Hmm... SPH lamps, yet to test them myself, timing and the quote of their specifications something like “some” Ellipsoidals. Test away please, you no doubt will get to it before me.
What’s the proper
bench focus test? 2M seems a
bit short, I’m thinking twice that at a white
screen at least = what is the
bench focus distance for the
fixture you are using? For me like 15 to 20 feet is good at a minimum but set distance.
Initial verses sustained. Ten hours is not enough but should be a start. Not so much worried about that for a
filament lamp however - the mortality / output curve of a
filament lamp will be less given overall output than that of a moving light lamp I would think. Interesting if you can do it an extend that time to 50% of the lamp life that test / curve but short of that I wouldn’t worry. For a good test you want both light meters in lumens /
foot candles, and a light
meter that measures
color temperature if you want to do it properly. Still for
stage usage, if you can see a blackspot or solid beam inside that of another beam when you cross beams that’s also important. Same lenses types how much brighter solid a beam, harder
edge and or more even is it?
This all given very well bench focused beams of light for all fixtures. Also assuming you start with new lamps for all and all are given the same test and attention. Way difference between that of a semi-focused
fixture and one that is true in a way that a radial
fixture might just seem better than S-4 say.
“The Sink” lamps in a S-4
fixture are not worth testing. Different and a
bit less efficient
filament structure and also no longer on the market so not more than educational in study between what lamp is in “the sink” and that of what
HPL it’s compared to. That’s a S-4 question and nothing really more that can be studied with such a question. Proper lamp for a S-4 is a
HPL and that’s what should be tested with. Same wattage and same voltlage. Same distance and if possible all right next to each other at distance to a white drape at the same beam spread.
If you cannot match beam spreads, at least lamp to lamp testing should be done with same beam spreads. A 6x9 in comparison to a 6x16 has no value by way of optics comparison for any form of study. Can do either but not both in forming a result in comparison.
Different school at that
point - 2M might be sufficient for a 6x9 test given a manageable beam to measure but wouldn’t be sufficient for a 6x16. On the other
hand, a slightly larger distance might be better for both.
Assuming you have the long life SPH lamp - not seen that yet, will add it to my spec in the morning, than I assume you would compare it with the Phillips sink or not GLA lamp (sink removed). Osram rep says they just re-engineered their own version of the GLA/GLC lamps to be the same as that of the Phillips ones so that’s also a consideration as with the GE/Thorn versions of HX-603/604 I believe they would be beyond
ANSI code.
Once well warm
shock testing would also be a concept to check if desiring to
base ball bat the fixtures once warm and willing to deal with such a potential problem.
Unfortunately the HPR lamp is TBA discontinued so other than for academic reasons it’s not worth adding to the test. It’s hoped that some day the GLA/GLC GLD/GLE will have internal reflectors on the other
hand.
Overall loose the FEL’s. Can test them but useless overall. Test the FEL verses a GLA and the GLA for the most part shouldn’t compete other than with gobos for all intensive purposes. This other than in
color temperature making up some for that. Test the GLC verses the FEL and perhaps some this also given
color temperature. The HX-755 is a GLE lamp by
ANSI code for it. That’s also a 750w/115v lamp which should more match up due to it’s long life to a EHG than a FEL for overall output and lamp life. On the other
hand with all cases, the FEL lamp is in
filament so large in inefficiency pinpoint source of light reflecting, anything is possible. Still better in comparison to a FEL in realistic would be a Philips 750w/115v #6981P lamp or at least a GLD / HX-754.
Same overall lamp life, different wattage but
color temperature in
voltage change to make up for that, this plus the #6981P is not for the most part far enough once
color temperature is added in, this much less
point source of light efficiency is added in no doubt brighter in not much huge difference in output after that.
Anyway, are you judging the SPH at 575w/115v verses other 575w/115v lamps in something that realistically is going to be seeming to be something like a 800w lamp in comparison to a FEL, or attempting to
beat the FEL lamp with a 750w lamp?
Many paint brushes, center around the 115v types in 575w or 750w but don’t mix and match between the two.
In setup, you got say a 40 to 60' bar and a white drape or
cyc say 15' away.... Place the lights on
line and shoulder
level and away you go. Stand behind,
meter and
swing beams of light between beams adjacent to each other. You will get a really good indication. Be fair and scientific and also its given best
bench focus’s of course.