Strand SL Lenses?

[Lightingguy32]

On the source four PAR, all you have to do is release the lens retaining clip that is opposite the gel frame retaining clip. Do this when the fixture is on a flat surface, also check out http://www.etcconnect.com/product.downloads.asp?ID=20085
and click on the Source Four PAR user manual, it gives detailed instructions on replacing and cleaning lenses. You probably have to clean your lenses. I have lots of Source 4 PARs too and they all have clear lenses not green. Perhaps the green tint is from the Dichroic reflector, depending at what angle you look at it and under how much light, the reflector (MCM) can appear to be green in color, only making the lenses seem to look green. The PAR lenses are definetly clear.

 

[Schniapereli]

ERS: Ya, so if there are 2 inversions, then wouldn't that make uninverted (double negative)? Or, is the first focal point before the gobos, shutters, etc, or is there one further beyond that, outside of the fixture. (maybe I'm just doing my math wrong, but there should be an odd number of focal points for it to be inverted)

PAR:
I've tried that.. but I think either our instruments are really old, or I am really incompetent. I can push in the lens stop that is keeping it in, but I can't grip the lens enough to get it out. I tried carefully turning the fixture over, so gravity would pull it out (was careful not to let it fall...) but it just stayed in there...
Are you supposed to push down on the other side, (across from the stop) and make it pop out on the lens stop side?
...I checked the site, and it just suggests you push in the lens stopper, but I'm having issues with incompetency, so they don't help much. Maybe they're just stuck from dust, and being old...

(but, it answered the lens question)

 

[gafftaper]

ERS: Ya, so if there are 2 inversions, then wouldn't that make uninverted (double negative)? Or, is the first focal point before the gobos, shutters, etc, or is there one further beyond that, outside of the fixture. (maybe I'm just doing my math wrong, but there should be an odd number of focal points for it to be inverted)
PAR:
I've tried that.. but I think either our instruments are really old, or I am really incompetent. I can push in the lens stop that is keeping it in, but I can't grip the lens enough to get it out. I tried carefully turning the fixture over, so gravity would pull it out (was careful not to let it fall...) but it just stayed in there...
Are you supposed to push down on the other side, (across from the stop) and make it pop out on the lens stop side?
...I checked the site, and it just suggests you push in the lens stopper, but I'm having issues with incompetency, so they don't help much. Maybe they're just stuck from dust, and being old...
(but, it answered the lens question)

The lenses can be a little tricky and I've had them get stuck a little too. To get the lens out, try having a friend hold the instrument stable on a flat surface while they push in the stop. You get yourself a SMALL screw driver and GENTLY work around the edge a little to see if you can losen up the lens a bit. I repeat SMALL screwdriver and GENTLY. While you are GENTLY prying on one edge with your SMALL screwdriver, gently wiggle the rest of the lens with your other hand. I've had a similar problem and it all came out easy once I got it started with a little GENTLE screwdriver action. Don't try this on a ladder!!

 

[gafftaper]

OK, a somewhat realted question, what part of the ERS actually inverts the image. I have heard that it is the lenses, and I have heard it is the reflector. I was then convinced on the reflector idea because it makes an ellipsoidal shape, which has 2 focal points. the forst focal point being the bulb, and the other being beyond the shutters/gobo/iris slot therefore, the beam crosses after the shutters/gobo/iris, thus inverting it. (the iris of coarse doesn't matter, since it is...an iris...)
But, then, I was walking around with a lens tube, and looked down, and saw my feet in front of me. (36 degree) I was holding it at about the same height as to where we drop our electric down, and focus them on the ground. If my feet were inverted, and the reflector is also inverted, it would just cancel out. So, I guess my real question is, where are all of the focal points in an ellipsoidal (particularly S4, if it matters).

Ok this is hard to do without a diagram but I'm not an artist. Forgive me if I miss something.

First off an ellipse has two focal points. All light passing through focal point #1 will be redirected to focal point #2. The filament of the lamp is located exactly at focal point #1 (that's why we have the lamp adjustments on the back). The mirror chamber is then cut off just before where the second focal point should be if it was a true ellipse. Focal point #2 instead is in the empty space about where the shutters are located. From there the light hits the first lens. Lens one takes all the light no matter what angle it's cominig in at and sends it forward in a straight line parallel to the barrel. In theory if you removed the second lens and fired it up you would have a circle of light about 6 inches across no matter how far away you aimed the instrument. This is great beause we have complete control of the light but a 6 inch circle of light is useless unless you are lighting a show of ants and fleas. So we add a second lens. The second lens takes this light that is coming in straight and focuses it at focal point #3 located in the space about a foot away from the front of the instrument (depends on the degree of the lens). It is at focal point #3 that the image flips. After the light leaves focal point #3 it gradually spreads out to be a useful full size circle of light. By adjusting the second lens size we change the angle of how rapidly the light spreads after leaving the instrument.

Does that help? It's 1am and I usually do this with sketches. Anybody notice any mistakes?

 

[Schniapereli]

Is focal point #2 before the shutters, etc.?

Here is a diagram of what I know as of now the inside to be like. (attatched)

Now, if this is right, there are two points after the gobo slot. Thus, #2 inverts the image, and then #3 inverts the invert making it not inverted at all.

Is #2 before the shutters & gobos, or is there something else wrong with this diagram?

 

[ship]

Another random question, we also have a lot of Source 4 Pars, and when you look through the lens at the bulb, it looks green, yet they all give off white light, and the bulbs are regular HPL's (with the little pokey thingy to lock it in...you know what I'm talking about...). I have tried to take the lens out, but I'm not entirely sure how (all the tiny screws holding the front together looked important, and I didn't want to tinker without knowing what I was doing.) So, unless the reflector, or something down there is green, then why in the world does it look green down there, and why the heck did ETC decide to have the lens spread the beam out like an oval, and have it be rotatable...
Anybody who can answer these questions gets browny points...

Green look to a S-4 PAR fixture? Assuming that it was not the light on the reflector, we are not talking some thick old Altman Leko lenses so it’s not really possible that it was persay a bad lot number of lens that’s green. I would not think bad lenses would not be detectable due to the thickness. Could be the light you saw it under or it could be a dirty coating on the lens/reflector - especially I would think sad dust particles which in being a amber would in some way show up green with white or bluish/white light. Could also be a fog goo coating (oil also showing up as amber) but I’ll bypass that. Simple dust if not the light and or greenish tint to ambient lighting once bouncing off say foliage.

Not to say that one lens or reflector that there could not be some older and less sufficient or some more green than others, just that it’s most likely dirt you saw. Should you visibly be able to see green when the light is not on, this fixture also when next to a clear one would put out a light that’s visibly more amber shift as it were than other more blue/white ones. Minds’ eye for bench focus or even general focus before gel - what did the last fixture’s light look like verses this one.

In noting the “green” ... good detection skills, keep with them observations. Next step after noting things is the scientific method for process of elimination.



On the retaining clip, Lighting network about a month ago had a discussion about this. If of help in finding it, I added to the topic. Technilux it would seem retails a lens extractor that’s worth looking into if not making one yourself. My belief is that while in general an interesting thing, some lots of S-4 lenses are more difficult to remove than others. Has to do with the lens clips and even rotating rings. There has been some bad lots numbers of rotating rings in the past. This not to raise your suspicions as to you having a bad lot number, just that at times it’s difficult to remove lenses at times. You do have concave side outward also correct? Also by memory of how to do so, you have rotated the clip to the top of the fixture right?

On the beam spreading out like an oval - it’s simulating the effect from a normal PAR 64 can.
Such PAR can lamps had long linear lamps that were off axis to the parabolic reflectors in the bulb thus you had an oval beam of light. That’s standard to most PAR bulbs that they have an oval beam of light. The S-4 PAR is attempting to emulate this.

 

[Schniapereli]

Green look to a S-4 PAR fixture? Assuming that it was not the light on the reflector, we are not talking some thick old Altman Leko lenses so it’s not really possible that it was persay a bad lot number of lens that’s green. I would not think bad lenses would not be detectable due to the thickness. Could be the light you saw it under or it could be a dirty coating on the lens/reflector - especially I would think sad dust particles which in being a amber would in some way show up green with white or bluish/white light. Could also be a fog goo coating (oil also showing up as amber) but I’ll bypass that. Simple dust if not the light and or greenish tint to ambient lighting once bouncing off say foliage.
Not to say that one lens or reflector that there could not be some older and less sufficient or some more green than others, just that it’s most likely dirt you saw. Should you visibly be able to see green when the light is not on, this fixture also when next to a clear one would put out a light that’s visibly more amber shift as it were than other more blue/white ones. Minds’ eye for bench focus or even general focus before gel - what did the last fixture’s light look like verses this one.
In noting the “green” ... good detection skills, keep with them observations. Next step after noting things is the scientific method for process of elimination.
On the retaining clip, Lighting network about a month ago had a discussion about this. If of help in finding it, I added to the topic. Technilux it would seem retails a lens extractor that’s worth looking into if not making one yourself. My belief is that while in general an interesting thing, some lots of S-4 lenses are more difficult to remove than others. Has to do with the lens clips and even rotating rings. There has been some bad lots numbers of rotating rings in the past. This not to raise your suspicions as to you having a bad lot number, just that at times it’s difficult to remove lenses at times. You do have concave side outward also correct? Also by memory of how to do so, you have rotated the clip to the top of the fixture right?
On the beam spreading out like an oval - it’s simulating the effect from a normal PAR 64 can.
Such PAR can lamps had long linear lamps that were off axis to the parabolic reflectors in the bulb thus you had an oval beam of light. That’s standard to most PAR bulbs that they have an oval beam of light. The S-4 PAR is attempting to emulate this.

Well, all of our S-4 PARs seem to do this, and the other guy I talked to says he has always seen that in ours, and in others outside of our school. The light it gives off is perfectly fine but, are the lenses supposed to have the concave side out? All of ours have the convex side out... Is that maybe the problem? (just double checking on my terminology, our lenses curve outward from the fixture...)
I did not know about rotating the clip, but I will try that.

...If anybody can answer the ERS question still...'twould be dandy...

 

[ship]

I"m not following the Leko line of question and there are seemingly lots of people on the website better suited to answer this question on more modern S-4 optics. Not something I have read about in like six years.

IF nobody answers it in like a week PM me and I'll have a look.

Doesn't absolutely matter but remember that concave means "cave" or typically the bowl part is outboard and the convex side inward if it's concave side out.

Convex side out would be the round side out or kind of looks something like you have a round ball sticking out of the front of the fixture as it were.


If convex side out, it's not going to effect the optics at all but does tend to get stuck much easier and also is less easy to remove. Flip them around so they are concave side out and they should come out easier.

Our Leko Dpt. manager when asked about looking green when you look into the fixture and or lenses green has never seen that - this out of hundreds of PAR's and lots of lot numbers of them. That said, it's possible. More likely or similar she noted that when the reflector starts getting "yucky" when you look into the fixture it will appear amberish. Perhaps and unknown what sort of lighting or it's the case but perhaps your reflectors are going bad.

 

[Schniapereli]

Well, as it turns out when I went to school today and looked at them again, they were actually concave on the outside, and I just remebered it wrong.

I also took the bulb out (it was a HPL type C, if that helps explain the little pokey thingy. It goes in one of the two holes that are to the side of the 2 holes that you actually connect the bulb to on the socket. (don't know if they have those on Lekos...))
Anyways, it was still green when the bulb was out, and I tried looking around inside, and tried to remove the lens, still with no success. I'm going to try to take one fixture entirely apart though. Then, I'll tell all ya'll what was making the green color if you guys aren't already sick of me by now

Thanks for all your help...

 

[Lightingguy32]

The "pokey thingy" you are referring to is the ground pin on an HPL 750 watt lamp. Other wise that shouldn't be there. Are the S4-PARs you are using MCM or EA? The EA are rated to 750. The MCM are only to 575 so the end cap shouldn't even be able to accommodate the HPL 750. The only two HPL lamps with three pins are the 750 (the third pin is ground) and the 77 volt lamps which are for dimmer doublers.

 

[Lightingguy32]

Source fours (lekoes) made after 1993 are rated to the 750 watt HPL I described in the last post. If you have a 750 source four leko, it is labeled on the insulated focus handle attached to the fixture. This focus handle is an upgrade to pre-1993 fixtures and on anything after that year, the fixture came with one of the insulated focusing handles that was labeled on the side edges "750". The 750 watt end cap has the 3 pin hole that you speak of.

 

[Schniapereli]

I assume the reflectors are EA, but I am not sure. When I take one apart (still haven't done that yet) I can maybe get some more specifics...

 

[Lightingguy32]

Source Four PARS are labelled on the side with a sticker (hopefully it hasn't been peeled or burned off) that says if it is an MCM or EA. You can also tell, the MCM from the back side when it is lit emits blue, purple, or red light (shows it is absorbing IR and UV radiation), An EA is identifiable by the fact that the lamp caps insulated back side has a wattage label telling you it is rated up to 750.