welcome to rocket science it's actually not rocket science but when i read through all these different books and articles and stuff like this it's like rocket science if you don't understand how the camera works and what the very basics are so advanced questions are not allowed because it might confuse somebody oh yeah i wouldn't even know how to ask an advanced question so that's great that's all right yeah that's good so uh so we're going to keep it very casual and if someone doesn't understand something we can stop and i can go through it different ways or to make sure that we understand everything before we move on because seriously if you don't understand what we're doing today all those things you read in that book are just going to say what do they mean by that so and then you can use this today for down down the road you're thinking gee i want to try this but then you think back oh yeah he did this demonstration of this or whatever and then that will make sense nice but it's pretty much physics and logic let's start with a very basic uh demo and this is going to come into play later and i'll tell you when it does but what we have here one glass of water and one empty list and if i take this and pour the water in it pours very quickly because of the big opening here and so what we're doing is the water is representing how much light it takes to expose a picture and so then the concept here is to pour the same amount of water the uh through a funnel and it takes longer to to go through but it's still the same amount of water that it takes to make the picture so the concept that i'm getting across here is that it takes a certain amount of light to make that picture whether it takes a long time at a small opening or a short time with a large opening and we're going to come back to that when we when we get to that point so i'll just put this away for now because it's uh chlorine water not like chlorine like that then i am going to go to okay the next thing we're gonna do is talk about that that speed that i that i ported in we're gonna pull out the of this equivalent exposure chart uh the one that says starts with one second at the top just take that one keep the others in there the uh the purpose of the shutter itself is to let the lot light into the camera to expose the film i'm going to talk about film because there's no it's all absolute digital just throws everything out the window but having the foundational knowledge about film allows you to easily learn digital right exactly yep or you'll understand all the complex parts of digital right which is to me a lot harder than film so hasselblad is kind of the standard of the industry this is like a 1972 and it's the same uh carl zeiss glass that the sony has basically only this 1972 this the same camera that they took to the moon on their flights because they can trust it so basically the original the original cameras if you remember the big box cameras the film was so insensitive that's not a word for this is it but it works uh it works you understand it makes sense uh that it took a lot of light to expose one image so that's why the old-timey ones that big burst they need a bunch of light right right but a lot of them that did not have the big flash powder which is a long exposure so what they did is they had a lens cap on this big box camera and they looked under a black cloth to get the focus right and everything because it's very hard to see very dark and then the grip is already and then that was known as mechanical shutter so basically they take the lens off and they might count to 10 seconds everyone's just standing there that's why those old-timey pictures they look like they're yep or they look very somber yeah because they have to stay there in that pose it wasn't a quick response no candid shots yeah so but then long came the mechanical shutters and what that did it's the same effect as taking the lens cap off and so forth except for it's all timed and i don't know if you can uh this one i don't know if you can see through here uh this is a one second oh yeah did you see it work yeah okay um but uh so so that's one second can you do it one more time i want to make sure it's on camera okay cool okay nice all right so then i want you to look through these uh from the top one that one second is the top one that i just did now these are standard shutter speeds and i'm talking about standard for a reason and i'll get that into that but what do you notice about these speeds there's uh they're fast huh they're fast they also split in half every time yeah okay that's key here yeah so you got one second half a second fourth of a second eighth of a second so if i take if i take a one second like i have and i change this to half a second how much light comes into the film half as much light half as much if i do fourth of a second you've got half again as much so every time uh you change the shutter speed with the standard shutter speeds you got half as much light hitting the phone okay so we with this chart i went all the way up to uh one two thousandths of a second but like my camera now this professional camera goes up to one to eight thousands so this hasselblad was the basically the cream of the crop in its day and its fastest shutter speed is 500th of a second so we got the basics of that right you get half as so you can imagine how much difference in light there is between one second and one two thousandths of a second if it does if it's half as much light every time you change there's a certain range that the eye will see and you might say this is one f-stop difference so it's half as much light every time i understand that the human eye has a range of nine stops that's why if you're just looking you can see stuff at night after you adjust to it or in bright sunlight you can see well the camera has to do all that mechanically so now we're going to pull out the big sheet and you can leave the third one sitting there the lens here has a big opening and it's got a diaphragm that shuts down like the people of an eye and um the relationship between the opening you don't have to remember this but just kind of understand that the f stops okay megan here's where it's confusing in the book so talk about aperture they talk about f stops f numbers uh all kinds of things but the f-stop is the opening in the lens itself when you take the picture and it's a relationship between the focal length of that lens and it's actually a fraction like f16 might be 1 16 of what it is if the lens is wide open or as big as it can be might be one sixteenth the size but what's confusing about it because these numbers have no correlation like the shutter speeds did whereas obvious that one second to two seconds is twice as much light these have no correlation because they're fractions but these are the only things that i want you to remember uh and you don't have to memorize them but i want you to know that f2 8 f4 f56 f8 f11 and f16 are standard f-steps and i'll tell you why after a while and uh the interesting thing about these is they're all calculated that the big opening 2-8 here you go to f4 and it lets in half as much light because it's a smaller opening okay f56 from f4 it's a smaller opening and it lets in half as much light so these numbers although they don't make sense as numbers they still do have they still do half every time and it's very very important to remember so the speed that's called the speed of the lens how big the biggest opening is and this 2.8 is considered pretty fast and that's what this has splat is the bigger option the bigger the opening the faster the lens and obviously the more light it can take in can i ask a question yes so when you buy a lens is this is this aperture rating um adjustable or when you buy a lens are you buying an f4 lens that's what you're buying interesting