andrewg112 Posted February 20, 2019 Share Posted February 20, 2019 Hi All, Had a little project ... I have a follow spot which takes a 250w MSD ... Im trying to improve the brightness output. One of our suggestions was to replace the lamp. The result is below: Followspot New lamp is on the left. I think its brighter, but it could just the a different colour temperature which makes it appear brighter ? What do you think ? Same style / shape of lamp, different manufacturer. Also ... thinking about LED ... we used a 350w LED follow spot in recent months and it seemed to be much brighter than say a 350w MSD would be. Is there any kind of conversion rule of thumb out there ? Thanks,Andrew Link to comment Share on other sites More sharing options...
Big Jay Posted February 20, 2019 Share Posted February 20, 2019 Focus it for a start, other things to look at is cleaning the lens and also, which a lot of people don't realise, is replace the reflector! Link to comment Share on other sites More sharing options...
pscandrett Posted February 20, 2019 Share Posted February 20, 2019 It looks to me that the pic on the left seems brighter because it's got something of a hot spot in the beam. That is to say, the lamp probably isn't centred in the reflector, leading to a non-uniform light output - in this case, focussing more light in the middle of the beam in an uneven splodge, and less round the edges. You can see a 'line' where the beam goes from light to dark quite abruptly just under the Evita poster, for example. I don't know what type of followspot you've got, but are there any adjustment screws that allow you to move the lamp in/out/up/down within the reflector? I'd check the manual and see if you can adjust it a bit better - then it'll be easier to make a comparison. The terms you might be able to find in the index are 'flat-field' or 'lamp alignment adjustment' or similar. Edit: I wouldn't hurry to replace the reflector - a clean (carefully) might be worth it, but ageing reflectors are normally /very/ obvious when they're deteriorating. Link to comment Share on other sites More sharing options...
gyro_gearloose Posted February 21, 2019 Share Posted February 21, 2019 Another way of making a follow spot appear to be brighter is to make the rest of the stage darker. If you are trying to cut through a brightly lit scene then you’ll need something bigger than a 250W lamp. For reference, the Marinas followspots are 1200W, and even they struggle when our stage is brightly lit. As for LEDs, I’m not really sure that there is much of a rule of thumb when comparing them with other light sources, as LED efficiency seems to be increasing year on year. The best thing to do would be a side by side comparison with the followspots that you’ve currently got. Of course, if you are thinking of retrofitting some to your existing spots then all I can say is have fun! :) Link to comment Share on other sites More sharing options...
Junior8 Posted February 21, 2019 Share Posted February 21, 2019 Clean, service, focus Link to comment Share on other sites More sharing options...
andrewg112 Posted February 25, 2019 Author Share Posted February 25, 2019 Thanks very much all. The followpots are actually quite new. For the use they have had, they should not need new parts. I have contacted the manufacturer to see if there is anything they can suggest. There is no adjustment on the lamp and those ugly lines in the beam actually are getting worse I think over time. LED would not be a retro-fit ... Im pretty certain a 350w LED spot would be far superior to the 350 MSD spot. Plus the added benefit of considerably less hot parts to touch. Link to comment Share on other sites More sharing options...
Brian Posted February 25, 2019 Share Posted February 25, 2019 As for LEDs, I’m not really sure that there is much of a rule of thumb when comparing them with other light sources, as LED efficiency seems to be increasing year on year. It's worth noting that there is a maximum efficiency for LEDs which is down to basic physics. Plus the added benefit of considerably less hot parts to touch. As the amount of light emitted from both LEDs and discharge sources is relatively low compared to the power consumed, then the amount of waste heat is pretty much the same Watt for Watt. It is true that getting waste heat away from an LED source is easier than for a discharge source but the amount of waste heat from a 350W LED is still nearly 350W plus you have the waste heat from the power supply. Link to comment Share on other sites More sharing options...
gyro_gearloose Posted February 25, 2019 Share Posted February 25, 2019 The only other thing I can suggest to increase the brightness would be to look at the lenses. If, for example, your follow spots beam when it reaches the stage is 20 feet wide and you iris it down to 10 feet wide then you are throwing away 75% of the light that your follow spot produces. If, in that scenario, you could zoom the spot in to something close to a beam diameter of 10 feet then you will condense the light energy into a smaller area and make it brighter. It's worth noting that there is a maximum efficiency for LEDs which is down to basic physics.Indeed there is. I wonder how close LED manufacturers are to reaching peak efficiency? What prompted my previous comment was the fact that LEDs efficiency has increased somewhat since I converted my Miniscans to LED. I had used a 40W 2000 lumen LED, whereas today you can get the same brightness for about half the Wattage. Link to comment Share on other sites More sharing options...
paulears Posted February 25, 2019 Share Posted February 25, 2019 I'm ancient enough to remember 1K tungsten lamps in follow spots and back then, they were pretty bright. Nowadays, with LED washes, the stage brightness is amazingly potent, the followspots get left behind. Link to comment Share on other sites More sharing options...
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