Choosing the Right Camera Lens

 

Lesson Info

Hyperfocal Distance

Alright the last section in this, or last part of this first part of the class is the hyperfocal distance. And this is one of the more complicated areas. And if you're new into photography, this may not seem real relevant right now, so it's a good reason to repeat this part of the class and come back to it later in a few months. When maybe you get more into a type of photography where this has more applications. But hyperfocal distance is kind of a concept, and it's the idea of where would you want to focus if you want everything in focus? Now there is kind of a general rule of thumb that isn't totally accurate but it's kinda close. The depth of field formula is that, one third in front of where you focus and two thirds behind where you focus will be in focus. Now when we talk about depth of field, we of course, know that depth of field is affected by our focal length, aperture, and subject distance and so there's a lot of factors playing in. Where should we focus if we want as much in...

focus as possible? And so let's go back to the studio here and take a a look, and in this case we're just gonna focus on the 10 inch mark on our ruler. And if we said that one third in front and two thirds behind is in focus, you get an idea of how this is going to grow. Let's start off with a wide open aperture in this case. And let's just say for theoretical purposes that we have one inch in front and two inches in back in focus. At this maximum opening setting. Now let's close our aperture down just a little bit. And maybe now we get two inches in front, and four inches in back. And we close it down a little bit more. We get three inches in front and six inches in back. And then we decide we want everything in focus, so we close our aperture all the way down to the smallest opening, and our depth of field grows quite a bit. The problem is, the back end of the depth of field, does not reach the infinity symbol in the background. So the mountains in the background that we're trying to keep in focus are not sharply focused. And so the mistake that some people make is that they focus their lens on the mountains in the background. Well we've just thrown away two thirds of our focus I'd say. A better option would be to move our focus just a little bit back so that the back end of our depth of field reaches the mountains. Now this is kind of a hard concept, so let me do it again with a different illustration this time from the side. And this is very common for the landscape photographer. And if you want to photograph a beautiful mountain and the flowers in the foreground, well there's a lot of different ways of doing it. If you focus on the mountain, and you stop your lens down to F22, you probably won't get the flowers in focus cause they're too close to you. If you focus on the flowers at F you're gonna get very shallow depth of field, which probably isn't gonna reach the mountain behind you. And of course this depends on lenses and the exact distance you are but this is a very common problem. But in most cases if you find the secret happy spot in between the two you can get the depth of field to reach all the way forward to the flower and to the back to the mountain. And so what does that look like in the real world? Well here are your flowers and here is your mountain. Their focus is all the way through from the flowers in the front to the mountain in the background. And this is a common technique with landscape photographers. Using a variety of wide angle lenses, a variety of apertures that are generally stopped down. If you want that subject in the foreground as well as the background in focus, you're gonna need to use a wide angle lens, stopped down, and you have your focus very carefully set, so that the foreground and the background are in focus. Now something I also use a lot in travel photography because I'm trying to show great sharpness throughout the entire range. Now, how you do this focusing is a little bit tricky, so let's talk about how you do it though a particular lens. Now this is where higher end lenses tend to have a little bit of an advantage because they will have a distance scale, and a hyperfocal scale listed straight on them. Inexpensive lenses do not have that. One of the best lenses for doing this is the Leica lens, because they have a really nice big clear depth of field hyperfocal scale right on the lens that you can use. And some of the inexpensive lenses, they don't tell you where you're focused, or the depth of field or anything else. But that's one of the things they cut back on on inexpensive lenses. Now, the ideal lens would have a really clear focusing scale like this. It would also have a great depth of field scale, like this now this is not of any real lens, this is what a theoretical lens that would be perfect. And so as we focus our lens, let's say we focus it right here, we're focused on about three meters. If we are shooting at F11 you can see we'll get everything from roughly two meters to five meters in focus, so it shows us where our depth of field would be. If we focus on infinity, you can see that we'll get everything from 10 meters to infinity, to some area beyond infinity, which is not really doing us any good. So we're kind of throwing away and wasting some of the depth of field. If we really wanted that depth of field, we would adjust our focusing mark, so that infinity hit that bright blue mark. If we were shooting at F11. If we wanted to get the maximum depth of field from our lens, we were gonna stop our lens down to F22. We would align the infinity mark with the 22 on the right hand side, and so we would do all this just simply looking at the camera. Now there is another way of doing it for all of you who don't have a scale, which is like me most of the time, my camera's don't have a scale like this. And so when you look at your scene in front of you, here's the best way to figure it out real world. The question you're asking is where should I focus the lens, I know I'm gonna stop down to 16 or 22, but where should I focus the lens. And the answer is pretty simple, it's not too hard to figure out. It's double the near point, and what I mean is, figure out where the nearest thing in the frame to you is, and double that distance from the camera. And so in this case it was probably about three feet away, and then I focused about six feet away. Set an aperture about 16, and got everything in focus. In this case I was very close to the ground in Death Valley, I figured out what the nearest thing in the frame was, I doubled that distance out there which really isn't that much further, but it was double the distance from the camera, set my camera to F22 and got everything in focus. So just figure out what is closest to the camera, estimate the distance from the camera to the film plane, not just the front of the lens, the film plane in the camera, double that distance and focus on that point. Now this is not an exact science, but it is a good rule of thumb that will work in most all situations very very closely. A very common lens for using this type of photography with is with a 24 millimeter wide angle lense. For those of you with a kit lens, that's like an 18 of that 18 to 55. Alright, now I wanted to look at, where would the hyperfocal distance be if you shot it at 2.8. If you shot it at 2.8, you would need to focus at 6.8 meters, and everything from 3.4 meters to infinity would be in focus. But that's typically not where we would set the lens if we're trying to get as much in focus as possible. We would start closing our aperture down. And so it starts getting really interesting in my mind around F8. So at F8 you're focused at two and a half meters, and so that's roughly about 10 feet for those of you from the United States, so you get everything from about three and a half feet. You're focusing on 10 feet, you get everything from three and a half feet to infinity in focus. But if you really want to get the maximum depth of field you're gonna stop your lens down to F16, or F22. So at F22 with a 24 millimeter lens, what you're gonna do is you're gonna focus at 88 centimeters which is a little over two feet I think, and you're gonna get everything from one foot to infinity in focus, and so this is just what you get with a 24 millimeter lens. In most cases people are using this at F11, F16 and 24. And just for fun cause I though it would make an interesting graph, I wanted to figure out the hyperfocal distance on lenses between 16 and 800 millimeters and you'll see why this is most practical with wide angle lenses. So with the 16 millimeter lens, if you focus on the right spot, you can get everything from 20 centimeters to infinity in focus. And the 24 you gotta go all the way to 88. And you can see how you get shallower and shallower depth of field, with the longer lenses that you were using until it becomes quite ridiculous with a longer lenses and so when we talk about hyperfocal distance it's really only practical with lenses from 35 millimeter range down to the 16 and so forth. So let's get ourselves all the way up to an 800 millimeter lens. If we wanna have hyperfocal distance with an 800 millimeter lens, this is kinda ridiculous, if you focus one kilometer away from you, you'll get everything from 500 meters to infinity. So I think that, that shows where hyperfocal distance will be the most helpful, 16, 24, and a little bit on the 35 millimeter side.

Once you’ve chosen the camera of your dreams, how do you know which lens will maximize your camera’s capabilities? Join camera expert John Greengo as he explains what the best lenses are to add to your camera bag. He’ll explain:

  • Which lens is best for specific areas of photography
  • The technology behind lenses
  • How to use specialty lenses including macro and fisheye
  • Tips on operating and maintaining your lenses

John will also talk about lens accessories including hoods, mounts, filters, and teleconverters. By the end of this class, you’ll understand exactly what lens you’ll need to take your best photos!

 
 
 
 

Reviews

  • Excellent class packed with incredibly useful knowledge. John is an amazing lecturer. He has also developed really great materials to help explain all the concepts and technologies that are explored in the class. Looking forward to my next class with him!
  • Great class. So informative. John Greengo is such a fantastic tutor and explains everything in such and easy-to-understand way. I would highly recommend this class. Prior to doing this class, I was so confused about which lenses are best for various photography. Now I understand lenses completely. Thanks John!
  • Another great JG class, my 4th. He gives a lot of individual attention to several popular lens brands. I really think after seeing this video series you could pick out three lenses that would fit your needs and your pocketbook. The class handout is spot on for what is covered in the video. Great job!! Thank you