Evolution_Mark Posted February 12, 2004 Share Posted February 12, 2004 Back in the old days of lighting, "Klieg Lights" and "fresnels" were the names that came to mind when people thought of spotlights. Today it's Source Fourâ„¢. Found this on the ETC Website... Do/did you think of fresnel when it comes to a spotlight? Or is this some meaning of spotlight I'm unaware of? :** laughs out loud **: Link to comment Share on other sites More sharing options...
JohnMcConnell Posted February 12, 2004 Share Posted February 12, 2004 Admittedly not seen a Source four fresnel....But E.T.C. do make source 4 PAR which you can buy with optional barndoor. Seen many people come to the Royal Exchange in Manchester and talk about them like they were fresnels. Maybe your source has seen one of these, or just doesn't really know what their on about...... either way :** laughs out loud **: Edit:Oops, sorry, completely missed the point!!! thought it said ETC make source 4 fresnels..... Anyway, I suppose a fresnel is techincally a spotlight, just a soft edged one... Link to comment Share on other sites More sharing options...
James Posted February 12, 2004 Share Posted February 12, 2004 what about the ETC Parnell? Link to comment Share on other sites More sharing options...
gareth Posted February 12, 2004 Share Posted February 12, 2004 what about the ETC Parnell?It's not a fresnel, no matter how much ETC try to convince you otherwise. Link to comment Share on other sites More sharing options...
Bryson Posted February 12, 2004 Share Posted February 12, 2004 Fresnels are spotlights. Yes, many people use spotlight to mean a profile, but technically, fresnels and pcs (and possibly even pars) are spotlights too. As for an ETC fresnel, it's something I never understood either. According to one of ETC's project managers, the advance in technology that makes the Source 4 better than an old-style profile doesn't really make an awful lot of difference in a fresnel, so they don't make one. I still think that the advance in lamp technology and the lower power ratings would be useful, even if they don't have any other advantage. They do make a ParNel thingy, which is a sort of Source 4 Par with a funny pebbled lens, which accepts barndooring quite well, but I don't know anyone that has one. Link to comment Share on other sites More sharing options...
woody74 Posted February 14, 2004 Share Posted February 14, 2004 New to the forum, and American, so bear with me... :D The Source Four PARnel is not a Fresnel because of the lensing (it's not a true Fresnel lens). The optics in it are actually intriguing, in that it is actually 2 lenses that rotate on top of one another and provide the spot/flood capability. The light quality of the PARnel is great, and the edge is a little more soft than your average 6" Fresnel. The drawback to it is, because you are shooting through two pieces of glass, unless you use the 750 lamps, the lumens are actually less than a 500w Fresnel. On the plus side, the Source Four barn doors are (IMHO) much better than an Altman because there is no "snoot" on it, so the blades are right at the gate of the light, which doesn't crop your light when you are at fulll flood. Lastly, the spot/flood adjustment is mechanical, so if you have ever blown a lamp by accidently slamming a fixure into full spot, it's a nice touch. -w Link to comment Share on other sites More sharing options...
Bryson Posted February 14, 2004 Share Posted February 14, 2004 Just a thought - perhaps the "real" reason that you don't get "new technology" fresnels is that the hpl/gkv lamps don't take kindly to being moved around inside the fixture. What do you reckon? Edit: I said "bulbs." Shock horror.... Link to comment Share on other sites More sharing options...
woody74 Posted February 14, 2004 Share Posted February 14, 2004 Exactly. I have blown more lamps that way. Lately, I let the light sit for 60 seconds so the filaments warm and become more flexible (less chance of them snapping). -w Link to comment Share on other sites More sharing options...
Shaun Foster Posted February 14, 2004 Share Posted February 14, 2004 I let the light sit for 60 seconds so the filaments warm and become more flexible (less chance of them snapping). I thought lamps were more fragile when warm? Link to comment Share on other sites More sharing options...
woody74 Posted February 14, 2004 Share Posted February 14, 2004 As I understand, if the filiment is warmed beforehand (a good tip if you have 0-count light cues), they become more flexible and can move around a bit inside the lamp. If not, it is still cold and stiff for a second and it will not flex between connnections, it will just move as a single unit and snap. Hope that makes sense. -w Link to comment Share on other sites More sharing options...
misterbassman Posted February 14, 2004 Share Posted February 14, 2004 If the filament is warmed it will heat up and become thinner thus making it more prone to breaking. Link to comment Share on other sites More sharing options...
Bryson Posted February 14, 2004 Share Posted February 14, 2004 Not sure why heating would make it thinner. If anything, it would surely get slightly thicker. But I agree that I've always thought lamps were more likely to blow when hot. I certainly let all my lamps cool before moving the truss, for example. Link to comment Share on other sites More sharing options...
woody74 Posted February 14, 2004 Share Posted February 14, 2004 Except that metal expands when heated, and would compress the filiment coils closer together (unless there is a reaction to the gas inside the lamp I don't know about). Bear in mind, I base this on my personal experience, and am not a physics major (which is why I do theatre :) ) All I can say is that I tend to get bettter lamp life by preheating before LQ's. -w edit: I do think that there is a middle ground, and yes, I will agree that once a lamp has been on for a good long time, it would blow more easily because it could now flex enough to make contact with the housing. My comments came from focusing Fresnels earlier. I could be totally wrong about this, I'm just basing it on what has worked for me. Link to comment Share on other sites More sharing options...
robloxley Posted February 15, 2004 Share Posted February 15, 2004 For the answer you need to consider how temperature of the filament affects its resistance and hence the current that flows. That's why we have the concept of pre-heat. With regards to the filament getting thinner, the tungsten-halogen cycle reduces that to negligible. I'm sure many people will remember the old T1s that got dimmer with age as all the tungsten was deposited on the glass envelope! As for general physics knowledge, surely you need a certain understanding to work in theatre: electricity, forces and mechanics, electronics etc.? Link to comment Share on other sites More sharing options...
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