And so the aperture is thie other device in the lands this is the second most important reason that we're choosing a particular lands first off we're going to choose it for its angle of you and generally the second reason is because of its appetite there's a few cases where we choose lenses because we need that specific aperture first but in general it's the second reason that we choose a lance been in this section we're going to talk a little bit about apertura range not very long because this is kind of more photo wanna one stuff we're going to spend quite a bit of time going through some of the more advanced and esoteric topics when it comes to aperture so first off just cover our basis with all of our new photographers we don't want to be mean and jump past them I want to bring them along with us talk quickly about the aperture range in a particular lands and so each lands is gonna have an aperture that you can close down and set two different apertures so a lens it goes toe one po...
int for he's gonna have a very shallow depth of field in this illustration here you can see those red hash marks over on the right hand side are illustrating the front edge of focus and the back edge of focus so that is our depth of field between those two lines as we stop our aperture down each time we get a little bit more depth of field with each subsequent setting and this is the aperture unit you can see closing down in the middle of the lens letting in a little bit less light that we're going to need to compensate with on shutter speeds so when we get down all the way to twenty two in this particular example that's as much depth of field as we can get and you can see on the right hand side of the screen that we've got everything from twenty two to the thirty three mark in focus but not stuff beyond its what extends greatly but it does have limitations and so that's the range different lenses they're goingto have different numbers that maybe extend further in either direction and so the visual that I keep in my mind and this is one of the most difficult things 00:01:57.166 --> 00:02:01. for newcomer photographers is one point four is a 00:02:01.05 --> 00:02:03. very small number but it's a very big opening and 00:02:03.96 --> 00:02:06. twenty two is a big number but it's a very small opening 00:02:08.12 --> 00:02:10. in a case like this let's say we're at f two point 00:02:10.34 --> 00:02:13. eight and we moved to two point oh we are opening 00:02:13.91 --> 00:02:16. up our apertura it's kind of terminology we like to 00:02:16.28 --> 00:02:19. use and in that case it's a full stop of light which 00:02:19.81 --> 00:02:21. means it's double the amount of light 00:02:22.95 --> 00:02:25. when we go from two eight two two point oh if we were 00:02:25.9 --> 00:02:28. to go, the other direction from to wait f or which 00:02:28.56 --> 00:02:31. is the next next number in the siri's going from to 00:02:31.67 --> 00:02:33. eight two f four we're stopping our aperture down 00:02:34.16 --> 00:02:36. and we're letting in half assed much light f four 00:02:36.96 --> 00:02:40. is the next number on our siri's and that is also 00:02:40.15 --> 00:02:43. a full stop so full stop khun b more or less you need 00:02:43.55 --> 00:02:46. more information as to which direction you're going 00:02:46.38 --> 00:02:48. and so that's one of the things that we're doing in 00:02:48.46 --> 00:02:51. our cameras there's mohr of this information in my 00:02:51.14 --> 00:02:53. fundamentals class we're going to pass by this pretty 00:02:53.24 --> 00:02:56. quickly because this is a slightly more advanced class 00:02:56.88 --> 00:02:59. now kanan has three different lenses we had somebody 00:02:59.82 --> 00:03:01. asking about these three different lenses they make 00:03:01.68 --> 00:03:04. a fifty one eight fifty one four and fifty one two 00:03:04.62 --> 00:03:07. question for all of you here in the studio and at 00:03:07.16 --> 00:03:10. home if each of these lenses is set to two point eight 00:03:11.58 --> 00:03:14. will they have the same exposure and the same depth 00:03:14.21 --> 00:03:17. of field now what's different is that we have a one 00:03:17.05 --> 00:03:19. point two lens a one point four lands in a one point 00:03:19.78 --> 00:03:23. eight but if they're set at two point eight are they 00:03:23.06 --> 00:03:25. really setting it are they really letting in the same 00:03:25.9 --> 00:03:28. amount of light for the exposure and for the depth 00:03:28.52 --> 00:03:33. of field and so I don't know how to address this question 00:03:33.25 --> 00:03:37. but think about it what is your answer yes or no let's 00:03:37.04 --> 00:03:39. just do an audience partition patient poland just 00:03:39.49 --> 00:03:43. raise your hand if you think the answer is yes, it's 00:03:43.59 --> 00:03:44. the same 00:03:45.92 --> 00:03:47. and raise your hand if you think it's no, they're 00:03:47.78 --> 00:03:48. different, 00:03:49.25 --> 00:03:53. okay? The answer is they're the same, all right? And 00:03:53.39 --> 00:03:56. so one of the things that I was confused about was 00:03:57.06 --> 00:03:59. if I bought a faster lands and this is a faster lands, 00:04:00.44 --> 00:04:02. no matter where I said it, it's always faster than 00:04:02.88 --> 00:04:06. everything else. No, you gotta shoot it at one point, 00:04:06.44 --> 00:04:09. too. If you want to be faster when you have these 00:04:09.02 --> 00:04:11. three photographers using these three different lenses, 00:04:11.8 --> 00:04:13. and they're set at two point eight, two point eight 00:04:13.97 --> 00:04:15. is going to be the same exposure in the same depth 00:04:15.89 --> 00:04:19. of field. Now, having said that, these are three very 00:04:19.48 --> 00:04:21. different lenses the size of the focusing ring, the 00:04:22.0 --> 00:04:24. construction, the brok, the out of focus area. All 00:04:24.76 --> 00:04:27. sorts of things are different, but if you're going 00:04:27.46 --> 00:04:29. to be buying the faster lens, you're often buying 00:04:29.65 --> 00:04:32. it for the fact that it can shoot down at this one 00:04:32.34 --> 00:04:33. point. Two aperture.