Light Rays

Graeme McMahon · July 3, 2012

Hello,

Over the weekend I did this shot.

I wanted this (taken by someone on set).

Apologies for the quality, I have spent some time trying to get these pics attached under the file size restrictions.

Obviously it came down to not having enough light to overexpose on the camera with having the light source come from a distance away, having a gel on, shoot through the lattice work.

I wanted to ask, what is the next level up in intensity is there from a source 4 that could help with a shot like this - a xenon would probably be out of the budget. Just noticed on the day too, when shooting back towards the light, the light needs to be obscured from the lens to get its maximum effect (is that a correct assumption?).

While I am here, (and I have noted in a previous post on this subject), the side view shot isn't as pronounced with the rays. My observations on the subject of getting shafts of light sideways is. The BG has to be dark, haze needs to be a place where it can be contained (not leak), the light needs to have punch, not spread all over the place and not bounce back from the far side. Is this true too? Is there anything else I am missing?

Thanks.

Graeme McMahon · July 4, 2012

Is this a subject covered too many times to get a reply, if so I am sorry.

Would value anyones input.

thanks,

Tim O'Connor · July 4, 2012

Is this a subject covered too many times to get a reply, if so I am sorry.

Would value anyones input.

thanks,

I think that part of the issue is that to get what you want, a much larger source is required. The brightness might be okay and the Source Four does produce

sharp well defined beam that helps make sharp rays but the area that you want to cover is more than that light can do satisfactorily. A big 10K Fresnel might be really

nice but that takes more budget; how flexible are you on adjusting the look to get more rays? If you are, what about seeing if you could get your hands on a bunch of

par cans or 2K Fresnels and see how that looks for you?

David Mullen ASC · July 4, 2012

The smoke will be the most lit-up, and look the heaviest, when looking directly at the light, but if you want to see beams, that light needs to be broken up, and it's easier to see the breaks if you aren't being flared by the source.

In terms of a sharp projected light like from an ellipsoidal, above a 750w Source-4 you'd have to go to a 800 Joker Source-4, but then, you'd be daylight-balanced, otherwise it's things like 2K SuperTroopers, but you might be better off using narrower lenses for the Source-4 and just clustering them. Otherwise, you just need to go bigger, like a tungsten 5K Molebeam or 5K PAR, and back up to maintain the sharpness.

Aapo Lettinen · July 5, 2012

I usually do this kind of stuff with 1.8K Arrisun or couple of 2K fresnels with lenses removed to get sharper beam :)

(but that's mainly because I have easy access to them, that 1.8K might be kind of a overkill for this kind of scene :rolleyes:

Something like a 1.2K hmi par would be nice if budget allows :) )

#with cc gel, of course...

Edited July 5, 2012 by aapo lettinen

Jaron Berman · July 6, 2012

Are the beams that make it through bright enough? Is the problem that the beams toward the edge aren't the same brightness as those in the middle? If so your issue is beam spread not source size. If the shafts of light themselves are spreading in too wide a direction from one another then yes - you need a larger physical source. But from the pic it looks like the beam is only really hitting the center portion of the lattice - when you're behind it does it look evenly lit?

Depending on the lens of the S4 (and whether you're talking about an ERS/Leko or S4par) you could go to a wider lens or even a smaller source - the closer to a point source you have, the wider the spread of the shafts - as the lattice is acting as your gobo literally. A tiny source like a 2K molette w/ some black wrap behind it may be what you're looking for - something to approximate an Arri X-light or my fave k5600 blackjack - both are EXACTLY the same as fresnels minus lenses - so I agree with Aapo - a fresnel minus the lens may do the trick (and be pretty cheap).

Can you hide the lights from the lens? Perhaps low? Depending on what you can hide from camera David has a great suggestion of clustering pars - maybe a row on the ground or vertical behind the column - and if you're careful about flagging beam edges you'll maintain sharp projections.

Graeme McMahon · July 6, 2012

Are the beams that make it through bright enough? Is the problem that the beams toward the edge aren't the same brightness as those in the middle? If so your issue is beam spread not source size. If the shafts of light themselves are spreading in too wide a direction from one another then yes - you need a larger physical source. But from the pic it looks like the beam is only really hitting the center portion of the lattice - when you're behind it does it look evenly lit?

Depending on the lens of the S4 (and whether you're talking about an ERS/Leko or S4par) you could go to a wider lens or even a smaller source - the closer to a point source you have, the wider the spread of the shafts - as the lattice is acting as your gobo literally. A tiny source like a 2K molette w/ some black wrap behind it may be what you're looking for - something to approximate an Arri X-light or my fave k5600 blackjack - both are EXACTLY the same as fresnels minus lenses - so I agree with Aapo - a fresnel minus the lens may do the trick (and be pretty cheap).

Can you hide the lights from the lens? Perhaps low? Depending on what you can hide from camera David has a great suggestion of clustering pars - maybe a row on the ground or vertical behind the column - and if you're careful about flagging beam edges you'll maintain sharp projections.

Thanks for your reply. Yes, happy with spread, just needed it to be brighter.

I'm not sure about the lens being taken out part of the fresnel. I said the same thing to Russell Boyd, isn't the fresnel designed to converge the light rays, and you get a definitive line, no penumbra? And are you talking about taking the lens out and blackening out the reflector portion?

Cheers

Aapo Lettinen · July 6, 2012

Thanks for your reply. Yes, happy with spread, just needed it to be brighter.

I'm not sure about the lens being taken out part of the fresnel. I said the same thing to Russell Boyd, isn't the fresnel designed to converge the light rays, and you get a definitive line, no penumbra? And are you talking about taking the lens out and blackening out the reflector portion?

Nope, I just turn the lens out of the way, or take it off from the fixture if I need the barndoors.

( Our 2K :s are mainly Desisti theater fixtures, you can just open the lock and turn the lens to the side. I use these a lot because our school has dozens of them just lying around and wasting space :lol: )

Removing the lens wastes quite a lot of light intensity, I only do it when I have to get sharper shadows with these fixtures.

You don't have to blacken out the reflector, tho. Fresnel without a lens is much like an very bulky open-face fixture with non-optimized reflector ;)

I don't know much about US rental prices, but I'd consider hmi par as the most versatile option if lekos are not enough and budget allows. You can get sharp shadows with it, and it has enough intensity to be backed off quite a lot to remove the spread :)