Female mallard duck with low depth of field.

Wide-open apertures cause out-of-focus backgrounds with long lenses.

If you look at a thumbnail (small image) of this picture, it will look like everything is in focus.  Enlarge it so that it fills a good portion of your screen, however, and you can see that the background is blurry.  This was done for a number of reasons, but the main purpose is to help draw your eye to the subject, which is the duck, and not the surroundings.  The fact that they are present though gives you a sense of the environment the photo was shot in and what the habitat is like.

It is relatively easy to make the background blurry with a sharp foreground.  It is well worth your while to understand the various factors that create depth of field.  Manipulating the camera's controls to obtain the precise shot you want is an important part of creating successful photographs.  It turns out there are five different ways you can alter depth of field.

1.  Aperture changes depth of field by varying the size of the circles of confusion which make up the image.  Wide-open apertures (small f/numbers) give less depth of field than small apertures (large f/numbers).  Shooting in aperture priority mode is a common practice, partly because you pick the aperture you want to use.  In the above photo, I used the lowest aperture value I could muster.

2.  Focal length alters depth of field; long lenses (high mm values) have less depth of field than wide-angle lenses (low mm values), given everything else being the same.  Telephoto lenses are more likely to produce an out-of-focus background than normal or wide-angle lenses.  I used a focal length of 180 mm (relative to a full-frame camera) in the above shot; it helped the background be blurred.  I had to be fairly far away though for the whole thing to work.

3.  Point of focus is where the lens focuses.  As the focal distance increases, there is more depth of field.  The closer your subject is to the camera the less depth of field there is.  This is part of the reason why macro shots have such little depth to them.  I could have been closer to the duck, but then to get the bridge in I would have used a lower focal length.  Also, due to perspective differences, the bridge would have been smaller relative to the duck than it is, and I did not want that as my composition.

4.  Size of sensor plays a role as well.  Large sensors must have longer focal lengths than smaller sensor cameras in order to obtain the same field of view.  I shot the above photo with a 1-inch sensor bridge camera, which has a crop factor of 2.7.  The actual focal length was around 65 mm, whereas I would have used 180 mm to get the same field of view on a full-frame camera.  Smaller sensor cameras have to use wider angle lenses to achieve the same shot, and they get more depth of field because of this.

5.  Amount of enlargement relates to how big you make the image and how far away you view it from.  As mentioned earlier, a thumbnail image may all look in focus, but enlarge it on you can clearly see the difference.  An 8x10 print will look different than a 2x3 print for this reason.

When shooting I think about these factors and try to play with them accordingly.  Usually, I am concerned with the first three as they are the ones I have immediate control over.  Play with these factors and see what happens.  It will make you a better photographer.

Thanks for reading.   www.ericspix.com

Yellow Headed Blackbird

Yellow-headed blackbird on a cattail perch.

I can remember seeing my first yellow-headed blackbird, now some 40 years ago.  The setting was very much like the scene above with it perched on a cattail on the outside of a pond on the edge of a city.  I haven't seen any since then, and this one was a welcome sight.  In my experience, red-winged blackbirds are much more common than their yellow-headed cousins.  Yellow-headed blackbirds prefer to nest in fresh standing water areas thick with bull rushes.  They stick to the center areas which offer more protection and easier access to insects, their main food source.

I was kayaking in a small pond and saw a flash of yellow.  Although there are many birds in Canada that display significant amounts of yellow, few of them are associated with pond edges and commonly perch on the associated vegetation.  Yellow and Wilson's warblers are often found in forested areas.  American goldfinches are often found in fields, especially if thistles are present.  I was hopeful that my glimpse would prove to be a yellow-head.

I continued paddling around the outside of the pond, keeping close to the reeds and on the watch for another sign.  Sure enough, twenty minutes later I spotted one.  The wind had picked up in the meantime.  It took considerable maneuvering to get the boat in the right position for light and visual access.  The reeds in front of it were thrashing back and forth vigorously; I had to take dozens of shots until everything finally lined up.  I am quite pleased with the end result.

Thanks for reading.   www.ericspix.com

Vignetting with flash - The Royal Albatross.

On-camera flash is a marvelous tool that can be used to shoot in dark areas and fill shadows.  Its ability to light up areas close to the photographer is limited due to its power and inability to alter dispersion patterns.   Since it is so close to the lens two additional issues pop up.  The first is the occurrence of the notorious "red-eye."  The second is what this blog is about, vignetting.

Vignetting, in photography, refers to the darkening of an area.  Most lenses suffer from some degree of vignetting where the image becomes darker as it progresses to the outside edges.  It tends to be most noticeable in corners as they are the farthest away from the center.  Fortunately, this problem is often mitigated with onboard software inside the camera or with a pixel-editing program such as Photoshop.

The second type of vignetting occurs with flash and can be seen in the above photo.  Since the lens sticks out in front of the camera, just underneath the flash, there is a chance that it may block the progression of light in lower aspects of the shot.  This likelihood is compounded in situations where a lens is physically long, a wide-angle focal length is selected, the subject is close to the camera, or a lens hood is mounted on the end of the lens.  Each of these by themselves represents a risk in creating vignetting, but a combination of them increases the probability significantly.

In the above photograph, a Panasonic FZ2500 all-in-one camera was used to capture the photo.  It has a relatively large lens in its own right, even when the widest angle focal length is selected.  Since it projects so far in front of the camera's flash there is a good chance that it will block some of the light from hitting the image, creating a vignette.  Shoot near a subject with a lens hood on and the likelihood becomes a certainty. 

There are several ways to prevent this or reduce the effect.  Photographing a subject farther away with a bit of zoom will help.  Since a flash's ability to illuminate a scene is reduced by distance and decreased aperture size (increased f/number), the camera's ISO may have to be increased to compensate if the shot is coming out underexposed.  Taking off the lens hood also helps. 

Two additional solutions are somewhat costly.  An external flash sits higher atop the camera and vignetting becomes all but moot.  It also addresses power and red-eye issues.  A shorter wide-angle lens, such as a prime 24 or 28 mm, is stubby enough that it won't get in the way of a built-in flash, unlike some of the multipurpose zooms out there which are very long.

Thanks for reading.   www.ericspix.com

Juvenile Red Breasted Sapsucker

I photographed quite a few birds this summer, and I could figure out what most of them were either from recognition or using one of my many bird identification books.  This bird, however, had me stumped.  It was definitely a type of woodpecker; its size, habits, and body form all attested to that fact.  But what type?  It did not conform to any of the birds in any of my books.

It had a back like a hairy woodpecker, the head of a red-breasted sapsucker, and its underside had a yellowish hue to it.  What really stumped me was the eyering and the yellow cere, which woodpeckers with red heads don't have.  There are 23 species of woodpecker in North America, ranging from the Acorn Woodpecker to the Yellow-bellied sapsucker.  It was none of them.

It wasn't until today that I took time to hunt down which species it belonged to.  I decided that maybe it wasn't an adult, and started looking at websites with lots of woodpecker shots.  I finely came across a juvenile Red-breasted Sapsucker which looked similar to the one in the photo.  It had even less red on its head, but the yellowish cere and eyering were present.  When checking adults to my photo, the body was a close match.

One of the challenges I find with identifying birds is how their plumage changes.  Juveniles often look different from their parents, but the nearby caregivers usually remove any uncertainty.  Some birds take two or more years to come into their adult feathers; some gulls take a full four years.  Then there is the eclipse phase where the winter dress of an adult differs from its summer wear.  Add to that breeding versus non-breeding plumage, variation within a species, and interbreeding between some closely related species and you have a recipe for thorough confusion.

Fortunately, I find the process of identifying birds fairly straight forward most of the time.  Part of it is being familiar with them in general and knowing which birds to look for and which to ignore when checking field guides.  This too becomes an issue when irregular migrants show up, as they are not usually included in the books which only covers the local areas.  Imagine the trouble one would have with all these confounding parameters acting at the same time.  Perhaps then, it is a new species?  Birdus svendsoni.  Cool.

Thanks for reading.   www.ericspix.com

Juvenile Bald Eagle.

Juvenile Bald Eagle on the bank of the Columbia River, near Golden, BC.

My post from yesterday featured one of the parents of this fledged bird.  Before I left on my small trek, I talked to a canoe instructor who paddled that stretch of river many times.  She mentioned that there was an eagle nest at a certain point along the river and that chick and mom were present the last time she went by.  I always love photographing chicks in a nest, but it was likely that the aerie was not going to be in a favourable position to shoot.  It was with mixed anticipation that I began my journey.

It took me about an hour to get to the spot, as described by the young voyageur.  I saw the nest, high atop a dead tree, but no birds were present.  Then, to my left, I saw the pair.  An adult and a newly fledged juvenile.  There was a modest amount of scrub present and I had to wait until they were reasonably visible.  The paddling I had done gave me some speed, that velocity was increased by the flow of the river.  It only took a moment or two before I was in a better position.

When kayaking I use waterproof bags to protect my equipment.  The advantage of it is obvious, and I have saved my stuff on more than one occasion.  The disadvantage though is that it takes time to access anything and time is often a very limited resource easily squandered.  So, I keep my camera handy in case a subject presents itself unexpectedly.  I lay it atop of the now-empty waterproof bag and place it just below the cockpit opening where water is less likely to find it.  It was in this position when I initially saw my quarry.

The adult fled almost immediately, although I managed to get a few shots off before it departed.  You can see one of those images in yesterday's blog (click here).  The chick, now a rather large bird capable of rending flesh with its talons and beak, stayed.  It either was not capable of flying or did not feel threatened by my presence.  I got a few shots off before I was past it. 

Turning around crossed my mind, but there was a rather formidable unknown.  The adult took up a spot not too far away, and I was concerned about its reaction regarding my intent.  The strong desire for self-preservation tied in with not wanting to disturb or alarm the juvenile led me to continue on my journey.  After all, I got some nice shots and had a memorable experience.  What more could you ask for?

Thanks for reading.   www.ericspix.com

Bald Eagle - Continuous versus Single point focus.

Bald Eagle on the bank of the Columbia River, near Golden, BC.

In previous blogs, I had mentioned that I did a solo kayak trip along the upper reaches of the Columbia River, near Golden, BC.  I had an APS-C sensor camera equipped with an 80-400 mm zoom lens, which was used mostly at the 400 mm focal length.  As I rounded a bend in the river I came across a bald eagle and its recently fledged (and now very large) chick.  I got a number of shots off of both, but none with them together. 

Whether a subject is changing its position relative to you, or you are changing your position relative to it, or even both at the same time, there is a problem with focusing.  Most of the time I try to keep still while peering through my viewfinder.  I always prefer my subject to be stationary and compliant, but the truth is there are plenty of exceptions to both situations.  In the case regarding the above photo, I was traveling downstream.  As I moved forward the distance between my subject and I gradually decreased.  This creates a problem for focusing.

The issue is that once focus lock is achieved and you have reframed the camera to get the desired shot, the distance has changed and the subject is no longer in crisp focus.  This is less of an issue with normal and wide-angle lenses, but telephotos have a very narrow depth of field, especially long ones, and it doesn't take much before your subject is blurry.  This is where continuous focus can help.

Continuous focus allows the camera to alter focus continuously as long as your finger is pressed halfway down on the shutter button.  Choosing the correct focus point is important to allow you to capture the image without reframing.  If you attempt to reframe it is likely your subject will snap out of focus as it is no longer in line with the active sensor.  You can get away from this using the AF-L button, but I prefer not to do this.  Instead, I chose a focus spot and keep my subject lined up on it as I am paying attention to the many variables of composition.

This is also a useful procedure when setting the drive mode to obtaining more than one shot at the press of a button.  Using CH (continuous-high) on the drive selector, with the focus mode being set to continuous, and the appropriate focus zone locked in, I can get multiple images, all in focus, of whatever dynamic situation I find myself in. 

A really interesting focus mode is 3-D focus-tracking, which I use in sports and for active wildlife such as flying birds.  That is a discussion for another time though.

Thanks for reading.   www.ericspix.com