Replacing CRT with LCD. Where to add weight?

[Jess Haas SOC]

I recently replaced the broken CRT on my rig with a very light LCD monitor. I see that most people use a battery on the back of the monitor to add weight. I have the ability to either add it there or on the bottom of the sled.

 

It seems like the bottom of the sled would be a better option since it would require less weight to have the same effect. Is there any fault in my logic? Will adding weight at the bottom/in front of the post cause problems with dynamic balance?

 

~Jess

[Rob Vuona SOC]

I recently replaced the broken CRT on my rig with a very light LCD monitor. I see that most people use a battery on the back of the monitor to add weight. I have the ability to either add it there or on the bottom of the sled.

 

It seems like the bottom of the sled would be a better option since it would require less weight to have the same effect. Is there any fault in my logic? Will adding weight at the bottom/in front of the post cause problems with dynamic balance?

 

~Jess

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Hey Jess,

I did the same on my rig, I added weight in front of the post on the bottom of the sled but I also extended the monitor arm.

 

I still would like to hear the others take on this , Garrett or Jerry the two yoda's of the business, do you guys have an opinion . . .LOL . .

 

Thanks

[Mike McGowan SOC]

I used an LCD instead of my CRT on my last feature. I didnt add any weight. I did have to keep everything forward though (the bottom stage was close to all the way forward and the top plate was pretty forward with the top stage close to neutral). Obviously, the post needs to be a bit longer to add some bottom weight but all in all it's not that much of a change. I suppose it depends on how heave your LCD is and your CRT was. My CRT is a PRO and my LCD is a Boland 8.4 inch daybright. The dynamic balance was likley off quite a bit but I confess I never checked it :( Mabye if I have some time on set tomorrow I'll give it a spin.

 

mm.

[Dan Coplan]

I have a Transvideo Cinemonitor IIIa. I added two pounds to it very inexpensively by purchasing a cylindrical-shaped SCUBA weight that conveniently has a slot going all the way through it length-wise. Got two L-brackets from the hardware store and some special cement to fix the weight to the brackets. The weight/brackets line up perfectly with the threaded holes already part of the monitor.

 

3 pounds would probably be perfect as 2 pounds isn't quite enough to get me into perfect dynamic balance for a number of cameras, but it's a great improvement over no weight at all.

 

Dan

 

PS - And it also serves as a resting place for the armed combat robot that guards my rig while I'm away at lunch [see picture]. The gaffer tape wrapped around the weight in the picture was a temporary solution until I got the cement to fix the weight to the L-brackets.

[Charles Papert]

Something about adding dead weight to a full-size rig seems just plain wrong somehow! There's always room for more battery capacity; why not make up the 2 lbs difference with a greater capacity batt, or adding an additional one?

 

I'm using the Steadyrig battery hanger which allows for the scenario Jess describes; the front battery can migrate forward a good 3 inches which will help restore the inequity when going to an LCD monitor. I think it's a great way to go.

[Mike McGowan SOC]

day rate on the armed security robot?? does he come with the gun or is that extra???

[Brad Smith]

I've done a little of both. I agree with Charles, and I have the same battery hanger (Steadyrig), but I've also added a little "dumb" weight to help the balance (east west) of my Transvideo Cine IIIa. Will try and post a pic tommorrow.

[Dan Coplan]

I considered adding a battery for "useful" weight but it didn't make any sense. The front battery on my sled provides plenty of power for the monitor so adding an additional battery wouldn't really do much for me. Rather than putting $5 towards the "dead" weight which really gives me all I need, I'd be shelling out $300-something for a battery bracket.

 

And the bracket doesn't provide as comfy a resting spot for the robot. Or in the case of the last movie I worked on, Barbie.

 

Dan

[Charles Papert]

But who said the additional battery had to provide additional power for just the monitor? Could be wired back to the camera battery too...

 

In any event, since this is a "permanent" solution that is being discussed (i.e. for those who are using LCD's full time rather than as a backup or lightweight rig) I think it's more than logical to spend a bit of money on a sensible solution. Having a properly balanced rig that provides the same amount of power but weighs 2 or 3 lbs less than a rig with CRT is a nice save, because you can always add weight if flying a big heavy camera but why carry it if you aren't? It leaves the option of going to a fatter battery (Hytron 140) if the job calls for it, giving you lots more power for the same weight as a CRT system.

 

If I had a PRO2 with an LCD as my primary setup, I'd be mounting the monitor battery behind the LCD or extending it from the front of the rig, possibly with a telescoping mount.

[Jess Haas SOC]

I have actually been flying with my LCD for a little while now but I just purchased 3 AB plates on ebay for $50 so I am trying to decide on how I want to design my permanent solution.

 

As is the rig will actually balance if I suck the battery all the way in to the post. This has been convenient on a few occasions where I was flying the HVX for long periods of time as I didn't have to add any additional weight to the camera (it already had 2 big audio receivers, a comtec and my video transmitter). With the CRT I would have had a lot of post above the gymbal with the same setup. This setup is not ideal for larger cameras so I have added a 1 pound scuba weight to the front of the rods on my bottom stage.

 

Now that I have the AB plates I am going to replace the weight with an AB plate. I also think I am going to buy some lithium ion batteries which are lighter than my trimpacks. By mixing them with the trimpacks I should have a wide variety of weight distribution options depending on what camera I am flying and how I want to fly it. I should be able to get my rig extremely light for flying small cameras without having to add additional weight or go to a 3 or 4 battery setup for heavier cameras.

 

~Jess

[Brant S. Fagan SOC]

Gents--

 

 

Why add weight when you could maintain dynamic balance by simply extending the monitor out away from the post?

 

 

Check into the DB primer from Jerry Holway which is available from the SOA site and see what you need to do to make this mod to your sled.

 

A parallel rod monitor bracket system would make a more suitable addition to a sled rather than a block of dead weight.

 

Just my .02

 

Best,

 

Brant

[Jess Haas SOC]

I have already moved the monitor out further, which is why I can get it to balance with one battery sucked all the way in. That works fine with very light cameras, but I lost a lot of weight at the bottom of my sled and for heavier cameras I like a little extra weight to keep the sled from getting too long.

 

~Jess

[Mark Karavite]

I bought a MK-V LCD early in 2007 in conjunction with switching from Hytron 120's to Dionics. With the LCD on board, and the lighter Dionics, I successfully lost a few pounds, and have greater battery capacity.

 

Like Charles suggests, having the extra bottom weight being another Dionic (or whatever battery you please) is very helpful for both film and power hungry digital cameras. Only when I do a concert video where the camera is powered down the triax or fiber cable, do I loose the 3rd battery.

 

I have a MK-V Nexus battery base. It's original design only allows the 3rd battery to mount directly under the post. This is a good position for a CRT monitor, but not ideal for an LCD. I had my machinist modify the base so I could mount the 3rd battery up front when I use the LCD, while I still maintain the below the post mounting position for a CRT.

 

Attached is a photo of the base in the LCD mode. With this set up, my rig will spin balance perfectly with 1, 2 or 3 batteries, with either CRT or LCD mounted. Following Jerry Holway's method of spin balancing, I can put my monitor where I like it for viewing, and still achieve a very nice spin balance.

 

Mark

 

3_Battery_LCD.jpg (51.79K)