Lessons
Class Introduction
05:06 2Lens Basics
10:55 3Focal Length
04:43 4Normal Lenses
10:14 5Wide Angle Lenses
09:24 6Telephoto Lenses
11:43 7Lens Comparisons
08:33 8Aperture
11:26Equivalent Aperture
04:07 10Depth of Field
05:25 11Maximum Sharpness
02:58 12Hyperfocal Distance
09:33 13Mount System & Lens Grade
04:03 14Lens Design
11:36 15Compatibility
17:29 16Lens Technology
05:21 17Focusing & Stabilization
06:39 18Image Quality
04:46 19Standard & Super Zoom
04:52 20Wide & Telephoto & Super Telephoto Zoom
07:48 21Prime Lenses
06:06 22Short, Medium & Super Telephoto Lenses
05:35 23The Macro Lens
07:14 24The Fisheye Lens
10:24 25The Tilt & Shift Lens
10:59 26Filters
06:34 27Lens Hoods
04:02 28Tripod Mount
02:42 29Extension Tubes
03:26 30Teleconverters
03:11 31Making a Lens Choice
04:15 32The Portrait Lens
08:44 33The Action Lens
11:23 34The Landscape Lens
06:51 35Lens Maintenance
09:40Lesson Info
Maximum Sharpness
All right, something else that you need to know about on lenses is that there is a place that you can shoot them to get the maximum sharpness from any particular lens. Now the general theory runs that lenses should be perfectly in every situation, even when they are shot wide open, and the reality is that they are not always totally sharp, there's imperfections and they are most easily seen when a lens is wide open, and so what the result of all this is, is that you need to stop your lens down, which means set it to four, five, six, F8, F in order to get the sharpest settings 'cause that starts disguising and hiding the imperfections that it had when it's wide open, but when you stop down too far, F11, 16, 22, 32, there's another problem that's called a diffraction, and this is caused by light scattering, passing through a very small aperture opening, as the light goes through that aperture it deflects, diffracts slightly and that light ends up someplace else on the sensor, which cause...
s a little bit of blurriness, it's not a lot, but it is a little blurry and so you'll find that shots taken with a very small aperture are not gonna be as sharp as ones taken with a larger aperture and so there is kind of a balance between one extreme and the other and so if you are just asking the question what is the best shutter speed, well let me give you some photographs to look at and we are gonna look at two cropped areas, one from the center and one from the corner of the frame and I want you to judge these photographs to see which are the sharpest set of photos. Probably the worst is the 1.4, this is where it shows the lens imperfections, but down at F22 it's not as sharp because of diffraction and so with any particular lens the sharpest area is gonna be towards the middle, now it's gonna vary from lens to lens, but if your lens is a 1.4 maximum aperture and it also goes down to 22, probably somewhere around five, six is the sharpest setting on the lens, it's not the most depth of field, depth of field and sharpness are two different issues, sharpness is how sharp is it in one particular area and if your lens goes to F4 as the maximum aperture, then probably something around F11. Now there are a lot of factors and we're gonna keep things a little bit on the simple side in this class and if you wanna go study up about this, you can do a little Wikipedia search for pixel size, airy disc and circle of confusion and you can dive in and find out more information about how sensor size and pixel size and how the viewing distance and the size of your images can effect where you might wanna be in shooting these sorts of things.
Class Materials
Bonus Materials with Purchase
Ratings and Reviews
E.L. Bl/Du
John is one of the best instructors Ive watched. he's clear, concise, and gets right to the point. His display's and diagrams are so great, he makes very complicated subjects easy to understand, and fun. He holds your attention and interest b/c everything he says is valuable. This really helped me understand the vast complicated world of lenses. I would highly recommend this class to anyone who doesnt know what hyperfocal distance is.
Boris Dimitrov
Excellent class packed with incredibly useful knowledge. John is an amazing lecturer. He has also developed really great materials to help explain all the concepts and technologies that are explored in the class. Looking forward to my next class with him!
Lettie Turner
Another great JG class, my 4th. He gives a lot of individual attention to several popular lens brands. I really think after seeing this video series you could pick out three lenses that would fit your needs and your pocketbook. The class handout is spot on for what is covered in the video. Great job!! Thank you