Saturday, February 27, 2016

The White Oscar Controversy

Last Week Tonight With John Oliver made this brilliant video about the white Oscar controversy:

 Jonathan Swift would be proud.

Sunday, February 7, 2016

My E350 Cargo Van

I bought a cargo van for work, finally.  I have needed one for some time.  I have too much gear anymore to fit it in my car.

It is a beast; an E350 Super Duty with the Ford factory towing package.  It will tow a 1400 amp plant with no problem.  It came with a great roof rack.  About the only thing I needed to add to it was a safety bulkhead, or partition, to keep the driver and passenger safe from the cargo.

I recently replaced the serpentine belt.  It had been getting noisier and noisier for sometime.  Turns out the tensioner pulley and one of the idler pulleys had gone bad.  I went ahead and replaced all the pulleys.

This was all relatively easy even though any engine work on the Ford E series vans is difficult.  The hard part was getting the new serpentine belt on.  It is like some kind of crazy IQ test.  Threading the kinky, non-cooperative, belt through a maze of inaccessible pulleys took almost as long as everything else!

Thursday, February 4, 2016

Evaluating Non-Continuous Light Sources With A Color Temperature Meter*

*Or Venturing Down The Rabbit Hole Where Things Are Not As They Seem. 

I recently took some time to adjust the daylight pre-sets on my Zylight IS3Cs to match them closer to my daylight Creamsource LEDs.  Every gaffer knows you can’t trust your color temp meter with non-continuous sources.  What I found surprising was the extreme difference in readings between 2 daylight LED lights.

I’ve seldom use my Zylights and the Creamsources at the same time.  When I do, it’s immediately obvious the pre-sets for Zylights do not match the Creamsources.  I wanted my Zylight daylight pre-set to match my daylight Creamsources.

If you are not familiar with the Zylight IS3Cs, these are strange and awesome light panels.  What makes them strange is each individual LED on the panel is actually a four color RGBW emitter.  This causes strange color fringing.  Using a chimera will eliminate this.  Of course the farther the head is from the subject, the less this becomes a problem.

The awesome features of the Zylight IS3Cs are adjustable light balance (color temp.), adjustable color correction (green/magenta), and a full RGB mode for colors.

My color temperature meter is a Minolta Color Meter IIIF.  I bought it new years ago.  It is a great meter that has been super reliable and accurate, but accuracy is a relative thing.  The first thing any color temp meter manual will tell you is this; a color temp meter is not accurate with light sources that have a non-continuous spectrum, or a spectrum with large spikes.  A film or video test is the only accurate way to evaluate these kinds of sources.

For a gaffer, the first time I learned this years ago, I was thinking “What!  That’s the whole reason I wanted a color temp meter!”

Of course, with experience, a gaffer learns a great deal about evaluating sources using the color temp meter as a starting point.

So back to the Zylight and the Creamsource:  on the left is a Zylight IS3C pre-set daylight with chimera and internal baffle only; and on the right, a Creamsource Mini daylight spot:
Clearly to the camera, and more so to the eye, the lights are not color matched, but they are similar.  That is not what the color temp meter says.  The readings are surprisingly differently; not even close to each other.  The Mini’s are in the ballpark for 55K.  The Zylight’s reading don’t make any sense at all.  Clearly, the meter is being confused by spikes and gaps in the spectrums of the LEDs.

Here, I have adjusted the Zylight and matched it to the Mini by eye:
I couldn’t tell any difference between the 2 sources to my eye.  The camera sees a subtle difference between the two; maybe a little more magenta in the Zylight on the left.   Again the color temp meter is unable to accurately read the Zylight.  Though the Zylight's numbers are now closer to the Mini's, the readings are still surprisingly different.

As an experiment, I tried to adjust the Zylight’s color to match the Creamsource Mini using the color temp meter.  Of course this isn’t going to work:
I added all the blue and green possible to Zylight in the white light mode.  Even then, I was unable to match the color temp meters readings of the Mini.  The numbers are closer, but clearly, the color temp meter is taking things the wrong way.  The light is a strange turquoise color.  My color temp meter wanted me to add even more blue and green.

I’m pleased with the new daylight pre-set for the Zylights.  It closely matches my Creamsources.  I would never be able to absolutely match the 2 lights source.  Though my color temp meter is unable to accurately read the lights, it does tell me there are differences in the spectrums of the 2 lights.  I cannot gel color into a source with gaps in the spectrums, or accurately control sharp spikes.  It is not fully correctable, but it is manageable to where the differences are not obvious or seen.

The best we can ever do in any situation where we are dealing with different lights with non-continuous spectrums is to make the difference manageable and not obvious--when possible.  Some lights have such poor spectrums, that correction is not possible.

Some postscripts:  This experiment with color temp meter readings is not a criticism or evaluation of either light.  Both are quality professional lighting instruments.

On my wish list is a Sekonic C-700 color temp meter.  I love all the features of it.  Graphing the spectrums of the Zylight and Creamsource, would have been interesting with this test.  I almost bought a Sekonic last year, but I bought another Creamsource Doppio instead!

Lastly, I’ve found test pictures with a still camera to be invaluable over the years.  Curiously, the eye can be deceived when looking at a subject directly, but not when looking at a still picture (or a monitor).  Subtle dynamic difference often become obvious looking at a still picture.  The same is true for color.  Subtle color differences often become obvious looking at a still picture, or a monitor.

Friday, January 15, 2016

The Variac That Took Us To The Moon

I generally don't have much work around the Christmas holidays going into the first few weeks of the New Year.  I hate not have much work, but there is an upside.  I have time to repair gear, and time for new work projects.

Here is one of my projects; a 20 amp variac.

This is an old General Radio type W20 that is in perfect condition.  It came from an old 3-phase lab bench type variac; cool but not suitable for use on a set.  I've had the parts for it sitting around on a shelf for the past couple of years.  I just hadn't found time to work on it until now.  I love old electric devices like these.  The design is simple and brilliant.  The construction is top-notch.  These were designed to exceed their rated capacities and last a long time.

One of the hardest parts in turning this into a studio-use variac is just finding an enclosure that it will fit.  Then there is a lot of cutting and drilling, before the variac can be put into the enclosure.

On the bottom of this variac is a super-cool old ID label from NASA.  This could be the variac that took us to the Moon.  Maybe.  Anything is possible.

Not having the original insulated shaft for rotating the brush assemble, I substituted an acrylic rod.  This assemble is energized when the variac is on.

Here is the finished "Moon" variac complete with it's original ID plate.  I have added a breaker and a power-on indicator light.  I also like to use indicator plugs.  These are very handy allowing you to see at a glance if there is power to whatever you are using.

This "new" 20-amp variac will be a nice addition to my gear.   Now I have 1-7.5 amp variac, 2-10 amp variacs, 2-20 amp variacs, and 1-50 amp variac.
Here is my largest variac, a 50-amp beast!  The unistrut cage is to protect the variac.  Variacs look indestructible, but actually are fragile.  They need to be handled carefully.  One drop, or an impact to the coil, could irreparably damage it.

Saturday, October 31, 2015

Oldest Electric Service I Have Ever Seen

Working at 19th century mansion in Martinsburg, WV, I saw this old electric service.  This is the oldest one, I have ever seen, and it is still in use.

The service has a finished wood case with a glass door.  It looks very cool.

Unlike a modern electric service, which is usually hidden somewhere, this service is meant to be seen.  It is conspicuously located in the entry hall.  When this was installed, it must have been a prestigious thing to have electricity.

This is a 40 amp service.  Each circuit has a 5 amp fuse, curiously on both the hot and neutral wire, with a double knife switch.  Typical of old electric services, there is no provision for a ground.

We joked about tying-in to the service.  We could have powered a few practicals.  Maybe.

Wednesday, October 14, 2015

LED Ribbon Light Kit

My LED ribbon light kit is coming along.  I used it gaffing on a Steven David Productions show in September, "American Speed", a mini-series about NASCAR.

Some components of my LED kit

 I love LED ribbon.  It is so easy to quickly add a little light in a small place.

My kit has been a work in progress.  I started over a year ago.  My motivation was a couple jobs using LED ribbon that did not go a quickly or trouble-free as I would like.  I was using LiteGear ribbon.  The biggest problems I found are unreliable and time-consuming-to-use connectors.

Any lighting gear that isn't quick and trouble-free, make me, the gaffer, look bad.

My kit is 24 volt bi-color ribbon.  I use simple electric connectors which just push together.  I put together my own dimmers; 2-channel PWM dimmers.  I also put together a couple 12 to 24 VDC transformers for car use, which plug into a lighter outlet.

 This scene is almost completely lit with LED ribbon:

iPhone picture of a monitor

My New LED Panel Light

Recently I purchased another Creamsource LED panel.  The new one is a Doppio Bender; a 1x2' bi-color spot.  Like all of Outsight's lights, it is awesome.  I have found the bi-color feature to be so useful, I almost wonder if all my lights should be this way.

My other Creamsource LED panels are a Doppio 1x2' daylight spot, and a Mini Doppio 1x1' daylight spot.