I found this photo of beautiful Decorative Silver Orb Spider (Leucauge cf. decorata) in my garden. I have used Canon EOS 5D Mark III with Canon EF 100mm f/2.8L Macro IS USM using 36mm Kenko extension tube. This whole setup is illuminated by Canon MT-24EX macro twin light flash. This is un-cropped full frame capture at nearly 2:1 magnification handheld.
An extension tube is simply a hollow cylinder that fits in between your camera and lens, causing the lens to move further from the sensor. This additional distance allows your lens to focus more closely, which in turn provides more magnification capability. The Auto Extension Tube Set DG for Canon EOS Lenses from Kenko that I use contains three tubes of different lengths–12mm, 20mm, and 36mm–which can be used individually or in any combination to obtain the desired magnification. They are compatible with Canon EF and EFS lenses.
There is a fairly simple formula for calculating the effect on max magnification. It essentially looks like X/focal length where X is the total extension.
Canon EF 100mm f/2.8L Macro Lens is actually 70mm at max magnification. If you added the 36mm tube, it will be 100 + 36. Resulting 136mm of total length. With extension tube the resulting maximum magnification will be (130/70) of 1.9:1.
A couple things to keep in mind when using extension tubes:
- The tubes cause additional light loss, making natural light shooting even more difficult.
- Your focus range is significantly reduced once you add tubes. You will not be able to focus anywhere near infinity with the tubes in place.
Leucauge spider is from the family of Tetragnathidae which is also known as long-jawed orb weavers. Usually around 7-9 mm in size. Just like in the photo above, at its web, this spider always stays upside down. These orb-weaving spiders are highly diverse, abundant in the fields and important regulator of pest populations in our ecosystems
They are distributed throughout India, Sri Lanka, Singapore, Indonesia, Thailand, Myanmar, Papua New Guinea, Taiwan, and Northern Australia.
Their usual habitat consists of low shrubs in shaded and moist environments and build their orb webs in shaded vegetation.
The cephalothorax is flat which is pale yellow, darkens medially and towards the margin. Pedicel joins the abdomen some distance along the ventral side. The abdomen is tubular, tapers to the front and protrudes to the rear over the spinnerets. There are silver white patches all over the abdomen. The legs are long and thin with dark brown annulations. Femora IV with uniform rakes of long curved trichobothria (hairs). The body and leg shapes and the silver, black and yellow markings of Leucauge females make identification of the genus relatively easy. They have two rows of long, slender curved hairs on the femurs of the fourth leg. In most cases the web is slanted rather than vertical and the spider rests in the middle of the web with its underside facing upwards.