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Phil Rhodes

Member Since 26 Dec 2003
Offline Last Active Today, 05:29 AM
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Posts I've Made

In Topic: Triggering Rainbow Streaks?

Yesterday, 02:03 PM

Diffraction grating. I'm not aware of them being used as filters for high power lighting, though. The type depicted below would not handle any useful amount of light.

 

s-l640.jpg

 

Simulate it with a video or slide projector?

 

 

 

P


In Topic: LEDs at night on batteries

16 July 2018 - 07:17 PM

That's a pretty reasonable approach, though I believe it's possible to run those lights directly from batteries if you make up the right cables.

 

Total load is 540 watts, so a large 12V, 220Ah leisure battery will in theory give you four hours. However, that's a load of 45A, which is quite high, and you will get much less than that in practice. It's better to use several batteries in series to create a higher voltage, say four for 48V, and using an inverter designed for 48V input. This distributes the load and reduces current to 10-12A, which is much kinder to all the electronics and will produce a more efficient setup.

 

There are significant safety concerns with all this. Wear eye protection and heavy gloves when making connections, and ensure everything is isolated properly for transport and while rigging. High power, low voltage systems like this will react energetically to being shorted out. Use heavy cable, as 12A is not a small load.

 

Your battery purchase should include good quality chargers. Lead acid batteries are a primitive and ancient technology but they are very difficult to charge well, and may explode (venting boiling acid and lead shrapnel) if mistreated. Charging them will tend to take more hours than there are between wrap and call, so if you need to do multiple days in a row, you may need more than one set.

 

Hope that helps.

 

P


In Topic: Suggestions on lighting a lobby to look like daytime...

16 July 2018 - 06:22 PM

In extremis you could play it as a magic hour, a sunset, then you don't have to blow it all full of daylight. But for a medical thing they'll probably want it all bright and shiny.


In Topic: Suggestions on lighting a lobby to look like daytime...

16 July 2018 - 12:04 PM

It can be done. I hope you have a lot of money, to the point where it would be cheaper to pay almost any amount of money for the location during the day.

 

notre_dame_82.jpg


In Topic: 50mm To 85mm A No Man's Land?

16 July 2018 - 10:47 AM

I noticed this. I have no idea why.

 

I happen to own all of the very old cheap Nikon series E primes, which make moderately good motion-picture lenses given their intent and age. They, too, leap from 50 to 85. Many people have said, of that range, that they have reasonable optical quality for their cost simply because Nikon built what they could easily build well. To your point, while I understand that a 28mm has different engineering challenges to a 135, I'm not sure why 60 is particularly more difficult than 50.

 

P


Glidecam

The Slider

CineTape

Ritter Battery

FJS International, LLC

rebotnix Technologies

Willys Widgets

New Pro Video - New and Used Equipment

Aerial Filmworks

Rig Wheels Passport

Broadcast Solutions Inc

Paralinx LLC

Technodolly

Media Blackout - Custom Cables and AKS

Tai Audio

CineLab

Metropolis Post

Abel Cine

Wooden Camera

Visual Products

Gamma Ray Digital Inc

The Slider

Ritter Battery

CineTape

New Pro Video - New and Used Equipment

CineLab

Rig Wheels Passport

Paralinx LLC

Glidecam

Visual Products

Broadcast Solutions Inc

FJS International, LLC

Gamma Ray Digital Inc

Tai Audio

Willys Widgets

rebotnix Technologies

Metropolis Post

Aerial Filmworks

Wooden Camera

Abel Cine

Media Blackout - Custom Cables and AKS

Technodolly