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Question:

I have a housed camera and I use a 60mm micro lens for fish and macro. I have trouble getting close enough to spooky little gobies, jawfish, and the like. Any suggestions would be appreciated. I am considering the purchase of a longer macro lens or perhaps a zoom lens.

 

 

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Questions and Answers (Q & A's)

From Alan Broder (from Ocean Realm Magazine - February 1995)

Answer:

Most zoom lenses generally considered for use underwater are intended to serve slightly wide-angle to short telephoto duties. A wide side of twenty-eight or fewer millimeters requires a dome port. The telephoto end of a 28-80 zoom behind a dome won't give you a bigger image than a sixty behind a flat port (which actually magnifies about 25 percent), so you get no help from the zoom in bringing in small, distant subjects. Most zooms don't yield magnifications greater than about 1:3.5 or so. If a film frame is one-by-one-and-a-half inches, then the macro on the zoom will fill the frame horizontally with a subject a little better than five inches long - okay for some subjects but not most of the small stuff. A 105 micro (micro = macro) will give you up to 1:1, allowing you to fill the frame with a one-by-one-and-a-half inch subject area. These "longer" macro lenses have longer working (camera-to-subject) distance than their shorter counterparts.

Whereas the sixty will yield a 1:2 magnification at a working distance of ten inches from the film plane in air, the 105 produces the same magnification at fifteen inches, an increase in working distance of 50 percent. A 200mm macro will give you the same half-life-size image on film at twenty-six inches from the film plane in air, an increase over the 105 of a little over 70 percent. Since there is only about a two-inch increase in lens length between the sixty and the 105, and between the 105 and the 200, the differences in actual distances between the front of the port and the subject are substantially greater underwater. Taking refraction of the flat port into account, your 1:2 subject is a little over six inches from the end of the port with the sixty, almost ten inches with the 105 (an increase of about 66 percent), and twenty-three inches with the 200, for an increase of 130 percent over the 105 and 400 percent over the sixty. The relative difference in port-to-subject distances with these lenses at a 1:1 magnification is even more dramatic.

It is interesting to see that problems in achieving a desired result in underwater photography have the same solutions as most other problems -- spending time and/or money. The 105 costs almost twice as much as the sixty, and the 200 costs more than twice as much as the 105. If you can take the time to learn the skills needed to move in on shy subjects and the time during the dive to slowly and carefully approach a subject, you can do it with the less expensive lens - with a very nice side benefit. Since you're closer, and are therefore shooting and lighting through less water, you'll get a sharper image with better color. What this boils down to is that a given photographer possessing a given degree of stealthmanship might be able, for the sake of argument, to fill the frame with a fire goby using a sixty macro in one to three dives of about sixty-minute durations, get the same frame with a 105 in no more than one dive, or make the same frame with a 200 micro in about three to five minutes.

All critters have a comfort zone - a distance at which they will just tolerate a stranger. That distance is generally longer for intruders making rapid motions, bubbles, or a lot of eye contact. The distance usually shrinks with time, as the subject starts to give you the benefit of the doubt on such matters as how fast you can move, how interested you are in him personally, and whether he's on your diet. Certainly, some species are tougher to approach than others, and individual members of a species vary in spookiness, as an individual might from time to time. I had long been aware of that fact when a yellow-headed jawfish in Fiji brought this awareness to a new level. On this particular dive, I had chosen to take the $1,300-three-to-five-minute approach to getting the shot I was after and had dialed in the focus on my 200mm ED Micro so that his eyeballs were sharp. I had just parked in front of his property, and he was kind of swimming up to what he considered a safe distance to check me out, then swimming a few feet away, picking up and moving a little sand, and, in general, trying to appear as nonchalant about me as I was pretending to be about him. Then he swam back to the edge of his comfort zone to take another good look at me. He did this several times, and each time he reached the magic distance, his eyes were at their sharpest in my finder. The fish is about three inches long and filled about 80 percent of the height of my frame when his eyes were sharp. Focusing is wide open at f4. The distance on the lens at this magnification is a little over two and a half feet and the depth of field is virtually nil. Could this particular jawfish's comfort zone be two and a half feet plus or minus absolutely nothing? Could be!

So back to that fire goby. His comfort zone is real, definite, and inviolable. He's drawn a line in the sand and said, "Cross it buster, and I'll pop down into my hole so fast you'll think I was a stinking hallucination! What to do? In all cases, you owe it to yourself to appear as non-threatening as possible. Most fish will accept you at a closer distance than they will tolerate your bubbles. It's often helpful to get a handhold on a rock or some other non-living structure and gently push yourself back to breathe. Movement should be slow and fluid. Don't maintain eye contact. Be sure that your gear isn't banging or dragging on the bottom. Some photographers swear by camouflage wet suits and camera gear to make them less obtrusive to their subjects. These principles apply whether you're determined to use the sixty to fill the frame with that goby at the shortest working distance possible for the sharpest image obtainable -- even if it takes the whole dive -- or if you're going to use the 200 and fill the frame with that goby, two of his neighbors, three jawfish, four different blennies, five species of hawkfish, six brands of nudibranchs, and a partridgefish in a pear seafan -- on that same dive. You fill your book a lot faster using the 105 for small subjects and the 200 for the really squirrely ones. You can go back and get them again with the shorter focal length as time and opportunity permit. The fact is that in reasonably good water, with proper lighting technique, you will get excellent images with the 200 macro on magnifications of 1:2 or 3.

Check this out: If you were to poll all of the wary creatures we try to photograph, they would overwhelmingly vote for bubbles as the single most disturbing thing about divers. If you were to poll all the divers trying to photograph these same wary critters, they would just as certainly agree that bottom time is the single most limiting factor in getting those photographs. Well, get ready for some great news! We are at the threshold of the first revolution in diving technology since the dive computer. This is an exciting time for divers --and especially for under-water photographers. Enter the closed circuit scuba unit -- the "rebreather." Many of us will soon be rebreathing our carbon-dioxide-purged, oxygen-replenished exhaled air. Zero - count em, zero - bubbles, markedly extended safe bottom time when properly used. And it's finally here - again! As there was with the dive computer, there is certain to be some spirited dialogue as to the wisdom of the sport diving public accepting this technology; however, these units have been in use in commercial and military diving since before the invention of Cousteau's Aqualung, our beloved bubble machines. Could you use a couple more hours bottom time a day? Could be! And all it will cost is money! Somewhere between the cost of three to twelve 200mm macro lenses -- a lot of money. But then, so do the better dive trips. Using the longer focal length lenses will net you many more, much better photographs. It won't be "Geez, I'd love to fill the frame with one of those fire gobies" -- you'll get to where you won't want to waste the frame if his dorsal isn't up. With your rebreather, you might have twice as much time underwater on every dive trip. Money can't buy happiness? Isn't a perfectly framed, technically perfect shot of that fire goby happiness?


 

 

 

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