Archives for August, 2011

Reef Silversides, Hypoatherina harringtonensis, are always a great site and make for very interesting Reef Silversides, Atherinidae, Clupeidae, Engraulididae, Orange Canyon, Grand Cayman (Steven Smeltzer)photographs.  These massive schools of fish are seen throughout the Cayman islands.  They form into large defensive schools to confuse predators and the “swarms” seem move as one as they react to changes in pressure underwater caused by the movement of predators or other threats.

They can be approached easily while scuba diving if you take your time and you can even swim through these schools and have the fish literally enveloping you.  There have been large schools around Orange Canyon, where I took these shots, the Oro Verde wreck, and many other locations.  You can find schools of these fish in most dive sites from time to time and be sure to take time to observe their behavior.   They prefer shallow protected bays and lagoons and protected areas around the reef usually staying at depths from 0 to 10 meters.

They are greenish white on back, silvery with bluish reflections below; moderate silver stripe covering 3 rows of scales down from top plus edges of two adjacent rows bordered above by an iridescent blue-green line, from gill opening to tail, at front silver stripe is nearly as wide as pectoral fin base; tips of tail dusky.  There are a variety of these fish and it is almost impossible to tell them apart in the water.

The pool is open…..

Sigma 17-70 mm (Steven W Smeltzer)

Candy Cane Shrimp, Sheraton reef, Maui Hawaii

Sigma 17-70 mm (Steven W Smeltzer)

Candy Cane Shrimp, Sheraton reef, Maui Hawaii

The Sigma 17-70mm F2.8-4 DC Macro lens available in Canon, Nikon, Sony, Pentax and Sigma mounts deserves strong consideration for underwater photography from the higher end amateur to the professional. While zoom rings for the Sigma 17-70mm are hard to find (if you can) the versatility and quality of the lens is such that if you are willing to invest a little time this could be a great lens for a variety of underwater settings. The lens is good for macro shots as seen in this image of a Candy Cane Shrimp in Maui

Sigma 17-70 mm (Steven W Smeltzer)

Bonnie’s Arch, Scuba Diving, Grand Cayman

It also is quite good for wider angel shots such as this photo from Grand Cayman.

I first took the Sigma 17-70 mm for a test drive in Hawaii. Since, I could not get a zoom gear for my Sea&Sea housing, I just made one. 🙂 If you are not intimidated this is not very hard to do especially if you have other zoom rings lying around that can be “modified” or you can also build a very passable zoom gear from PVC pipe from your local hardware store, but I will leave that for another story.

Sigma 17-70 mm (Steven W Smeltzer)

Sigma 17-70 mm f2.8-4 DC Macro Lens

When compared to other similar lenses, the Sigma 17-70 mm is one of the heaviest and largest instruments of all. This is not a surprise, though, because the lens is also the fastest and similar lenses such as the Sony/Zeiss 16-80 mm, which has a better focal range, doesn’t have an ultrasonic autofocus motor.

The Sigma 17-70 mm f/2.8–4.0 DC Macro OS HSM is an optically complex instrument. It has 17 elements in 13 groups. One element is made of low-dispersion ELD (Extraordinary Low Dispersion) glass and three other elements are aspherical (one hybrid element, two made using the “glass mold” technology). It is definitely superior to its predecessor that had just one SLD (Special Low Dispersion) element and two ordinary aspherical ones. Inside the lens we can also find an aperture with seven diaphragm blades which can be closed down at 17 mm to f/22 and at 70 mm – to f/32.

All in all a versatile lens that can deliver great shots in most situations and is great when you are not sure if you will be shooting macro or wider angle shots on a particular dive.

The pool is open…..

Technical details: Sigma 17-70 mm

Lens Construction: 15 Elements in 12 Groups
Angle of View: 72.4 – 20.2 degrees (Sigma SD format)
Number of Diaphragm Blades: 7 Blades
Minimum Aperture: F22
Minimum Focusing Distance: 20cm/7.9 in.
Maximum Magnification: 1:2.3
Filter Size Diameter: 72mm
Dimensions Diameter: 79mm X Length 82.5mm
3.1 in. X 3.2 in.
Weight: 455g/16.0 oz

 

 

 

Shark Week is an annual, week-long TV programming block created by Tom Golden at the Discovery Channel.  This annual series of programs provide some awesome information on these wonderful creatures.

Shark Week (Steven W Smeltzer)

White-tip Reef Shark, Triaenodon obesus, mano lalakea, Maui Hawaii

Shark Week originally premiered on July 17, 1988. Featured annually, in late July and/or early August, it was originally devoted to conservation efforts and correcting misconceptions about sharks. Over time Shark Week grew in popularity and became a hit on the Discovery Channel. Since 2010, Shark Week has been the longest-running cable television programming event in history. Now broadcast in over 72 countries, Shark Week is promoted heavily via social networks like Facebook and Twitter. Episodes of recent years are also available for purchase on services like Google Play Movies & TV/YouTube, Amazon Video, and iTunes. Some episodes are free on subscription-based Hulu.

Shark Week (Steven W Smeltzer)

Shark Week

Since its early days, Shark Week has evolved into more entertainment-oriented and sometimes fictional programming. In recent times, it has attracted much criticism for airing dramatic programs to increase viewers and popularity. This fictitious programming, known as docufiction, has been produced in the last few years. Examples of such programs include Megalodon: The Monster Shark Lives, Shark of Darkness: Wrath of Submarine, Monster Hammerhead, Lair of the Mega Shark, and Megaladon: The New Evidence.

This strategy was hugely successful, especially for the program Megalodon: The Monster Shark Lives, as it became one of the most watched programs in Shark Week history, primarily for the controversy and backlash it generated. The mockumentary was based on an ancient giant shark called megalodon, which is now long extinct. The airing of this program fueled an uproar by viewers and by the science and science-loving community.[4] It eventually started a Discovery Channel boycott.[4] Since then Discovery has increasingly come under fire for using junk science, pushing dubious theories, creating fake stories and misleading scientists as to the nature of the documentary being produced

 

The pool is open…..