The ten principals of flash photography

Mar 22, 2024 | Technical

“Show Notes”

The ten principals of Flash Photography

These apply to all types of light including natural light.

1. There are only two types of light, hard light and soft light. Hard light is the sort of light you would get at midday in a sunny place. Very contrasting light. The imagine it’s a cloudy day then the light becomes soft.

2. The closer the light is to the subject, the softer the light. And so the further away the light is to the subject the harder the light.

3 As you move the light source from the subject, the light intensity drops very quickly. If you double the distance the light is from the subject you quarter the amount of light that reaches the subject.

4. The harder the light is the more contrast you have. Contrast is highlights and shadows. The harder the light the further away from each other the highlights and shadows become. So in soft light the highlights and shadows are closer and have more variations in between.

5. A shadow will have a hard edge with high contrast from a hard light. It will have a soft edge and low contrast from a soft light

6. Light can be direct or indirect / bounced. A direct light comes straight from the light source. Indirect light is often bounced off something like a ceiling or reflector. By reflecting the light you are changing the size of the light source.

7. Light travels in straight lines, unless it meets an obstruction. So particles of light behave like snooker balls, they bounce off objects. Grids are objects that go over lights to channel the light to prevent it spreading out and as hard light is becoming more popular, so are these.

8. Light coming from the side of a subject will show more texture than a front on light. You can see this in landscape photography, when photographers tend to like early morning or late evening light, when the light is coming from the side, which gives more texture.

9. Flash light varies in speed. The speed of a flash is measured using it’s T number. If you are capturing moving subjects, like sports then you need very fast flashes so that you freeze the action

10. If using flash outside, especially on a sunny day you will need a much more powerful flash than you would indoors. So for indoor photography you don’t need that much power from your flash.

“Show Transcription”

Sam: Hello, Marcus, how are you on this good day?

Marcus: It might be a good day for you. But not for me. Yeah, I’m very well, thank you so very well, indeed. Yes.

Sam: Excellent. Marcus, it’s good to be with you know, and we’ve got a kind of a photography lead topic today. So that’s going to be definitely Marcus, and you’re going to give us 10 tips about flash photography, is that right markers?

Marcus: Well, that’s correct. I get good call the principles of flash photography without sounding too grand.

And what I’m aiming to do is in the same way I did with the talk about creativity, I’m trying to break I’ve tried to break flash lighting into 10, Not rules, but principles that you can follow. Okay, so hopefully that now obviously, it probably a bit easier if I was showing you pictures and stuff I’m not obviously can’t is your broadcast. So hopefully, this will work.

Sam:  we can always put some on the website because we’ve got so for every show that goes out on the shoot to the top website. You can listen to it, and we’ve got the whole script so we can put your we can put the photos in there to go with it. If can’t be Marcus.

Marcus: Okay, that’s good. Okay, well, you disinfect it, Sam and tell me if it works, or really or visually, okay. Okay. So these principles that I put together, obviously, I Sam said, it’s about flash, but they do apply to all types of lighting, you know, ambient lighting, which people call natural light, or maybe tungsten lighting, or whatever it might be. But principally, they are aimed at flash. So the first one I’m going to go for is the very bold statement that there are only two types of light, hard light, and soft light brackets, but many variations in between. So hard light is the kind of light that you would maybe see on a sunny day with no clouds in the sky, midday, it no somewhere exotic and warm, maybe. But these that kind of light that is very, these terms are going to go over but they we call it contrasty. Soft Light, is if you can imagine that same day, but with the clouds coming in and giving you a much more diffused light. And so those are two ends of the spectrum. And obviously, in between that there are many, many different variations.

Sam: So is that kind of like if I’m thinking, if I’m equating it with the one I’m buying light bulbs in my home? Is it kind of like that? You know, that sort of pure white versus warm, white? That type of thing? Marcus: Actually no? That’s all to do with color temperature. Yeah. Yeah. But that’s a good point. But it’s more or less more to do with color temperature. Yeah, maybe as I’m going through this list, that might become a little bit clearer. Now, the second principle is the closer to the subject, the softer the light, and consequently, moving the light further away. And that light then becomes harder. Now, simply said, I’ve got this Hey, that took me years to understand that.

Sam: That sounds counterintuitive. But you think about having, you know, a really basic compact camera. Yeah. And you know, the picture is your granny has taken they’ve got too close. And then everyone’s face is white, because the flash is too close. Now that seems to me that was hard light.

Marcus: That’s hard light. Correct. But that’s the dude exposure. Yeah. If you’re, it is confusing, because you think if you put something closer, as you say to a subject, it becomes hotter. You know, brighter, but it’s actually it’s the other way around the firm. Think of the sun. When the sun is it’s obviously tiny in the sky. And on that said sunny day, the light is hard. When you get the clouds coming in. It’s not changing the light, shorter lights were still the sun, but it’s striking that light source over so it becomes bigger than light source is now the whole of this guy has a cloudy day.

Sam: Out of the whole sky instead of one point.

Marcus: Exactly. The sun is still the light source. But it’s the clouds. And what’s it done, the clouds have come closer to the subject of light is now closer to us, instead of being it 9 million kilometers or 3 billion kilometers long right away.

Sam: I can’t remember how it is. I can’t do that.

Marcus:  But that’s  a good way look like linnets. Yes, a couple of minutes. Two minutes to get to here. That’s right. Okay. So the closer you place that light to the subject, the quicker it falls off. This is the inverse square law, the dreaded law of photography that is quite difficult to understand. Now your physics teacher, Sam, you probably understand inverse square law more than me.

Sam: I’m just drawing you a little graph here, Marcus. There we go.

Marcus: Yeah, that’s exactly why it’s basically it’s double, isn’t it? It’s a high patch news or something or false.

Sa:  It’s an exponential curve. So yes, double as if you. If you double the distance between you and the flash, you will quarter the brightness of the flag.

Marcus: Oh, God, that is so complicated. You’re quite right. And but the way I look at it is if you have like when I do a portraits, I love using gray backgrounds for my headshots. The closer that the subject is to the background, i.e the light instead of back to the subject, the brighter the background, as you pull that subject away from the background, even leaving the light in the same place, the background goes darker. That is to do with inverse square law, you can see it happening a lot easier there than you do on the subject.

Sam: Okay, that makes sense.

Marcus: Okay, so let’s talk a bit more about the hard light. So my fourth principle is a heart like has more contrast than a soft light. Okay, contrast is basically highlights and shadows. So the more contrast to have the further away those two items are a highlight in shadows. The softer the light, the closer there’s more gradations in there, you can see more Gray’s as it were within that tonal curve. So hard light, you can say is black and white highlight and shadows. Soft Light is variations in between that many variations. And a hard light is a term we call specular. A hard light gives you more specular, what this means specular, you might say, it gives an object shape, or like on the skin, you might sit on your paws a little bright bit, it gives it texture. And that can be defined by sometimes like you might have a white coating on the inside for light or a silver coating on the inside of a light dome or whatever the reflector that goes on it, the white one will be less specular than the silver one. So a little bit more advanced there. But yeah, that’s something to be aware of. But mainly the main principle there is a hard light has more contrast. Again, on that sunny day, your shadows are going to be much more defined. Oh, and in fact, that’s my next principle, a hard edge with high contrast from a hard light or a soft edge with low contrast from a soft light. So yeah. Okay, so we’re about halfway through now. Light can be direct, or it can be indirect or bounced. Okay. So by direct, I mean, it’s pointing straight at your subject at a person or still life or wind, but what you’re photographing or whatever it might be. Indirect is when it’s bounced, maybe off a reflector of a ceiling, typically, or a wall.

So direct or indirect.

Sam:  Yep. And presumably, then, which you use not just depends on the light effect your but also on whether you’re doing a still lighter a person. Conversely, if you’re shining a flat straight in a person’s face, they’re a bit like, oh, well, if you’ve got the indirect is delighting them, but you’re not kind of given that shock. So they look like you know, the rabbit in the headlights in your photos.

Marcus: Yeah, I think that your white selling that applies more I think when you’re using constant lighting. Flash lighting happens very quickly. And yeah, you do. If you look in a flash bulb, it is a bit unpleasant. But yeah, I think it’s more that’s more like the one on a sunny day, or if using constant lighting. I mean, bouncing a light is interesting again, because what that is doing is it’s not it’s changing the size of the light. So you punch if you have a subject and might be quite small, a small head, but by batching, that small head of a ceiling, it becomes bigger.

Sam:  It’s a bit like times again, it’s suddenly a bigger act a bigger lights off.

Marcus: Yeah, So you haven’t moved the light closer, but you’ve increased the size of the light. And you might do that with, you know, different modifiers as well. Like a softbox or an octave box or an umbrella will make the light source bigger, and then you can put a diffusion screen on that to make it softer as well, or you can go the other way. And you can have a small reflector or a bear bulb, which is going to give you a much harder light. Because it’s direct, not diffused. Light travels in straight lines unless it meets every faction, I can see you laugh, because you mentioned that before an obstruction. And that will be faster. But Sam: I like the physics lesson here, Marcus, I mean, doing this fit?

Marcus: Yeah, that is very physics. Yeah. So when you’re thinking of lighting, you can apply that by thinking of snooker or billiards or pool for American listeners. So you strike a cube the cue ball, and it will create another object and then go into in traffic in a different way. So what you’re doing by bouncing light or putting a diffuser or a grid in front of him get his or changing the direction of that light.

Sam: Makes sense? You’re either bouncing off a subject or you Yeah, it’s going through a subject through an object. Yeah, can reflect the start again, because I said a subject reflecting off an object or Yeah, it’s going through an object and changing because it goes through, like you said, a diffuser or something.

Marcus: Yeah, I mentioned grids. They’re the sort of thing that used to be quite popular. See, they’re really coming back in again, it’s hard lighting is coming back into fashion a bit more grids are basically, again, Americans call these honeycombs is literally a grid that goes in front of the light with a reflector, and it channels the light, so it’s not going in different directions in straight lines, it’s going straight ahead in a straight line. And it gives you a very specific look, which I really like. It also contains that light, it gives you a pool of light. So if you want to light up, for example, a watch on somebody’s wrist, you can put a grid on that, a lighting that with a grid, and then fill it in the area around it with a softbox or something.

Sam: So you can really focus the light in one area.

Marcus:  focusing the light in one area. Exactly. Okay, good. How are we doing? Oh, good. Okay, time is good. So, three more to go. light coming from the side of a subject will show more texture than a font on light, which gives a flat light. So that basically means landscape is where you can really think of IT landscape photography, you know, the people when they’re doing landscape, they really sets out that low light in the sky, sunset Dawn, or whatever it’s going to be. And that gives you much more texture in the grass and the trees or whatever, it’s been the rocks.

Sam: You sit on a portrait as well. And you’ve got that side, you can just think one side and the dark one side in the light of a face.

Marcus: Exactly. And in portrait. It works the same way. But in some way, you know, if you want to make a more flattering porch rate, you want the light coming from the front, you know I mean aren’t you know, I use that headshots again, you tend to have the light tend to have the light coming from more the front direction, because it’s more flattering. It doesn’t show wrinkles or skin hides things.

Sam: It’s interesting is it when I had a telescope, you look at the moon. And if there’s a full moon, you don’t see that? Well, you don’t really see well is a half moon, especially at that point where it’s half in the light and a half in the dark and all the mountains stick out on the craters. And they’re really, really yes, that text you show.

Marcus: That is a great demonstration of exactly the difference between sidelight and hot and font on light. You know, not everything is better or worse. They just don’t work.

Sam: You just need to know the difference.

Marcus: Yeah. Okay. And a couple of more things now that are more specific to flash. Flashlight varies in speed.

Sam: Is that got a number Marcus? What number are we on?

Marcus:  Yeah, it’s got a number. It’s called the T number.

Sam: No, no, I meant like, Oh, I’ve lost.

Marcus: Oh, yeah. Number nine. But yeah. the speed your flash is actually awful. How did he know that? But the speed is not that fast. Yeah, the speed of a flash is does vary depending on the pack and the flash gun you’ve got. And it can go from, I think it may be about 300 feet per second, up to 10,000 feet per second. And if you’ve got somebody moving like a dancer, or an acrobat or whatever, you’d need those really faster speeds just to freeze the action. So if you’re doing that type of photography, your T number, your T number is going to be very specific to you. So you’re going to seek out flattie that have got a very high tea number. Ironically, speed lights, you know, the small flash guns are very good at high tea numbers.

Sam: Yeah. Okay. Excellent.

Marcus: Yeah. And this is my last one coming on now. Well, no for number 10. If you’re using flash outside, especially on a sunny day, you will need a lot more power than in a studio. So when you’re working outside you’ve got to overcome. Well, unless it’s a very, very dull day. But if you’re working outside on a sunny day, you do that when you need those big flash, big power flash packs that, you know, that are quite big and quite bulky to overcome this sun.

Sam: Yeah, there’s so much like they’re ready, you’re gonna have to have something pretty powerful to get noticed, aren’t you?

Marcus: Exactly. And quite surprisingly, so as well, quite surprisingly.

Sam: Sounds quite a big nuclear lab to market. A fair bit. Apparently, there is. Yeah, that’s during the physics in the show market. And I’m already building up to putting some sort of inverse square little graph onto the show notes.

Marcus:  Oh, yeah. You could do it. You can do that.

Sam: There’ll be a PowerPoint presentation about light reflection and refraction included. Now. I’m joking, though.

Marcus:  So yeah, so those little so when you’re buying a flash gun, and you can be working, you can be working inside or photographing events, you don’t need that much power. You know, small flash gun bands to the ceiling will do all you need. If you’re working outside and a lot more power that where the advance of power does come in, though, is and maybe this is something for another time, I think it is but it’s recycling time. That’s a thing that is very annoying. If you’ve got a small flash gun and you want to fire it very fast and catch it and it takes a long time to recharge and it’s on full power. That’s when you need to flash back. Okay, I rambled on a bit there. But there we go. Yeah.

Sam: Right. Thank you, Marcus. That has been really interesting. As usual, there’ll be an extra tip from Marcus in for newsletter listeners. If you’re not signed up for the newsletter, go to our website, shoot to the and you can sign up there and you will get the extra tips from Marcus about lighting. And I will see you next week Marcus.

 Marcus: And keep flashing.

Sam: Thank you. See you next week. Bye.