Friday, 22 May 2009

Some Dutch insects

Some common insects of the Mariapeel. From top to bottom: Banded Demoiselle (Calopteryx splendens /Weidebeekjuffer), Speckled Wood (Pararge aegeria/Bont Zandoogje) and a worn Painted Lady (Vanessa cardui/Distelvlinder) on flowering bramble. I tried to photograph them with ‘context’. Below you find more detailed species information.
Banded Demoiselle ♂, as on the photo, has translucent wings which each have a broad, dark iridescent blue-black spot (or band) across the outer part and a metallic blue body. Large numbers can be found in lush bank-side plants and on floating objects in slow-flowing streams and rivers and sometimes channels as well. ♂♂ court ♀♀ by opening their wings and performing an aerial dance.
Speckled Woods are highly territorial and will defend their territory against intruding ♂♂. For finding ♀♀, there exist 2 basic strategies: 1) Vigorously defend a perch and the immediate surroundings, waiting for ♀♀ to pass by. 2) Patrol a larger territory. Perching behavior is more common in ♂♂ of conifer woodland, whereas ♂♂ of meadows tend towards patrolling behavior. The nominate form has orange speckles, the tircis race, seen on the photo has yellowish cream-coloured speckles.
The Painted Lady occurs in any temperate zone, including mountains in the tropics. The species is resident only in warmer areas, but migrates in spring, and sometimes again in autumn. On average a Painted Lady butterfly travels around 1000 miles in its life. This spring huge numbers of migrating Painted Ladies are seen everywhere in The Netherlands.

Wednesday, 20 May 2009

Yes, my first HDR!

HDR (High Dynamic Range) imaging is a technique to capture scenery with a very large dynamic range, such as sunsets or sunrises. Generally, the range of these scenes doesn't fit on the camera sensor. The technique works as follows: In the field different exposures (in this case, -2 stops, -1 stop, neutral, and +1 stop) are taken with a fixed aperture (only shutter time varies), and later at home these exposures are combined and compressed into a single photo with a computer program. Ideally, the most underexposed image should not contain clipped pixels in white, and the most overexposed image should not contain clipped pixels in black.The combining part results in a 3x32-bit HDR color image. The compressing part, called tone-mapping, downscales this large range to a normal 3x8-bit color image. An important requirement for success is that all the exposures are perfectly aligned. In other words, no camera motion and no motion in the scene itself is allowed within the time-frame in which the series of exposures are taken. In practice, this means working with a tripod and a (wireless) remote control, and of course calm weather.
For this orchid field sunset it did the HDR postprocessing with Photomatix 3.1 using default settings.
There is a lot of debate going on the Internet about whether HDR technique gives realistic results (by the way, what are these?). Plain sensor readouts are certainly not realistic. Playing around with Photomatrix for just an evening gave me at least the feeling that I have something in my hands for the first time in my life to handle sunsets and sunrises shots properly.

Sunday, 17 May 2009

Fresh water pioneer

♀ Broad-bodied Chaser (Libellula depressa/Platbuik). Note the characteristic wing markings and the very broad abdomen. This dragonfly is among the commonest species in much of Europe. A strong flier that is often the first one to claim newly-created or cleared habitats.

Friday, 8 May 2009

New wide-angle lens

This photo is taken in National Park “Groote Peel”. In my opinion cloudy weather fits in with a boggy area well. Flowering Common Cottongrass (Eriophorum angustifolium/Veenpluis) cheers up the image a bit. I used it as a foreground for this wide-angle shot with my new Canon EF 17-40mm f/4.0L objective.