| June 10 Newsletter Depth of Field Considerations I |
What depth of field to use when photographing birds and animals is a topic that I could spend a lot of time
discussing and illustrating so this month's newsletter and the next month or two will explore this topic.
The amount of depth of field you have in any situation is a function of your lens aperture, lens focal
length, your camera body and the distance to your subject. There is a website www.dofmaster.com
where you can enter these variables and the website will calculate the amount of depth of field you have
in inches, feet or meters. The answer is the amount of depth you should be able to get into focus in your
image. The one variable that you will have to estimate is how far were you from the subject because
neither Nikon or Canon cameras record the distance to the subject during use.
For starting points when I am doing bird or wildlife photography I will generally have my aperture set to
about 1 stop or 2/3 of one stop down from wide open. The reason for this is with that amount of depth of
field I can usually get most of a bird in focus and increasing my depth of field more may bring in unwanted
distractions in terms of having my background busier than I like. In addition I find my lens and camera
combo generally produces the sharpest images about 1 stop down from wide open. For beginners wide
open means that the largest aperture (and smallest F-stop) your camera is capable of shooting with. If F4
is wide open for your lens, then F5.6 will be 1 stop down from wide open. Whole stops are F2.8, F4. F5.6,
F8, F11, F16, F22 and F32.
Shooting at 1 stop down from wide open is just my starting point for deciding what my depth of field will
be. In many cases I will end up shooting more wide open than that. This is particularly the case when the
light is low and/or the background of the shot would be distracting (the background is full of branches
and other distractions which are fairly close to the subject).
discussing and illustrating so this month's newsletter and the next month or two will explore this topic.
The amount of depth of field you have in any situation is a function of your lens aperture, lens focal
length, your camera body and the distance to your subject. There is a website www.dofmaster.com
where you can enter these variables and the website will calculate the amount of depth of field you have
in inches, feet or meters. The answer is the amount of depth you should be able to get into focus in your
image. The one variable that you will have to estimate is how far were you from the subject because
neither Nikon or Canon cameras record the distance to the subject during use.
For starting points when I am doing bird or wildlife photography I will generally have my aperture set to
about 1 stop or 2/3 of one stop down from wide open. The reason for this is with that amount of depth of
field I can usually get most of a bird in focus and increasing my depth of field more may bring in unwanted
distractions in terms of having my background busier than I like. In addition I find my lens and camera
combo generally produces the sharpest images about 1 stop down from wide open. For beginners wide
open means that the largest aperture (and smallest F-stop) your camera is capable of shooting with. If F4
is wide open for your lens, then F5.6 will be 1 stop down from wide open. Whole stops are F2.8, F4. F5.6,
F8, F11, F16, F22 and F32.
Shooting at 1 stop down from wide open is just my starting point for deciding what my depth of field will
be. In many cases I will end up shooting more wide open than that. This is particularly the case when the
light is low and/or the background of the shot would be distracting (the background is full of branches
and other distractions which are fairly close to the subject).
HOATZIN - Photographed January 2010 at Sani Lodge, Ecuador. Canon 1D Mark III, 500mm F4 lens at
1/250 F4, iso 1000, evaluative metering -0.3. This image was shot from a canoe which was moving slowly
on the oxbow lake at Sani Lodge. Because I was shooting from a canoe and I was already at a fairly high
iso I shot this image wide open to keep my shutter speed at a reasonable speed. This is a large bird and
typically I would have wanted to stop down some but in this case the low light forced my hand. Luckily
when the bird raised it's wings it was fairly parallel to my plane of focus so it worked out pretty well. An
added benefit of the wide open aperture I used here is that the background jungle is nicely blurred. This
image made it to the semi final round of this year's BBC Wildlife Photographer of the Year contest in the
animal portraits section. I wish I hadn't clipped the lower toe but shooting with a fixed focal length from a
moving canoe made framing challenging.
On the other hand if you have plenty of available light, a clean background and especially if you have
multiple subjects there's no reason not to stop down to get all the details in sharp focus.
1/250 F4, iso 1000, evaluative metering -0.3. This image was shot from a canoe which was moving slowly
on the oxbow lake at Sani Lodge. Because I was shooting from a canoe and I was already at a fairly high
iso I shot this image wide open to keep my shutter speed at a reasonable speed. This is a large bird and
typically I would have wanted to stop down some but in this case the low light forced my hand. Luckily
when the bird raised it's wings it was fairly parallel to my plane of focus so it worked out pretty well. An
added benefit of the wide open aperture I used here is that the background jungle is nicely blurred. This
image made it to the semi final round of this year's BBC Wildlife Photographer of the Year contest in the
animal portraits section. I wish I hadn't clipped the lower toe but shooting with a fixed focal length from a
moving canoe made framing challenging.
On the other hand if you have plenty of available light, a clean background and especially if you have
multiple subjects there's no reason not to stop down to get all the details in sharp focus.
GIRAFFES photographed October 2008 in Etosha National Park, Namibia. Canon 1D Mark III, 500mmF4 at
1/1000 F13, iso 500, evaluative metering -0.3. This image was shot handheld out my car window. I posted
this image on one of the nature photography critique sites and one of the comments from one of the
moderators was why F13? I think implicit in his question he was wondering why I had stopped down so
much. My answer was that I wanted to get both Giraffes in sharp focus and since they weren't lined up
(one was behind the other) I needed a lot of depth of field to get both of them sharp. I went to the depth of
field master website that is referenced earlier in this article to try and determine just how much depth of
field I had. This is full frame out my car window and the Giraffes were quite close. If I was 70 feet from
them (about 20 meters) then I would have had a total depth of field of 3.61 feet. That sounds like it would
be quite a bit more than I would need in this situation. But that is misleading. The autofocus point was on
the cheek of the front giraffe. Drilling down into the numbers further the depth of field at 70 feet would give
me 1.76 feet in front of the focus point and 1.85 feet behind it. While 1.76 feet is plenty for in front, 1.85 feet
behind is probably about right when you consider how thick a Giraffe's neck is and that there is a little
space between the 2 Giraffes. 70 feet is just an estimate, if I was only 60 feet away I would have only had
1.35 feet behind the autofocus point and that would have been really pushing it in this situation. So given
all the lighting conditions, the clean background and the mutliple subjects if I was to change the depth of
field one direction or the other I would have erred toward more depth of field than I used not less. In terms
of the iso and shutter speed, 500 iso is very good with my camera body in terms of not producing noise
and shooting handheld it's always nice to have some shutter speed.
Something else which is illustrated by the depth of field info provided by Depth of Field Master is that the
old 35mm slide film rule for depth of field that you get 1/3 in front of your focus spot and 2/3 behind doesn't
necessarily hold true for telephoto lenses paired with digital cameras. For my Canon 1D Mark III with a
500mmF4 lens at F13 at 20 meters, 49% of the depth of field is in front of the subject and 51% behind the
subject. I plugged in different lens sizes from 300-500mm and different Canon and Nikon bodies and
always came up with numbers that are close to 50% in front and 50% behind as long as the subject was
close (20 meters away or less) and the F-stop was F16 or lower. As the distance to the subject increases
and the F-stop increases the numbers begin to get closer to the 1/3, 2/3 ratio which is so often quoted. For
example with a Canon 50D and 400mm lens at 100 meters at F8 45% of the depth of field plane is in front of
the focus point and 55% behind it. With a 50D and 300mm lens at F16 and 100 meters we get a perfect 1/3
front, 2/3 back depth of field ratio. In practical terms most of the time with bird and wildlife photography
we will be working at closer than 100 meters at an F-stop which is not really high, so 1/2 in front of and 1/2
behind the subject is going to be a more accurate estimate than the 1/3, 2/3 rule on most occasions.
1/1000 F13, iso 500, evaluative metering -0.3. This image was shot handheld out my car window. I posted
this image on one of the nature photography critique sites and one of the comments from one of the
moderators was why F13? I think implicit in his question he was wondering why I had stopped down so
much. My answer was that I wanted to get both Giraffes in sharp focus and since they weren't lined up
(one was behind the other) I needed a lot of depth of field to get both of them sharp. I went to the depth of
field master website that is referenced earlier in this article to try and determine just how much depth of
field I had. This is full frame out my car window and the Giraffes were quite close. If I was 70 feet from
them (about 20 meters) then I would have had a total depth of field of 3.61 feet. That sounds like it would
be quite a bit more than I would need in this situation. But that is misleading. The autofocus point was on
the cheek of the front giraffe. Drilling down into the numbers further the depth of field at 70 feet would give
me 1.76 feet in front of the focus point and 1.85 feet behind it. While 1.76 feet is plenty for in front, 1.85 feet
behind is probably about right when you consider how thick a Giraffe's neck is and that there is a little
space between the 2 Giraffes. 70 feet is just an estimate, if I was only 60 feet away I would have only had
1.35 feet behind the autofocus point and that would have been really pushing it in this situation. So given
all the lighting conditions, the clean background and the mutliple subjects if I was to change the depth of
field one direction or the other I would have erred toward more depth of field than I used not less. In terms
of the iso and shutter speed, 500 iso is very good with my camera body in terms of not producing noise
and shooting handheld it's always nice to have some shutter speed.
Something else which is illustrated by the depth of field info provided by Depth of Field Master is that the
old 35mm slide film rule for depth of field that you get 1/3 in front of your focus spot and 2/3 behind doesn't
necessarily hold true for telephoto lenses paired with digital cameras. For my Canon 1D Mark III with a
500mmF4 lens at F13 at 20 meters, 49% of the depth of field is in front of the subject and 51% behind the
subject. I plugged in different lens sizes from 300-500mm and different Canon and Nikon bodies and
always came up with numbers that are close to 50% in front and 50% behind as long as the subject was
close (20 meters away or less) and the F-stop was F16 or lower. As the distance to the subject increases
and the F-stop increases the numbers begin to get closer to the 1/3, 2/3 ratio which is so often quoted. For
example with a Canon 50D and 400mm lens at 100 meters at F8 45% of the depth of field plane is in front of
the focus point and 55% behind it. With a 50D and 300mm lens at F16 and 100 meters we get a perfect 1/3
front, 2/3 back depth of field ratio. In practical terms most of the time with bird and wildlife photography
we will be working at closer than 100 meters at an F-stop which is not really high, so 1/2 in front of and 1/2
behind the subject is going to be a more accurate estimate than the 1/3, 2/3 rule on most occasions.
Here's the same image with a small crop. I did this to put the x where the Giraffe's neck's cross right
in the center of the frame. When you have opposing subjects like this that are facing different
directions I think a centered crop works really well to create a look of symmetry. Normally I try to
avoid centered compositions but this is one of the situations where a centered comp works well. The
other adjustment I made in this version was to zoom in close on the eyes and use the lasso tool to
select only the eye, then I ran a selective levels adjustment on the eyes. You may have to look hard to
see the difference in these 2 images but this adjustment can make a big difference on images that lack
a catchlight, without artificially adding anything to the image. Don't overdo this adjustment or it can
look unnatural.
in the center of the frame. When you have opposing subjects like this that are facing different
directions I think a centered crop works really well to create a look of symmetry. Normally I try to
avoid centered compositions but this is one of the situations where a centered comp works well. The
other adjustment I made in this version was to zoom in close on the eyes and use the lasso tool to
select only the eye, then I ran a selective levels adjustment on the eyes. You may have to look hard to
see the difference in these 2 images but this adjustment can make a big difference on images that lack
a catchlight, without artificially adding anything to the image. Don't overdo this adjustment or it can
look unnatural.
WHITE-HEADED MARSH TYRANT photographed August 2007 in the Ibera Marshes, Argentina. Canon
20D, 500mmF4, 1.4x teleconverter at 1/1250 F5.6, iso 400, evaluative metering -0.7, 580ex fill flash at -1.3,
handheld from a boat. When using my 20D and 50D I've found that the sharpness is very good when
shooting wide open. This fact and the plants in the background which would have made the background
more distracting led me to shoot this image wide open. At F8 those background plants would have been
more of a distraction. This shot also illustrates how great shooting from small boats in the Ibera Marshes
is. Many of the birds and mammals are quite tame and allow a close approach. I'm planning to lead a tour
there in August of 2011.
20D, 500mmF4, 1.4x teleconverter at 1/1250 F5.6, iso 400, evaluative metering -0.7, 580ex fill flash at -1.3,
handheld from a boat. When using my 20D and 50D I've found that the sharpness is very good when
shooting wide open. This fact and the plants in the background which would have made the background
more distracting led me to shoot this image wide open. At F8 those background plants would have been
more of a distraction. This shot also illustrates how great shooting from small boats in the Ibera Marshes
is. Many of the birds and mammals are quite tame and allow a close approach. I'm planning to lead a tour
there in August of 2011.
White-winged Doves photographed May 2009, Bill Forbes's Pond at Elephant Head near Amado, Arizona.
Canon 1D Mark III, 500mm F4 lens at 1/800 F10, iso 500, evaluative metering -0.3, Gitzo tripod, blind. If you
have multiple subjects that are fairly close it's almost always necessary to stop down a fair bit to get all of
them sharp. This was a setup shot with a cactus in a wheel barrow so I was able to position it with a clean
background. Bill Forbes's place about an hour south of Tucson is one of my favorite places to do bird
photography. To see more information about his place see his website www.phototrap.com . Next month's
newsletter will feature more information on depth of field with an emphasis on close up portraits.
Canon 1D Mark III, 500mm F4 lens at 1/800 F10, iso 500, evaluative metering -0.3, Gitzo tripod, blind. If you
have multiple subjects that are fairly close it's almost always necessary to stop down a fair bit to get all of
them sharp. This was a setup shot with a cactus in a wheel barrow so I was able to position it with a clean
background. Bill Forbes's place about an hour south of Tucson is one of my favorite places to do bird
photography. To see more information about his place see his website www.phototrap.com . Next month's
newsletter will feature more information on depth of field with an emphasis on close up portraits.
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