The Three Main Optical Issues
the three main optical issues that we have to deal with. Okay, depth of field is truly ah, well, they're all they're all very important, But kept the field is something that it's just almost impossible to work with. And frankly, before the digital age was impossible to work with. Um, as as well as we will see as your magnification increases, your depth of field shrinks very, very, very dramatically. That's probably the biggest understatement I'm gonna make here today. Now you can use smaller apertures. We're all we're all familiar with depth of field when we do a landscape way closed down to get the flowers in the mountains little short so you can use smaller apertures. But when we get into these magnification as we come up against the optical phenomenon known as diffraction, where the image just becomes soft, it has to do with the wave. Nature of light is really nothing we can do to avoid it. Ah, as with any use of depth of field, careful subject orientation will make the best use of ...
whatever available depth of field you have. And then we get into really what the solution is for not every image for a lot of images. Is the image the focus stacking? Where, um, you take a series of pictures and you take the sharpest portion of each picture and you combine them in a computer. So let's just take a look at a depth of field and how it is seen and how is problematic. This is a photograph of a midge and this is my end. My finished image, my final image. Ah, and this is where the stack of 86 separate images combined. If we look at this on the left is one image from that stack. So that's what what my actual depth of field is. If I would take a single picture, that's what it would look like. And they went on the right again is the combined image where have combined my depth of field? So let's go back. That's the That's the finished picture. Ah, here we have on the left. We have ah one image in this stack and on the right, we have the finished image. These are moth eggs. These are very, very small. This is photographed at 10 X now, if in the in the film days I would have tried to shoot at an angle straight down from the top, because I have to make maximum use of my depth of field. But now that I could stack, I can choose an oblique angle like this and you could see that on the left is one image from that stack of images that I used to make this composite. This picture on the right is the finished image, and it took me 291 Focus steps to get that that final image. Okay, And here again, this is a mosquito head, all right. And I I is that 20 x 20 times Life size, one image on the left you can see in fact, if you look, I don't know how easy it is to see there, but you can see how the eyes bulbous. And we're already I picked one image where you can see this is a radio. I start with the focus on the furthest point and I worked my way in, and I've only got a small band of focus there. So again, at 20 x in the film days, this is about what I would have gotten on the left. This is what I can get now, using these extended depth of field techniques. Um, and I I'm into the natural stuff, the bugs and the butterflies and things. But I also do some work for a manufacturer that makes these incredibly incredibly small mechanical devices. And this is one that is already this is already stacked image. But he wanted to close up, and he wanted at an oblique angle, so he wanted basically, he wanted this image And is this This is now getting to the extreme of what I'm able to do with this with this technique, but he could see what one image looked like on the left. Okay? And it took me What did it say? That 332 images to composite to get that depth of field, and I'll be real frank with you. It also took me a lot of photoshopped time because when you got a very complex image like that and you put them together, as good as the software is to do this, you got a lot of artifacts. You got a lot of stuff you got to clean up. So you you do need, uh, some really good for not all images, but for a lot of them. You do need some pretty good photo shop skills in particular. Ah, something you don't maybe use all that much is not just the union, the universal control of the contrast in the color bouncing, but the actual pick solidity. You got to be pretty good at pixel editing for a lot of these things. As, uh, kind of joking with when the individuals here the other day. I am. I've been here in this across since West Coast here since but I grew up in New York, so I tend when I think I got a lot of material that I want to cover. I tend to talk fast. Okay, so I apologize for that. But this little chart again, you don't need to know these numbers. I just want to really reinforce the point that I just gave you at the top. You have a magnification, and then you have your depth of field and I encourage you to start thinking in the metric system. Okay? And you'll see why here not only millimeters millimeters of small this 25.4 millimeters in an inch. But we're talking now. My crimes, which are thousands of a millimeter. We're talking at a scale that beyond what most people deal with on a regular basis, unless you read intel or, you know, into some sort of scientific endeavour. But I'm just gonna make show two points on this on this chart and you could see And when I say that your problems increase exponentially, they dio at one access. So this is with my macro lens at 1 to 1. I can get a good, nice, clear depth of field for about one millimetre. And that doesn't sound like much. You say, My gosh, how can you can you know if you use it properly and one millimeter is 1000 microns? Okay, let's not just go through the trouble. Let's look at 10 X kind of in the middle, because that's a very, very nice area. They're working at 10 millimeters. Might depth of field has dropped from ah 1000 microns toe eight microns. Okay. From one millimeter to eight, thousands of a millimeter. So now you can see why I take so many pictures. If you're trying to accumulate to get a shot that has a sense of depth of field. And again, if you if you're not a metric system person and even if you are, most people don't think in terms of microns and millimeters so down below. I give you a few ah sort of benchmarks, if you would. Standard CD is about 1.2 millimeters thick. That's 1200 microns, you know, and again you can look at these and this is justice. Maybe just toe reinforce the point that I wanted to make you mind. The head of a pin is about a millimeter. It's about 1000 microns. Um, typical grain of salt. Obviously, they're all different sizes, but you know, about 300 microns. A red blood cell is about 6 to 9 microns and a sheet of paper. The copy paper that you have in your printer at home. That's actually somewhere between 97 111 microns, so you could see that you depth of field. In some cases, here is way, way less than even thickness of a sheet of paper, and you could see if you look at the right hand column inches. You can see definitely why we don't use interest. Yeah, I know. I have to sit and look at those numbers to try and think how I would even say them, you know, mostly used scientific notation. You just don't work in inches in this field, Okay? The next, um, optical issue that we have to deal with this diffraction, Um, and a fraction is caused by the wave nature of light. It bends as it goes through it through an opening. Uh, and it's unavoidable when we're dealing with the full light spectrum. You know, if there's a limit to what we can do with visible light after that, you start going into electron microscopes. You get you start getting into all more exotic things that were not obviously gonna touch upon here, but you avoid the problems of the wave Nature of light. Um, the problem is, so we have this tiny, tiny depth of field. So are as photographers are natural. Inclination is I'm just going to stop this lens down. I'm going to use a small aperture, and I'll get lots of depth of field. You can't do it anymore at these modifications because you hit the fraction and give you an example here in a little while, but diffraction just destroys an image quality. It just turns your images to mush. Eso you have to avoid it. Uh, very consistent. And that's why it's important to know what magnification you're working out because it'll kick in at different points of different magnification. You know, as photographers, we work in f stops. We think of app attrited F stops F numbers at 2.8456 11 16 22. Okay, and that's fine. The problem is, these numbers are only valid. These numbers are only accurate for subject aside affinity. Okay, so if I take a 50 millimeter to eight lens and I take it outside into a landscaping and I doubt that infinity but you know, fairly normal distance 10 feet to affinity. Yeah, to eight. It's accurately to eight if I put it on the bellows. If I put it on extension tubes, it's no longer to eight. It's going to be small, and it's gonna be, you know, is going to be at It's gonna be F 11. It depends how much you magnified, the more you magnify it small of this effective apertures and that this is an area. When I was putting this together, I'm thinking, you know, do we really want to get into the weeds here with this stuff? And I do I really have to because you have to understand and you'll see very clearly the impact this could have on your pictures that this is Ah, a little bit everything. Every field of photography has its own technique and has its technology, and it has things need to know. This is Grant. I'll grant you right now, this is a little more. A little more tech. It is a little more of a foundation that you need to understand toe work effectively, you know, But my often total photography I've ever done and most things in life you try to get the tools and the techniques to be second nature. Because otherwise you can't be creative. You can't be creative If if I'm sitting there thinking, Oh, my gosh, You know what is this? What's this house? My tripod work musician can't be creative and created music if he has to think. Okay, let's see. B flat. You know what key is that? Yeah, the equipment, the technique that has toe all become second nature and you have to have a foundation. And this is part of the foundation. You won't think about this. A whole lot in the terms were talking about it here now necessarily. But it will be there and it will just be Oh, yeah, It's just like if you do Ah, portrait. And you've got a nice canon 85 12 lens and you want really soft background and just you don't even think you don't think. Okay, let's see what f stop, though I need 1.2. You know our F 16. I can't remember now. You didn't think about you. Just open the lens upto 1. and you shoot away. So it actually becomes sort of the same thing here and formulas. You don't really need to know. But I want to show you that affect how the effective aperture is really directly related to your magnification. In fact, the f in this formula is the marked the marked aperture like a to eight for And to get the effective aperture, you literally multiplied times, magnification, magnification plus one. Okay, now why? Why Why do I even bring this up. I didn't. You know, this isn't a physics classes in a math class. Now it's it is a photography session. But, you know, on the left, we have at five x a stacked image that was shot at five X with the lens set at 3.5. Okay, my effective aperture is F 21 on that left hand shot. This is the This is this cannon lands. You know, we have here on the right. We have, Ah, a single image. I said, you know, I can't be bothered with the stacking stuff. This lens goes down to F 16. No problem. I was going to shoot this baby. It f 16. Okay, so now at this size, this medication and it's hard for me to tell on the screen how much you can really see the difference. So what I did is I just took a section the same section of both at to 1 on the screen. And this is what they look like. You No wonder. One so you can see the difference. I think hopefully very obviously. Here, everybody gave a couple of head nods. Can you see the difference? A. Yeah, the red. The image on the right is totally destroyed because of diffraction. And this is not something you typically will encounter in ordinary photography. Because they're your F stops are fairly accurate. And lo and behold, the camera manufacturers know never to Ah, you know, make a lens for you for 35 millimeter or on a PSC center that you could stopped down to F 96 because you're going to think it's the world's worst lens. In fact, when can it came out with this lens? They made it very easy toe work at five X and there are There were more than one person I've seen that got that wins this the hottest lenses garbage, These pictures, What a piece of junk. And I really wasted my money. No, it's a great lens, but they're out there at five X, and they're taking their pictures. I'd have 16 because they think they need to stop that for depth of field. So they're getting stuff like you see on the right there. When in reality, lynch is more than capable enough if you use it properly, okay? And, ah, I have benchmarks. Now that this is This is tricky. Now we used to have everybody had 35 millimeter pretty much. Now we have different slice sensors, but the three most common or the micro 4/3 the a P S C. I call it app C and 35 millimeter format, which is a 24 by 36 millimeter center. Now, just, you know, we're not going to get into the physics and wise and wherefores, but these are the benchmarks I I use. In other words, I'm photographing with it with the can is that I have, which are a PSC. I try to avoid any combination that will get me down with an effective after small in F 22 soon as soon as I look and and I don't calculate this every time. But when I'm contemplating a set up or something, I'm going to use on my desktop studio. If you would indoors, I think Well, what if I did this and I look and say, Gosh, that that gives me an effective after ah, 45. I can't I can't work that I got to come up with another solution because I know with that size sensor once I get below F 22 things that things were going to get really soft really fast, you got a little more leeway. 35 millimeter. I use that 32. And if you're one of these real pixel peepers and you just got yourself, you know Sony with 42 megapixels, or canon with 50 mix because you're going to see things that they're going to say. Well, you know this cameras diffraction limited at 56 or F eight or something like that. And yeah, maybe, But good luck. When you get into the macro, will you You're not gonna get those type of apertures. And if you did, you have image stacks that were 6 700 pictures long, and you know you'd be running a stack for a day and 1/2. You know why you went on vacation or something to get to get an image out of the thing. So now these are the benchmarks I used or not your bench watch could be different. If you're just doing small pictures on the Internet, you may be able to accept a little more diffraction of the smaller It is the lesson lesson or disabilities. If you're you know, if you got to make the big 20 by 30 inch prints on the wall, well, then you you know you want to go the other way instead of 22. I may be trying to get f 16 or something like that as my smallest effective effect of the keywords effective aperture. Now you're gonna find when you get it into the higher magnification is that you simply cannot always get it where you want theon sickle solutions don't exist. Yeah, they maybe do exist. But I have a friend who works for intel, and he was telling me about one of the lenses that they usedto create their chips. And it's like a $1,000,000 ones. You know, there's only like, one or two of them in the world, so, yeah, I mean exist. But you don't have I don't have him. Intel has one. Um, in the last optical issue is something we think about in conventional photography, but not to the degree we need to think about it. And we're working at higher magnification. And that's vibration now. Mirrors, mirrors, single lens reflex. I don't know what cameras you guys air using. I use single lens reflex or be using from a 1,000,000 years and is a mirror that goes up, flops up and flops down. And that creates vibration, and that's that's almost a no brainer. I don't even talk about that anymore because anybody that does close up work, they know that the mirror creates vibrations. So you have a work around for that. You have a Merrill lock up or you you know, you have other missions that you use so I don't even talk about Yes, you know, the mirrors that there is a real bad actor. You gotta You gotta take care of that. But what a lot of people don't think about is the shutter vibration. Most of our cameras still have mechanical shutters. Now this is many magnitudes, less vibration in a mirror, flopping up and down. So people will say, Well, I got this new camera. It's a muralist camera. I don't have to. I have to worry about vibration now. That's not true, because he's still more than likely In the vast majority cases, you'll still have a mechanical shudder, even though it's controlled electronically there to blaze that come and they move, and when they hit the 1st 1 hits, there's a little bit of vibration set up. You don't see it in 99% of your conventional. For target for photography, I guarantee you that you'll see it when you start doing table top. Set up the 10 2050 x and you will definitely see if you got a camera mounted on a microscope where it's hard couples, right toe everything and you're working at even higher magnification sometimes. So the mechanic shutter is something you have. Teoh. You have toe have to think about handling your camera. You know you were taking as we'll see, we're taking stages of focus where changing the focus. We're doing things on. We're handling the camera. We're changing. Maybe the the ice or something. You need to let things settle down a little bit at that. You don't you don't really, until I have a x magnified live you? My eyes just popped open, I said, Holy smokes. You know, I'd be downstairs working and the dryer on the other side of the house or the clothes washer would be on spin cycle, and I look at the 10 x magnification and everything be shaking. You know, uh, somebody walks heavily across the room upstairs. Everything. Everything shakes, you know? So you really, really have Teoh pay attention to handling and external environmental. Ah, sources of vibration. Now that you typically the your in house you could control, you know? Yeah. Sit down. Run around upstairs. Are you done with laundry? You know, and I can work External could be tough. Most of us don't have to deal with what external. I mean, you know, if you live in the city on a very busy street, I did a job for Comcast, were in a high rise, and I had to photograph some things and the elevators were right next next to where they had me set up. And the building, actually, you know, moved a little bit. And I think, yeah, this is fine for lots of things. But this is a little bit of a problem for me and, you know, just really interesting to to case of the stick out of my mind about environmental, uh, vibration. I had a fella like I had conversations with online, and he was from Finland, and they lived next to a rock quarry. So when they were working at the rock quarry between blowing things up and loading in my truck so he couldn't work. And at another fellow recently, who somewhere South America might have been Costa Rica with is an active volcano going all the time? A literal has pictures of the volcano from his deck. I mean, it looks like Mt. Rainier does from downtown sailing. And you see the smoke and he says, You know, I can't work a lot of the time anymore. What can I do? Eliminate the external vibrations? Fortunately, this is something we don't have to deal with very much. And a little bit of external vibration that we have weaken were usually in control of it. And so, you know, external vibration. Yeah. You pay attention to that. The loud music. Good grief. If you had speakers on, if you got a real base line going on now, you know everything's moved, uh, in the mirror. Yeah, you'll know about that. Everybody knows with shudder. Vibration. Okay. A fully mechanical shuttle will negatively impact Image quality. Guaranteed. Guaranteed. I don't care if you've got your set up embedded in cement. I've got a microscope, please. About £100 at home. I still worry about it. It's still the shutter vibration. So if you have a fully mechanical shudder, you can get away from you. Get around this by using a very long shutter speed. That seems weird. That seems counterintuitive. But the reason is because the shutter vibration that causes problems typically acres for just a a few milliseconds at the very beginning of the exposure. So yeah, boom, Click the shutter opens and think shake, but they stop very quickly. So if you got a one second exposure to second exposure 99 95% exposure, everything dead calm. So ironically, you know, you can use long exposures to, uh, uh, take care of Ah, shutter vibration problem. You can use electronic flash electronic flash, Obviously the power levels we using doing severely low. So your effective showed a speed is the flash duration which which can often be sometimes of five thousands of a 2nd 10 thousands of second the speed lights. You know, the on camera flashes that we use have very, very, very short flash durations, and, uh, that will take care of usually most camera vibrations. And if you're really obsessive compulsive and you have, ah, three like you can use both along shutter speed and flash with the second curtain sink and then, yeah, then you got it licked. You have to work in very subdued light, but you know, like a one second exposure with second current sink and electronic flash. Man, you've taken care of all your camera vibration problems right there that I don't resort to that because I now have a camera. I use only cameras that have what's called an electronic first shut occurred. This has become mawr and more common, uh, many of the canon cameras have. It is actually the only one night content aware of the d. D. A. 10. I think it is the latest Nikon. Um, some of Sony's have it. Some of the muralist cameras have it now, too. But what this is, it's sort of a hybrid system. When you're alive, you you're looking the shutters actually open. That's why you could see it, because the light's hitting the sensor when you initiated exposure. Typically what happened? What used to happen was the shutter would close and then reopen again on you see? Got that bang bang of the shoulder going now with electronic first shutter curtain they Elektronik Lee clear the shutter. The shutter doesn't have to close to initiate the exposure, but they still use a rear mechanical curtain to finish the explosion. But at that point, I'm done. I don't care what the cheddar hits when that the pictures done a little bit of vibration. It kicks in, does not affect my pictures. The difference can be night and day, especially. I never used to mount my cameras on my microscope, at least not this type of camera. Um, because because of the vibration from the shutter, Soon as I got cameras with this Elektronik first shutter curtain, I now will mount them on the microscope. Before, I used to have a set big, heavy, duty separate stand and I would have separation between the camera and microscope, so any camera vibration couldn't be carried over into the microscope. So, Charles, you mentioned muralists cameras. It seems like Marylise cameras it would eliminate a lot of the eliminates the mirror clear, open including, But I say that's That's a no brainer. Most people are aware of that. Yeah, what a lot of people don't realize is that if you have a muralist that does not have an electronic for showed a curtain, you're actually worse off than a single lens reflex that has Merrill locker. Because what happens is you're looking Tiu c the image the shutters open. And then if it doesn't have electronic shirt, the shutter has to actually close and then reopen to start the exporters. So you so you get you get bam bam! So s So instead of having nothing happened mechanically, you actually have a mechanical shutters closing and reopening. And I don't know if you, you know, you may even if you're not into ah, uh, this type of photography For a while, I have some of these mirror cameras they were having issue issue with something that called Shutter Shake to the point where in in certain Canon Lipkis cameras, they actually made ah, setting that you could set so that when you hit the thing that there would be a delay almost imperceptible. But enough of delay that bother people for that to die out that first down, to die out before it opened again. And so it's ironic but a Marylise camera? Yes, it doesn't have the mirror, but it could give you double mechanical shudder hit as opposed to Ah ah, single one. Or better yet, none at all. Now we're starting to see a few cameras with interchangeable lenses that have Ah, fully electronic shutter. Okay, that's great. I can't wait for the day. They have that. Uh, right now, they don't. The first shutter curtain works very, very well. Fully. Elektronik would be even better. Um, the fact, the only one I know interchangeable, that's now that has a really functional, fully electronic shutter is one of these new Sony ones. I forget which one it is. The new 42 megapixel. And there might be another Sony model, but But that's great. I mean, that that will be now the scientific cameras that they make for microscope. Yeah, they're all electronic shows. They don't None of them have mechanical shows. But you know what? I'm trying to gear this. I don't use one. Uh, but but I always have to consider the workarounds. How can I How can I deal with vibration? That that I do have