Lesson Info
12. F Numbers
Lessons
Buttons, Dials and Switches: What This Course is All About
03:37 2Setting Up Your Camera
05:25 3JPEG or RAW
03:11 4Compression
01:38 5Menu Settings for JPEG Shooting
05:19 6Module 1 Summary
01:42 7Applying White Balance
03:41 8Using White Balance Creatively
01:19Auto White Balance
03:07 10Module 2 Summary
01:31 11Controlling Exposure
01:23 12F Numbers
03:06 13Lens, Aperture, and Shutter Speed
03:32 14Exposure Modes
01:48 15Too Little or Too Much Light
02:34 16Manual Exposure Mode
01:37 17Aperture Priority Exposure Mode
02:23 18Module 3 Summary
01:40 19ISO in Practice
01:16 20ISO and Noise
05:03 21An Acceptable ISO
01:23 22Module 4 Summary
01:29 23Metering Modes
03:06 24The Light Meter
02:11 25The Bucket Test
02:12 26How To Read Tonality
02:32 27Being Creative With Tone
01:14 28Exposure Compensation
01:35 29High Contrast Lighting
03:39 30Histogram
02:06 31Highlights Alert
01:32 32Never Underexpose
04:16 33Digital Exposure Mantra
01:25 34Module 5 Summary
02:57 35Focus Modes
01:23 36Autofocus
02:59 37Point of Focus
02:35 38Depth of Field
02:41 39Hyper-Focal Distance Focusing
02:51 40Focus Tracking
04:19 41Manual Focus
01:57 42Predictive Focus
01:03 43Summary
02:32 44Buying Lenses
05:00 45Summary
01:45 46Quality of Light
01:32 47Direction of Light
01:52 48No Such Thing as Good Light
02:00 49Final Word
02:52 50BONUS - In Conversation with Art Wolfe
07:11 51BONUS - The Source of Creativity
06:34Lesson Info
F Numbers
So what do all the different exposure numbers mean? Well, shutter speed, the pretty obvious. They're measures of seconds and fractions of seconds. The numbers relating to lens aperture, however, are a bit more confusing. But honestly, they do make sense. They equate to the area of the hole in the lens, the aperture through which light passes Now. In the old days, each number related to a whole one stop change on the scales looked a bit like this. In the simplest terms, each number is a doubling or harding of the exposure. For example, if I change lens aperture from F A 12 11 I'm having the quantity of light entering through the lens. If I do the opposite and change from F eight, where 5. I'm doubling the quantity of light similarly with shutter speed, if I change the shutter speed from 1 to 50th to 1 500 I'm having the length of time the shutter is open. If I go the other way and change from 1 to 50 with the 11 25th I'm doubling the time now to confuse things. Modern cameras enable adj...
ustments be made in smaller increments. 1/2 or 1/3 stops, and the scales now look more like this and notice the addition of the intermittent markers. But whatever the incremental change, the principle is the same. Each change increases or reduces exposure by a fixed amount. So now you understand the principle. Let's look at how this works. In practice, I'm starting with a portrait shot of the horse and rider. I've said the lens after a 5.6 and a shutter speed of 1 2/50 and this gives me a correctly exposed image. Next, I want an action shot. But my shutter speed 1 2/50 is too slow to freeze the movement of the horses, so I need to increase it. I'm going to put it upto 1 1/1000 which means the shutter is open for 1/4 of the time compared to my original setting of 1 to 50. To compensate, I need to open the apogee of in my original setting of 5.6 F four F 2.8, which quadruples the quantity of light passing through the lens. So now, even though my shutter speed and aperture have changed, the exposure value is the same which will give me the same correct exposure. Finally, I want an image that captures a sense of where we are now. I need a smaller aperture to get some detail in the background. I'm going to adjust my aperture from F 2.88 which is a three stop change. Again, I need to compensate for the loss of light by reducing the shutter speed by three stops that takes it from 1 1/1000 toe 11 25th. As before, my exposure settings have changed, with the total amount of light affecting. The sensor is exactly the same, resulting in the correct exposure. And you can see this if we compare all three images and look at the sky. The brightness is the same across each photograph. When it comes to exposure, you are constantly changing you the lens aperture or shutter speed. The question is, does it matter which of the two you change? The answer is yes, it does. In fact, it's about the only thing that matters
Class Materials
Bonus Materials with Purchase
Ratings and Reviews
mark jacobson
What a marvelous course! What a marvelous teacher! When I went to college, my father would always ask me about my professors, more than the courses themselves. He was passionate about learning and although too busy with earning an income to go beyond an undergrad degree, continued to read 50 books a year. I still remember how he'd get almost visibly excited when I'd tell him about some special professor who taught with such enthusiasm and, more than just passion, evident delight and joy in the subject. 'Ah they're the best, son. How wonderful you have such a teacher." Well, he passed away decades ago but if he were still around I'd get a kick out of telling him about Chris Weston, the 'Prof' of this course. He's one of the very special ones: a teacher who's loved and lived his vocation--his avocation--since he was a boy--and still is as excited about it now as he was then. The result: a course that seems to be more a labor of love--of pouring far more energy and thought into the details then one typically finds in these courses--than anything else. Bravo Chris! I'm already on to your next one.
user-6402bf
Chris is an amazing instructor who dissects theory giving amazing analogies that bring concepts to life. I have rarely been able to sit through most video course for more than a half-hour but watched this one from beginning to end. A good refresher course if you've been away from the camera for awhile or there are some concepts that still illude you. I highly recommend this course and look forward to watching his others. Thank you for the clarity and great explanations.
Sky Bergman
This was an amazing class. I have looked at a number of basic photography classes. This one was by far the best I have seen. Chris is an exceptional teacher. He breaks things down into digestible information and then inspires you to be creative. Thank you!