Friday, 20 June 2014

Extension tubes and flash for macro photography

Bee Orchid, Ophrys apifera
natural light, f11
On Wednesday I used an extension tube on my Sigma 180mm macro lens. For those not familiar with extension tubes, they are tubes fitted between the lens and the camera to move the lens away from the sensor, thus magnifying the subject. The greater the distance of the lens from the sensor, the greater the magnification. There is no glass in the tube, so there is no degradation of the image. However, there is a price to pay – the further away the lens is from the sensor, the more light is required and a flash is needed. I have to set exposure and focus manually. Exposure is not a problem as the aperture and flash output can be set, results checked after shooting and adjustments made. The problem is focus. I usually use a monopod, but the depth of field seen through the viewfinder is very narrow and it is difficult to steady the camera at the optimal distance. I may have to use a tripod on stationary subjects for better results. The advantage of using extension tubes is that I can fill the frame with the subject and using a small aperture (>f32) the depth of field is excellent. I need greater flash-light for some shots so am looking at ring-flash or mounting the flash on the end of the lens.
  I found a variety of micro fauna at an Arundel site and then Rewell Wood and was able to practice on various sized subjects.

  Yesterday I bought a Benbow tripod from Arundel Photographica, an excellent second hand photography shop. I then returned to Rewell Wood to try it out. It’s a steep learning curve using extension tubes and tripod in the field. 
  I found a Hemp-agrimony Conch and an interesting sawfly larva.

Arundel (no extension tubes):
Bee Orchid, Ophrys apifera
flash, f40
Bee Orchid, Ophrys apifera
natural light, f10
Common Froghopper, Philaenus spumarius
natural light, f9
Crab Spider, Misumena vatia on Pyramidal Orchid, Anacamptis pyramidalis
flash, f45
Dark Bush Cricket, Pholidoptera griseoaptera
flash, f22
Garden Grass-veneer, Chrysoteuchia culmella
natural light, f22
Large Skipper, Ochlodes sylvanus
natural light, f16
Large Skipper, Ochlodes sylvanus
natural light, f20
Rewell Wood using extension tubes and flash:
Dark Strawberry Tortrix, Celypha lacunana
Springtail species (thanks to Jamie for the id)
Dicyrtomidae or Sminthurididae?
unidentified fly 1
unidentified fly 2
Goose Grass, Galium aparine
Hedge Woundwort, Stachys sylvatica
Leafhopper, Thamnotettix dilutior
Mirid bug sucking juices from prey, Grypocoris stysi
Mirid bug, Grypocoris stysi 
pupal case?
Red Piercer, Lathronympha strigana
Sciomyzid species
Speckled Bush Cricket nymph, Leptophyes punctatissima
female Wolf spider with cocoon, Pardosa lugubris
Rewell Wood on Thursday using tripod, extension tubes and flash:
unidentified butterfly caterpillar which looked dead
Common Froghopper nymph, Philaenus spumarius
Common Froghopper, Philaenus spumarius
looks like a click beetle wrapped up
Hemp-agrimony Conch, Cochylidia rupicola
Mirid bug, Grypocoris stysi
Nettle Weevil, Phyllobius pomaceus
Red Piercer, Lathronympha strigana
unidentified sawfly larva

Pollen Beetle, Meligethes aeneus, one of many of these tiny (2mm) beetles
 on Marsh Valerian, Valeriana dioica.
thanks to Richard for the id

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