Depth of Field, Part 2
Several years ago I wrote an article called Depth of Field Part 1. That article was a very good introduction to the basic principles of depth of field and described how to get good depth of field when shooting small point-and-shoot cameras. If you are a little hazy about what depth of field is or why it is probably the most important technique used by landscape photographers, I think you should go back and read this first article before reading the current article. You should also read this firsts article if you are using a point and shoot camera rather than an SLR camera. Point and shoot cameras are those kinds of cameras that have a single built in zoom lens and don't use interchangeable lenses.
The current article is about how to achieve a great depth of field when using using SLR cameras, not point-and-shoot cameras. SLR cameras are larger, more professional cameras with interchangeable lenses. Since more and more people are buying digital SLRs, I thought I had better update the article on depth of field.
Let me review some of the basics of depth of field very briefly. (To read a much more complete explanation of this quick discussion, I again urge you to read Depth of Field, Part one.)
First, what is depth of field? Briefly, it is a technique of shooting that allows you to keep both the very closest foreground as well as the most distant background very sharp all at the same time. In extreme cases you can keep foreground a foot away super sharp as well as the mountains miles away. This technique, more than any other, is the reason great landscape photographs are great. The photograph above of large, sharp wildflowers in the foreground and sharp, distant background is a good example.
To get the best depth of field, use the widest angle setting on your widest lens. This will usually be about 28mm, but if you are in luck and have a very wide angle lens, it may be 17mm or so. Next, you need to shoot at your smallest f-stop which will probably be f-22. If you are really lucky, you may have an f-stop of f-32 or maybe even f-45. You usually don't find really small f-stops like this on wide angle lens, because you don't really need them on these lenses. You do often find them on longer telephoto lenses, like 200mm or 300mm lenses where you really do need them.
Once you are using a very wide angle lens and a very small f-stop, you have to focus your lens at what is called the hyperfocal distance. The hyperfocal distance is the distance that will give you the maximum depth of field. It is the distance where everything from 1/2 the hyperfocal distance all the way to infinity is in sharp focus.
In the old days of manual focus photography, all lens had what was called a depth of field scale right on the barrel of the lens. To set the lens at the hyperfocal distance, the distance that gives you the best possible depth of field, all you had to do was rotate the focus ring of the lens until the infinity symbol (a sideways 8) lined up with the f-22 mark on the lens and, if your lens was set at f-22, you were automatically focused at the hyperfocal distance. If you were using a 35mm camera, you could look at the other end of the depth of field scale and know that if your f-stop was f-22, you were in focus everywhere from infinity to about two feet.
Don't worry if you didn't understand the above explanation of setting the hyperfocal distance on manual focus cameras. I doubt if anyone reading this article actually has a manual focus lens. Maybe one or two of you who are still shooting with film may have such a camera. If you do, just set up your camera with the infinity symbol on the lens aligned with the f-22 mark, set the camera at f-22, and everything between about two feet and infinity will be in focus. Magic.
Now, for all the rest of us who are shooting digitally and who have autofocus lenses, ie 99% of the world. You have to do the same thing the manual focus guy did, but without a depth of field scale: just focus your lens at the hyperfocal distance for the f-stop you are using. But how in the world do you do that? You have no depth of field scale on any of your lenses and you may not even be able to focus your camera manually. Now what?
At this point, depth of field may be sounding really, really complicated, too complicated to even bother with. But it's really not. It's really very simple. Trust me. Hang in there until the end of the article and all will be crystal clear and very easy.
The first thing you need is a simple cheat card that gives you the hyperfocal distances for specific lens settings at specific f-stops. You can order these online for almost nothing. I like the cards sold on a web site called fotosharp. You can find them at fotosharp.com. Click here to go to the page on their site where you can buy a hyperfocal distance card.
When you get to the fotosharp.com site, you will see that they have different cards for different digital cameras. Which one you get depends on whether your camera has a full frame sensor (the same size as a 35mm piece of film) or a small sensor like 1.5x. It isn't hard to choose a card, you almost certainly have either a full frame sensor or a 1.5x or a 1.6x sensor. Just choose the proper one for your camera and order it. These cards cost $5.00 from fotosharp the last time I looked, a real bargain. They also have a discussion of depth of field and lots of info on their site if you are interested.
Once you get your depth of field card in the mail, you're all ready to go. Find the aperture you are using in the top row, find the lens setting in the side column, and then find where the column and row meet in the center and there is your hyperfocal distance. I would begin with an aperture of f-22 and a lens setting of 28mm. The hyperfocal distance for my Canon 1DsMark II, which is a full frame camera, is 4.7 feet.
Now all you have to do is set your lens aperture on f-22, zoom your lens to the 28mm position, and focus the lens at 4.7 feet. Your camera will now take pictures that are sharp all the way from 1/2 the hyperfocal distance, about 2.5 feet in this case, all the way to infinity.
Setting up your camera to do all this is easy. You should have a dial on the top of your camera for various shooting modes. Set it to A for aperture priority and then dial in f-22. Zoom lenses have marks on them to show how far you are zoomed in or out. Zoomed all the way out is usually 28mm. Or just look for the 28mm mark and set it there.
Focusing the lens to 4.7 feet is easy also. If you have manual focus mode on your camera, you could turn it on and manually focus to a little under five feet. This is probably way too much trouble though.
However, for all of you real-world photographers, you really don't have to mess around with getting a depth of field card and all of that. Read on to see just how easy all this is for the pragmatic, seat of the pants, real world photographer.
In the real world what I usually do is much, much simpler. For instance, say I want to take a picture with a bunch of Columbines in the foreground and mountains in the background and I want both to be sharp. I'll set up my camera on a tripod and set up the composition the way I want it. I'll make sure the flowers are at least 2.5 feet away or maybe just a touch more to make sure. Then I'll make sure the f-stop is f-22, the lens is set at 28mm. Finally I'll move the the focus point in the viewfinder to a point about 4.7 feet away. I just guess at the distance. When I push the shutter button down to take the picture, the camera will focus on the spot that is about five feet away and I'll have taken a picture where both the flower and the mountain are in sharp focus.
This really isn't rocket science. I don't even think much about depth of field anymore. When I'm taking pictures where I know I want close foreground and distance to both be very sharp, I just make sure the camera is set at f-22 and 28mm, keep the foreground about 2.5 or 3 feet away, no closer, focus out a bit beyond the foreground and shoot away. It will all work quite well.
The distances don't have to be exact. If you are going to err, do it on the background focus though, not the foreground focus. The background mountains that are miles away can be a touch out of focus and it won't really make much difference. But the foreground has to be absolutely razor sharp or the picture will be worthless. To make sure the foreground is absolutely sharp, I usually focus directly on the middle of the close up flower bush to be sure it will be razor sharp a little in front of the focus point and quit a bit of the way behind the focus point. I know the far away background will be a little soft, but who cares when the incredible sharpness of the foreground is blowing the viewer's mind.
I used to think all critical depth of field work had to be shot from a tripod. But lately I've begun to think a lot of landscapes with a long depth of field can be shot with a handheld camera. As you can imagine, handholding the camera makes the whole operation much easier. To get the right focus distance, just make sure you are not too close to the flowers, focus on a spot right on or maybe a little beyond the foreground, press and hold the shutter button half way down to set the correct focus and then move the camera back to the composition you want and finally press the shutter button all the way done to finish taking the picture.
Skipping the tripod enables you to move quickly and easily between shots before that great light is gone forever and it also results in very spontaneous shots as you rapidly move to get various angles and frames and backgrounds. If you have to wrestle with a tripod, none of this happens. You get maybe one shot and then the light is gone, or the wind comes up or you get so frustrated with setting the tripod up over and over that you just give up.
Several years ago I became so enamored with handheld shooting that I wrote a whole eight part article about how to do it. If you are interested here is Part One of that article.
A word of warning about handholding though. When you set your camera at f-22, you are using a very small aperture that eliminates a lot of light and the camera automatically compensates by choosing a very slow shutter speed, sometimes as slow as one or two seconds. Since nobody can hand hold a camera at such a slow speeds and not get blurry pictures, you have a problem. This is the reason I always used a tripod in years past when I wanted a lot of depth of field.
There is one critical piece of equipment that you need to make handholding work. This is a camera that is good enough to shoot at 1000 ISO without digital noise. Using high ISO speeds are the only way to use small apertures and still get shutter speeds fast enough to handhold the camera. And unfortunately, the only cameras that will do this are usually pretty expensive cameras.
If you cannot shoot at ISO 1000 or at least ISO 700 , you just won't have enough speed when shooting at small f-stops to be able to hand hold. You have to use an f-stop of at least f-16 and much more preferably f-22, at speeds of at least 1/125 (or maybe 1/25 if your lens has image stabilization,) in order to make handholding work. Read the handholding article, it explains all this much more clearly and it has a lot of good information in it.
Different lenses have different effects on depth of field. A really wide angle lens, like a 17mm lens will give you a lot more depth of field than a 28mm lens. With the 17mm lens you can keep everything from less than one foot to infinity in focus. This is a good lens for handholding since it is very short and easier to hold without movement. Use this kind of lens when you love the foreground and want to emphasize it in the picture but the background is ho-hum. This lens will make the foreground huge and the background tiny and insignificant.
On the other hand, a long lens will have less apparent depth of field. If you are shooting a 150mm lens, you will be able to keep everything sharp from only 65 feet to infinity, everything closer will be out of focus. This is why long lenses often have smaller apertures. If you can use f-32, the close end of the sharp range will drop to about 45 feet. f-45 allows even closer foreground to remain sharp. Use a long lens when the part of the picture you are really interested in is the background and the interesting foreground is 30 or 40 feet away from you. This is a good technique to use when the very close foreground is ugly and you really don't want it in the picture at all.
At any rate, once you practice depth of field a bit, you will soon be doing it quickly and naturally without even thinking. Pictures with both sharp foreground and sharp background have a whole new look that will quickly mark you as a pro. Work on it. It's really not very difficult.
Updated, Dec 8, 2013
Millinocket Lake in the Maine North Woods