Controlling depth of field

Coluber constrictor (blue racer) Ann Arbor, Washtenaw County Michigan, 1997

I love this shot; especially that the depth of field (DOF) is shallow and dead on with the eye. If you look at the large version on Flickr, you will see that the tip of the snout is just at the end of the area of focus and is a bit fuzzy. The out of focus parts of the snake exaggerate the length and draw your attention to the obvious glare of the subject. DOF is the phrase that describes the area in front and behind the focal point that are would be described as having acceptable sharpness.

I had everything going for me. It is a pre-digital taken with Minolta X370 and a Tamron 70-300SP on Ektachrome 200. I was about 5-6 feet back with the lens at 300mm, it's not recorded, but it was a cloudy day so I'm sure that I was shooting with the aperture pretty open. I was going to launch into a long discussion of factors controlling DOF, but there are others who have done a better job of explaining than I could. They involve issues of constant magnification, circles of confusion, and effective apertures.

Still for most, there are three classic factors to consider when controlling DOF, and the greatest impact is on those who use digital SLRs and SLRs. Point and shoot cameras are at a disadvantage for creating images with shallow DOF. These are the focal length of the lens, distance from the subject, and aperture (how much the iris is opened for the shot). To minimize depth of field, long focal length (telephotos), being closer to the subject, and large apertures (actually the smaller numbers f/1.8, f/2.8 rather than f/16) are better. Of course, the opposite is true when trying to broaden the DOF.

An important fourth factor that has more relevance with the advent of digital photography is the size of the sensor. If you have ever tried to get shallow depth of with a point and shoot digital, even if you can control the aperture, you have likely been left wanting. It hasn't been talked about much because a camera owner can do little about sensor size, whether that sensor is electronic or film, and on many less expensive cameras you have little control over the primary controlling factor, aperture. I shoot with cropped sensor cameras, that is cropped compared to 35mm film equivalent sensors like ones found in the Canon 5DmII or the 1DsmIV. This smaller sensor means with all other things being equal, the area of adequate sharpness is going to be about 1.6 times greater than "full-frame" cameras. So, if you want to take photos where you can easily control DOF, think bigger, and generally, more expensive. The larger the sensor, the easier it will be for you to control what is rendered as being in focus and what is not.

I can tell that it is spring

This is an egg of Ambystoma laterale at Black Pond Woods Park in Ann Arbor, Michigan.

Even if I lost all sense of time, I would be able to tell the seasons. In the winter, photos of warm spots become popular, in the fall photos of changing leaves and pumpkins, and in the spring photos of amphibians and their eggs are searched for. This photo, rarely looked at, was a hot commodity today.

Mole salamanders (like tigers, spotteds, blue-spotteds, etc) tend to move to the ponds to breed when the ground begins to thaw. The migrate to ephemeral ponds that form in the spring from the melting snow and spring rains. They rarely seem to use ponds that don't, at least occasionally, dry up. Drying up keeps out fish.

These salamanders pick tend to pick the most miserable night of the year to move to the ponds. It is still cold, but just above freezing, with pouring raining. Still, watching them make their march, and then seeing them in the ponds doing their courtship dances is a sight to see and I forget the cold. For many years, watching the salamanders, listening for frogs was spring for me. From people using my photos and recordings, I see that it is still spring for many. I think I need to take an evening drive this weekend. It has to be rainy, though a little warm. I won't see the salamanders, but frogs like to travel in the rain, too.

One last thing... oddly, well maybe not, in the summer no one is looking for pictures of blizzards.

The price of a Creative Commons license

I took this photo at wildlife sanctuary in Costa Rica. This white-faced monkey had been injured and was recovering from surgery. It had been flown to San Jose to the veterinary school for the operation, flown back, and cared for weeks. When cleared by the vet, who would travel from San Jose, it was to be released back where it had been found. An amazing amount of time and effort had been devoted to this monkey so it could be released back to the jungle. So, what does this have to do with Creative Commons licenses?

I release the majority of my photos on Flickr under a CC-BY-NC license. What does that mean? If you would like to use my photos, you may do so without asking as long as you attribute the image to me, and as long as the use is not for commercial gain. I find my photos all over the web, and I like that. I have been able to go places and do things that I want to share, and if those photos help others, especially educators, I like that. I don't even need to agree with the person using the photo. For example, several of my photos are used on a creationist web site. I am an evolutionary biologist and have seen no evidence that supports their ideas. That said, they are in full compliance with the terms of the CC license. This was use was test of my resolve to use open licenses for my content. I thought of ending my use of CC licenses, but there is an honesty in their use. I did not agree with their interpretation, but they were true to context in which photo was taken. I am glad this was the first case where I disagreed with the party's use of my image, but, in the end, support their right to use it.

This brings me back to the photo. Every once in a while I do a vanity search. Given that attribution is a requirement of using my images, it allows me to find them. It is really a thrill to see your images used by the World Wildlife Fund, International Union for Conservation of Nature, and personal blogs. Well, I found a case that is again testing my resolve. Well, okay, not really, but I am less pleased with this use than the use of my images by creationists. An poster in a discussion board (that I will not link to so that I drive no traffic to the site) has taken this photo and is using it as an example of the illicit animal trade. It is not that they used the photo. It is not that they have placed photo in another hosting service so people can't find my other images. It is not that the attribution does not lead people back to my other images. They are in compliance with letter of the CC license. What makes me angry is the author's invented context for my image. The person suggests that this animal was part of that despicable trade. The person says you can see the sadness in in its eyes, or some other rot. What you see in that monkey's eyes is greed. It was trying grab my camera. This image is not of a monkey in the illegal animal trade. This animal is being well cared for, and who will get a chance to go back to wild.

As I think about how others use of my images, context may be as important to me as attribution. Inventing a story as a work of fiction and described as such, it fine. Inventing a story and portraying it as fact, even when plausible, is not. Fortunately, it is rarely a problem. I think most people understand that the story behind the image can be as important as the image itself. I don't need to agree with the user, but I want the honesty from that user. The occasional uses of my images by people with whom I disagree, and by the dishonest is a price I am willing to pay to see my images used for good causes, and in fun and creative ways.

You can't go back again

This photo has been used in many places around the web: travel sites about Costa Rica, people dreaming about a vacation, people just dreaming. It was a place to relax and wait for the monkeys come and nap with you or, more likely, flip you out. I love to look at the photo and dream, but the thing is, when I was there, I couldn't sit still long enough to enjoy this. There were things I had never seen before behind every tree, and sitting still while that was happening seemed a waste. For me this was the ideal place, half accommodations, half wildlife rehab facility/sanctuary. Happily for the animals, the Crews have been able focus entirely on the wildlife mission through the Fundacion Santuario Silvestre de Osa . Sadly, for us, we can't go spend another week with the animals, having breakfast with monkeys and macaws. Still, the Crews have used my photos in many of the promotional materials, I wonder if they would take me on as a volunteer photographer for a week some January or February?

Rana aurora

This reminds me of different times. I was still a herpetologist. I was working on the evolutionary relationships of a group of North American ranid frogs and needed some related specimens from the Pacific Northwest lineage. I was attending the ASIH/SSAR/HL meetings in Seattle and colleague from Washington had brought a few tadpoles of Rana aurora and Rana muscosa for the live animal exhibit that is a feature of the meeting. That was just what I needed to fill things out, so at the end of the meeting he let me take them home.

I carefully carried them back to Ann Arbor in a plastic soda bottle in my carry on luggage. You can't do that anymore. From most of the specimens I collected tissue samples, and submitted them to the museum. But, I studied frogs because I like frogs. They fascinate me, and seeing tadpoles was not enough. I wanted to see what he would look like grown up. I took a pin head sized chunk of tissue from the margin of his tail, and proceeded to raise him. It was easy to get him to metamorphosis, but that is not the hard part.

I now had a very small, very hungry frog. What do you feed a very small frog? Well, they eat very small insects. They are harder to find than you might expect, but being in a biology department has its advantages. I popped down the hall to one of fruit fly labs. There are mutants of fruit flies that do not have wings or their wings are deformed so that they can't fly. I got a couple vials of curly wing flies. The adults were a bit challenging for him to eat at the start, and getting him to grow quickly would make the job of keeping him fed easier, so I trained him to eat the fly larvae off of a needle probe.

From the picture you can see that he grew into a fine young frog with amazing colors. He lived for more than 10 years, a very respectable age for a frog of his kind.

Phantom Ship, the right place at the right time

The Phantom ship is one of two islands in Crater Lake. This one apparently reminded people of a ship, especially on misty days.

I don't think you can take a bad photo at Crater Lake, but we reached the area at just the right time. It had been snowing and most the road around the crater had been closed. We did not know, but we drove up to back gate with a couple of cars ahead of us. We didn't understand what was going on, so we waited a few minutes and a National Park Service vehicle drove up and opened the gate. We drove around the crater with untouched snow all around. Absolutely spectacular. Go if you can, whenever you can, but I hope that you can see it with fresh snow. More photos...

Studies in light and dark

Grinnell Point in Glacier National Park

Photography is painting with light, we take light through a lens and let it fall across a medium to record it, whether it be film, a CCD, or CMOS. The challenge of photography is that there is a issue of sensitivity to light and dynamic range. Each of these capture media have range of light that they will capture, and that range can be adjusted either by changing film speed or changing the settings of your camera's sensitivity. Generally, the higher the sensitivity, the greater visible grain (film) or noise (digital). In digital photography, that noise is amplified when you try to pull details out by making adjustments to the photo to extend the dynamic range in a photo. Ideally, you make a perfect exposure every time, but life doesn't work that way. The other two options are to fix it in software, or to move high dynamic range techniques (HDR). HDR takes multiples of photos is exact,or at least close, registration and overlays them and in software you choose which layer to reveal to give you a broader range of exposures to work with.

In this case, I was trying to boost the exposure in ways that minimized blowing out the highlights, while pulling detail out of the dark. You can see the amplified noise on the dark side of the mountain. Part of that might be further amplified by the processing that Flickr does in rendering versions of the image that is uploaded. I don't have the aligned multiples, I wish I did as these were great conditions for HDR. Looking at this makes want to go back to the original and reprocess it.

Long exposures

Ghosts of games past

Wynkoop Brewing Company 8s f/5 ISO 80

I love making long exposures that contain movement. I was in Denver for the NSDL in 2005 and we had gone out to try the local beer and play some pool. This was a great place for long exposures, dark, great warm colors, interesting features (in this case repeating elements in long lines - another angle), and lots of movement. The people moving about the tables become ghosts in the photo. I tried this at 15 seconds and it was too long, people were not in one place long enough to render a trace, and shorter made the people too "solid."

Pups on the beach

This Australian sea lion pup is on Seal Beach, Kangaroo Island.

Not much to say, but sea lion pups sure are cute. Ok a little more. The male sea lions are pretty hard on them. This one was waiting for its mother to get back from feeding and a young male chased it into the mallee.

Hawksbill turtles

Hawksbill turtles are critically endangered sea turtles, so seeing my second one in the wild was a thrill. We were snorkeling at the Indians just off the coast of Norman Island, BVI. The first time I saw one was last in while snorkeling at Jost Van Dyke and that one spooked when it saw me. The one pictured ignored me and slowly swam around the reef eating while I followed at a safe distance. I followed it for about 5 minutes before it decided to move on. A couple quick strokes and it far out-distanced me and faded into the blue.

Sunset at the Caves

I can't get enough snorkeling, and it usually means that I am trying to squeeze every last minute of time that I can from companions. I was pushing the limits of the day at the Caves on Norman Island. Beth had gone back the dingy, and I was trying to get a few more shots of the amazing creatures around the reef. The sun had set and it lit the sky a brilliant orange. I was swimming back, when I saw this lovely shot. This was taken with my underwater camera, not the best camera, but it sure worked here. More orange-y Norman Island sunset goodness.

Who doesn't love an egg-laying mammal?

This is a short-beaked echidna. This one is a resident of the Toronga Zoo in Sydney. It was the first first time seeing a live specimen. It was great fun to see it emerge from the clumps of bunch grass. Only thing better would be seeing it live in the field, maybe the next trip.

This was another case (like the bat photo), where the Optio 750Z's swivel screen was a useful way to frame the shot as I had to reach down to get this ground level shot. I love the face-to-face perspective.

Bats

These are disk winged bats in Costa Rica. We were hiking the trails in forest around the place we were staying, and I was peeking into heliconia leaves looking for frogs when I found these most unexpected residents. I had just bought my first digital SLR and was snapping like a mad man, but I was stuck. The top the the plant was about two meters, and I did not want to bend it down further than I had to peek in, which I would need to do if was to use my shiny new 20D. I had not yet had enough practice to shoot blind with that camera. Then, I remembered we had along our first digital camera, a Pentax Optio 750Z, with its lovely tilt-swivel LCD screen. I could take the picture while minimizing the disturbance to the occupants. It is still one of my favorite photos from the trip, even if it isn't a frog. Even with the thought put into getting the shot, the photo's quality is really a case of a blind hog turning up a peanut. This photo has been republished all over the web and used in several exhibits about bats. I like that.

Three toes on a two-toed sloth

This was the first time I saw a two-toed sloth up close. This was one of two orphaned sloths that were being fostered until they could be released. To keep them safe they were in a tub with the bamboo lattice that they could hang from. This is the hind foot of one of them. Two-toed sloths have two toes on their front feet, and three on the back. The surface of the sole of the foot has an amazing texture, so soft. Caña Blanca Resort and animal sanctuary, Costa Rica.

Polar bear

by alumroot

Winter is fighting for a couple more days. We have a little new snow on the ground, so it seems like a good day to pull out a wintery scene. This polar bear at the Henry Vilas Zoo in Madison Wisconsin was simultaneously enjoying the cold and the sun. I converted this shot to B&W because the bear was a tan color and polar bears should be white.

Why?

I love getting views of my photos on Flickr, but that leads to a select audience seeing them, and the oldies but goodies being left behind. I have been trying get into blogging for a while, but I needed something that is easy for me to write about. I will use this space to write about my photos and tell a bit more of the story.

In this case the photo below is my most viewed image on Flickr. I am not sure why, but it has more than 60,000 views. It is a midland painted turtle hatchling found in Dolph Park in Ann Arbor Michigan. I took it when it was my job to walk around in parks and find things like this. I miss that job. The turtle was photographed and released.

This was taken on film in the late 1990's with my old Minolta x370. I wish my finger behind its head was a little more centered as it would look a bit more like a halo.