Alternative for USL convergence camera?

[Gordon McLeod]

I agree with Steve test equipment aka toys are a important item
Ideally I would like a single unit that combines the PSA and the PCA in one device

[Tony Bandiera Jr]

It would be cool if MIT would dabble into the test equipment market. I'm sure it is even more difficult as a publicly traded company since test equipment is, by definition almost, low-volume things. However, there really does need to be a source of test equipment that is not being fulfilled right now. The convergence camera being an example. I think we'd be better off with a modern PSA as well and, honestly, I like the PCA 100 for my daily driver over our other "better" meters. It isn't quite as accurate as the PR-655 (my favorite in terms of accuracy and repeatability) but I've shot them against each other on the same tripod and they are plenty close. The PCA-100 can go off into outer space at times but it will, eventually, settle back in the real world (particularly on red).

I really liked that Jack and USL made niche cinema-specific test equipment that really did benefit the industry even if not super profitable for the manufacturer.

Funny thing is, in the film days, there were several "niche" companies that supplied test equipment, film supplies, etc. all things that were mostly very specific to cinema.

Since the switch to the digital "always a perfect show" equipment we are stuck with now, we have lost not only the tools to service equipment as good as we used to, but also the pool of knowledgeable technicians and machinists to maintain them.

Some progress, huh?

[Steve Guttag]

Much of the film-centric tools could be made small-scale and the companies that supported film were also smaller. How many techs, in the film days, carried around a color meter of any type? What would be the point? You couldn't do much about a color issue. You just tried to get as matched a set of reflectors as you could (presuming 2-machine) as one's ability to filter was limited, at best. I did have one color lab where we did attempt to get both xenon and tungsten color (via filters). But that was the exception and I'd say that the tungsten one was an approximation.

USL came up with the convergence camera for DCinema. The PSA line was for film though it was great for digital cinema too as one could really dial in a cold mirror as well as if you want to see the effects of a gain screen, flat versus curved...etc. It can get you 45 light readings very fast compared to shooting at 45 targets.

[Mark Gulbrandsen]

It would be cool if MIT would dabble into the test equipment market. I'm sure it is even more difficult as a publicly traded company since test equipment is, by definition almost, low-volume things. However, there really does need to be a source of test equipment that is not being fulfilled right now. The convergence camera being an example. I think we'd be better off with a modern PSA as well and, honestly, I like the PCA 100 for my daily driver over our other "better" meters. It isn't quite as accurate as the PR-655 (my favorite in terms of accuracy and repeatability) but I've shot them against each other on the same tripod and they are plenty close. The PCA-100 can go off into outer space at times but it will, eventually, settle back in the real world (particularly on red).

I really liked that Jack and USL made niche cinema-specific test equipment that really did benefit the industry even if not super profitable for the manufacturer.

There actually are places that exist that repair test gear. Doing so is no different than repairing sound processors or amplifiers at board level. The main thing you need is a known accurate light source and a master refrence oscillator so you can verify the operating frequencies of oscillators in the gear you're repairing. Often, but not always, the shops master oscillator feeds the ext refrence input on the shops frequency counters.
There are at least several places here in Nashville that repair and calibrate test gear.

[Harold Hallikainen]

When I started at USL in 2007, my first projects were the JSD-80, the IRC-28C, and "Popeye", a replacement for the PSA. As I recall, it did a 3x3 or 3x5 luminance matrix. You could adjust the side "masking" to match the screen edges. It measured the level of 9 pixels in each measurement rectangle, scaled to fL and nits and displayed. It also could log to a CSV file. There was also wifi so you could look at a web page of the display from the booth with the unit in the auditorium. But the project got cancelled.

Later, maybe around 2015, we also worked on a replacement for the PCA based on a new spectrometer module. That mostly involved playing around with the module.

At USL, there was a dark room just for calibrating light instruments. Later, LSS equipment was calibrated automatically in a small projection room above the dark room. A PR-650 would be used for reference measurements out of a Barco projector of red, blue, and white luminance. A JSD-60 provided pink noise. At the beginning of a test session, a tech would put the red, blue, and white luminance levels, as measured by the PR-650, into the test script. Also, the pink noise SPL was measured and put in the script. After that, the script ran the red, blue, and white images on the Barco, told the LSS to calibrate, ran the pink noise, and told the LSS to calibrate. A final report was generated with the LSS luminance and chromaticity for each of the colors and percentage difference from the PR-650 for luminance and xy differences for chromaticity, and the SPL difference in dB. It was a really quick process to go through units.

The LSS-100 used an RGB sensor, while the LSS-200 used an XYZ sensor. I ran some tests in Boulder CO at Real D to see how the LSS-200 did on their laser projectors. They did really well right out of the box without the need to recalibrate for laser.

I did VERY LITTLE work on the convergence camera. Most of that work was done by Jack (hardware) and Rick (software). As I recall, there was a very small PCB with the image sensor and USB interface. For testing, there was a large checkerboard pattern on the wall at the other end of the shop that the test tech would try to get a good image of.

Fun stuff!

Harold