.jpg
BELLFLOWER'S COATWOLF CAMERA.jpg (87.83 KiB) Viewed 2234 times


The images conferred a unique aesthetic for the film.
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rick.lang

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Re: A SWANSONG FOR THE "BIG" URSA

PostTue Oct 22, 2019 5:12 pm

Robert, great to hear from someone with such an intimate knowledge of the genesis of the SI2K. I highly recommend you add to the scant history currently on Wikipedia for this camera which has only a fraction of what you’ve covered here.


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robert Hart

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Re: A SWANSONG FOR THE "BIG" URSA

PostTue Oct 22, 2019 5:13 pm

I shall have to learn how to do that wikipedia thing. Cheers.
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robert Hart

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Re: A SWANSONG FOR THE "BIG" URSA

PostTue Oct 22, 2019 5:16 pm

For those who may still have an SI2K in the back shed, likely they have read a few of the handy hints I published on dvinfo.net, unfortunately after the SI2K had run its popular course. However here is the link for anyone who might be interested.

https://www.dvinfo.net/forum/silicon-im ... hints.html

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