Shutter Speed and the Reciprocal Rule
Another reason why you might not be getting tax write images is simply due to shutter speed now of course we already know that your shutter speed needs to be fast enough to freeze the subject that is you're shooting for example, if we're shooting a portrait well, if the subject isn't moving on, we can get away with slow shutter speeds one fiftieth of a second one hundredth of a second those going to totally fast enough so long as we have steady hands but if you're shooting faster moving object say a person running if you want to freeze that action we need to be around one two fifty or one, five hundred of a second if we're shooting faster moving cars again around one, five hundred or one one thousandth of a second and so forth so that's pretty simple but what about shake or movement that's caused by your hands? Well, this is known as camera shake and camera shake we can mitigate by making sure that we follow a simple rule of thumb. The rule that I'm talking about is the reciprocal rule...
, but the reciprocal rule is really I'm going to say more of a suggestion or guideline because in some situations it's not gonna work and you need to use your common sense but essentially what this rule states is that your shutter speed needs to be at least the inverse of your focal length so I know that sounds complicated, but these are just words to make me sound smart, okay? What it really means is that if you're shooting at, say, fifty millimeter lens, you're going to shoot at one over fifty for your shutter speed at least that is your minimum. If you're shooting on one hundred million lens, you're going to be shooting at least have a shutter speed of one over one hundred this is the reciprocal rule because basically what's happening is that the longer the focal length of the lens, the mohr exaggerated any movement becomes and I have a little example for you all to help you understand this I brought along with me too pvc pipes okay, this is a short pvc pipe I'm going to say this pvc pipe represents a twenty four millimeter lens let's just say, for example, now I hold my twenty four million lens lets see if I can hold it from this side the same way I would hold the camera or roughly the same way I hold a camera and hold it in a way that would be steady on the other side pretty easy not too bad we're getting a little bit of a fight regulate my breathing I think we can get that pretty steady not too hard right? The problem is if I grab this other pvc pipe and this is roughly I don't know nine, ten feet long pvc pipe, the movement on the other side becomes very much exaggerated. So for example, I hold in the exact same way. Look how much movement is being introduced in the other side of this long pipe and this is the same thing that's gonna happen with your lens. The longer the lens, the more exaggerate the movement becomes on the other side of that lens. So for telephoto link lenses, say, a two hundred million lens, three hundred million lens you need to be sticking with at least the inverse of whatever that lenses so one over two hundred won over three hundred for your shutter speed. Now, of course, things like in camera stabilization or inline stabilization do help out a lot and allow you to get lower if necessary. But really, when you're going with a telephoto length, you should keep the shutter speed relatively high, but here's the thing the reciprocal rule kind of starts to fall apart when you get to wider angles. Why? Because, well, if I'm on a fifty millimeter lens, I wouldn't necessarily always want to shoot at one of her fiftieth of a second, of course I could if my subject was still bought more often than not, I have to consider my subject in my subject movement in my shutter speed same thing if I go to a wide angle say a twenty four millimeter a seventy millimeter is sixty million even down to say ah fourteen or a ten millimeter lens I'm not going to drop my shutter speed down a one tenth just because I know that the reciprocal rule tells me to so that's what I mean where you need to use this rule as more of a guideline? Yes use it for those telephoto links and what I would say is at the telephoto links basic on the effective focal length on the written focal length I'm going to talk about that in just a second, but when it comes down to the wider angle lenses that you're using, keep in mind whatever seen it is that you're shooting if you can't shoot the scene at a certain shutter speed because you need to freeze the motion and that's the rule that you should be following the rule that frees the motion whatever speed that's going to be so forget the reciprocal rule kind of at those lower or wider angle links okay let's, go ahead and show you guys an example here I have my rebel right here and on the rebel I have the standard kit lands this is the fifty five two two fifty millimeter lens now honest, linda does have image stabilization, although it's not that solid, this is just a standard kit lens, ok, but what we're gonna do is we're going to shoot this shot, and we're going to shoot at two hundred thirty millimeters and remember that effective length of this is two hundred fifty times one point six, so I want to keep my shutter speed fairly high, especially if I'm standing up. If I do other things like sit down or use a tripod, of course I could slow down, but for standing shots, I do want to keep it fairly high if possible one, four hundred of the second is where I would want to be to make sure I don't get any camera shape whatsoever, but we'll probably see that that's not possible is our scene is rather dark now, why is it that I'm shooting at a four hundred millimeter effective focal length is something we do a lot. We shoot for linz compression in a lot of different kind of scenes because it creates really cool effects, and that compression effect again is the pulling of the background closer to the subject for this kind of scene, we have our runners, they're about, I don't know one hundred fifty feet. Maybe around a hundred feet down this little path way and we're going to shoot them so that it looks like this pathway kind of disappears over this hill and we just have them standing there. The trees there in the background are going pulled right up right behind our subjects, winning a really cool kind of just portrait shot with them sold out on the scene. It's going to look pretty awesome as far as that compression effect goes and that's why we're going for this length, but we are going to have to play around the shutter speed to make sure we can get an adequate shutter speed so we don't get and a camera shake, okay, so I've got tony's screaming, blocking that spotted light now I'm sitting down here, we have two options here, I could go with my knees up, but the thing is, this isn't that comfortable for me, so I'm gonna go ahead and just go cross legged style, okay? If I had a curve or something to sit on, I probably good news that, but I don't, so we're going to cross legged, and now I'm going to bring my elbows right to both sides of my knee and then here to my eye, and now we have a nice little tripod action, okay, so a human tripod action piper we're done here. We got some really nice portrait and because I like this scene so much, I'm probably gonna shoot some nice shots of them. Just running we're gonna do is bring my shutter speed upto one to video, the second we're going go probably two hundred, and we're going to try and get some sharp shots of them running along this path right towards me. I'm gonna probably used a I servo, too, just because they were running directly into the lens. I'm not gonna make you stick around for that because we're going to doing a ton of this stuff, and we have been doing a ton of stuff, so hopefully you enjoyed this tutorial. Hopefully, you have a better idea of how len's compression worked and how you can use it in your artistic compositions and also how that reciprocal rule kind of correlates to your lens, focal length and to your overall shutter speed. All right, we'll see you on the next video.