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Autofocus Defined

Lesson 2 from: Using the Nikon Autofocus System

Mike Hagen

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Lesson Info

2. Autofocus Defined

Next Lesson: How Autofocus Works

Lesson Info

Autofocus Defined

Let's talk about autofocus itself. Let's define autofocus a little bit so that you understand the terminology. So focus happens when, I'll hold up my camera here, focus happens when light from the lens converges on the CCD, or on the sensor of the camera. So when light converges on that sensor, it's in focus. When light converges in front of the sensor, it's out of focus, and then when light converges on the back of the sensor, or behind the sensor, it's out of focus. So it's important that we understand what focus means. Focus happens when light converges on the sensor. Now, focus is slightly different than clarity, which is also slightly different than sharpness. So the three images I have here on the screen really illustrate the difference between those three concepts. The photo on the left, where it says original, that is in focus, okay? So that bird is in focus, and to be technical, what that means is the light converged on the sensor properly. Now that photograph actually might l...

ook better if we added clarity. So clarity is a perception of sharpness. In fact, we can add clarity in software after the fact, using mid-tone contrast. A lot of software has a slider, that has a clarity slider, sometimes contrast itself can add the look of clarity. So this image has high clarity, but this image doesn't have high sharpness. The last image here on the right, that has high sharpness, and you can see the feathers on that bird, just really detailed in the feathers. So that has a lot of sharpness, or high sharpness. In other words, edge detail. So all three of these photos are in focus, right? But they each have a different look, because one has high clarity, and one has high sharpness. So as photographers, a lot of time we talk about sharpness, or we talk about clarity, it's just important to know the terms. You can add clarity, and you can add sharpness after the fact, but I will make this point, if your original image is out of focus and soft, you can't add clarity and sharpness enough to make that photo look good. So it all starts with an in focus original image. Another thing that I really wanna cover here today is this concept around gear and your skill level as a photographer. I run a lot of workshops, and I even teach a lot of private workshops around the world, and people always ask me ahead of time, they're like, hey you know what, I wanna work on autofocus, and I think you know what Mike? I think it's my lens, I think my lens has a problem, or I think it's my camera, I think my camera's autofocus system's all outta whack. Well on the phone I'm listening and I'm saying yeah, yeah, yeah, yeah, yeah, but then when we get together, I always impress upon them that it's very rarely the gear that has the problem, it's almost always here. So almost always your skillset and your technique. So skill always trumps gear, well almost always. Your skill level matters, so that's what I want to impress upon you today is that you need to practice. Practice, practice, practice, practice as much as you can. This image here is almost in my backyard, it's in my hometown. I live in Washington State, in a little town called Gig Harbor, Washington, and we have a lot of arctic terns and a lot of seagulls, and so a lot of times I'll just go downtown, sit on the public dock, and take photographs of the seagulls. It's not really an exciting photo session, I'm not gonna really do anything with those images, but I'm practicing and that's the key. You have to keep practicing at this. It's a skill that will atrophy over time, unless you practice. So before I go on a big trip, like say before I go to Africa this year, I'm gonna actually spend a little time ahead of that trip and I'm gonna get out my cameras and get out my lenses, and I'm just gonna practice on birds. You know, I try to practice every single week. I would say that over 99% of blurry photos are caused by operator error, so don't be that person, be the person who doesn't create blurry photos, because you've practiced, and because you know the system.

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.

Cindy Manly-Fields

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.

Catherine Lucas

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...

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