We are talking about macrophotography, which is basically taking pictures of small objects at short distances. I'm not going to get into the magnified "super macrophotography" of teeny tiny insects or spiders. I'm not going to be talking about focus stacking or other tricks. We're just going to be talking about photographing tarantulas (or scorpions, etc.) and using basic macro techniques to maximize things like depth of field, which is what APERTURE is all about. And aperture is this first installment's subject matter.
SLR stands for single lens reflex and, of course, DSLR stands for DIGITAL single lens reflex. Simply put, a single lens reflex camera uses a mirror and prism system so that you are looking directly at your subject THROUGH THE LENS. This is different than the point-and-shoot camera where you are looking through a viewfinder and seeing the subject slightly differently than will be captured by the film or digital sensor. When you use a smartphone you see what the lens is capturing on a screen and this is what is called "live view" on point-and-shoots or DSLRs (different manufacturer's have different names. I'm a Nikon guy so some of my terminology will be theirs. As we get further into this topic I will give the Canon equivalents, but for other maker's you'll have to look up the slight nomenclatural differences).
The simplest definition of APERTURE is that it is a hole through which light travels. Aperture can be a very technical subject if you get into things like cone angles and bundled rays and how collimated they are. But we don't give a flock about those. We're keeping it simple so all I want you to know is that your camera's aperture is related to how much light you are allowing to pass through the lens to the sensor. (I'm going to refer to sensor as I am assuming almost all of you are using DSLRs).
Aperture is measured by what are called f-stops. For example, f/2.8 and f/18. I'm going to use these two extremes to explain further. One thing that is hard for people to grasp is that the smaller the aperture the larger the number. Let's state that again. f/18 is a much smaller aperture than f/2.8. We'll skip the technical explanation. Just remember that each stop decreases the amount of light as you move from smaller number to larger number and that this increases the DEPTH OF FIELD.
Now depth of field is what aperture is all about. The smaller the aperture, the less light reaches the sensor and the greater the depth of field is. That means that more of the subject from the front to the back of the image is in focus. We don't need to burden ourselves with the physics involved. Just trust me.
Getting back to our f/2.8 and f/18 ... Large apertures like f/2.8 or even larger ones like f/1.4 or f/1.8 are highly popular with portrait photographers. They put a person's face in perfect focus while blurring the background in a pleasant way that is referred to as BOKEH. If you are photographing a group of people (e.g., a foursome) that aren't on a single plane (exact same distance from lens) you may have to go to, say, f/4 or f/5.6 to slightly increase the depth of field so all the people are in focus. When you buy a lens it is normally rated with its largest aperture (smallest number) as the largest aperture achievable by the lens is related to its quality and price. This is for lenses with FIXED FOCAL LENGTHS. This means that a 35mm lens only shoots at 35 mm. I have a Nikkor 35mm f/1.8 (a steal at $200 and great for portraiture). It can shoot at smaller apertures than the largest (f/1.8), but it cannot shoot at focal lengths longer than 35 mm. Then you have your zoom/telephoto lenses. These can adjust from a minimum focal length to a maximum focal length. For example, I have a Nikkor 18-200 mm f/3.5-f/5.6. This means that it's largest aperture is f/3.5 and that would be at shortest focal length (18 mm), but if I zoom out to 200 mm than my largest aperture becomes f/5.6. Very expensive zoom/telephoto lenses will have a single maximum aperture (f/stop) throughout its entire focal length range. Some of these cost as much as a good compact car. OK, let's get back to DEPTH OF FIELD.
The shortcomings of point-and-shoot cameras is that even if you put them in their macro mode (generally represented by a cute little flower icon) the smallest aperture is typically only f/8 (or greater) and that IS NOT sufficient for quality portraits of arachnids. I've joked in previous blog entries how I carry 30 pounds of camera gear while Guy walks up with his fancy point-and-shoot and quickly captures his images. His results are good, but they don't compare to mine. The benefit of his point-and-shoot was it's great zoom ability, which would be a $10,000 lens for me. However, those long range shots are lacking in detail and full of what we call NOISE. A point-and-shoot is no substitute for a DSLR. The point-and-shoot camera automatically raises the ISO to make the sensor more light sensitive and capture more light (that's a topic for another day) resulting in poor results due to what is called LUMINANCE NOISE. It is a small package of compromises that doesn't duplicate the performance of a DSLR.
So if f/8 is not good for macrophotography, what is? I can tell you that the majority of my macro shots are taken at f/18 using a Nikon 7100, which is a camera body among the highest end of their cropped sensor DSLR range. I can tell you that my bud Chad Campbell, a more accomplished photographer than I, also shoots most of his "macro" shots at f/18 using the same Nikon 7100. f/16 can be used for larger subjects and you may go as small as f/22, so we will focus on a range of f/16 to f/22 noting that f/16 and f/18 are more useful than f/22 for most photographers and most shots and that Chad and I both agree that f/18 is the "sweet spot" for our D7100s paired with the Tokina 100mm macro lens we both use.
So we are using small holes. That is, small apertures with larger f-stop numbers. That means we need good lighting as we are limiting what makes it to the sensor. I won't squeeze a discussion of lighting into this APERTURE article. Simply put, you need to get good light, with good diffusers OFF OR ABOVE the body of your camera. Built in speed lights will only give satisfactory results; they won't excel.
By using these small apertures we are maximizing DEPTH OF FIELD. We want as much of our small subject in focus as possible. My example of portrait photography was the exact opposite. We want our model's face in perfect clear focus, but we want the background to have that pleasant blurred bokeh. As a rule of thumb, most landscape images are taken at f/8 or f/9 and you focus on part of the landscape approximately one third of the distance between you and the background. This gives pleasing results. In fact, there is a photographic adage that when in doubt shoot everything at f/8. If you want the far background of a landscape to be detailed than you use a smaller aperture like we would for macrophotography. That is f/16 or smaller. Depth of field will make more sense when I show you a series of example photos using the exact same subject at the exact same distance at the end of this article.
So, by now you may be wondering about HOW TO CHANGE f/STOP. First thing you have to do is get your camera out of its AUTO MODE. This mode is a compromise that gives reasonable results for NOVICES but you are now going to be changing aperture and you have graduated to INTERMEDIATE. AUTO does all things OK, but nothing WELL. We want to tell the camera what to do now. We are edu-muh-cated. We are smarter than some Japanese machine. If you are a Nikon user rotate that dial to A (aperture). If you're a Canon user they make it a bit more complicated and call it "Av" (aperture value). You are now in APERTURE PRIORITY mode. Don't be scared, we're still going to trust the camera to do some things for us. We aren't going completely MANUAL. At least not yet. I will tell you that I do 90% of my shooting in aperture priority (again, that means my MODE DIAL is set to A). What this does is tell my camera, "Hey, bud, I am going to choose my own damn aperture and all I want you to do is choose what you think is the best shutter speed". Now if you have your ISO set to AUTO your camera buddy will also choose the ISO for you. However, I don't have my ISO set to AUTO. I want it as low as the light will allow and that is ISO 100 so I set that manually (again, this is beyond today's discussion). I use good lighting so I don't need extra light sensitivity from my camera's sensor. (ISO is similar/equivalent to what was ASA for film ... you old-timers will remember buying ASA 100 or 400 or 800, etc.). Now that we are in APERTURE PRIORITY MODE we can select f/16 or f/18 and then let the camera do everything else. Let's not go cowboy and go all MANUAL yet... You can set aperture several ways and I'll let you Canon (and other) people consult your own manuals. But for you wise Nikon users you usually rotate the command dial left for larger apertures (lower f-numbers) and right for smaller apertures (higher f-numbers). You should see these numbers display on your small LCD screen or on the large rear display if you are in INFO mode.
You now know a lot more about taking proper macro shots than most people do. I can tell you that I travel the world with a couple guys who buy macro lenses and then just leave their cameras in AUTO MODE. What a waste of money ... just buy a point and shoot and put in in "flower mode". You'd have better results at a fraction of the cost. If you do not understand APERTURE and DEPTH OF FIELD, and all of you should now, you are not taking good macro images.
That brings us to one last topic before I show you some example images and end today's lesson. Macro lenses. As I said, getting into lighting would be a topic of its own, but all of the above rambling assumes you have a MACRO LENS. The best value in macro lenses is the one Chad, I and other friends all use: The Tokina f/2.8 100 mm 1:1 macro that goes for around $400. You need to have a 60-100 mm lens made for macro (Nikon tends to call them micro). The 1:1 in our Tokina's name is ideal if you can afford it. It means that we can get "life size images". In other words, we are capturing actual size. A 1:2 lens captures images at "half life size". The Tokina we use has a minimum focus distance (how close we can get) of just under one foot and a maximum aperture of f/2.8 (again, that is in the lens name) with a minimum aperture of f/32. Without a macro lens your ability to capture quality images of small subjects is limited or impossible. Practice with what you have, but save the money for the Tokina I mentioned. It is by far the best lens at the best price.
So now let's look at the same spider photographed the same way at different apertures (f/stops). For the record, I am using my Nikon D7100 handheld at the same approximate distance with the camera set manually to ISO100 and in APERTURE PRIORITY MODE. The lens is the Tokina 100mm macro. The camera's computer will decide my shutter speed for these shots and I will include it in the photo description. For lighting I will be using a Nikon SB-900 mounted to the hot shoe with a Pocket Box 6" x 9" softbox diffuser. Everything else will stay the same from image to image except for aperture (f-stop). I'm sure the spider will move a bit (she did!) so it will not be posed exactly the same, but the distance between lens and subject will stay approximately the same. I will shoot at f/5.6, f/8, f/10, f/13, f/16, f/18 and f/20. A larger aperture like f/4 or f/2.8 would be crap, which the f/5.6 is, but only worse. I didn't bother going above f/20 as hopefully you can see that f/18 is superior to all the others. Unfortunately, the f/16 example is poorly focused and I don't have time to reshoot. Because I am using good lighting all the shots will have a shutter speed of 1/60 sec. Again, I am letting the camera set the shutter speed, but it did not change throughout the series of images. We'll cover shutter speed and how it relates to hand holding or tripod in a future lesson.
The subject is a juvenile female Harpactira pulchripes approximately 2.5" in diagonal legspan. Although I normally shoot only in RAW (another lesson, another day), I will be using completely unprocessed JPEG images for the photo examples at the end.
These images should reveal how important aperture is to macrophotography and why a point-and-shoot (or DSLR IN AUTO!!!!) cannot yield the same results. As I wrote, I use A (Aperture Priority, Av on Canon) for 90% of my photography. For spiders and snakes and such I am usually at f/16 to f/18. For landscapes I am typically at f/8 or f/9, but may go to f/16 or smaller if the scenery in the distance is the important subject. For portraits I use the largest aperture possible (smallest f-stop number). f/2.8 is very good, but f/1.4 or f/1.8 can produce the best bokeh.
In closing, I will remind you that a complete rundown on my camera rig is in Blog #12A. And remember, the greatest thing about digital photography is you can take as many images as you like for free. Practice. Experiment. Get this aperture thing down and then start thinking about composition and lighting. Macrophotography is fun and there are plenty of subjects both in your spider room and outside in your bushes. Capture images of the latter before winter comes. Happy shooting, MJ
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| 100mm, f/5.6, 1/60 sec, ISO 100 |
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| 100mm, f/8, 1/60 sec, ISO 100 |
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| 100mm, f/10, 1/60 sec, ISO 100 |
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| 100mm, f/13, 1/60 sec, ISO 100 THIS IMAGE IS A BIT OUT OF FOCUS AND IS A POOR EXAMPLE |
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| 100mm, f/18, 1/60 sec, ISO 100 |
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| 100mm, f/20, 1/60 sec, ISO 100 |
The f/18 image puts the entire spider in focus with exceptional detail and no noise. Look carefully at the spider and the background in all of the images.
Hope you learned something new, MJ
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