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#1
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How to determine distance from KEY light to subject
I've read a lot about where the key light can be positioned as far as
angle and elevation are concerned, but I'm uncertain as to what distance I should place it from the subject. I'd appreciate some advice. |
#2
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How to determine distance from KEY light to subject
I've read a lot about where the key light can be positioned as far as
angle and elevation are concerned, but I'm uncertain as to what distance I should place it from the subject. I'd appreciate some advice. Your exposure should be based on your fill light. From there it all depends on how contrasty of a lighting ratio you want. |
#3
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How to determine distance from KEY light to subject
I've read a lot about where the key light can be positioned as far as angle and elevation are concerned, but I'm uncertain as to what distance I should place it from the subject. I'd appreciate some advice. they need to as close as you need to get the lighting effect you desire. With modern lightboxes and scrims you get them as close as you can till you see it in your view finder then back off a couple inches. for moderately reflective surfaces such as human skin commercial photogs tend to use a light source twice as big as the subject. in many considerations of photography there a give and take, to get some effect you loose on something else, stop down a lens and get more depth of field but need more light or longer shutter, open up to get a shallow depth of field, use a slower shutter but risk camera shake. In lighting you similar effects. Move light in close and you have a shallow depth of light, (consider the inverse square root on exposure, now if your light is 2 feet away and your subject has 16 or 18 inches across will the left shoulder have the same exposure as the right, one mistake folks make with window light images is they put the window too close) but it is softer as the size ratio of light source to subject can be 1:1 or better. Move it out and get more depth of light but more contrast, smaller spectral highlights, more rapid highlight to midtone to shadow transition. sometimes the equipment suggests or dictates usage styles, they used to place those huge 2,000 watt spot lights as close as 18 inches (and with barn doors and feathering could actually achieve a soft light. Those 18 inch parabolic flood lights were used typically about 3 feet away. When they introduced strobes and umbrellas you had to be careful to not get the damn shaft in the image. this reply is echoed to the z-prophoto mailing list at yahoogroups.com |
#4
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fill based/key based was: How to determine distance from KEY light to subject
I've read a lot about where the key light can be positioned as far as angle and elevation are concerned, but I'm uncertain as to what distance I should place it from the subject. I'd appreciate some advice. Your exposure should be based on your fill light. From there it all depends on how contrasty of a lighting ratio you want. what if he wasn't using a fill light? the fill based exposure system is a very old fashioned concept, predicated on methods of development and exposure designed for black and white photography, and hi volume studio portraiture. with black and white photography you had the luxury of varying the development times, so the rule was, "expose for the shadows and develop for the highlights." modern color, especially transparency, and even more critical with digital, requires excellent highlight exposure. If you blow out your highlights you will never get anything but white. the fill based system required a darkroom or lab that was aware of what you were trying for. They had to adjust the print exposure to print down to the level of highlight detail. If you moved your lights around for more or less contrast, more or less dramatic imagery your lab had to recognize and adjust the exposure of the print cause the fill light was set and never changed. However a system of exposure based on the highlights would mean that the photog controls the image from the camera level, he places and meters the key light, and adjusts the reflector, or if you are still a fill light user... and sets that level to capture the effect desired. the lab is instructed to expose for the best highlight and print the entire series the same, if the photog is doing their job then each print will come out as intended, without depending on a lab guy to pay attention, to fix things. this reply is echoed to the z-prophoto mailing list at yahoogroups.com |
#5
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How to determine distance from KEY light to subject
I appreciate your advice.
I've been reading (in "Fred Archer on Portraiture"), that the key to subject distance should be determined by observing the quality of the highlights produced on the face. If the key is too close, the highlight will look "washed out;" if the key is too far, the highlight will flatten out and won't notice, and if the key is at just the right distance you should see a well-defined highlight giving good modelling. The book was written in 1948 - perhaps the advice applies only to tungsten lighting (I'm using strobes)? Thanks again. this reply is echoed to the z-prophoto mailing list at yahoogroups.com |
#6
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fill based/key based was: How to determine distance from KEY light to subject
what if he wasn't using a fill light?
Then he needs to learn about portrait lighting. the fill based exposure system is a very old fashioned concept, predicated on methods of development and exposure designed for black and white photography, and hi volume studio portraiture. Did the laws of physics change and nobody told me? It's not old fashioned, it's the right way to do things and get predictable results every time. modern color, especially transparency, and even more critical with digital, requires excellent highlight exposure. If you blow out your highlights you will never get anything but white. What moron does portraits for people on slide film? the fill based system required a darkroom or lab that was aware of what you were trying for. They had to adjust the print exposure to print down to the level of highlight detail. If you moved your lights around for more or less contrast, more or less dramatic imagery your lab had to recognize and adjust the exposure of the print cause the fill light was set and never changed. I never had to tell my lab anything. The negatives were properly exposed so that automated equipment made perfect prints. |
#7
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How to determine distance from KEY light to subject
I've been reading (in "Fred Archer on Portraiture"), that the key to subject distance should be determined by observing the quality of the highlights produced on the face. If the key is too close, the highlight will look "washed out;" if the key is too far, the highlight will flatten out and won't notice, and if the key is at just the right distance you should see a well-defined highlight giving good modelling. The book was written in 1948 - perhaps the advice applies only to tungsten lighting (I'm using strobes)? the shape of light matters little where it came from. So the type light makes some light styles easier than others. IE: strobes are much better for large soft systems cause you need a lot of power to push through a layer or two of fabric and spread it around like a sprinkler system, whereas hot lights, and lots and lots of it wrapped in layers of fabric are a fire hazard. spot lights make good use of tungsten cause it concentrates every bit of energy and focuses it right on the small area you aim it at. for a through explanation of how light source size and distance effects the rendering of a subject I highly recommend Dean Collins 3D lighting. he breaks things down into separate highlight ratios and shadow ratios, spectral highlights to midtones, penumbra transition rate etc. This short but packed video explains why a photog should be more concerned about their highlights, how they render shape and texture, and that what may appear to be a problem with shadows is usually a symptom of a bad highlight. this reply is echoed to the z-prophoto mailing list at yahoogroups.com |
#8
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fill based/key based was: How to determine distance from KEY light to subject
what if he wasn't using a fill light? Then he needs to learn about portrait lighting. so there is no good lighting without a fill light? Is this like a religious dogma? what lights do is place highlights, that is all they do, they are light sources. using a fill light means you have more than one source of light coming from more than one direction. the fill based exposure system is a very old fashioned concept, predicated on methods of development and exposure designed for black and white photography, and hi volume studio portraiture. Did the laws of physics change and nobody told me? It's not old fashioned, it's the right way to do things and get predictable results every time. The point behind a system of doing things is to get predictable results. The laws of physics haven't changed, but when a system of beliefs comes a religion then you can't see any other way. modern color, especially transparency, and even more critical with digital, requires excellent highlight exposure. If you blow out your highlights you will never get anything but white. What moron does portraits for people on slide film? A. Morons that work for Time/Life Magazine, Nat Geo, Sports Illustrated, any of a thousand magazines and stock agencies in the day. B. Morons that have a client that comes in and says that corporate wants a portrait but their specs say they require a transparency. C. Morons that wanted control of their imagery, what they get on film is what they shot and not what some other moron in a lab whom they never met decides to do with their image. D. Morons with digital cameras cause those CCD and CMOS chips act more like transparency film than negative. the fill based system required a darkroom or lab that was aware of what you were trying for. They had to adjust the print exposure to print down to the level of highlight detail. If you moved your lights around for more or less contrast, more or less dramatic imagery your lab had to recognize and adjust the exposure of the print cause the fill light was set and never changed. I never had to tell my lab anything. The negatives were properly exposed so that automated equipment made perfect prints. So you never shot a rim light profile? or deviated from your standard 3:1 lighting? Look, I spend most of my life with a fill based system. I used a separate power pack for a bank of heads that was my fill system. I heard of folks who put their fill light bank on a voltage regulator so their f/6.3 was 6.3 as sure as IBM sent out dividends to widows and trust fund orphans. Heck I even had these way cool plans, I was going to make a hi key background wall with four flash heads smoothly lighting this coved wall, and that white wall was also going to be my fill light for the low key other side. But the fill based system is predicated on a basic fact. You set your exposure based on your threshold exposure, the minimum exposure to get maximum black. And once set it never changes, you install a screw on the lens barrel so the idiot assistants can't change the f/stop. Then if you want a more dramatic lighting you bring in the key light closer to raise the ratio. move from a 3:1 to a 5:1 for a dark dramatic image, a rim light profile. But your lab man must recognize that is what you are doing, cause if they give you the same shadow detail as the 3:1 kiddie pics you are going to get a washed out hi-light. your perfectly exposed machine prints still require a lab guy to adjust exposure on each neg, usually using a video analyzer. That's why we paid pro labs 60 -70 cents a 4x5, cause we needed someone intelligent hitting the key pads to adjust. Fill based systems made perfect sense in black and white days, they were big on shadow detail, you gotta get it on the neg, so you made sure it was on the neg, the highlights you could develop for by pulling the neg, the base exposure would develop just as fast as the highlights but end early, the dense parts would keep building so you could pull the neg before they got too dense, or you could print down with a flatter paper, or you could reduce the neg. In color, in digital you only have one chance to get detail in the highlights, when you shoot it. Yeah sure with RAW capture and 16 bit files you could have two stops leeway (which is getting close to color neg results) but still. Fill light systems made perfect sense back in days when the only artificial light was hot lights, which required highly specular spot lights and reflector bowls to redirect, to concentrate, to focus every bit of light onto the subject cause film was slow, lenses were slow and it took an awful lot of light to expose an image, soft lights were just not practical, in the beginning days of photography, which was invented before they invented electrical lights, they used soft light, ONE light systems, northlight windows or tents to shape the light that same way, of course in those days the client had to put their head in a brace to keep from moving too much. So as soon as artificial lighting came practical, (arc lights in metal boxes with barn doors) they invented blown out specular highlights and then invented the fill light, to FILL the shadows they created. And ever since this kludge fix has been THE WAY a portrait must be done. There can't be any other way, or you're just not knowledgeable in the proper way. Look, commercial guys don't use fill lights, they hang a big assed softbox, twice as big as the subject, they get large diffuse highlights and enough detail in the shadow areas cause the spectral to midtone and the midtone to transition is so smooth and gradual. Its based on the laws of physics... |
#9
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fill based/key based was: How to determine distance from KEY light to subject
zeitgeist, what is the purpose of attempting to conduct an intelligent
dialogue with Randall Ainsworth? "zeitgeist" writes: what if he wasn't using a fill light? Then he needs to learn about portrait lighting. so there is no good lighting without a fill light? Is this like a religious dogma? what lights do is place highlights, that is all they do, they are light sources. using a fill light means you have more than one source of light coming from more than one direction. ... etc. ... |
#10
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fill based/key based was: How to determine distance from KEY light to subject
zeitgeist, what is the purpose of attempting to conduct an intelligent
dialogue with Randall Ainsworth? I still disagree with him. |
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