Impacts on Autofocus
Impacts on Autofocus
7. Impacts on Autofocus
Class Introduction05:53 2
Autofocus Defined04:45 3
How Autofocus Works06:39 4
Focus Servo Modes09:02 5
Focus Patterns17:20 6
Autofocus Settings19:55 7
Impacts on Autofocus16:17 8
Mode Selector Switch & Multi Selector05:28 10
The AF-ON & Back Button Focus12:45 11
Lens Switches07:31 12
Autofocus for Portraiture05:54 13
Macro Photography with Autofocus04:39 14
Landscape with Autofocus07:04 15
Bird in Flight with Autofocus05:30 16
Outdoor Sports with Autofocus08:05 17
Indoor Events with Autofocus09:18
Impacts on Autofocus
Let's talk about other impacts to autofocus. We've talked about configuring the menus, we've talked about configuring a couple of the switches, but there's other stuff that impacts sharpness, clarity and focus. Start with this one, depth of field. I get a lot of photographs from people who send me images, they send to me an email or Facebook or whatever, and say, "Hey, check out this image. "Why is it blurry?" And I'll look at it, well, sometimes it's not because they focused poorly, it's actually because their depth of field wasn't adequate. You know, in a landscape photo like this you need a lot of depth of field. Foreground, midground, background. This is in Lake Tahoe, one of my favorite places in the world. Well, to get this image I actually used a small aperture like f/16. I then focused about a third of the way into the scene. So, to get good focus or to maximize the focus I used the small apertures, gave me great depth of field. So that's something you need to think about when ...
you do your landscape photography, right? Use a small aperture, get more of the scene in focus. As opposed to maybe this, f/1.4. F/1.4 is a very wide aperture and it provides a very narrow depth of field. So, if you're doing portraiture and we're gonna shoot a portrait in a little bit here, you'll see how f/1.4 you have to nail the focus. You cannot miss focus by even a millimeter or two millimeters sometimes. If you miss it, if you focus on the eyelashes and sometimes the actual eye won't be in focus. You got to be very cognizant always thinking about what aperture do I need to maintain depth of field so that my scene looks like it's in focus? Finally, if you're using longer lenses like 50 millimeters, 75, a hundred, 200, in those situations, your depth of field for a scene like this with a longer lens you're gonna focus more towards the halfway point rather than the third point. Wide angle lenses focus around 1/3 into the scene, more telephoto lenses focus more like halfway into the scene. It's called your hyperfocal distance. Hyperfocal distance changes with respect to the lens you use and longer lenses you usually focus about halfway into the scene. So, what else impacts focus or our perception of focus? Well, shutter speed does. You've all done this, right? You've all taken a photo. You're looking at it in your camera when you take it. You're like, it's in focus but then you take your picture and you hear this. Clunk, clunk. Like, whoa, what was that? Why did it feel so heavy? Well, the reason why is because maybe your shutter speed was pretty long. So, I've done this a lot in my life, I go to my daughter's band concert or I go to my son's cross country meet and I get home and the shots are just blurry. I'm like, really, is my focus technique that bad? Well, no, it's more your shutter speed. So what I do is for sports I'm always thinking about a very fast shutter speed. 1/1000 of a second. 1/2000 of a second if things are really moving. This photo here, 1/2000 of a second. That was in Maui, Hawaii. How about walking? Just freezing the movement of walking, just the normal gait, you really need about a 1/125 of a second to get a sharp photo. How about flowers in the breeze and when I say breeze I mean light breeze. I'm not talking the whipping windstorm but if your flowers are moving about like this, you need at least a 1/60 of a second to freeze the movement. So always be thinking about shutter speed as it impacts your clarity, as it impacts your sharpness. Next one. Camera shake, that's a big one and I see people making mistakes on this all the time. This photo here I took at an aquarium. I had a 300 millimeter lens on my camera and then I tried to shoot it handheld at 1/25 of a second. That's a really long shutter speed for a really long lens. Anytime I'm hand-holding I'm always thinking through what I call the inverse focal length rule and this is an old school rule. Everyone should learn it. Basically whatever your focal length is, let's say I'm shooting at 200 millimeters, okay? I want my shutter speed to equal my focal length. So, if I'm shooting with a 200 millimeter lens I want my shutter speed to be about 1/200 of a second. If I go to a 50 millimeter lens I want my shutter speed to be about a 1/50 of a second. That rule of thumb and that's all it is, it's just a rule of thumb, will hopefully get you sharp pictures, you know? So, I'm gonna take a picture of my camera there. I'm looking and it says 1/5 of a second. (chuckles) That is not gonna be a very good shot, (shutter clicks) you can just hear it. Clunk, clunk. So, how do I get a higher shutter speed? Well, I open up the aperture, I go to f/2. or maybe I increase my ISO. I'm gonna go to ISO, let's just amp this thing way up. Let's go to ISO 3200 and see what we'd get. All right, now my shutter speed is at a 1/200 of a second. Pow and I look at that photo, fantastic. It's a sharp image of the camera versus the other one, oh my goodness, look at this. Very blurry. That was at 1/5 of a second. So, shutter speed for hand-holding the inverse focal length rule. The next thing I wanna show is hand-holding technique. So, hand-holding technique matters. I want you to think through your body position when you're hand-holding especially with the longer focal length lenses. So, what I typically do is I face the subject like this. I actually bend my knees just a little bit. I hold the camera and I cradle the whole weight of the camera in my left arm, left hand actually, and I bring it in. Then with my right hand I usually don't actually bear any weight with my right hand. My right hand is just for pressing the shutter and stabilizing the whole system. I then suck in the arms, I press it up against the face, I match my nose into the back of the camera like that, and then I breathe in and then I hold my breath, (shutter clicks) and then I take my shots. (shutter clicking) And if you have burst mode on your camera I often will shoot off two or three photos in one sequence. And that gives me the, usually the second or the third photo is actually sharp. So here we go again. Push, hold and then hold my breath. (shutter clicks) And I shoot a burst just like that. So, that's proper hand-holding technique. There's another technique I learned from a pretty famous photographer. He uses this method. He crosses his arm over like this and balances the camera, and he shoots with his left eye like that and that can also be a good hand-holding technique especially for longer shutter speeds. And finally, let's talk about long lens technique. I'm gonna over to the tripod here. I should have brought my long lens out to show but I got a fairly long lens here. Okay. Anytime you have a lens like 300 millimeters, 400 millimeters or longer here's what I want you to do. Okay, so first thing is your tripod matters. This is a really sturdy, Really Right Stuff tripod. So Really Right Stuff makes really great gear, I love their gear. And the sturdier your tripod the less you have to worry about long lens technique. But here's what I typically do. When I'm taking my shot I don't shoot like this. I think this is a poor technique because the whole camera can wiggle and you're not really stabilizing anything at all. You're just relying totally on the tripod. And this tripod actually will probably do a good job in this scenario because this is only a 200 millimeter lens. But with longer lenses here's what you do. You take your left arm and you drape it over the top and with the really long lenses you can actually bring it out like this, and touch the lens hood out there. This is a little shorter so I'll go like that. You just drape it over the top and you actually push down like this, and then you hold your breath, (shutter clicks) and you take your shots, okay? So long lens technique matters. Again, that process is drape your arm over it and if you have a lens hood oftentimes I will wrap my hand around the front of the lens hood, and then just hold really still. And then when I squeeze, this also matters when I take my pictures I don't stab at the shutter release button. I actually roll my finger (shutter clicks) just so slightly because I don't wanna induce any more movement in the camera system. So, those three methods matter. I talked about your inverse focal length rule for hand-holding, I talked about your technique for hand-holding like this and then also long lens technique. Those all impact focus, well, they don't impact focus but they impact camera movement and camera shake. How about your lens choice. Lot of people think that cheap lenses equates to poor quality photographs. Well, to some extent that's true. You all know that you get what you pay for, right? You buy a big expensive lens from Nikon you expect a sharp image as a result. Yes, that is true but you'd be amazed when you test this out that if you're shooting like a middle aperture, let's say like f/8, you will hardly be able to tell the difference between $120 lens, this is the 18 to 55 millimeter. You'll hardly be able to tell the difference between this lens versus a $1,000 lens which is the 16 to 35, or almost a $2,000 lens which is the 14 to 24. Almost all the Nikon lenses are sharp lenses if they're used in the right way. So, you at home watching this I don't want you to use the excuse that oh, I need to go buy a $2,000 lens to get sharp photos. No, you don't. You just have to know how to use it well. Use the right hand-holding technique, use the right long lens technique, use a middle aperture, maybe f/5.6, f/8, f/11, somewhere in that range. You're gonna get really sharp images. I have published lots and lots and lots of photos in my career with kit lenses. They sell just as, the photos sell just as well as the photos that I took with my more expensive lenses. So don't let that be excuse. I said early on that technique trumps gear just about any day of the week. Another thing that impacts sharpness is ISO noise. Look at this photo. Now this photo I took quite a number of years ago. I took it with the Nikon D300s. And so, I don't know how many years old that camera is now but it's definitely out of production. It's like three or four generations old in the Nikon world. ISO noise really impacts our perception of focus. Now this image is actually in focus. So this was taken at a YMCA and at a basketball game. The lights were really dim and you've all been in a situation before, you know, with the mercury-vapor bulbs or the sodium-vapor bulbs or whatever inside of these gymnasiums. It's just dark, hard to get great photos. So, the way that you get sharp photos or I should say in focus photos is to amp up your ISO. Here I used ISO and in those days on the D300s, 2500 was really high, and you can see the noise. So, what's my solution? I mean, how do I fix that problem for this image? Well, you have to learn post-processing. Lightroom, Nik Software, Photoshop, lots of other different plugins. There's lots of software out there that allows us to do noise reduction after the fact, and I do and this one definitely needs it. Get rid of the noise and it improves the perception of sharpness. Now, today our modern cameras, this D500 will shoot at ISO one million and it just blows my mind. ISO one million. The native ISO, in other words the ISO that where we're not like really pushing the extremes, the native ISO on these cameras 50,000, something like 50,000 which is incredible to me. I'm trying to remember the number but I don't remember the exact number. Anyways, new cameras, don't be afraid to shoot ISO 3200, ISO 6400, ISO 12,800. You can get just as good of results even better results than the older cameras at the high ISO. Finally with respect to these other factors let's talk about your lens autofocus motor, all right? So, the motor matters in terms of focus speed and responsiveness. Old school lenses from Nikon used a mechanical drive and that mechanical drive is actually the motor lived inside of the camera body. There's actually a little, a screw motor that when you mounted your lens it connected there and you could hear that motor whirring. This one here this is a Nikon 50. It's a 50 millimeter, it's the f/1.8. Love this lens. It's really inexpensive by the way. It's still sometimes available. It's like 110 bucks. Great lens for the money but it uses the older autofocus method. So when you take the photo you can actually hear it go (buzzes) and it's slower. It doesn't respond as fast. Compare that to the new silent wave motor lenses, the AF-S lenses. Well, there's that term again, AF-S. It's a different term here though. Before we're talking AF-S which stood for single servo autofocus. This AF-S stands for silent wave motor. You'll see it there on the lens barrel. It says AF-S, well that means it's a silent wave motor. Well, the AF-S lenses are faster, they're almost silent, you can't hear them when you focus. That means they're good for weddings and good for taking photos of your kid when they sleep in their crib. The newer lenses are great because they're quiet and they're fast. The motor actually lives inside the lens. It's the silent wave, it's actually a linear motor. So, given the option if you have the money I generally recommend purchasing the AF-S lenses over the older AF-D or the mechanical drive lenses. But you can find these a lot of times, the older lenses for a much better price. So, go ahead and pick your poison for money versus performance.
Ratings and Reviews
Good course! I am a beginner and this course helped me a lot. I agree with some students that a better work could have been done in preparing the presentations. It seems to me that Mike is great in having informal live workshops. However, for recorded classes like the ones we buy in Creative Live, the teaching technique should be adjusted. Overall I am glad I bought this course.
This was a great course. I just got a Nikon z5 and I also shoot a D750 and your explanations helped me understand how the autofocus works. I pulled out the cameras while you were teaching to follow along and now I have a better understanding. i appreciate at the level you teach, you keep it simple and practical which is helpful. Good job and thanks.
After having my camera D800 for 5 or 6 years and never really got the focussing down I can finally do it. This video should be included with every Nikon sold. I am so happy that I am finally get the fullest out of this great camera, I am more of a visual person. Reading the manual is not the same as actually see it done... Thanks Mike, you rock! I have watched the sequences over and over and learned so much. Thanks. And always welcome when you pass in New Mexico...