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-   -   Diffusion Panel vs. Softbox (https://www.dvinfo.net/forum/photon-management/27719-diffusion-panel-vs-softbox.html)

Greg Matty June 17th, 2004 05:38 PM

Diffusion Panel vs. Softbox
 
I have seen many still photographers use a diffusion panel for their strobes and got to wondering if anyone has ever tried one of those with Tota or Omni lights and the like?

I know softboxes are the normal route, but a diffusion panel can be made by me much cheaper than a good Chimera costs. With a softbox, you can't control the distance between the light unit, say a Tota, and the diffusion surface. With a diffusion panel, you can vary that distance as well as the distance of the two of them from the subject.

I am looking for a way to get my diffusion surface further from the actual light and panels would be cheaper than soft boxes.

Any thoughts on this?

Greg

Patrick Gault June 18th, 2004 03:23 PM

Diffusion panels will work fine with tungsten light.

The size of the panel and the its closeness to your subject will dictate softness -
same with a softbox . The advantage with a panel is flexibilty in contolling specular highlights. If your light is close to the panel, you get a tight specular highlight. When your light is further from the panel you get a larger and more diffused specular highlight.

Cheap experiment - buy a translucent shower curtain from the dollar store. They are approx. 6' x 6'. Great soft source. Play with light to panel and panel to subject differences. It becomes more obvious when you light something reflective.

Draw back...panels are a bit more work to control. Rather than having built in light control (that's what the box does) you will have to use flags to control light spill.

Anything you see a still photographer do can be adapted to video.

Steve Rogers June 19th, 2004 12:54 PM

Diffusion panels are an old trick that is cheap and easy to setup.

A good 4 x 4 frame and silk is not particularly expensive, I found one for 65.00

Add a cheap light like a Lowel (found one on ebay for 60.00) with barndoors and you are good to go, and you spent a lot less than a Chimera rig.

You just want to make sure that you don't have uncontrolled spill all over the place around the edges of the silk.

If your light has barndoors, just adjust them so the light covers the silk to it's edges without going over. Also if you don't have barndoors, use cinefoil to shape the light so that it doesn't spill past the edges of the silk.

As a frame of reference, this setup is less than 150.00 my Chimera speed ring alone was like 275.00, not counting the frame and softbox itself (almost 500.00) plus the light to go with it, in my case, Mole Richardson lights, 450.00+

there is certainly something to be said for doing things on the cheap.

EDIT: I notrice you seem concerned with the ability to gain a larger distance between the light itself and the diffusion material.

The diffusion material itself becomes the source of the light. Moving the light source further away from the diffusion is only going to make it harder to control spill.

you are going to gain no real benefit from adding distance.

Greg Matty June 20th, 2004 01:20 AM

<<<-- Originally posted by Steve Rogers : Diffusion panels are an old trick that is cheap and easy to setup.


EDIT: I notrice you seem concerned with the ability to gain a larger distance between the light itself and the diffusion material.

The diffusion material itself becomes the source of the light. Moving the light source further away from the diffusion is only going to make it harder to control spill.

you are going to gain no real benefit from adding distance. -->>>

Glad to see I am on the right trick here. Here is why I mentioned moving the diffusion source further from the light unit. Also, I understand that the diffusion material becomes the light source.

When using total gel frames in 10" x 12" size on my Tota's I still get very sharp shadows. Obviously I do not have talent placed properly if a wall is that close, but for the sake of arguement. . .

Well I tried that same gel frame on my 250 watt Pro-Light and if I placed the gel frame the same physical distance from the bulb as my tota, I got the same shadows. Well for some reason you can get the gel frame further from the bulb on the Pro-light than with the Tota and doing so, really softened the shadows. I don't know what the physics behind this is but it was impressive to see such a difference. So what I need with the Tota is a way to get the diffusion more than 6" from the bulb. A Chimera soft box would probably be closer to 12" and that may be all I need but the arm on the Tota gel frame isn't long enough. That is what led me to research diffusion panels and the author of the book did mention being able to control the distance between the light and diffusion source.

I agree that spill will be much more difficult to control but it is nice to at least have the option to change that distance, even if just a little bit.

Greg

Patrick Gault June 20th, 2004 06:15 AM

Two things make your light softer.

1) The size of your source. The larger the source the softer the light. As you know, the source in this case is the diffusion.

2) The distance of the source to the subject. The closer the source to the subject, the softer the light.

A 12" x 12" piece of diffusion will not soften much.

The reason the Lowel Pro appears softer:

a) The pro has diffused glass covering the globe, so the light is double diffused when it passes through the diffusion. I use the same trick with my medium photoflex softbox. The light passes through two pieces of diffusion when leaving the softbox. I then set up a larger piece of diffusion (3' x 4') about 18 - 24" in front of the softbox suspended from a boom pole. I now have a much softer source. Some would say this is overkill. I think it makes a big difference.

b) The size difference between the pro and the diffusion is greater than the size of the tota and the diffusion.

c) Perhaps the different wattage of the globes helps with the appearance of softness.

Charles Papert June 20th, 2004 12:40 PM

It's very common on big sets to use a double diffuser setup like Patrick described. A heavy diffusion near the light and a lighter one in front of that will create a nice big soft source. And as mentioned earlier, there will be plenty of spill on the set; this is indeed why the Chimera was invented. I've seen upwards of 6 separate flags, each with their own stand, in use cutting down the spill on this sort of setup!

Jack Barker July 3rd, 2004 09:50 AM

Let me jump in here with some additional questions, since I am in the final stages of putting together my own light kit and diffusion vs. softboxes is of great interest to me.

Most everybody agrees that softboxes do a great job at providing soft light for video, but they are also expensive, cumbersome and require a cheaper dedicated light source, or giving up one of your hard lights in situations where soft light is called for. What if you choose a so-called zip light as the source for diffusion? It's already indirect. Most have a gel frame holder as a part of the fixture and you can use an additional universal gel frame in front of that for under $50 and mount it on the same stand as the zip light. Of course, the zip light can be used as a stand-alone source softer than a fresnel, but not quite a softbox.

This is indirect light with two layers of diffusion, but will this combination give decent soft light? Can cinefoil/blackwrap take care of the spill?

Charles Papert July 3rd, 2004 10:36 AM

I assume that by zip light you mean these, Jack. They work fine, although they don't necessarily have as much bang for the buck (aka the output for the wattage) as a softbox, due to the bounced light. And the size of the source is somewhat smaller than a softbox, thus less soft.

Jack Barker July 3rd, 2004 10:48 AM

Charles, those are exactly what I mean. Regarding output, it's also true to say that the final output through a Chimera is reduced - some light is diffused by the fibers, some light is reflected back into the soft box. But even the smallest of theses zip lights start at 1K and you can lamp down from there.

My question was directed to the "quality" of the indirect light once it had been through 2 or 3 layers of difussion. And while most manufacturers make an eggcrate accessory for their zip lights, I was wondering about other methods of control.

Wayne Orr July 3rd, 2004 10:48 AM

The "zip" light you refer to is generally used to provide fill light, rather than as a key source. It does not provide the same quality of light as a softbox (or shooting through silk or muslin). Also, as has been mentioned, the large face of a softbox is one reason the light is so attractive. To get to a large source with a zip light, you need to get into the 1K-2K lights, which are much heavier and require amperage that is not available in most non-professional situations. Zip lights are great for lighting modest sized green screen backings, BTW.

One reason soft boxes are so popular is the limited amount of gear required to set one up, and the ease of moving the set-up should you need to for some reason.

A couple other comments: A 250 watt is really limited when shooting through diffusion or silk. More firepower would be better. For instance, using a 650 watt Arri fresnel. First set your diffusion, such as a 4x4 sheet of 216 in a frame, so it is just out of camera. Set the focus adjustment on the fresnel to flood position, turn the lamp on, and walk the lamp in toward the diffusion until you see the circular pattern from the fresnel just filling the frame, edge to edge. This is maximum effieciency. Tweak to taste, and start adding flags to kill spill. (With a softbox, you just turn it on and walk it in to where it is just out of camera, and you are set. You can easily move it around your subject to see the effect of the light from different angles)

Wayne Orr, SOC

Jack Barker July 3rd, 2004 11:17 AM

Wayne, you have an unerring radar for sniffing out my lighting questions on the boards! Do you have a bug in my computer, or something?

I know in my heart of hearts that I am looking for someone to give me the answer that I WANT to hear, rather than the answer I NEED to hear. I'm first and foremost a designer and that colors my view of the world and lighting equipment purchases. I think the Lowel Pro-Light is a clever design. I also think that the zip light is clever and I'm just hoping that someone will tell me that it will work. Alas.

I also know that you are a great proponent of the JTL Softlight kits and the prices are great, but I've been resisting because they don't look very well designed or built and it's money spent on a fixture with only a single purpose. I was just hoping to find a way to buy 4 or 5 hard lights and soften 1 or 2 without the cost of a softbox.

Wayne Orr July 3rd, 2004 01:12 PM

<<<-- Originally posted by Jack Barker : Wayne, you have an unerring radar for sniffing out my lighting questions on the boards! Do you have a bug in my computer, or something?

Search your computer for the notorious "Wayne Orr" cookie, Jack.

"I also know that you are a great proponent of the JTL Softlight kits and the prices are great, but I've been resisting because they don't look very well designed or built and it's money spent on a fixture with only a single purpose. I was just hoping to find a way to buy 4 or 5 hard lights and soften 1 or 2 without the cost of a softbox."

I hope the group will notice that you brought up the JTL kit, rather than me. I know I sometimes sound like a shill for the company, but it certainly is not the solution to every problem. That said, I believe you can find a JTL softbox as a single unit on e-bay for under $200.00. It might help you. Their design is just fine; I can't imagine what your problem is there. The quality is very reasonable for the price, as I have always said. It is a good kit for a serious amatuer, and a professional who has adequate time to set up and tear down, and won't be giving the kit serious abuse. I took the kit with me to Panavision yesterday to photograph a CineAlta camera on a pedestal dolly for a class I am teaching next week, and the lights performed admirably, as usual. But of course there are other options.

BTW, buying "4 or 5 hardlights" may not be the best way to spread your dollars around, but then, I don't know what your intended use is for your lighting gear.

Wayne

Jack Barker July 3rd, 2004 03:35 PM

Let me change the subject (slightly) before Wayne chews me off at the elbows!

Rules of thumb:
1. Use the largest softbox practicable.
2. Get the softbox as close to the talent as you can.

If you can get the box close in because your camera is 10' back and you are using a long lens, then shouldn't you use a lower wattage lamp so as not to fry the talent? Would a 300W fresnel in a 24 x 32 box (I'm thinking Photoflex Cinedome here) be a reasonable combination?

Wayne Orr July 3rd, 2004 06:56 PM

<<<-- Originally posted by Jack Barker : "Let me change the subject (slightly) before Wayne chews me off at the elbows!"

LOL. Not to worry, Jack, I'm cutting down on my red meat intake.

"Rules of thumb:
1. Use the largest softbox practicable.
2. Get the softbox as close to the talent as you can."

Absolutely correct.

"If you can get the box close in because your camera is 10' back and you are using a long lens, then shouldn't you use a lower wattage lamp so as not to fry the talent? Would a 300W fresnel in a 24 x 32 box (I'm thinking Photoflex Cinedome here) be a reasonable combination?"

Sounds perfect, Jack. But that's about the bottom limit, wattage-wise. I flew to Florida about a year ago and shot an interview with Chick Corea. I used a Photoflex with a 300 watt lamp, and as I remember, I added an extra sheet of diffusion to the front of the box. The softbox ended up little more than a foot from Chick, and he was cool, man! I used a linen napkin, which I hung on a bellman's trolley, for a bounce fill. Just enough. Added a nice blue (like Roscoe 69) to the background, and I was good to go. I was shooting at f2.8 using a Sony DSR 500.

I set almost everything up before Chick arrived, and just fine tuned it when he sat down. Great thing about the softbox: Chick was wearing glasses and I had to the raise the softbox a bit to lose the reflection. I couldn't do that as easily punching light through a 4x4 frame on a C-stand.

You'll do fine with that Photoflex combo, but you still might consider a larger wattage lamp that you can bulb down (or scrim down) to lower wattage. You wouldn't want to be stuck with a speed ring for a smaller light, and then need a bigger unit.

Wayne

Jack Barker July 3rd, 2004 10:46 PM

Chick Corea! You met Chick Corea? Did you know that he had a 2 hour documentary playing at the Avignon Film Festival in NY? Did you have anything to do with it? Can I have your autograph while you're still relatively unknown? ;)

So, now I should by two $100 speedrings (one for a 300 fresnel and one for a 650 fresnel - I'm getting a pair of each) or just one for the 650 and lamp down as necessary, right? I know there is a 500 watt lamp for the 650 and there must be other lamp wattages between the two. Is there a 400W? That would cover just about every contingency, wouldn't it? 3, 4, 5 and 650. With scrims, I could have almost infinitely variable softlight and I really like the CineDome.

I'm so happy, now!


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