Lens Quality

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

Lessons

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