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Member Since 14 Sep 2009
Offline Last Active Oct 06 2015 02:50 PM

Posts I've Made

In Topic: Minimum focus distance question

14 September 2015 - 08:15 PM

I use the Canon 14mm on my 5DII and find it almost able to focus on the scratches on my 8" acrylic dome. I doubt the minimum focusing distance is your issue. If the centre is sharper than the sides then it's more to do with the curvature of the virtual image caused by the dome port vs the flat focal plane of the rectilinear lens.


If you have enough light, I would increase your f-stop as far as possible. For critter identification I would find it easier to see the details with a higher ISO and higher f-stop rather than the reverse.

In Topic: Using nalgene or latched acrylic jar to put your non-waterproof torch?

25 August 2015 - 02:54 PM

Without the camera, how would you capture scenes of enthusiasm like this? On mobile otherwise I'd post the photo itself, sorry.


In Topic: Using nalgene or latched acrylic jar to put your non-waterproof torch?

24 August 2015 - 04:39 PM

Sump diving is a UK term...looks a bit like this:


Attached File  image1.JPG   93.38KB   12 downloads


The cloud of silt is from dragging a bag of extra gear through the mud. Visibility is a first-diver-only privilege. It's also pretty rough on the equipment and having gear that needs to stay dry after a dip adds complexity.


The peli case and the nalgene may be strong enough not to collapse completely but they are likely to distort slightly and upset the o-ring seal. There's an easy way to test though - leave it empty and take it to depth. Take a spare pair of undies in case it goes bang  :)

In Topic: Using nalgene or latched acrylic jar to put your non-waterproof torch?

20 August 2015 - 03:24 PM

I use nalgene bottles for caving and sump diving (3m - 10m deep) and they are relatively robust and waterproof. I also use pelican cases which are more indestructible, but even a small-ish pelican case will flood at depth - the cubic shape doesn't compress well. I left mine at 6m for two hours to test it and it had four or five tablespoons of water in it afterward. 


For that kind of depth I would suggest an old light canister of the type that had a battery and the light head connected by a cable. Remove battery and cable, find some way of blocking the cable gland, et voila, dry tube. You may have an old lead acid battery-powered dive light in your garage, or know someone who does. Don't forget that containers of air will float underwater. You may need some extra lead and a way of storing the floating part such that it doesn't get in your way.

In Topic: Canon 5DMarkII Camera and Aquatica Housing System

19 August 2015 - 06:12 PM



Your picture has a single ikelite bulkhead, not a dual nikonos bulkhead. Do you have the nikonos bulkheads separate? If so, can I buy them off you?