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Image Quality

Lesson 18 from: Choosing the Right Camera Lens

John Greengo

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Lesson Info

18. Image Quality

Lesson Info

Image Quality

When it comes to image quality, one of the ways that we technically judge it is with an MTF chart. And this is a way of visualizing the sharpness of a particular lens. And at first, it looks like just a bunch of squiggly lines, but once you learn what it does, it really tells you how that lens is gonna perform when it comes to sharpness. And this is, on the left, a very good lens, and on the right is a not so good lens, or a less good lens, shall we say. Now the way this is measured is zero is the middle point of the lens. So it's measured from the middle outward. And, the right hand side would be the corners of the frame. Everything above 0.6 is considered sharp, and everything above 0.8 is considered very sharp. Now the different colored lines will mean a different type of sharpness. Maybe sharpness at infinity, or sharpness close up, sharpness at F28, or F8, sharpness with different types of contrast on there. It depends on who's doing the MTF chart, and how much information you're ...

putting on there. But here's a couple of MTF charts that I've pulled off to look at. And the more squiggly and wavy the line, probably the less sharp it is. But there are some lenses that are really, really challenging to make, and you're not gonna end up with a straight line across the top. Which in theory, would be about the best one. That 500 millimeter F1 in the top left, that's about as good as you get, when it comes to an MTF chart. Those are sometimes published, and they're sometimes available at the website of the manufacturer who made your lens. A final little tidbit is some lenses suffer from creep. And that is, that is, you're holding the lens around your shoulder, the lens kinda zooms out. And this will happen on zoom lenses. And so some lenses have a little lock that'll allow it to stay locked in, so that it doesn't extend unintendedly when it's carried in a downward position on it. So, some big zoom lenses and some smaller zoom lenses will have that feature in it as well. Okay, it's time to get into our lens review. And we're gonna talk about what I would recommend for particular lenses, or lenses that are just really popular for a particular type of use. Now, it's obvious there are going to be lots of other good choices beyond what I'm gonna mention here. I have about nine different systems, let's see, no, yeah, nine different systems I'm gonna be talking about, and it's impossible for me to talk about all the lenses here, it's more than we want to do. But I do want to go through and highlight some of the most important categories. And so this is the way I'm gonna break things up. We're gonna talk about zoom lenses. I have those in four different categories. And we'll look at basic lenses and premium lenses from all the manufacturers. In prime lenses, we're gonna look at three different levels of wide-angle, normal, and three different telephoto lenses. Once again, basic and premium options. So, I'm gonna give you a recommendation for your camera in each of these different categories. Now, what the heck do I mean by a basic lens and a premium lens? Now this is a personal definition. A basic lens is a general purpose lens, it's affordable, it's a good value. Yes, you'll get good results from it, but it may not have the highest-end features. It may not be built to the most durable standard. It may not be weather sealed. And so the premium lenses are for people who says, hey, I know what I'm doing, I'm willing to spend a little bit of money, and I want the best tool that I can get for doing that particular job. A lot of these lenses are weather sealed, it really depends on the individual lens. And let me tell you, it was really tough making these categories because sometimes a lens was right in between, and I just had to make the best call as to what decision it goes in. Now, as we go through this section here, I'm gonna have two pages. On the first page, is gonna be Nikon and Canon. Their full frame and their crop frame system listed at the top. I'm gonna tell you the name of the brand, the lens, the focal length, the maximum aperture, and then I'm gonna take all the letter designations and put 'em down at the bottom. But, here's a note: I have rearranged the letters because Nikon has put letters all over the place. Sometimes they put letters before the numbers, and then, here, they move 'em around. So I've just kinda put all the letters down there at the bottom. So I had kinda redone that a little bit. So, first page is for your DSLRs. Your Canons, your Nikon full frame, crop frame. On the second page, we go to the mirrorless cameras. First up are the Sonys, and then we have the Fuji, and then we have the Micro Four Thirds. So we kinda have it by size as we go through this. Now, a lot of this is gonna be in the PDF handout, as far as the final lenses that I'm looking at.

Class Materials

Bonus Materials with Purchase

Choosing The Right Camera Lens Handout (15 pages)

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!

a Creativelive Student

Great class. So informative. John Greengo is such a fantastic tutor and explains everything in such and easy-to-understand way. I would highly recommend this class. Prior to doing this class, I was so confused about which lenses are best for various photography. Now I understand lenses completely. Thanks John!

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