cardmaverick
Well-known member
I hope this isn't too over your heads, but I thought I'd post this. If you don't get it right now, print this and save it. Keep refering back to it as you mature as a DP or Gaffer....I wish I had this tip when I was starting.
My incidnet readings look good, why does my image suck!?
Ok, well, first off, a little explanation about what each reading type is.
Incident Reading: This is light that actually falls onto an object.
Reflected Reading: This is how much light BOUNCES off a subject.
Helpful analogy: You throw 100 bouncy balls at hot model. 4 of the balls bounced back. You're incident reading would be 100 bouncy balls. The reflected reading would be 4 bouncy balls....She must be a REALLY dark skinned model, which leads me to my next point.....
In the world of video and film, and still photography there is a lot of talk about lighting ratios. Key light compared to fill light. This, as far as I'm concerned, is the one of the biggest sources of confusion for people who are new to lighting. Lets face it, its easier to understand Incident lighting, thats why lighting ratios are polluting the internet, heck, college text books......workshops, lectures, bla bla bla. Why do they create confusion? because people don't immediatly understand the utmost importance of reflectance.
A bright object is only bright if it BOUNCES lots of light
A dark object is only dark if it BOUNCES small amounts of light.
Therefore you can have too ojects, evenly lit to say a ratio of 1:1, and exposed using the meters suggested f/stop. Also, your shooting on DV. This is supposed to be a "good rato" and "good exposrue" one that will keep your blacks from being crushed and your whites from blowing out.....or at least thats what all those college books preach. However, after shooting it, you look at the footage on some waveform scope, and see that your whites are blown out and the blacks are crushed. "WHAT!?" you scream out loud. "But its a 1:1 ratio (insert crying, cursing, kicking monitor, general anger here)!"
The "WHY"
Ok, Fist off, All formats have whats called a "dynamic range" sometimes called "lattitude". This is simply how many different levels or brightness the format can see, or to be more technical, how many shades of gray it can reproduce. Each shade is twice as bright as the previous, or another way of saying it, each shade is half as bright as the one ahead of it. In the pro world, each "level" is measured as an f/stop, but for the sake of keeping this easy, I'll just call them brightness levels. With DV, your lucky if you get 5 levels of brightness, its more like 4.5 ish. My Nikon D70 can see a good 6 different levels or brightness. A really nice film stock can see as much as 11 brightness levels, so can the newest HD cameras if used properly.
Still hanging in there with me? Good.
Now that we have established that fact that each format can only see a limited numer of brightness levels, it's time to address the "Why" of lighting ratios, and why they are so misleading. The basic explanation is, drum roll please.....
It's just easy.
Thats it! It's just easy. Its a blanket statement and technique that assumes the whole freakin world only contains the limited number of brightness levels your format can handle. Thats why its so misleading.
Going back to my example above about the white and black objects being lit to a ratio of 1:1. If you measured the REFLECTANCE of each object, you know, how much light actually bounces off the object, you'll quickly see that it EXEEDS 5 brightness levels in difference. You're exposing for the middle level, therefore your balck ovbject is way crushed, and the white object is just glowing hot with no detail.
Get it?
Its not so much the light hitting a subject, but how much light it's throwing back that makes the big difference. Lighting and grip gear (flags, nets, scrims) only exist to help squeeze more "brightness levels" into what really amounts to a small, cramped amount of room.
Some common questions answered:
If Incident is so misleading, then why use it?
Well, here's a great example of why I actually LOVE incident readings. SPEED. Let's say you have a scene that takes several days to shoot, and its a location where you have to tear your lights down each day. A good DP will take plentiful notes on how bright certain areas of the set are with an incidnet meter. Combined with fixture placement notes, what originally took you two or three hours to light can now be reset in just 30 or so minutes with enough man power!
How do you determine the right f/stop to use if you measure with a reflectance meter?
I hate to say this, but thats another thread! Not too hard once you understand, but to properly explain, I'm just going to devote another thread to that topic.
Last Thoughts
I hope this helps some of you out, if your still a bit confused, leave a message. Like I said, I wish I had this explanation a long time ago....
My incidnet readings look good, why does my image suck!?
Ok, well, first off, a little explanation about what each reading type is.
Incident Reading: This is light that actually falls onto an object.
Reflected Reading: This is how much light BOUNCES off a subject.
Helpful analogy: You throw 100 bouncy balls at hot model. 4 of the balls bounced back. You're incident reading would be 100 bouncy balls. The reflected reading would be 4 bouncy balls....She must be a REALLY dark skinned model, which leads me to my next point.....
In the world of video and film, and still photography there is a lot of talk about lighting ratios. Key light compared to fill light. This, as far as I'm concerned, is the one of the biggest sources of confusion for people who are new to lighting. Lets face it, its easier to understand Incident lighting, thats why lighting ratios are polluting the internet, heck, college text books......workshops, lectures, bla bla bla. Why do they create confusion? because people don't immediatly understand the utmost importance of reflectance.
A bright object is only bright if it BOUNCES lots of light
A dark object is only dark if it BOUNCES small amounts of light.
Therefore you can have too ojects, evenly lit to say a ratio of 1:1, and exposed using the meters suggested f/stop. Also, your shooting on DV. This is supposed to be a "good rato" and "good exposrue" one that will keep your blacks from being crushed and your whites from blowing out.....or at least thats what all those college books preach. However, after shooting it, you look at the footage on some waveform scope, and see that your whites are blown out and the blacks are crushed. "WHAT!?" you scream out loud. "But its a 1:1 ratio (insert crying, cursing, kicking monitor, general anger here)!"
The "WHY"
Ok, Fist off, All formats have whats called a "dynamic range" sometimes called "lattitude". This is simply how many different levels or brightness the format can see, or to be more technical, how many shades of gray it can reproduce. Each shade is twice as bright as the previous, or another way of saying it, each shade is half as bright as the one ahead of it. In the pro world, each "level" is measured as an f/stop, but for the sake of keeping this easy, I'll just call them brightness levels. With DV, your lucky if you get 5 levels of brightness, its more like 4.5 ish. My Nikon D70 can see a good 6 different levels or brightness. A really nice film stock can see as much as 11 brightness levels, so can the newest HD cameras if used properly.
Still hanging in there with me? Good.
Now that we have established that fact that each format can only see a limited numer of brightness levels, it's time to address the "Why" of lighting ratios, and why they are so misleading. The basic explanation is, drum roll please.....
It's just easy.
Thats it! It's just easy. Its a blanket statement and technique that assumes the whole freakin world only contains the limited number of brightness levels your format can handle. Thats why its so misleading.
Going back to my example above about the white and black objects being lit to a ratio of 1:1. If you measured the REFLECTANCE of each object, you know, how much light actually bounces off the object, you'll quickly see that it EXEEDS 5 brightness levels in difference. You're exposing for the middle level, therefore your balck ovbject is way crushed, and the white object is just glowing hot with no detail.
Get it?
Its not so much the light hitting a subject, but how much light it's throwing back that makes the big difference. Lighting and grip gear (flags, nets, scrims) only exist to help squeeze more "brightness levels" into what really amounts to a small, cramped amount of room.
Some common questions answered:
If Incident is so misleading, then why use it?
Well, here's a great example of why I actually LOVE incident readings. SPEED. Let's say you have a scene that takes several days to shoot, and its a location where you have to tear your lights down each day. A good DP will take plentiful notes on how bright certain areas of the set are with an incidnet meter. Combined with fixture placement notes, what originally took you two or three hours to light can now be reset in just 30 or so minutes with enough man power!
How do you determine the right f/stop to use if you measure with a reflectance meter?
I hate to say this, but thats another thread! Not too hard once you understand, but to properly explain, I'm just going to devote another thread to that topic.
Last Thoughts
I hope this helps some of you out, if your still a bit confused, leave a message. Like I said, I wish I had this explanation a long time ago....
