56 vs 30 inch moonunit

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Archive 2007 · 56 vs 30 inch moonunit

xrayvision
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p.1 #1 · 56 vs 30 inch moonunit

I am trying to decide on which to buy. I suppose both would be a good answer

Please correct me if I am wrong. The larger 56 inch unit would be good for getting whole body shots and the small one more suited to shadow free head and upper torso shots.

Thanks for your input!

charlie

Nov 09, 2007 at 12:38 AM

tmronin
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p.1 #2 · 56 vs 30 inch moonunit

dude...at $120 for both, it really isn't a question.

get both and get shootin'!

Nov 09, 2007 at 02:13 AM

Jonathan H
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p.1 #3 · 56 vs 30 inch moonunit

I think the 56" is way too large to ever use conveniently. You don't really see it until you actually assemble it for the first time.... it's immense.

Nov 10, 2007 at 05:22 AM

cgardner
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p.1 #4 · 56 vs 30 inch moonunit

The moon unit is designed to be used with a ring light. If a ring light is around the lens it doesn't create shadows the camera can see. That creates a visual riddle similar to the one which asks, "If a tree falls in the forest and there is nobody there to hear it, does it make a sound?" If a light doesn't create any shadows the camera can see, do you really need a huge diffuser on it?

But if you plan to use the moon unit as a conventional key light and have low ceilings think about how high you can put the big one above the eye line of a six foot tall subject in your studio space.

Chuck Gardner

Nov 10, 2007 at 08:14 PM

tmronin
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p.1 #5 · 56 vs 30 inch moonunit

Jonathan H wrote:
I think the 56" is way too large to ever use conveniently. You don't really see it until you actually assemble it for the first time.... it's immense.

i beg to differ - i have used the 56" in bathrooms...it depends on how badly you want to use that size of mod in the space you have. you think that's immense - wait until you see a 7' dome or 60" umbrella in use - at least the moon unit is pretty flat and narrow.

i guess you don't use anything above 36" cuz it's "too large to ever use conveniently"?

Nov 10, 2007 at 11:06 PM

Paul Buff
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p.1 #6 · 56 vs 30 inch moonunit

Nov 11, 2007 at 06:42 AM

cgardner
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p.1 #7 · 56 vs 30 inch moonunit

Paul Buff wrote:

I beg to differ. There is a huge difference in direct ring flash and with Moon Unit.

Depends on how soft you want your shots, but I personally prefer the 56" because you can keep more distance between you and the subject.

Paul Buff

My statement was in the context of the practical differences between the two sizes of moon units. You are certainly correct that there will be a significant difference between direct ring light and a ring light with a soft box attached, just as there would be in comparison of direct flash vs any softbox. But you would see the difference more on a subject with hair than you would with one who is bald because clues provided by the perceived texture of the hair (shiny and textured with direct flash and dull and flat with the SB) and other specular highlights will be a big part of what your brain uses to make the determination whether the light is "hard" or "soft". But how much difference would you see between a 30" and 56" moon unit (the question being asked)? As you seem to imply, that would depend on the distance to the subject.

The perceptual aspects of photography have always been an interest of mine. In the mid-1970s I worked a few years at National Geographic photomechanical lab creating 4/C relief plates for physical maps you see in the magazine from B&W artist renderings in pencil and it gave me a great deal of insight into the way the brain is fooled into thinking a pattern of contrast and color is a 3D object and a great deal of respect for the artists who were able to create that illusion with a pencil, a piece of paper, and a colorwheel telling them what percentages of CYMK needed to create a specific color and tone. The value the artist specified had to be delivered within +/- 2% or we started over. My part of the magic was manipulating the B&W halftone process to create the huge range of specified CYMK color values from the single B&W pencil rendering. It required doing things the halftone process was never designed to and is also one of the reasons I understand process control and color management so well. That background, plus having earlier taught myself the Adams zone system, are the reasons why I am process control oriented in my approach to things and believe that to really understand lighting one first needs to understand at some level -- intuitively or by education -- how the brain converts a pattern of contrast in a photo into a perceived mental image that a nose is large or small, smooth or bumpy, etc.

From seeing light hit objects with our stereo vision our brains are conditioned to recognize patterns of shadow to represent the shape and texture of objects. "Soft" is a perception created in the brain from the clues provided by patterns contrast the eye sees. With the possible exception of Laser dermabrasion light does not change the physical properties of a nose to make it more spongy and resilant (i.e., soft) or smoother the shadow the nose casts simply makes it appear less tall, steeply sloped, or less bumpy.

When a key light is placed to the side the nose will cast a significant shadow and the brain is provided with many clues to what its shape is from both the highlights and shadows. The shadow side defines the overall shape, but provides few visual clues regarding texture. The highlighted side blends in with the other surrounding skin areas and absent any color differences creating color contrast the highlighted side provides few clues regarding the overall shape. But what happens on the highlighted side is that every tiny variation in height will create a small shadow to some degree, depending on angle the light hits. It is those secondary shadows created by relief within the highlighted side with give the brain clues regarding the texture of the object.

Map relief artists understand how the brain is fooled and will define the overall shape and amplitude of a mountain by drawing the shadow it would cast when hit by the sun at 45 degrees, then add smaller bits of shadow detail over on where the sunlit side of the mountain is to define its texture. The same is true for any fine artist who creates images on paper or canvas, which is why every photograher should take some drawing classes. You are a very accomplished artist Paul and based on the ratio of photos to paintings I've seen you make seem to exercise your muse more with a brush than a camera. But I suspect somewhere long ago you started like most artists trying to make a bowl of fruit look like more than a collection of flat colored disks and by now understand the relationship of shadows to shape and texture intuitively when you draw or make a photograph.

When a face is hit with flat light there is no significant nose shadow to provide a clue to what shape it is. In fact that is exactly why flat lighting is used in fashion and glamor work, to hide the nose in plain sight so it disappears from the consciousness of the viewers brain. If the viewer doesn't see the nose they will pay more attention to the eyes and mouth which are selling the lipstick and the eye shadow. There are still some shadows on a nose, even with ring light, but they are of the secondary shadow within highlight variety which the brain uses for clues regarding texture.

So to the degree that a bare ring light vs a 30" moon unit vs a 56" moon unit will change the perceived appearance of a flat lit face it will be a result of how the appearance of the secondary texture clue shadows on the face change on any forward protruding, overhanging parts of the face where the flat light is casting visible shadows: lips, the base of the nostrils, the teeth and inside of the mouth, eyebags and lashes, hair hanging down in front of the face, etc. But the bigger clue regarding the overall shape of the height of nose will be missing with all three methods.

In any case the question was regarding choosing the 30" moon unit vs the 56" and you seem to have answered that question indirectly by implying the main difference in practical terms is that you can get similar lighting from further away from the subject's face by using the 56" unit. That is actually a very valid concern if it it is used as a ring light on the camera because facial perspective is controlled by camera / subject distance and you need to be 7-9 feet from the subject's face, regardless of what focal length lens is used. So in that respect the ideal moon unit size would be the one which gives the photograher the desired look to the lighting from a distance of 8 ft.

How about sending me a ring light and a couple of moon units so I can do some testiing?

Absent that why don't you humor me and shoot the same subject from a distance of 8' with ring flash and both size moon units. If you have a mannequin head shoot one series with hair and a second without and you will see the difference the hair makes to the overall perception of the illusion of "Softness". Shape and texture in a photo is really all a figmentation of our imaginative

Chuck

Nov 11, 2007 at 01:30 PM

Ravitej
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p.1 #8 · 56 vs 30 inch moonunit

What a great idea, Chuck. Haven't seen a test like that and it would be quite valuable to anyone considering the ABR / Zeus and moon units. I think your perimenters are right on for the test. Wonder if Paul Buff or one of his crew would do it. Either that or start a Chuck Gardner ringflash fund. Knowing how much Chuck would get into it, who wants to chip in?

Nov 12, 2007 at 11:55 PM

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p.1 #9 · 56 vs 30 inch moonunit

cgardner wrote:
The moon unit is designed to be used with a ring light. If a ring light is around the lens it doesn't create shadows the camera can see. That creates a visual riddle similar to the one which asks, "If a tree falls in the forest and there is nobody there to hear it, does it make a sound?" If a light doesn't create any shadows the camera can see, do you really need a huge diffuser on it?

Chuck Gardner

Chuck, much of your writing on this forum has to do with perception. Keeping with that spirit, let's take a tongue-in-cheek look at your paragraph above.

Sentence #1) The reader's perception right off the bat is that you are talking about the moon unit and ring light separately, "The MOON UNIT is designed to be used with a RING LIGHT". This sets the scene for the reader to follow through the rest of the statements.

Sentence #2) "If a RING LIGHT (here already perceived to be referring to the ring light only) is around the lens it doesn't create shadows the camera can see." This statement is not only untrue*, but also plants information in the reader's mind that will be used as a pivoting point in the next line.

Sentence #3) Here's the lead-in: "That creates a visual riddle similar to the one which asks, "If a tree falls in the forest and there is nobody there to hear it, does it make a sound?"" Chuck, you've gone existential on us!

You speak often about leading a viewer's eye through a photo, in this case you seem to lead the reader to draw an analogy between the tree scenario and the use of a ring light along the lines of, 'If a ring light creates a shadow, and the camera can't see it... does it need to be softened?'.

Sentence #4) Here you spell out your analogy for the daft out there who might not have gotten it the first time around. "If a light (still in the readers mind as without the moon unit) doesn't create any shadows the camera can see, do you really need a huge diffuser on it?" Okay, this brings it all home for the reader, who is now perceiving this whole paragraph as you questioning the need for a moon unit at all.

Take armed with this information, the reader then perceives your next reply to Mr. Buff, "My statement was in the context of the practical differences between the two sizes of moon units. You are certainly correct that there will be a significant difference between direct ring light and a ring light with a soft box attached, just as there would be in comparison of direct flash vs any softbox." as you doing some major back-peddling.

* On the point of a ring light being around the lens, and thus creating no shadows seen by the camera: You know as well as I do that this isn't the case. The only way to get truly shadowless lighting from a hard light source is to have the light coming from a point directly at the center of the lens. Any variation from that point will result in some type of shadow visible to the camera, however small it may be. Distance to subject and distance from subject to background will determine the angles involved and how much shadow is visible. The flash tube is two or three inches away from the lens, and any point on the flash tube will create an opposing shadow. This is why one of the tell-tale signs of a direct ring flash can be a thin halo of shadow surrounding the subject on all sides. Now, with a broader light source such as the moon unit, the angle has changed, or rather, the light is coming from a number of angles allowing some angles to fill the shadows of light coming from other angles (whew, that's a lot of angles!). We have all seen how that works from your own diagrams (you know, the yellow ones with the little blue light rays being parallel, then not).

Anyway, I'm just poking some fun. Maybe I'm just in an argumentative mood. At any rate, I mean no harm and appreciate your contribution to this forum. Please feel free to completely blast me out of the water!

- Jeff

Nov 13, 2007 at 12:33 AM

cgardner
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p.1 #10 · 56 vs 30 inch moonunit

Jeff,

You are correct that I over generalized about ring light being shadowless. There of course no such thing as a shadowless light source, but the point I wanted to make was that that the fewer shadows you actually see the light source create, the less you need to worry about diffusing it. I was actually only thinking in terms of the difference which would be seen between the 30- and 56-inch Moon Unit SBs not direct vs the sofboxes when framing my initial reply, but I'll be happy to I'll cop a plea to over-generalized explaining of why diffusion is necessary at all and "back-pedalling" to address the differences between direct and diffused ring flash if you that's what you want to call it when Paul pointed out that I'd failed to consider its differences. I did make an attempt to clarify and expand on how shadows are perceived my and hopefully Paul will shoot a comparison test at 8ft so we can see the differences between the three methods at normal portrait distance.

FWIW - My frame of reference is learning flash with two direct undiffused speedlights which taught me to control perceived softness with a combination of key light very carefully placed to avoid unnatural looking shadows and fill to reveal the shadow detail. In six years I've been hanging out on and contributing to lighting forums the most common lighitng misconception I see beginners make is to assume that when it comes to modifiers bigger is better. They buy the biggest modifier they can afford and then wonder why their lighting is flat and lifeless. So I like to make people who ask how big of a softbox they need to stop and consider why a light needs to be modifed and how a softbox actually makes a shadow soft.

The latest knee-jerk reaction in lighting seems to be buying a ring light without really understanding how they work or what they are really useful for. Credit Paul Buff for the "me too" ground-swell of ring light usage by making them so affordable anyone can afford one and practical in the sense that a softbox can be added so a ring light can be used like any Octobox. Don't misunderstand, I think the ABR ring light and Moon Unit are great, but the only things I would use one for are fill light outdoors when overpowering the sun because I don't like the ring characteristic catchlights in close-ups or the big centered catchlights. Outdoors I could shoot from far enough away that the catchlight wouldn't be objectionable, but I have other tools which will do the job of fill just as well which I why I haven't jerked my knee in the direction of Nashville.

As I thnk I mentioned previously ring lighting and other flat styles are used in fashion to intentionally create a blank canvas for the make-up artist or to take the focus off the face and put it on the clothes or whatever else is being sold in the ad. So what happens when Joe Megapixel buys a ring light to take a fashion-style shot of Mrs. Megapixel but she isn't wearing professional make-up? More likely than not she winds up looking like a blank canvas with a face as flat and round as a dinner plate. We can sit around and debate exactly how soft and flat a dinner plate the face will look like with direct vs 30-in. vs 56-in. moon units, but its a pretty pointless debate if they all make a person look bad.

So to the extent I make people think twice before throwning money at lighting solution I think they don't fully understand I'll cop a plea for that too. All my advice has a money back guarentee and I've never once had anyone ask for a refund

Chuck

Nov 13, 2007 at 02:16 AM

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p.1 #11 · 56 vs 30 inch moonunit

Chuck,

I think you're doing a great thing by passing on the knowledge and perspective that you have. I think we share a passion for teaching and explaining. Do you ever run into the same problem that I often do where you really want to explain something in full detail to someone, and you just know that the surface answer they are wanting will mean so much more if they understand the full picture, but they just don't have the patience to listen? My wife drives me crazy with that! There are so many questions that people just float out there, like "Do you think we should take out that wall separating the kitchen from the butler's pantry?" I feel the need to start explaining framing and load bearing and so on, really probably more than is necessary. But, I enjoy it, and I can see that about you, too.

I am with you on the "FWIW" paragraph. Questions come up all the time on the forum about what setup to use or what equipment to buy, and I just think that if they took a minute to think about what they were trying to do, it would be pretty clear. Please note that I am in no way judging, as I have plenty to learn as well. Also, there are just some things that are more concrete once you have done them yourself, and that is a great reason to ask around for input from those with firsthand experience.

So, keep up the good work and try to ignore my childish horsing around.

Nov 13, 2007 at 03:57 AM

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p.1 #12 · 56 vs 30 inch moonunit

I am resurrecting this thread because I have just ordered the Zeus pack system with a standard head and a ringlight. I also ordered the 30" Moon Unit.

Paul partially answered the question by stating the 56" Moon Unit could be used at a greater distance than the 30".

"I personally prefer the 56" because you can keep more distance between you and the subject."

I would think the opposite would be true. Wouldn't the light be stronger and more concentrated with the 30" unit, and as such be more effective at a greater distance?

Aug 06, 2008 at 09:51 PM

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p.1 #13 · 56 vs 30 inch moonunit

I give up. Just spent 10 minutes posting a complete reply to all this, posted it and it immediately disappeared. Happens over and over.

Aug 07, 2008 at 02:53 AM

kkertz
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p.1 #14 · 56 vs 30 inch moonunit

Paul, you might want to type your replies in TextEdit. Then just copy and paste your thoughts in the reply box. If you lose it, no worries, just cut and paste again.

Kevin

Aug 07, 2008 at 03:18 AM

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p.1 #15 · 56 vs 30 inch moonunit

I have the 30" MU and use it a lot for fill light. I think the 56 would be even better for large, soft fill light, or main light for an appropriate subject.

All modifiers have advantages and its better to have too many than not enough.

I am thinking about setting up two 42X78" skrims with an AB800 behind each with about 24 inches between them for me to stand. And then there is clam shell lighting, with an giant SB above the camera and a 10X36 strip box under the camera.

Aug 07, 2008 at 03:59 AM

SKYWESTR
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p.1 #16 · 56 vs 30 inch moonunit

I'm only resurecting this thread because I'm picking up an ABR w/56" MU on Friday. Besides my 550ex w/cybersyncs this is gonna be about my only light source until I can panhandle more money.

I'm quite sure my first foray into studio light will suck but I'll do my best to post as many cool photos here as possible.

Carl

Aug 21, 2008 at 01:09 AM


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