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Member Since 20 Sep 2012
Offline Last Active Nov 26 2015 01:44 AM

Posts I've Made

In Topic: Anyone have experience with Meikon Aluminum housing?

26 November 2015 - 01:48 AM

Alright, its dark here, so I had to adjust the exposure on some of the photos really quickly.

I've also took some photos with the camera from within the housing:

With the h100m67(type 2) screwed directly to the meikon housing port, the vignetting almost disappears by 30mm. I next unscrewed the h100 and placed some step up/down rings to simulate a bayonet adapter. results were not good. I had to zoom in ALOT before the vignetting goes away, and clearly(pun unintended), the quality and clarity of the image becomes almost unusable. In fact, I had to zoom in until it was close to the FOV of the 24mm flat port without wet lens, so it renders the additional wet lens almost useless. 
This test/result demonstrates that the distance between the housing port and rear element of the wet lens also plays an important role.

As the h100 I have is a m67 type 2(rear element flush with m67 threads), I will be ordering a type 1 screw ring(rear element protrudes out from m67 threads) to see if I can get the rear element even closer to the housing glass. I would eventually like to adapt the h100 into a LD bayonet mount.


Interesting.  You also have to take account of the gap being filled with water instead of air, thus causing more magnification, thus less vignetting.  Not sure how much of that would be true since in my last camera setup, I had no vignetting so that was never an issue.


Here is how the lens fits on the RX100's plastic housing:


Attached File  rx100_28mm.jpg   67.03KB   5 downloads


You can see that the lens sits much further back probably 7-8mm from the rear of the glass port (at 28mm, when zoomed to 33mm (or 12mm, as picture specs indicates)), it is maybe a mm or 2 further back.  It seems that Meikon was on a learning process in their design of housings, with the earlier housing the least thought out in terms of design and lacking the most features.


Strangely, the beveled recess of that lens port mates perfectly with the UWL-100 28AD's rear lens protrusion.  I did some measurements of the type 2 vs the bayonet mount depth and if I put a type 2 mount on the 28AD, the 2 lenses could mate almost perfectly once it is screwed down, avoiding the vignetting from the UWL-100, and being a much smaller lens.  I tried to do the swap, but my screwdriver stripped and didn't want to do harm to the screws, so I will be using the UWL-100 for the upcoming trip.

In Topic: Anyone have experience with Meikon Aluminum housing?

25 November 2015 - 12:57 AM

What I meant with all the gibberish above is that a camera with a 24mm lens zoomed in to remove the vignetting will not get you a wider angle of view than one with 35mm, nor should a housing with the lens butted right up to the housing's port.  The only inconvenience is that one has to slight zoom in from the widest setting.

In Topic: Anyone have experience with Meikon Aluminum housing?

24 November 2015 - 07:23 PM

How tight does the lens sit behind the port glass? I am asking because i want to use wet lenses and too big spacing results in vignetting/poor iq. I would like to get the mIV, but i guess the mkIII housing is more or less the same as the mkIV.


From the little experiments I did, it doesn't seem to be how close the lens sits to the housing that is the only factor to whether it vignettes or not.  It seems to be also based on the rear lens diameter of the wet lens and how big an image it can project to the camera's lens.


I have a UWL-100 w/dome and no matter how close I bring that lens to the RX100's 28mm lens, it will vignettes (it looks like it is dome port or front of wet lens vignetting).  Pulling it outward, maybe up to 10cm does not change the vignetting much, and zooming in to get rid of the vignetting does not affect the angle of view compared with the lens butting together.


I put the same UWL-100 w/dome onto my old Oly c5050 w/35mm lens, the angle of view with the 2 lenses butted together is only a tiny bit wider than when the above lens setup when they are 10mm apart.


I also tried a UWL-100 28AD, which has a smaller rear llens, with the RX100 and it goes from no vignette to vignetting before I could pull the lens 10mm away from each other, thus requiring zooming in and incurring a lost on angle of view.  It was similar but slightly less so with the c5050.


I had a panny w/24mm, and effect is similar to above scenarios.


So in effect, zooming in slighly (from 28mm to 32mm) doesn't always cause you to lose 10% of your angle of view.  Result could be different if I took the dome lens off, and I do in fact lose angle of view when the lens are farther away and I have to zoom in, but then if this test was performed underwater, the angle of view would be narrower and vignetting by the dome might become irrelevent, and water between the 2 lens more or less makes it an optical coupler, decreasing the angle of view of the camera's own lens, thus reducing vignetting.


All you have to do is set your memory recall mode for it to zoom in just enough so it doesn't vignette.

In Topic: Dry lens for underwater use

18 November 2015 - 01:32 PM

Did you try this dry diopter underwater?  As a wet lens?  I would think it being a achromatic double lens, water seeping into places becomes an issue, especially between the space between the lenses.  I would think a single lens, even with its inferior image quality, would last longer as a wet lens.

In Topic: Anyone have experience with Meikon Aluminum housing?

17 November 2015 - 10:19 AM

You probably should disassemble the dome and verify that the rubber gasket is installed right, as per the 2nd video.


Good thing the thread is metal.  Although from some video I saw, the sound it made while they were mating the threads sounded like plastic, though that could be the resonance of the hollowness of the dome unit.  The metal thread is one part I am relieved about.  I thought the thread was plastic based on the review here:




Given that I had a circular float on my last housing in which I had to thread the wet lens blindsighted and alot of the initial turns were just to get the threads to meet up.  A plastic thread would have surely caused them to strip, especially if it has to be re-done underwater due to it not having venting holes for the air to escape.   Plus having an extra heavy wet lens with a dome port on it, the rough handling of cameras when you hand it over to a crew when getting onboard is always a concern.