All right folks, we've been looking at a lot of basics of lenses so far, we've been talking about focal length and aperture, and next we're gonna be getting into individual lenses but before we do that, we wanna talk about what goes into those lenses, kind of in a lens and technology appreciation moment if you will. So we're gonna talk a little bit about Olympus Technology, the way that they design lenses, and what they put into their lenses. So let's first talk about what goes into designing a good lens. Now, it's not as easy as you might think. There's a lot of things going on and there's a lot of elements, and a lot of ways of altering those elements to make them do what you want them to do. And so if you were designing a lens from scratch, you would probably wanna start with great resolution. You want a lens that's sharp, that's important. Of course you want good contrast and that is related to sharpness but it is a slightly different subject, but also very important. You of course...
want accurate color, and you don't want any distortions like barrel distortion or pin cushion distortion. You want straight lines to be rendered straight. It'd be nice if the lens was as small as possible, of course, and you want it light weight so it's easy to bring about. You want it simple to use and simple to build so that you can build it more efficiently and it'd be nice if it's low cost, that's just a good benefit to everyone. But trying to get all of those at the same time, well that's a very challenging thing for the lens designers and engineers to do. Let's talk about a few of these things in particular. Resolution, well that's pretty simple. It's how much resolving power a lens has. And they have very good high resolution lenses from Olympus, they're always trying to achieve something better. And in general, the collection of lenses that we have today are better than the ones that we had 20 years ago but this is something that they're always working on to achieve greater and greater resolution because the sensors are increasing in their pixel density. Next up is a particular problem when you are shooting into the sun and that is flare. It's light reflecting and refracting through the lens elements in the lens, and where light is starting to end up where it shouldn't because it's getting bounced around. And there's a lot of coatings and different types of glass that they can use to reduce the flare that you might get in a particular photograph. Diffraction is where light is coming through the lenses and goes through a very small aperture opening, and when it hits the edge of those aperture blades is slightly diverted onto a new path where it lands where it's not supposed to land. And you get a lowering of contrast and your images just don't look as sharp when you have this happen. And so this is a particular problem that needs to be dealt with in a number of different ways. Another problem is chromatic aberration. This is a color ghosting, and this will happen most frequently when you have bright backgrounds and something solid in the foreground. And what happens is that on either side of that solid object you might get red or purple or bluish fringing of colors that is not natural. Once again, engineers can design lenses with lens elements and coatings to avoid for this in certain types of lens designs where that is more prone. Another problem, particularly for wide angle lenses, is distortion. And this is where it could be a barrel distortion, where it's kinda pushing outwards, or pin cushion distortion, distortion where it's kind of pulling inwards. And of course you want straight lines to be rendered straight, and so ideally a lens doesn't have this and so there are various ways of correcting for that problem. Vignetting is something that happens quite frequently with very fast lenses, or lenses that are shot wide open. And this is where the corners of the image are darkened up a little bit. Now, the weird thing about vignetting is that sometimes it's good and sometimes it's bad. It's bad when you want a nice even tonality, in say the sky of a landscape photograph. But in many portrait photographs, it's nice to have a little bit of vignetting to draw the eye inwards to where your subject is, probably closer towards the middle of the frame. And so, personally, I add vignetting on as many photographs as I try to remove it from. And so it depends on the type of photograph as to whether you like it, and what style you like in a photograph. Next up is bokeh, and this is the quality of the out of focus area. And this will become very apparent with shallow depth of field lenses. And there is smooth bokeh, and what sometimes people describe as jittery bokeh, it's less smooth. Also with bad bokeh, you'll notice the aperture shape. A well-defined aperture in a round shape will generally yield more pleasing bokeh areas in the background. And so there's a number of steps that the designers can do in engineering a lens to give it better bokeh, which is something the Olympus engineers have done, particularly for a series of their lenses. And so there's a lot of different problems and challenges that you get with making lenses. Finally, construction. How do you build a lens? What sort of materials is it made out of? What sort of features does it have on it? So all of these things are compromises when it comes to any lens, and every lens, no matter how good it is, no matter how much money is, is a bit of a compromise with money and size and weight and what's available, and these things change in time. So let's take look at some of the technology that Olympus is using that they're putting into their lenses that you will see as advertised as one of the things about a particular lens that's in there. Now, when you take any lens from Olympus and you start dissecting it, you're gonna see a lot of information so let me decode what some of this information means. So the "M" before "Zuiko," is their mirrorless systems. So that is for their current lineup of cameras. It's the M. Zuiko system. And so "Zuiko" is just the Olympus lens brand. A lot of the manufacturers over the years have wanted to have kind of a separate, independent department for making the lenses, as opposed to making the cameras. And they've kind of rewarded these separate internal, external companies with their own brand name. And so a Zuiko lens is an Olympus lens, but it's their branding for the particular lens. Digital simply means that these lenses are new to the digital era, they're not designed for film and then adapted to digital, they were designed, and from the very get go, designed for working with digital sensors which is a little bit different than film. There are some manufacturers who've had to change their film lenses in order to work better with digital sensors. Most lenses will have filter diameter that you can screw in appropriate filters for that. The maximum aperture and the focal length we've covered pretty much in detail in previous sections of this class. Many lenses will have an "ED." This stands for extra-low dispersion. This is gonna help get all the colors landing in the right spot on the sensor. Some lenses will have an image stabilization built into the lens. Now, it's not super important because the cameras that Olympus has has a built-in image stabilization system with a sensor that moves around to compensate for your hand movement. But lenses that have image stabilization built into them can work with the stabilization in the body and achieve even a greater effectiveness when compensating for movement. The PRO lenses are a series of lenses from Olympus that are designed at the highest quality level that they can make. And these are lenses that are typically very sharp, they're well-constructed, they have nice, big, manual focus rings, they've got good buttons on them that are easy to press. It's kind of everything a serious photographer wants in a lens is gonna be in those PRO lenses. Some lenses might have an "R" which means it's a revised version of it, or a number two for a second generation or possibly down the road a third or fourth generation as lenses progress and are improved over the years. A couple of lenses are electronic zoom lenses so they have a motorized zoom for the action of zooming in and out. Typically, that's a little bit more helpful for people shooting video but there are very few lenses that have that. So something that I have mentioned a number of times is the PRO lenses from Olympus and they have been coming out with a lot of these lately, they've been concentrating, you might say on the higher end of lenses, and they are wanting to have a great collection of lenses for a professional doing a wide variety of work and so, the first thing with these is that they try to make these lighter weight and smaller than competition from other manufacturers. They are weather sealed better or as good as anything els I have seen out on the market. And so if somebody was looking for a weather-resistant system, I think Olympus would be at the very top of that list to look at. And that kinda goes right into the durability. The construction that these lenses go through, especially these PRO ones, is very good. They're using top quality components, they're weather sealing them in there, and that makes them very durable for the long term. Image quality, obviously this is something that's very important to them, something they've taken seriously for a long time, very good quality results from these. The image stabilization as I say for the most part is built into the bodies, but we also have it built into some of the lenses and it is class-leading which means it is the best out there right now. And so there is some pretty unbelievable examples of what you can do. I was watching someone else use an Olympus camera system and they were shooting an eight second night exposure hand-held, getting good results. Wouldn't guarantee that for everybody in every situation, but it's getting ridiculous at how slow of shutter speeds that you can hand-hold these cameras and lenses at. And also close-up shooting. Many of these PRO lenses are just gonna be able to focus closer than many of the competition. And so these are the common benefits that you get when you get to these pro lenses. Now the general idea when Olympus went to this 4/3 system was a new lens design for new sensors. And what they decided to do is kind of re-engineer from the ground up, a new system that would work with digital sensors. And one of the ideas was a telecentric design. And that basically means the light takes a straighter path in order to get to the pixels. It's easier to work with the light, the light gets into the pixel wells and exposes the sensor a little bit more easily and allows them to do more with their lenses. And so that's why this is a little bit different than systems that were adapted from previous film systems. And so we're gonna have sharper edge quality and less vignetting because of that. I mentioned ED before, extra-low dispersion lenses, the problem is is as light goes through certain types of glass, different wave-lengths will land up on the sensor at different points, either before or after it, and that's not gonna make for a sharp image and so they need to use a special type of glass that is of course a little bit more expensive, more difficult to work with, in order to get it to be as sharp as possible. And so this is gonna suppress that color-bleeding that you might get. It's gonna give you the greatest possible sharpness, now there are also "Super ED" elements that you might see listed as part of a particular lens and that's just taking this to another level. The refractive index of a lens indicates how much light is actually getting through the lens. Obviously, if you have a piece of glass, we want as much light to get through that glass as possible. But glass is going to eat up a little bit of the light and it's never going to be 100%. And so the Olympus engineers had to design special types of glass that let through as much light as possible, and obviously that's good for a lot of different reasons. And now we can reduce the size of the lens, for instance, and have slightly smaller lenses. You'll also see "Super HR" in some particular lenses. Now "HD" is a combination of the two features that I just talked about. It's a highly refractive so it lets lots of light in but it's also a dispersion lens to make sure that all the light lands in the correct spot. And so this is gonna be shown in the 40-150 for instance, and so I know for a lot of you some of this doesn't make a lot of difference because when you're out shooting you're not thinking about this. But when you see the lenses advertised, it is kind of nice to know what goes into this lens and what does it have compared to other lenses. Another very tricky, more modern lens design that they were not able to do many years ago is an aspheric lens. Normal lenses are spherical, which means they're rounded, it's very smooth, it's very easy to grind these lenses and make them smooth and even. But an aspherical lens is more difficult to make just right. And they need to do this in order to correct for the light rays in a number of situations. And when they do this, they're able to make lenses that they were not able to make before, or lenses of a smaller design, or a greater zoom capability. And so they can reduce the number of elements and make all this into a smaller package so the 9-18 lens uses this technology and the benefit is pretty clear. They've been able to design a very, very wide-angle lens in a very, very small size package. It's an incredibly small lens. And so that comes out to be a big benefit for a lot of different types of photographer. So a dual super-aspherical glass will have aspherical sides on both sides of it, but the super part of it comes in from the fact that it's just so thick. It's kind of unusual and it's very difficult to make. And Olympus is proud to announce that they have the thickest, most unusual dual super-aspherical glass element on the market today. And this is maybe why they're one of the only companies, or the only company, to have a 12- or equivalent style lens with a fixed aperture on it. So this is an f4 aperture constant from 12-100. And so this is the best super-zoom I've ever seen in my life of photography. Most super-zooms are gonna have this very wide-spreading maximum aperture but having a constant aperture of f4 is very unusual and part of that is thanks to this unusual element in the lens. "EDA," extra-low dispersion aspherical lens, and so this is combining multiple pieces of their technology. So, we have standard glass which may not have all the light hitting the sensor at the right place, and then now they're gonna exchange that with an aspheric extra-low dispersion glass. And so that's gonna fix up a number of problems and that is an example of what is used in the 12-40, which is one of my favorite general purpose lenses. One of the best all-around lenses that you can have on the cameras. 'cause it gives you a little bit of wide angle, little bit of telephoto, and a reasonably fast aperture, all in a small size with very sharp optics. And so that's how they were able to achieve that in that small package. Something that you're gonna find on pretty much all the lenses is their standard coating of the lenses. And they're gonna do this to reduce flare, get you the maximum amount of contrast, gets you the maximum amount of image quality out of there. So this is just a coating that goes on top of the glass itself. One of the more unusual coatings that they put on is this thing called Z coating nano. And it's these nano-sized particles filled with air, which doesn't make a lot of sense to me, I'm not an optical engineer in this case. But what it's doing is it's suppressing certain types of ghosting and flare, which I know is a good thing 'cause you wanna have the cleanest light coming into the lens possible. It's also gonna reduce the surface reflection so that you get as much light coming into the sensor as possible. Not really associated with the glass, but more the focusing motors in the lenses, is a feature that they call MSC. It's movie and stills compatible mechanism. And this is gonna give you fast and smooth auto-focusing whether you're shooting stills or shooting in the movie mode. And one of the things that I've seen if you've ever watched reviews about general cameras is that they may have a camera that takes really good still photographs and has very fast focusing but when they shoot video, the lens makes a lot of noise. Well, the reviewers don't say that about the Olympus lenses because all of the Olympus lenses are really quiet. And so while these cameras are designed for still photographers, we all know that video is a big part of these cameras these days, and these cameras arguably do one of the best jobs when it comes to focusing because it's so quiet and smooth and quick in its focusing. Sync IS is something I've talked about before, and this is where the cameras have in-body stabilization. And some lenses, particularly the 12-100, the 300 f4, and the new 150-400, will have stabilization built into the lens itself so that can match up and handle certain types of movement and the body will handle other types and combine, they will get up to 7.5 stops of stabilization. Now you will see a number of different numbers thrown around when it comes to stops of stabilization and it may very from person to person so you might be different than me. The 7.5 stops of stabilization will come with 12-100 lens and the EM1X. If you were to use the 12- with say the EM1 mark two camera, then you're gonna get 6.5 stops of stabilization which is still better than anyone else. But, the newer the camera, the newer the lens, generally the better the stabilization that you will get. Snapshot focus is available on a number of lenses like the 17 lens here. There is a manual clutch that you can push back and forth, it's also available on the 12, and I might be able to bring out a lens to show you a little bit more closely right here what it looks like. And so this is the 17 millimeter f1.8 lens, and it has a manual focus snapshot where you can go back and forth. And the advantage to this is that you can flip it back to be in manual. Manual focus wherever you want, put it back, auto-focus as you wish, and then whenever you want to go to manual focus, a preset manual focus point, you simply, let's hold this up here to make sure it's in focus, or I'll just move it back. We can see this moving back and forth here, you can have it set to a particular distance so if you wanna focus on infinity, you can go to infinity, dial that in, put it back in auto-focus, focus as you wish automatically, and then when it comes time to focus on an infinity, just drop it there and it's instantly in infinity focus and so it automatically goes back and forth. And so there's a few lenses that have this clutch mechanism on it and it can be very handy for certain types of photography. And so they had that technology but then they improved it and then they changed the name of it and so the improved version of this is the "MF clutch." And this is something that you'll find on the PRO lenses. It works in the same way, it has a clutch system that you push forward and back for auto-focus and manual focus, but the new system is a little bit more smooth at focusing especially at close up. And so this is a great way of just quickly going in and out of manual focus and auto-focus. Something that you won't find on too many of the lenses is the electronic zoom, and so this extends and retracts the zoom mechanism automatically when you turn your camera on and off, and can make for very smooth zooming if you are shooting video. Something that their PRO lenses in general will have is their waterproofness, and they talk about being splashproof, dustproof, freezeproof, they guarantee it down to 14 degrees Fahrenheit and it's one of the only companies that I've heard of that has a very specific, weather-resistant rating. A lot of companies will say, "Yes, our stuff is weather-resistant." Not weatherproof or waterproof which are different ideas, but this actually meets a specific standard, and that standard states that it can handle ten minutes of water from above, dripping on it from above. Now, I've seen a number of examples that people have taken it to extremes and done much more than that, but that has been certified as rating, as being better than for waterproof. So when it comes to interchangeable lenses with waterproofness, probably no other camera is better than the Olympuses with a waterproof lens on it. Something that you will see if you look up for technical information about the particular lens is the MTF chart. This is the modulation transfer function, it's basically showing you the sharpness of the lens. And they seem like kinda confusing little charts at first, but it's pretty easy to figure out. Lines towards the top means a sharper image. And so a good lens on the left will look like that, a lens that's not quite as sharp will be like the one on the right. And these are made up lenses that I did for graphics. What's going on is the zero, vertical on the left side is the center of the lens, and over on the right-hand side is the corner of the lens and so if you were to look at the sharpness, sharpness tends to be better in the middle and then gets a little bit weaker over on the edges for most lenses. Everything above .6 is considered to be pretty sharp, it has lots of contrast to it. Everything above .8 is considered to be very sharp and have a lot of contrast to it. And so if we were to pull up some of the MTF charts for different lenses, these are supplied by Olympus, these will give you an idea of their performance. You really wanna get them out and shoot them, it's just kind of a general idea. A word before you start comparing these with other brands, don't do it because every manufacturer has their own system for rating and testing and doing their own MTF charts. So unless you are looking at exact MTF charts from the same independent organization, they are not directly comparable from one to the other, it's best just to stay in brand and compare one lens versus another lens. Another aspect to Olympus lenses is their feathered bokeh, and this is gonna be most notable on three of their most current lenses, the 17, the 25, and the 45, all maximum aperture f1.2 lenses, and they have gone back to re-look at how the lenses are designed in order to give the smoothest possible quality bokeh to it. And so if those of you who are into photography, and really into it, because if you're looking into the out of focus areas you know you're really into photography. These lenses are gonna perform as well as anything else on the market when it comes to the quality of the bokeh in the background. Having said that, bokeh is subjective, and so it's gonna be a little bit matter of opinion, but these lenses are designed to give you the smoothest possible bokeh possible. And one of that aspects goes into having a nine bladed rounded aperture so that no matter what aperture you're at, it's as round as it can possibly be so you don't see those shapes in the highlights and that'll help make for a smoother quality bokeh.
John Greengo is an award-winning photographer specializing in outdoor and travel photography. Shooting for over 3 decades, John has developed an unrivaled understanding of the industry, tools, techniques and art of photography. When he's not traveling for a new shoot,
John Greengo's class on lenses was EXCELLENT! This information is very helpful for any prospective Olympus customer or any current Olympus user overwhelmed by the company's lens assortment and interested in learning how the individual components might fit - or not - in their shooting requirements.
Covered all aspects of types of lenses and what they do and even what they don't do.
Would highly recommend this class to beginners but helpful for someone ready to go the next step as well.