Great! I'd like to pick your brains about a few things if you don't mind. Haven't encountered another snorkeler who used a camera with a sensor larger than 1" before. And I think snorkeling and diving present quite different photographic challenges/requirements.
I definitely agree on the different challenges for snorkelers and divers. At the surface, you're at the mercy of the chop, and even on a calm day, the water surface is going to move you a little bit no matter how steady your hands are. When I first got my E-PL10, I watched the Backscatter recommended settings video about 30 times before I first got in the water...which is when I instantly discovered that those settings weren't going to work.
– I've used the OM-1 and its predecessors for many years above the water for bird and insect photography. But I find I I'm not missing much about the OM-1 versus the EM-10 iv (which basically has the same sensor) underwater. The main thing I wonder about is the autofocus. I get a lot of mis-focused shots when a subject (usually a fish) is moving against a busy background – in my experience that is the most challenging situation for any camera's autofocus. I find above the water it is also challenging for the OM-1 (e.g. birds in flight), though I find the creature detect AI can help a lot with birds jumping around in foliage. How do you find the OM-1 autofocus for fish? A clear improvement over the E-PL10? I would think creature detect might help in some situations, but less so when there are multiple fish in the frame, as is often the case.
I can't comment on the OM-1 vs the EM-10iv specifically as I never had the EM, but the reason I moved up to the OM-1 was for the IBIS. In my time snorkeling with the E-PL10, I ended up with so many shots with motion blur--it wasn't missed focus, it was simply that the motion of the water was moving me by a few pixels on the sensor (how many microns is that?) over the course of a shutter actuation. I won't pretend that I never got a blurry shot with the OM-1, but my hit rate substantially improved.
As for the auto-focus, that was also a massive improvement. The AI detection was no help underwater (in fact, I had to turn it off because occasionally it would decide that a feature on the coral in the background was a cat or something) but the upgrade to phase-detection autofocus over contrast autofocus was a game changer. With my E-PL10, the subject tracking autofocus was more or less useless as a snorkeler (I suspect I was moving too much for it to keep up) whereas I use it every day now with the OM-1. It's wonderful.
As I said, I don't use the AI creature detection as it didn't seem to help with fish and occasionally seemed to hurt, but the customization modes for autofocus points on the OM-1 were also a huge improvement over the other underwater cameras I've used. I could really dial it in to where I position the camera when I identify my quarry, then use back button autofocus to activate tracking while I compose the shot.
-- What lens or lenses do you use? I use the 14-42mm EZ; super light and gives me flexibility similar to a TG to shoot both wide and close as the situation dictates. (I also have the 60 and 90mm macro lenses but only use those above water because I want the flexibility to go wider and don't want to carry bulky dome ports; plus, I'm skeptical that high end optics have much benefit in most underwater situations given the other limiting factors.)
I use the 14-42mm EZ as well, with the AOI UWL-09Pro wet lens on my housing for exactly the same reason as you. I can get great close focus wide angle using that combination, which is as good as I could ever hope as a snorkeler. Realistically, I'm never going to get a pygmy seahorse or a Shaun the Sheep nudi snorkeling anyway, so no need for macro lenses underwater. The UWL-09 Pro is a glorious lens but pure glass and not very light topside. When I used the TG-5, I had the FCON-T01 wide angle converter as well. I love that you can get closer with these without filling the frame, which means less chance for hazy water or loss of red colors.
I just bought the 90mm macro too and it's currently on a USPS truck headed my way! I can't wait to play with that, but probably topside only.
– How are you carrying your rig? One of the reasons I opted for the EM-10 iv was I wanted something light that would be easy to carry on a wrist lanyard, like a TG. I'm leery of the big metal bracket approach, especially if I need to battle the current. But I assume you will need to go that route if you opt for strobes.
Yeah, underwater thus far I've also only had the wrist strap on my housing and it's worked great. I snorkel in a rash guard, and I specifically shop for rash guards that have the thumb slits so that the sleeves can't ride up your arm. The benefit of this is that I can put the wrist strap on my hand, then slide the rash guard up and put my thumb through the slit. Now that camera's not going anywhere even if I have to release it and let it dangle in an emergency.
I've never shot underwater with strobes, but... guess what's sitting on my table right now waiting to get wet for the first time. I just picked up two of the new Hybrid Flash strobes from Backscatter and the associated tray/arms/etc. The whole setup is a lot heavier (15 pounds on land on my bathroom scale), but I'm really hoping the results will speak for themselves. If not, watch the classifieds section the next few months for a good deal on two Hybrid Flash units....
– I'm considering getting maybe one strobe for night snorkels. I haven't had much problem with low light – though so far I've been fortunate in having plenty of sun during my snorkels. My exposure approach so far is to set a minimum shutter speed of about 1/200 and Max ISO of 12,800. I then use auto exposure and DxO pure raw in post to control noise if necessary – though my ISO rarely gets high.
For my night snorkels, I've always just used my underwater flashlight. It's substantially inferior to a strobe in terms of light distribution (hot spots everywhere that would take weeks to clean up in Lightroom) but works ok as long as you can hold the camera steady with one hand. If you want to try a strobe for night use, think about whether you could mount it on the cold shoe of your housing. That's a lot less bulky than getting a tray.
Daytime, your settings sound very reasonable. I usually shoot aperture priority and tend to open the 14-42mm EZ up as wide as it will go at a given zoom. I watch the shutter speed, and I assume that any time it goes below 1/120, the shot didn't work, and I manually elevate the ISO accordingly. With the E-PL10, I had to keep the ISO pretty low (sub-1200) without grain becoming noticeable. With the OM-1, that was no longer a problem, and I could easily crank it sky high without a meaningful loss in quality.