Jump to content

Glasseye Snapper

Member Since 11 Oct 2005
Offline Last Active Today, 10:30 AM

Posts I've Made

In Topic: SLR vs. Mirrorless. What is the best camera for macro?

19 July 2015 - 11:45 AM

For me the whole discussion around pixel size, dynamic range, ISO performance, noise, etcetera isn't that important. I'm really not that good a underwater photographer and with one dive trip per year I am unlikely to reach the stage where image quality is limited by the equipment. But there are very practical issues that do matter like lens selection, housing selection, quality of view finder, strobe sync speed, autofocus performance, ergonomics, size/weight, and for many of us cost.


Where sensor size does matter to me is that it is proportional to focal length needed to get the same angle of view. So for m43 you use about half the focal length as on FF. For most applications I consider that a m43 advantage because shorter focal length means less bulky lenses and they tend to have a closer minimum focus distance, which is important underwater. However, the argument changes for macro lenses where you can already get very close and unless you dive in low visibility, getting a bit more working distance for lighting and not spooking critters becomes a benefit. It also matters for (wet) diopter users where the extra magnification depends on the focal length of the diopter AND the focal length of the lens. With the same diopter you get more magnification for longer lenses, so larger sensors have the advantage. [note some of the newer "super macro converters" may not be true diopters but I think they still work better on longer lenses]. Finally, if you aim for 1:1 magnification the maximum subject size that you can still fit in your frame is proportional to the sensor size. So with FF you can record twice the size subjects compared to m43. In other words, rather than saying m43 has 2x higher apparent magnification than FF with same focal length and distance, you can say you are seeing 2x less.


At the moment I am shooting m43 with Olympus EM5 and am very happy. I would only consider going FF if I get to do a lot more diving (or win the lottery). However, of all the arguments for and against you can make the "it has to be Canon" seems to be the weakest unless you have a large lens collection or have specific Canon needs for topside shooting. Not saying Canon is not good, I used a Canon DSLR for 6 years or so, but other brands have been progressing much faster.



In Topic: Red Sea long white shell

18 July 2015 - 07:21 AM

OK, it is indeed a Scaphopod and a member of the Dentalium genus. Scaphopod shells were used by pre-historic cultures in the region (Natufians) for beads and they are also found in burials. They collected them in the Mediterranean and Red Sea, as well as from fossil deposits (Scaphopods have been around for 360My). The Natufian Red Sea shells belonged to the Dentalium reevei species complex. Likely that is what the one in my image is as well (but there are other similarly looking species in the Red Sea).


They live in the sand with the wide opening pointing down and feeding on diatoms and other small sand creatures. The other end has a much smaller opening (smaller than in the image, probably due to damage) and touches the surface of the sand.



In Topic: using a shorter lens in a standard port

17 July 2015 - 08:14 AM

If Belgium and the Netherlands are your home turf then getting close is even more important, it is where I learned to dive in the 80s. I think you made a wise decision to focus on getting better with what you have. I haven't used the 14-42mm but of the many aspects that determine final image quality, my experience is that the lens quality is normally not the biggest factor (unless you are already really good at everything else). And you should be able to get spectacular images with it. Other lens properties such as ability to focus close, speed and accuracy of autofocus are more important so perhaps think about a true macro lens down the road.


I agree with Griff that photography, and especially learning it, works a lot better with a dedicated guide or no guide at all. With your 1000+ dives in cold murky waters you really don't need a dive guide. Just go to the Red Sea and get an unlimited shore diving package. I just returned from Marsa Abu Dabbab where you have reefs, seagrass/muck and a pretty beach. The diving can't get any easier and navigational skills are not needed for the reef dives. Just swim out and back. To train compass navigation the seagrass is very good. Without clear visual cues it is easy to get lost as you turn around a few times but heading home is as simple as going West. I found it a good learning experience to try to get out as close to the dive shop as possible but if you hit the beach 100m away, no harm done.



In Topic: What's wrong with harassment?

15 July 2015 - 05:30 PM

Last month I attended a presentation by the Hurghada environmental protection and conservation association (HEPCA) while diving at Wadi Lahami. They made a lot of progress with dolphin tourism, dive boat mooring systems and waste disposal in coastal resorts and towns. I brought up the point of dugongs and they recognize the problem of their disturbance but unfortunately no regulations are in place at this moment.



In Topic: using a shorter lens in a standard port

15 July 2015 - 05:06 PM

yes you can stay away a bit farther but at the cost of image quality, even in clear tropical waters. Moreover, at the same distance, you only get about 1.5x magnification compared to the 14-42 set to its longest focal length. I've thought about getting a stronger telelens myself to stay away farther from shy small critters and recording natural behavior was more important than image quality. However, in many cases patience, good buoyancy and breath control allows you to get a lot closer than you might expect. I think there can be good cases for a stronger telelens but it can also become a crutch to compensate for inability to get close and take away the stimulation to improve your skills.