My Favorite Non-Photographic Photographic Accessory

Author: Vern West

As a Volunteer Trip Leader on The Best of the West Workshop I became friends, as I usually do, with one of the participants. His name is Alex Tilley and he is the founder of a Canadian company Tilley Endurables. They make clothing for travelers. At the end of the workshop he gave me and my fellow VTL a Tilley Hat similar to the one he wore. At the time I did not appreciate what a nice gift this hat was. It has become one of my most valued “photographic accessories”.

Here in the desert a good hat is valuable to keep the sun off your face, neck and ears. This hat is washable, crushable and it floats. I have soaked in a river to help keep my head cool when it is hot. I have also had it blown off my head into a river and was able to retrieve it.

Tilley_endurables

There are other uses for it.

  • I have rolled it up and used it as a temporary bean bag when I need to steady my camera resting on a boulder or the ground.
  • When photographing and the sun would shine on the lens, flare shows up in the photograph. I frequently use the hat sun shade to my lens and prevent the flare.
  • It can be used as a wind block when photographing a flower. This helps keep the flower from moving so much in the wind.
  • I have used it as a makeshift lens protector by wrapping it around a lens when I had to stick an extra lens in my pocket and sprint across the desert chasing the light.

 

Old Way of Focusing

Author: Vern West
All images © Vern West

Back in the film days at the advent of auto focus lenses there were two options for initiating focus. The first one was initiated by the shutter button. This is the way most of us have our cameras set up today. Your camera probably came this way by default from the manufacturer. The other way was to initiate auto focus using a button on the back of the camera and the shutter button only controlled exposure and shutter release. This method usually had to be reprogrammed through the menu system on the camera. Most modern digital cameras still have the option for back button focus and in many ways it solves some focus and exposure issues that we all have to try and deal with.

Let’s look at some of these issues.

  • First we decide what we want to be in focus (our subject) but then we recompose to get the desired composition. One way is to move the focus point around to put it on the subject. Of course this assumes that there is a focus point that falls on the subject and gives us the desired composition. If it doesn’t we have to depress the shutter button ½ way to lock the focus and then recompose the frame. This may cause the exposure to be over or under because the holding the shutter button ½ way down also locks the exposure and that is not always the correct exposure after we reframe for composition.
  • If the subject is stationary such as a mountain then the focus is achieved and locked until after the shutter is released. Canon calls this One Shot. Nikon calls it Single AF. In this case the camera will give an audible beep when focus is achieved as well as visual indication in the view finder. If the subject were to move the focus would not change and that subject would be out of focus.
  • In the case of moving subject set your camera to AI Servo (Canon) or AF-C (Nikon) and the camera lens will try to follow the subject. For a moving subject only a visual indication shows in the viewfinder.
  • Exposure is set where ever the focus point is adjusted and is usually affected by the overall scene brightness. There are several exposure options that you can set but this is a discussion for another time. As an example, if your subject is darker colored, and you lock the exposure by depressing the shutter ½ way, but the overall scene is bright you camera meter can be fooled into over exposing the image.

Now let’s look at moving the focus to a button on the back of the camera. You may have to read your manual to determine how to achieve this but with

some practice it will become natural. When you do this there will be a learning process because you are probably used to just pressing the shutter release for everything.

  • Set your focus mode to AI Servo (or whatever your camera calls the continuous mode). You won’t hear the beep anymore but you will get a visual

    Image-1. © Vern West

    indication of focus.

  • On my Canon camera I have the * button set to initiate AF.  This is where you may have to use your manual to get your camera setup properly
  • I usually leave the focus point set to the middle position, on most cameras this is the most accurate focus point anyway. I also usually have the exposure set to evaluative although I change it depending on the subject.

So now we can look at some real world scenarios.

  • When you are photographing a stationary subject, put the focus point on the subject and momentarily depress the back focus button. Now you are free to recompose and take the photo, in fact as long as you or your subject do not move you do not have to refocus and the camera will set the exposure when the shutter is depressed. This can be particularly helpful when photographing birds with a telephoto lens and the lens keeps hunting for focus on a small subject in a tree.
  • When you are photographing a moving subject such as a flying bird or panning such as with a bicycle and running dog all you need to do is keep your thumb on the back button and the focus is set to continuous it will track the subject.

  • When you want the lens in manual focus while doing a macro shot of a cactus flower and Cactus Wren flies in and lands on the cactus next to you. You are immediately able to take a properly focused image of the bird by depressing the back button focus button instead of having to fumble with a switch on the lens or finding some menu item. A Cactus Wren may not hang around long enough for you to get set up. This ability to change from manual focus to AF quickly is one of the advantages that I really use and value.
  • This past spring my wife, Barbra & I were scouting for a good place to photograph the full moonrise. We saw a pair of Gila Woodpeckers flying into a hole in a saguaro, feeding baby chicks. When photographing flying birds like this you must pre-focus and then shift the lens to manual because the bird is moving too quickly for the lens to achieve focus. I simply pointed the lens at the hole, pressed and released the back button to achieve focus and I was ready to capture the action.

  • The proper way to do a stitch panorama is to set you lens to manual focus so each frame is not focused at a different point. Instead of switching the lens from AF to manual and back again, I simply press and release the back button focus as appropriate.

 

Is this a better way to autofocus your camera. It all depends on how you work and what your preferences are for switching AF back and forth from single shot, continuous and manual. Give it a try, it might work as well for you as it does for me.

Vern West is an avid nature and wildlife photographer and a trip leader with Arizona Highways Photo Workshops.

 

Focus and Depth Of Field

Author Vern West
All images are copyright by Vern West

One of the questions that I get on various workshops is how to control Depth of Field (DOF) or sometimes understanding DOF. The explanation requires setting your camera to focus on a single point.

So let’s go over critical focus first. Most cameras have several ways of automatically focusing the lens, this is usually called autofocus or AF for short. I shoot the Canon System so my terminology tends to use their terms but the concept applies to all camera systems.

The first AF concept is what Canon calls One Shot and AI Servo. One shot means when you press the shutter button down half way the lens is focused on the subject. If the subject is moving the lens focus does not follow the subject while you have the shutter depressed half way. AI Servo is a continuous focus so that as long as you have the shutter depressed half way the lens will try and follow and maintain focus on the subject. Of course this means that you must keep the focus point on the subject as well as the shutter depressed half way.

This leads to the next AF concept. All camera systems have the ability to set a single focus point or multiple points these points are typically arranged in a diamond pattern or rectangular pattern. In the case of the single point the lens will AF on that point precisely. In the case of the multiple points the camera actually picks one or more of the multiple focus points to focus the lens.Focus-Image-03

This works well in some instances but not for our purposes of controlling DOF. Every camera has a different way of selecting the focus points so you will have to refer to you camera manual to find out how to set a single point. It seems like every Canon model in the last few years does it a little differently so I cannot even explain how to do it even on the different Canon cameras. Now, the first thing to do to control the DOF is to set your camera so that only one AF point is on and have it set to One Shot.

There is another focus mode on some Canon cameras called AI-Focus. It is explained as a combination of both One Shot and AI Servo in that it maintains focus on a stationary subject and tracks a moving subject. After some personal testing I don’t think that it works as well as either One Shot or AI Servo so I use those modes instead,

DOF is defined as the area in an image that is acceptably sharp. A lens can only be in focus at a specific distance but an area in front of and behind the focal point can be sharp enough to be acceptable to the eye. This acceptably sharp area or DOF is approximately 1/3 of the distance in front of the focus point and 2/3 of the distance behind it. If this seems too technical just bear with me and I will simplify it in a minute. I want to explain some of the concepts before going on. I use a free Smart phone APP to quickly determine my DOF in the field without having to calculate anything. The one I use is DOF Calculator but there are many and you need to pick one that you like and is easy to use.  Just search for DOF Calculator in your phone’s APP Store, there are lots of them.

There are three things that affect DOF. The first is sensor size but since we cannot change the size of our sensor we can ignore this factor.  Basically the smaller the sensor the greater the DOF which means that a point and shoot camera or camera phone will have a large DOF and there is very little that you can do control it. However, the other two things that we can control are focal length of the lens and F/stop.

The longer the focal length the shallower the depth of field. A 50mm lens will have a greater DOF than a 200mm lens at the same F/stop. You have probably seen images of a bird on a perch or animal where the background is just a blur of color such as image 01 . This is an example of longer focal length lens and a shallow DOF. The reverse would be a scene with everything in focus from the Ocotillo in the foreground all the way to the mountain in the distance such as image 02. This is an example of a shorter focal length lens and a greater DOF.

The next factor that we can control is F/stop or the opening that lets the light through the lens to the sensor. The smaller the lens opening, larger F/stop numbers, the more the DOF. I like to think of it as a bigger F/stop number gives me more DOF. These two examples show you the DOF of a 70mm lens at F/4 and F/16.


I said that I would simplify this so here goes! Looking at your Smartphone App. The DOF at F/4 in the example above is less than 1 foot but at F/16 it is nearly 4 feet when both are focused at a subject that is 8 feet away. So all you really have to do is let your App do the calculation for you. Adjust your lens F/stop to get the DOF that you want. If you don’t use a smartphone then you can print out DOF charts for the lenses that you use and refer to the chart.

Let’s look at a more real world example. Looking at image 05. Both the Cholla and the mountain are in focus. This was taken at F/16 and 24mm. Using the DOF Calculator App we see that at a subject distance of 8 feet everything would be acceptably sharp from around 3 feet all the way to infinity, the mountain in this case. Since the Cholla was about 8 feet I focused on it and knew that mountain and moon would be in focus. For a wide angle lens, stopping down to F16 will insure a large enough DOF most images.

DOFImage-05

Longer focal length lens require paying more attention to the DOF App and subject distance. The Saguaro flower was taken with 400mm lens at F/6.3 from an about 20 feet away.   The DOF in this case is only around a quarter of a foot.

DOFImage-06

Notice the bud behind the flower is out of focus and the more distant background is a very soft blur.

In the field armed with the DOF App or a DOF chart found on the internet you can improve your images by controlling the depth of field. I’ll save a discussion of Hyper Focal distance for another time.

Vern West is a nature photographer and trip leader for Arizona Highways Photo Workshops.

Photographing the Moonrise – Part 2 of 2

Author: Vern West

Your chance to practice photographing the moon-rise is right around the corner.  June 2nd is the next full moon.

As mentioned in Part 1 of my blog, there are some key factors to review prior to shooting the moon-rise.  The first is identifying the day before the full moon appears, which is this case will be June 1st.  Secondly, you will need to calculate the time the moon rises, which can be determined with the help of a smart phone app like LunaSolCal.  Once you have this knowledge and have scouted your location you will be ready to setup your shoot.

While the sun is still up, use your aperture priority mode and capture the scene.  This is to ensure that both the moon and landscape have been exposed correctly.  In Arizona it’s the last few minutes before sunset that offers the most pleasing light to both the moon and the landscape.

MoonriseImage-04

If you capture the moon while the sun is still high in the sky the moon will be washed out.  Pay attention to your exposure as the sun is setting as it can cause the moon to be over-exposed. Remember the moon is illuminated by the sun but the sunlight gets diffused by the atmosphere at sunset so the landscape becomes not as bright as the moon. To monitor this situation, I usually have the highlight alert turned-on (AKA the blinkies) to let me know when this occurs.

MoonriseImage-06

Getting the moon-rise at exactly the right time to show landscape colors and texture in the moon can be very frustrating and take time to scout but getting it right can produce some really stunning photos. Even if you don’t succeed the first time there is always next month!

Photographing the Moonrise – Part 1 of 2

Author: Vern West

MoonriseImgw-02

We’ve all seen photos of a seemingly full moon-rise with beautiful sunset colors on the surrounding landscape and the moon bright and full. Here is how it is done without trickery or Photoshop skills.

The day before the full moon, it rises before the sunsets and yet it is close enough to full that most observers won’t notice the difference. So the trick is to determine what time and at what azimuth the moon will rise.

MoonriseImage-03

Azimuth simply means what compass heading.  The moon is at it farthest South heading in mid-summer and farthest North heading in mid-winter. I typically use the  smartphone app, LunaSolCal to determine the azimuth. Remember the azimuth is based on true North so you will have to correct your compass for the declination in your area. Here in Central Arizona it is about minus 11 degrees. The smartphone app will also give you the time of the moon-rise at the true horizon. Hills, mountains or other obstructions will delay the actual moon-rise from the time given.  MoonriseImage-01

MoonriseImage-05Armed with the knowledge of time and azimuth you are ready to scout for locations to shoot the moon. Being primarily a landscape photographer, I like to get out of the city and find a mountain or some other natural landmark to capture the moonrise. This does require guess work as to when the moon will actually be visible and if it shows before the sunsets.  Remember we want the sun to still illuminate the landscape.

Tune in next Friday, May 29, 2015 for Part 2 on how to capture great moon photos.

Vern West is a nature photographer and trip leader for Arizona Highways Photo Workshops.