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Member Since 10 Jun 2012
Offline Last Active Feb 01 2015 01:07 PM

Posts I've Made

In Topic: Oly 12mm f2 in Nauticam 3.5" mini dome.

01 February 2015 - 12:47 PM

You shouldn't need an extension. The 12mm is shorter than the 8mm FE which fits fine behind this dome. By foregoing the extension, the 12mm lens will not be able to focus (the 8mm FE focuses much closer). However adding a diopter to the 12mm will fix that problem. The problem with adding both an extension and a diopter is that the extension causes the lens to see a much more curved virtual image. That necessarily results in corners which are very soft and a strong +5 diopter (or more) will be needed to fix this problem. But instead of adding the extension, a diopter, by itself, will allow the 12mm lens to focus. Without an extension, the lens sees a flatter virtual image and the corners will be sharper. A lesser diopter (+2 or +3) with no extension should result in shaper corners, a wider field of view, and less distortion, plus there's no need to buy an extension.

In Topic: Oly 12mm f2 in Nauticam 3.5" mini dome.

01 February 2015 - 10:36 AM

I'd be inclined to use a diopter on front of the 12mm lens behind the 3.5" dome without an extension. The extension will allow the lens to focus, but the cost is corner sharpness. A diopter will also allow the lens to focus, but corner sharpness should be better (as the lens is seeing a flatter section of the dome than with an extension).  It's unclear exactly what diopter is optimal, but +3 would be a good place to start.

In Topic: Nauticam em-10 housing gear movement

22 July 2014 - 06:10 PM

I have the E-M5 housing and the 12-50mm lens/gears/port. I'm not entirely sure what movement of the gears you are referring to, but the springs in the 12-50mm gears are very stiff. I believe this is necessary because the springs in the 12-50mm gears have to be able to turn back the external knob when pressure on the knob is released. This isn't easy and it has to be able to do this at maximum depth when things may be even more difficult.

In Topic: Olympus 12-40 F/2.8 and the Zen Underwater DP 170 n85 port

05 July 2014 - 12:17 PM

Many thanks for posting these. I'm thinking about getting the DP-170 n85 version 1 and some extensions, for more versatility. I'm confused about all the different DP-170's though, there seems to be three?

1) DP-170 n85 version 1

2) DP-170 n85 version 2 (like version 1 with 25mm built-in extension)

3) DP-170 n120 (no idea what this is -- seems to be the same dome as the n85, but hard to tell, perhaps it's for DSLR housings?)


Presumably all use the same glass and same optical coatings?


Is it possible to attach the DP-170 n85 version 1 to the housing without using an extension?

In Topic: Nauticam 6" dome ports use with 9-18 mm Olympus

02 July 2014 - 05:34 PM

The Nauticam 6" dome and the 4" semi-dome have the same optical radius, i.e. the 4" semi-dome is just a piece of the larger 6" dome. All other things being equal (like the distance from the body to the front of the dome), the two domes will perform identically.