Lens Quality


Fundamentals of Photography


Lesson Info

Lens Quality

All right, a final little section here on lens quality. And so we talked about the angle of view, we talked about the aperture, but there's also a few things that impact the image quality that you're gonna get from any particular lens. So, first off, we wanna talk about some of these optical challenges in making lenses. And we wanna have lenses with the highest resolution possible, and there is no rating on this, as far as a number, when you buy your lens, but lenses tend to be getting sharper because we have higher resolution cameras now. And so there are some older lenses which are quite nice but on newer cameras, with higher megapixels, they don't stand up as well as they used to back in the days of film and lower resolution sensors, and so that's one of the things that we're getting just inherently in the newer lenses. Some lenses deal with flare better than other lenses, and so when light strikes the front of the lens, it causes ghosting and light hitting different parts of the se...

nsor, and so this is why you wanna use a lens hood, and why some lenses are better corrected for lens flare than others. I talked about diffraction, when we stop our aperture down. And so what happens is that, when we stop our aperture down, the light hitting those aperture blades gets diffracted, sent in slightly different directions, which causes just a little bit of blurriness. So stopping down to f22 and 32 is not recommended, unless you really need it, because it's gonna cause a loss of sharpness on any particular image. Chromatic aberration. Chromatic, color. Aberration, ghosting. Color ghosting will occur when you are shooting a solid object that has light behind it, and so as the light comes around the solid object, the light kinda gets a little misdirected, and it doesn't land in the right spot on the sensor, and you get this color ghosting. Now, this can be corrected sometimes in camera. You can turn on chromatic aberration correction, or you can do it in post-production in a program like Adobe Lightroom. Hit the checkbox and it knows what lens you have, how bad that problem is, and can automatically fix it. Or you can even go in and manually fix it, where it looks for edge lines of a certain color and corrects it and de-saturates it, basically. And so it's something that'll happen even with the best of lenses in bad conditions, you might say. Distortion is something we talked a little bit about before. Barrel distortion is more common on wide angle lenes and pin cushion distortion is a little bit more common on telephoto lenses. And all lenses should be perfectly corrected, but the reality is is that all lenses have a little bit of distortion, and to fix this, programs like Adobe Lightroom will have a little checkbox or they'll have a slider where you can fix this up later. In most images, you're not gonna notice this is a problem, but if you have buildings and straight lines, you might see that and you might wanna correct for that, if you have a lens that has a bit of an issue with these. Vignetting is something we talked about earlier. It's a darkening of the corners, and sometimes we like it and sometimes we don't like it. It depends what type of photograph it is, and what you want from the photograph. This is a problem of fast lenses, wide angle lenses, and cheap lenses. In the early days, some of you might remember, we had TVs that had rounded corners, and that's because the image was really dark and blurry in the corners, because the lenses weren't very good at getting sharp edges. So they just said, "Well, let's just make it like this." And there were some TVs that were round, because they had really bad lenses, I think, at the time, and they couldn't get anything sharp from the corners of them. The bokeh, the quality of the out of focus area, and you know your getting picky about lenses when you're worried about the bokeh of this. And I'm not even going to get into the how do you pronounce it thing. There's a whole thing on the internet about it. I call it bokeh, it's my class, that the way I like to call it. (instructor and students laughing) So, a good bokeh is gonna have a smooth and creamy out of focus area. The bad bokeh, you might be able to see an outline of the aperture, and it's a little bit more jittery and less smooth, and so this is something that some people will grade and qualify. There is no number on this, it's just more of a feeling, it looks more smooth than it does over here. On the right hand side, it's not very good. It kind of goes bright and dark very, very quickly there. And so some lenses are a little bit better than other lenses. Construction of the lens. This is really important to me. I like working with a lens that feels good in the hand, that's comfortable, that focuses smoothly, has nice click stops on the apertures, things like that. And so, metal lens mounts, because I tend to change lenses a lot. The less expensive lenses will use plastic lens mounts. I like a real focusing ring with a rubber grip on it, so that I have a good area to grab onto. Distance scales, and there's other factors in here we'll talk more about as we talk about lenses. But there are some pretty big differences between the lowest end and the highest end lenses. And so, it's not just optical quality, it's the entire quality of that entire product that you're gonna be looking at. And so, when it comes to the optical hierarchy, of what are the best lenses and what are the worst lenses, it generally falls into this category of professional prime lenses, and so a prime, like a 200mm lens, is gonna be a really high quality lens. Next up is gonna be a prime lens, just your standard 50 or 35mm lens. They're not necessarily quote unquote pro lenses, they're just prime lenses. They're gonna be very, very sharp. Next up are your professional zooms, your 24-70, 70-200, 2.8. Kind of next down on the list of sharpness are gonna be your standard zooms. Now, the difference between the 18-55 and the 200... Noticeable, but not huge. You could shoot a cover of next month's National Geographic or whatever magazine you wanna think of with any of these, would be my guess, if it's a good subject. But when you get into the pixel peeping, you will notice greater sharpness with those primes, and especially those high end primes. The lowest on the list are the superzooms, the ones that zoom a really large range, you know, the jack of all trades, master of none philosophy. If you design a lens to try to do everything, sharpness is going to suffer a little bit. And what I have found is that teleconverters will take any lens and lower it by one step on this list. And so, what you probably don't wanna do is put a teleconverter on an 18-200 superzoom lens. Kind of falls off the chart then. But, if you use it on a high quality lens, you'll be getting decent results still, but it's gonna lower it just a little bit from its original native abilities without using teleconverters. We'll talk more about teleconverters in the gadget section in this class.

Class Description

As a photographer, you will need to master the technical basics of the camera and form an understanding of the kind of equipment you need. The Fundamentals of Digital Photography will also teach something even more important (and crucial for success) - how to bring your creative vision to fruition.

Taught by seasoned photographer John Greengo, the Fundamentals of Digital Photography places emphasis on quality visuals and experiential learning. In this course, you’ll learn:

  • How to bring together the elements of manual mode to create an evocative image: shutter speed, aperture, and image composition.
  • How to choose the right gear, and develop efficient workflow.
  • How to recognize and take advantage of beautiful natural light.

John will teach you to step back from your images and think critically about your motivations, process, and ultimate goals for your photography project. You’ll learn to analyze your vision and identify areas for growth. John will also explore the difference between the world seen by the human eye and the world seen by the camera sensor. By forming an awareness of the gap between the two, you will be able to use your equipment to its greatest potential.


1Class Introduction
2Photographic Characteristics
3Camera Types
4Viewing System
5Lens System
6Shutter System
7Shutter Speed Basics
8Shutter Speed Effects
9Camera & Lens Stabilization
10Quiz: Shutter Speeds
11Camera Settings Overview
12Drive Mode & Buffer
13Camera Settings - Details
14Sensor Size: Basics
15Sensor Sizes: Compared
16The Sensor - Pixels
17Sensor Size - ISO
18Focal Length
19Angle of View
20Practicing Angle of View
21Quiz: Focal Length
22Fisheye Lens
23Tilt & Shift Lens
24Subject Zone
25Lens Speed
27Depth of Field (DOF)
28Quiz: Apertures
29Lens Quality
30Light Meter Basics
32Quiz: Histogram
33Dynamic Range
34Exposure Modes
35Sunny 16 Rule
36Exposure Bracketing
37Exposure Values
38Quiz: Exposure
39Focusing Basics
40Auto Focus (AF)
41Focus Points
42Focus Tracking
43Focusing Q&A
44Manual Focus
45Digital Focus Assistance
46Shutter Speeds & Depth of Field (DOF)
47Quiz: Depth of Field
48DOF Preview & Focusing Screens
49Lens Sharpness
50Camera Movement
51Advanced Techniques
52Quiz: Hyperfocal Distance
53Auto Focus Calibration
54Focus Stacking
55Quiz: Focus Problems
56Camera Accessories
57Lens Accessories
58Lens Adaptors & Cleaning
60Flash & Lighting
63Being a Photographer
64Natural Light: Direct Sunlight
65Natural Light: Indirect Sunlight
66Natural Light: Mixed
67Twilight: Sunrise & Sunset Light
68Cloud & Color Pop: Sunrise & Sunset Light
69Silhouette & Starburst: Sunrise & Sunset Light
70Golden Hour: Sunrise & Sunset Light
71Quiz: Lighting
72Light Management
73Flash Fundamentals
75Built-In & Add-On Flash
76Off-Camera Flash
77Off-Camera Flash For Portraits
78Advanced Flash Techniques
79Editing Assessments & Goals
80Editing Set-Up
81Importing Images
82Organizing Your Images
83Culling Images
84Categories of Development
85Adjusting Exposure
86Remove Distractions
87Cropping Your Images
88Composition Basics
89Point of View
90Angle of View
91Subject Placement
92Framing Your Shot
93Foreground & Background & Scale
94Rule of Odds
95Bad Composition
96Multi-Shot Techniques
97Pixel Shift, Time Lapse, Selective Cloning & Noise Reduction
98Human Vision vs The Camera
99Visual Perception
100Quiz: Visual Balance
101Visual Drama
102Elements of Design
103Texture & Negative Space
104Black & White & Color
105The Photographic Process
106Working the Shot
107What Makes a Great Photograph?