Archive for January, 2013

Green-winged Teal (male, female)

January 29, 2013

A couple of Green-winged Teals (Anas crecca) spotted during a photowalk at Huntley Meadows Park, Fairfax County, Virginia USA. The male is shown in Photos 1-2; the female in Photo 3.

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Tech Tips: BorderFX, a free plug-in for Apple Aperture, was used to add a text watermark to the photos.

Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com

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Stop-action photography of dragonflies in flight

January 27, 2013

It is estimated a dragonfly flaps its wings at about 30 beats per second. I shot several photos of a dragonfly in flight using a shutter speed of 1/1,300 second. Turns out that shutter speed was a little too slow to stop wing motion completely.

I posed the following question to Phil Wherry, my good friend and technology/photography guru: How fast would the camera shutter speed need to be in order to freeze all motion of a dragonfly in flight? Phil’s answer is as follows.

To freeze all motion? Infinitely fast. Even if your exposure is one-millionth of a second long, the wings are going to move a little bit during that interval.

You’re going to get some motion no matter what; the question is simply how much is tolerable. At some point the motion will be small enough that the image will look sharp to you. (This same principle, by the way, applies to depth of field: Focus is only perfect at a single plane no matter what the aperture, but the “depth of field” defines the area where the error is small enough that it’s not obvious.)

We’ll start by considering a simpler scenario. Let’s say you have a motor that makes one full rotation per second. Let’s also say you take a paper plate and draw a thick black line on it, then attach that to the motor shaft. Now you have something that looks a bit like a one-handed clock, with the “hand” making one full rotation every second.

Now, let’s say you point your camera at this setup. If you take a one-second exposure, the “hand” will rotate once during the exposure; clearly you’ll have a lot of motion blur. If you shoot at 1/4 second, the “hand” will traverse just one-quarter of the circle. Shoot at 1/100th of a second, and you’ll get a little bit of motion blur as the “hand” swings through 1/100th of a circle. If you shoot at 1/1,000th of a second, there’s still some motion blur but it’s probably not enough to make you perceive the result as blurry.

Now let’s consider the motion of the dragonfly’s wings in detail: If the wings are beating 30 times per second, that means the wing goes through one complete cycle of its motion 30 times per second. Let’s say for a moment that you shoot a picture at 1/300th of a second. This is ten times as fast as the wings are beating, so you’ll capture 10% of the range of motion. At 1/1,300th second, you’re capturing 30 / 1,300 (or about 2.3%) of the wing’s beat cycle.

This is made more complicated because the wings aren’t moving at a uniform speed; they accelerate and then slow down, reverse direction, accelerate, etc. The result is, as one might expect, roughly sinusoidal in shape (though not exactly; see the blue line in Fig. 2 of “Dragonfly Flight“).

If that 1/1,300th of a second exposure happens to occur when the wings are at the end of their travel and beginning to reverse direction, very little motion will occur and the image will look sharp. If the wings are mid-stroke, then some 1/1,300th of a second is likely to have some motion blur.

Experimentation is really the only way you’ll figure this out. Flash might help, too, since a major contributor to the overall exposure would then be a pulse of light that’s only a fraction of a millisecond long.

Phil

The following photos illustrate the relationship between shutter speed and stop-action photography of dragonflies in flight: Photo 1 of 2 was shot using an aperture of f/5.2 and a shutter speed of 1/200 second; Photo 2 was shot at an aperture of f/3.8 and a shutter speed of 1,300 second.

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Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com

Great Blue Skimmer dragonfly (female, oviposition, in flight) redux 2

January 25, 2013

The following photo gallery shows a female Great Blue Skimmer dragonfly (Libellula vibrans) laying eggs by the process of oviposition. The dragonfly skims the water repeatedly, picking up drops of water that are used to flick fertilized eggs toward the shore. The process typically lasts a few seconds to a few minutes.

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Habitat: Huntley Meadows Park, Fairfax County, Virginia USA.

Tech Tips: The photo was shot using an aperture of f/3.8 and a shutter speed of 1/1,300 second. The shutter speed was a little too slow to completely stop the motion of the dragonfly’s wings. BorderFX, a free plug-in for Apple Aperture, was used to add a text watermark to the photos.

Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com

Blue Dasher perching on Cardinal Flower

January 23, 2013

Now you see it, now you don’t. Huh? I was so focused on composing the photo of a Cardinal Flower (Lobelia cardinalis) I never noticed a male Blue Dasher dragonfly (Pachydiplax longipennis) perching on the flower in Photo 1 of 2. Embarrassing!

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Habitat: Huntley Meadows Park, Fairfax County, Virginia USA.

Tech Tips: BorderFX, a free plug-in for Apple Aperture, was used to add a text watermark to the photos.

Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com

Common Whitetail dragonfly (immature male)

January 21, 2013

A Common Whitetail dragonfly (Libellula lydia, Plathemis lydia) spotted during a photowalk at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an immature male. As a young male the dragonfly’s abdomen will be covered by white pruinescence, hence its common name, “Common Whitetail.”

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Tech Tips: BorderFX, a free plug-in for Apple Aperture, was used to add a text watermark.

Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com

Blue Dasher versus Twelve-spotted Skimmer

January 17, 2013

The following photo features two dragonflies: a Twelve-spotted Skimmer (Libellula pulchella), shown lower-left; and a Blue Dasher (Pachydiplax longipennis), shown upper-right. Both dragonflies are males. Photo forensics reveals the action sequence: The smaller Blue Dasher, already fully in motion, encroached upon the larger Twelve-spotted Skimmer’s territory and caused the Twelve-spotted Skimmer to take flight in defense of its perch.

[Male Blue Dashers are] fiercely aggressive to other skimmers with blue pruinosity.” Source: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Location 10847). Princeton University Press. Kindle Edition.

The Blue Dasher’s abdomen is bowed upward, probably showing aggression toward the other dragonfly.

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Tech Tips: The photo was shot using an aperture of f/5.6 and a shutter speed of 1/200 second. Although the shutter speed was too slow to stop the motion of the dragonflies completely, it was perfect for conveying dynamic tension in the scene. BorderFX, a free plug-in for Apple Aperture, was used to add a text watermark to the photo.

Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com

HDR composite image of Hollin Hall

January 14, 2013

The following semi-photorealistic HDR image of Hollin Hall is a composite of three bracketed exposures, +/- 2 stops of exposure: Photo 2 (0 ev); Photo 3 (-2 ev); Photo 4 (+2 ev).

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Photo 1. HDR composite image.

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Photo 2. 0 ev.

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Photo 3. -2 ev.

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Photo 4. +2 ev.

Tech Tips: I used my Panasonic Lumix DMC-ZS150 superzoom camera to shoot three bracketed exposures of the same landscape. The camera was set for manual focus at the hyperfocal distance for an aperture of f/4, based upon the instructions provided in the excellent video tutorial by Graham Houghton, “Panasonic Lumix FZ camera easier manual focus method — super point-and-shoot tip.” I used Adobe Photoshop CS5 and Lightroom 4 to create and edit a 32-bit HDR composite image of the three exposures: Photoshop was used to create the HDR image; Lightroom 4 was used to adjust the composite image.

Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com

HDR panorama composite image of Hollin Hall

January 12, 2013

The following panorama photo of Hollin Hall is a composite of six overlapping photorealistic HDR images.

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Tech Tips: I used my Panasonic Lumix DMC-ZS150 superzoom camera, Adobe Photoshop CS5, and Lightroom 4 to create a panoramic of six overlapping 16-bit HDR images; each HDR is a composite image created from three bracketed exposures, +/- 2 stops of exposure. Photoshop was used to create the HDR images and merge them into a panoramic; the resulting image was adjusted using Lightroom 4.

Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com

Honorable Mention Photos of 2012 (Part 2)

January 2, 2013

The following gallery shows Part 2 of my “Honorable Mention Photos of 2012.” The photos are presented in chronological order. All of the photos were taken using either my Panasonic Lumix DMC-ZS150 superzoom camera (No. 1-7, 10) or a borrowed Canon EOS Digital Rebel XTi (No. 8-9). All photos were post-processed using Apple Aperture 3.

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Photo captions:

  1. Northern Flicker (male, chicks, nest), 02 June 2012
  2. Twelve-spotted Skimmer dragonfly (male), 09 July 2012
  3. Great Blue Skimmer dragonfly (female, in flight), 12 July 2012
  4. Needham’s Skimmer dragonflies (mating pair), 12 July 2012
  5. Blue Dasher dragonflies (mating pair), 16 July 2012
  6. Green Heron (predator-prey), 23 July 2012
  7. Blue Dasher dragonfly/owl wearing sunglasses (male), 14 August 2012
  8. Black Saddlebags dragonfly (male), 10 September 2012
  9. Blue-faced Meadowhawk dragonfly (male), 12 September 2012
  10. Blue-faced Meadowhawk dragonfly (male), 12 October 2012

Related Resources:

Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com

Honorable Mention Photos of 2012 (Part 1)

January 2, 2013

The following gallery shows Part 1 of my “Honorable Mention Photos of 2012.” The photos are presented in chronological order. All of the photos were taken using my Panasonic Lumix DMC-ZS150 superzoom camera and post-processed using Apple Aperture 3. Adobe Lightroom 4 was used to reduce the chromatic abberation in Photo 1.

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Photo captions:

  1. Red-bellied Woodpecker (male), 24 January 2012
  2. Great Egret, 27 January 2012
  3. Bald Eagles (pair), 31 January 2012
  4. Bald Eagle, 07 February 2012
  5. Southern Leopard Frogs (mating pair), 06 March 2012
  6. Red-shouldered Hawk (in flight), 18 March 2012
  7. Osprey (nesting pair), 22 March 2012
  8. Osprey (male, in flight), 11 April 2012
  9. Red-bellied Woodpecker (male), 21 April 2012
  10. Red-winged Blackbird (male), 18 May 2012

Related Resources:

Copyright © 2013 Walter Sanford. All rights reserved. www.wsanford.com


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