Scuba Diving in Roatán, Honduras - March 2020 (4K)

PHXAZCRAIG wrote:

Hilifer wrote:

UPDATE: Found a window of opportunity and we made it! Just a few days left, but I’ll finish my OW certification tomorrow with my two sons. Weather and water clarity has been amazing for the last several days. I’ve been bitten by the bug so starting to research a housing and port(s) for my Z7. Hopefully I’ll be able to use focus peaking. Candidate glass would be my Voigtlander 21/1.4 VM and 125/2.5 APO.

Be prepared for some surprises in what lenses you can actually use. The selection is more limited than you think for full frame.

I'm currently using a D850 in a Nauticam housing. I don't do fisheyes, so can't comment on those. What is left for me is:

1. wide zoom. Basically I have the choice of 16-35 and a big dome port. And 16mm underwater behind a dome port is pretty wide, while 35mm is still a bit wide. Means you get frustrated trying to shoot small subjects with a dome port.

2. macro. Either 60mm or 105vr. I have both and tried both. The 60mm is what you probably want for DX, but it's far too short for FX. The 105vr is a gem that works very well underwater. I find it a bit short and end up cropping a lot. What would fit me best would be a 150mm macro as it would eliminate most of the cropping I typically do. I tried adding a 1.4TC and got the focal length that worked, but I didn't like the slight image degradation and went back to the bare 105 (and cropping). Note that there is a 20% magnification factor for an image passing through a flat glass/water interface. (Dome ports do not magnify). So the 60mm works underwater like a 72mm lens and the 105 works like a 135mm lens above water. Which is one reason the 60mm doesn't seem wide enough to be midrange.

3. Midrange. [crickets] There are basically no mid-range zooms and the 60mm macro is a bit long to be considered for this. The 60 on FX is in no-man's-land. Too short for macro, too long for normal.

Here's the issue I see you having with your lens choices: ports and focus/zoom gears. For every lens you choose, you need to select a port type (domed or flat) and that glass needs to be the proper distance from the sensor for that lens. To get the proper distance, some ports require an extension, basically a big spacer tube between camera and glass/acrylic port. Extensions come in a variety of lengths, so finding the right one is a matter of ordering the right one (once you figure out how long it should be).

However, if you want to zoom a lens or manually focus it, you also have to have a part that fits around the lens and is geared into the camera housing somehow so that you have something to turn that moves the lens. Unless you have a 3d printer you probably need to find a focusing or zoom ring already made, and they are very limited.

On my 105vr, I don't use a manual focus gear, though I have one for it. I'm generally floating along while photographing and would not be able to maintain position as accurately as needed to make tiny changes to focus so I rely on autofocus.

The 16-35 needs to be zoomed, however. There is a ring that fits around the lens that has gear teeth on the outside. Those teeth mesh with a gear train in the housing that leads to a knob on the left. I turn the knob to zoom the lens. Would be the same knob for focusing, which does mean you can't both zoom and manually focus a lens.

That said, if you can deal with the focusing issue, you'll also have to deal with big dome port issues. And when I say big, you better believe BIG. I had never seen a 230mm dome port before mine showed up at my house in a box. I was shocked. And it's a real pain to travel with due to the size and the fact you can't really cram hard stuff around it in the bag.

Thank you for all of this valuable information! I have a lot to learn about this... at least I have six months or more before I’ll get another chance to dive, so plenty of time to study.