Colortran ERS Lens Identification

[Javert]

Greetings everyone,

The previous LD at my high school left unexpectedly some time ago, leaving me to cope with a collection of conventional instruments including around 20 or 30 old-style Colortran lekos. They appear to be largely the same as the newer 5-50 series, with the various lens positions. Most (presumably!) are equipped with 6x9 lenses, but some are marked as 6x12.

The musical coming up will require many of these instruments set to 40 degree field, which is not possible with a 6x12 lens.

I'm wondering if there's an easy way to tell the difference between a 6x12 lens and a 6x9, short of hanging the fixture and measuring the field.

Thanks to anyone who can help here.

 

[SHARYNF]

AFAIK these did not use a different lens but rather a different lens positoin

Here is a link to an older CB post on this. It MIGHT be that the person was marking them with the "altman system" of 6x9 6x12 but actually referring to 30 or 40 degrees.

http://www.controlbooth.com/forums/lighting/5315-changing-degrees-colortrans.html

Some other folks might have a better first hand experience

Sharyn

 

[derekleffew]

Are these, post#8 the fixtures? This line, simply called "Ellipsoid," used (mostly) the same lenses in different configurations to accomplish 20°, 30°, and 40°, so perhaps the fixture labeled as "6x12" has simply been set to 30°?

But to answer your question, a 6x9 lens is ~1.5" at its thickest point, a 6x12 is ~1". Best way is to take one outside on a sunny day (need near-parallel rays going in), focus it (as if burning bugs), and measure its focal length.

 

[Javert]

Are these, post#8 the fixtures? This line, simply called "Ellipsoid," used (mostly) the same lenses in different configurations to accomplish 20°, 30°, and 40°, so perhaps the fixture labeled as "6x12" has simply been set to 30°?

It certainly looks like the same fixture (minus the "Berkey" wording, but that shouldn't matter).

I suppose they might be set to 30°, but I'm probably going to have to relabel them anyway - previous Lx crews couldn't mark gels to save a life, so who knows if the fixture labels are accurate.

As soon as the storms clear up, I'll follow your advice and find out just what those lenses are. Thanks Derek!

 

[ptero]

We have a bunch of the Colortrans that can be set to 20, 30, or 40 degrees. I'm pretty sure they match what derekleffew referenced. In our case, all of the 6x lenses are the same - but dunno which the are. I have the cut sheets that came with them - I'll take a look. If desired I could send you one.

The factory labels mean nothing. We color code them with vinyl tape on the yoke to keep straight which is which. For us, no color tape means 30deg which is our most common use. We use white for 40deg and red for 20deg. Anything could work, this ties with our PAR64 coding (white wide, red narrow).

It's kind of a pain to reset lenses, though our alternative would be fixed units, so I'll take the flexibility. Typically 6 or less (of the 21 we own), if any, are anything other than 30 for a show.

I think Production Advantage was able to come up with a couple of the field stops (donuts) when we misplaced a few.

 

[church]

I still have the Colortran 5/50s and the earlier 213 model that you refer to in inventory. The lens and field stop positions for the 5/50 and 213 are the same with one notable exception: the 5/50 can be adjusted to give 20, 30 and 40 degrees; the 231 lens tube can also be used to achieve a 12 degree field. The 20, 30 and 40 fields as already mentioned are achieved by relocating the 6*9 lens the use of one of the two field stops and the removal of the 4.5*9 lens this information is usually on a label on the tube but can be found on the Leviton website. The lens tube for the the earlier 213 fixture has an additional lens groove right at the front of the lens tube which accomodates a 6*12 lens to achieve a 12 degree fixture when used with the small diameter field stop in the same position that it would go for a 20 degree fixture. I have four of these fixtures in stock.

The easiest way to tell if you have a 6*12 0r 6*9 lens is to hold the lens parallel above a piece of printed paper and measure the distance between the paper and lens when the print is focussed. It is a bit crude but works well enough to differentiate a 6*12 lens from a 6*9 lens. there is a slightly more complex method which is better at identifying lenses but the method described will let you identify any 6*12 lenses.

 

[GreyWyvern]

This should tell you what you need to know.

Dave

 

[sthed]

Does anyone have the ID and OD of the field stop used in the old school Colortran 213 series? I have a couple with tubes setup for 40deg and would like to use them for 30 and 20.

Thanks
Scott

 

[derekleffew]

From this pdf from this post, it looks like position#2 would be OD 4.5" and position#3 would be OD 6", ID ~4".

 

[church]

Does anyone have the ID and OD of the field stop used in the old school Colortran 213 series? I have a couple with tubes setup for 40deg and would like to use them for 30 and 20.

Thanks
Scott

I think you are asking for the external diameter and the hole diameter for the two different field stops: these are different for the 30 degree and the 20 degree. I can measure them tonight.