Barnaby Coote Posted January 19, 2020 Share Posted January 19, 2020 I have a shoot coming up and we're planning on using a chimera L on a daylight fresnel. I don't use chimeras much and I need to pick which size light to use. A D12 is going to be much easier to rig, but we have the option of using a D25 if we need the extra stop of light. Budget is tight and we can only afford one light. I find the arri photometrics app handy for direct sources and was wondering if I could find any info on how much the chimera is going to cut the light by ? Say x ft away, for a 1.2k source how much light will I get centre and off to the sides by about 30º ? Would be nice if chimera provided a photometric map of the light falloff for 1 or 2 typical sources, but they don't unfortunately. Link to comment Share on other sites More sharing options...
Stuart Brereton Posted January 19, 2020 Share Posted January 19, 2020 Chimera softboxes mostly use grid cloth as their rags. The transmission data for the various strengths of grid cloth is available on the LEE filters website. That should get you a ballpark figure, although it wouldn't account for the extra reflectance of the chimera interior. If you can only afford one light, get the big one. Link to comment Share on other sites More sharing options...
Barnaby Coote Posted January 19, 2020 Author Share Posted January 19, 2020 Thanks, I was thinking the same but wasn't quite sure. Full grid cloth is -2 1/2 stops so I'm ballparking off that, but yes i'm hoping the reflective sides of the chimera will up the output a bit more to something like -2 stops. Crew is limited so a d12 might be easier if I need to boom it. I'll post measurements if I get the chance ! Link to comment Share on other sites More sharing options...
Ryan Emanuel Posted January 23, 2020 Share Posted January 23, 2020 What stop do you need from what distance? If the softbox diffusion is heavy enough, there really shouldn't be a heavy fall off from the center. Link to comment Share on other sites More sharing options...
Barnaby Coote Posted January 23, 2020 Author Share Posted January 23, 2020 Stop was t4 with the option to go up to 800 iso I only had a few minutes to meter the lights at the rental house, but on a flooded D12 I got around t4@400 asa at 4m/12ft which was ok. The would mean I'm getting around 500 lux or 50fc. The arri photometrics app gives 3500-4000 lux for a flooded undiffused d12 so looks like either the light was underperforming or the loss is closer to 3 stops. The flooded d12 could have done with an extra layer of diffusion though, its not nearly as even as what I get with a redhead on a medium softbox. I was in a country where domestic power is limited to 10A but I'll definitely go with a bigger light and internal diffusion next time. Link to comment Share on other sites More sharing options...
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