Some shots from the Red Sea with Meikon/SeaFrogs gear

[Barmaglot_07]

Diving the Ras Mohammad/Straits of Tiran area from VIP Shrouq liveaboard with a Sony A6300 in a SeaFrogs Salted Line housing, mostly with the Sony 10-18mm f/4 lens behind a 6" dome; one dive (Dunraven wreck) was done with a 7Artisans 7.5mm f/2.8 fisheye lens behind a 4" dome. A pair of SeaFrogs ST-100 strobes were used for lighting, augmented on some dives with a pair of Archon D36V LED lights on triple clamps.


Corals at Woodhouse Reef


Fan corals at Ras Umm Said


Ras Umm Said again


Ras Ghamila


A batfish at Ras Ghamila


Soft corals at Ras Nasrani


For all the abundance of corals, there's surprisingly few sea anemones


Luckily, this titan triggerfish at Jackfish Alley wasn't feeling combative


Stonefish are found in great abundance near the Dunraven wreck


Entering the Dunraven - this was shot with a manual fisheye lens


Swarms of tiny glassfish meet us inside the wreck


...and we're through!

This was my first time diving with Meikon's new Salted Line housing. I have it on a generic tray from Aliexpress, with a Nitescuba trigger extension fitted to the right handle. The housing, tray, trigger, arms and camera functioned flawlessly, although the zoom rings are a bit fiddly - they have to be placed just so, in a way that they won't rub against the housing on the one side, and won't miss the quite narrow driving gear on the other. Once properly set up though, the zoom operation (focus in case of 7.5mm fisheye) is smooth and reliable. Note that 7.5mm fisheye does not have a dedicated focus gear; instead, I used double-sided tape to pad out its focus ring, then squeezed on the zoom gear from 16-50mm lens.

The 7Artisans 7.5mm fisheye lens turned in an acceptable performance, considering that I'm a fairly inexperienced diver, using a fisheye lens for the very first time, and a fully manual one at that. I will need a good deal more practice in order to focus it quickly and accurately. I do intend to keep using it, because I very much like its output, even though it's not as 'universal' a lens as the 10-18mm is.

I'm not nearly as happy with Meikon's strobes though. While TTL operation is functional, and they do provide considerably more light than my Archon torches, the manual modes flat out don't work - I still see the double flash of TTL operation. The power/EV compensation dial has no effect - I tried doing test shots (on land) with the camera in M mode, 1/160 shutter, f/8, ISO 100, dark room, white wall a couple meters away, and results are identical with the knob turned to minimum and maximum. I'm guessing that the strobes lack a TTL cancellation (ignore pre-flash) circuit, which, paired with Sony's implementation of on-camera flash (only TTL operation, no manual mode) locks these strobes into TTL, although this does not explain the power/EV compensation dial having no effect. Now that I think about it, I should test the flash compensation options on the camera, see what effect they give me.

I'm also somewhat disappointed in their power output - it may be a case of excessive expectations, but they don't really have that much range; shooting a large (a couple meters across) fan coral required fixing the white balance in post. This may be a limitation of on-camera flash in TTL operation - I read a post by Pavel Kolpakov of UW-Technics where he claims that on-camera flashes typically pulse for up to 1ms, whereas powerful underwater strobes take up to 4ms for a full dump, so with the manual mode not working, it is possible that my on-camera flash is simply incapable of extracting the strobes' full output.

I have written to Meikon's support about it last night but haven't received a response yet. It might be possible to overcome these issues with a TRT Electronics s-TURTLE trigger, but one of those, shipped to Israel, costs as much as my two strobes put together. A macro lens and port (most likely Sony 90mm f/2.8) and a new laptop are much higher on my wishlist right now. I'm also not certain that the strobe's optical receiver is sensitive enough to trigger off an LED - it does trigger off my phone's LED flash, but I don't know if s-TURTLE's LEDs are anywhere near as powerful, and wired sync is not an option with this housing.

 

[daveco2]

Very nice shots. The place names in your photo credits brought back fond memories. I'm wondering how you found the stone fish. I had to rely on my guide for all the findings as I didn't see anything but the most obvious.

How did you find the liveaboard: comfort, privacy, convenience?

I was very interested in your comments about the ST-100 TTL performance. as I have only trigger sync mode available on my case now, and did not opt to modify for the Turtle. The price was a little too steep and the discussions about manual vs TTL didn't convince me to go either way. I anticipate that there could be another strobe purchase in my future.

Did you find the low level pointing light on the ST-100 of any use?

How far out were the strobe arms?

Any comments on strobe and camera battery life?

Thanks,

Dave

 

[Barmaglot_07]

Very nice shots. The place names in your photo credits brought back fond memories.

Thank you

I'm wondering how you found the stone fish. I had to rely on my guide for all the findings as I didn't see anything but the most obvious.

We dived that area at night, the water was clear, and with two wide-angle lights illuminating a wide area, they were actually not super-difficult to spot - I shot five of them on that dive, even finding some that the guide missed. Also found two spanish dancers and and octopus on my own on that dive.

How did you find the liveaboard: comfort, privacy, convenience?

I only have one other data point for comparison (MV Pawara by West Coast Divers in Thailand), but I wasn't overly impressed. Most importantly, the boat lacked a camera table and rinse tank - between dives, I had to haul my camera rig down to my cabin and keep it on a towel on my bunk, and the very first thing I did upon coming home, at 2AM, was to fill the kitchen sink with fresh water, drop all the camera stuff in, and keep it there for 30 hours.

It also wasn't nearly as well-run as the Pawara - the dives didn't adhere to a set schedule, they didn't have dedicated nitrox tanks with that green/yellow paintjob and a couple times, nitrox tanks (though not mine) got topped up with air, on multiple occasions not all tanks had been topped up in time for a dive, the shower in my cabin was cold and the bathroom leaked into the carpeting, etc. There were two guides for fifteen divers, and for whatever reason, they swapped the guides between the groups every day.

On the other hand, for the same 14 dives that I got in Thailand, I paid NIS 2800, which included nitrox fills and transportation from Eilat - that's $783 at current exchange rate. Pawara liveaboard cost me THB 32700 plus THB 1800 national park entry fee, which comes out to $1055 or so. For an Israeli, a bus ticket to Eilat is obviously much less expensive and more convenient than a plane ticket to Bangkok and another to Phuket, although my Similans trip was part of a much longer vacation, so it kind of evens out. Funnily enough, it's actually cheaper and more convenient for me to get to Thailand than to mainland Egypt locations such as Hurghada or Port Ghalib, as opposed to Sharm el Sheikh. Still, next time I book a liveaboard, I'll make damn sure it has a camera rinse tank, or at least bring a cooler bag to use as one.

I was very interested in your comments about the ST-100 TTL performance. as I have only trigger sync mode available on my case now, and did not opt to modify for the Turtle. The price was a little too steep and the discussions about manual vs TTL didn't convince me to go either way. I anticipate that there could be another strobe purchase in my future.

Does the power adjustment work for you with wired sync? I recall you have an oscilloscope with a photodiode receiver - can you compare pulse length in wired sync mode with your A7RII and optical sync mode with your RX100?

Did you find the low level pointing light on the ST-100 of any use?

Didn't use it in daylight; used it on night dives when I didn't want to turn on the Archon D36V floodlights.

How far out were the strobe arms?

The water was very clear, so on close-focus shots, I tucked them all the way in, while for larger objects, I spread them maybe 20cm out from tray handles. With 10-18mm lens, I had them pointed forward or even slightly inward; with 7.5mm fisheye, I pointed them well outward to cover its near-hemisphere FoV. Diffuser plates helped a lot. Never needed to even come close to utilizing the full spread of my strobe arms (2x8" on each side) - only time I needed that was on Koh Tao, when full moon tides kicked up a bunch of silt, and I was night diving with video lights which were blinding me with backscatter otherwise.

Any comments on strobe and camera battery life?

I took about 30-40 shots per dive and didn't turn off the camera between shots to conserve battery power. In this mode, I used up about 1/3 of a camera battery charge for each dive, swapping camera batteries every two dives. I only have a single set of eight Eneloop Pros for the strobes, and I recharged them every two dives as well - the chargers showed me that battery voltage after two dives was about 1.3V, as opposed to 1.5V when fully charged. I opened the housing and dumped the shots into my laptop after each dive.

 

[primozp]

Tiger fiish could also be very playfull:

 

[daveco2]

Those teeth look a little too serious for me to play around with. Very charming video.

 

[daveco2]

Thanks for the details. Very interesting. I'll get some data regarding your questions.

 

[daveco2]

Pulselength with ArRii and sync cable to ST-100 increased with increasing power setting. Increased light output with power setting easily visible by eye. Pulselength with RX100 and fiberoptic trigger to ST-100 fixed, independent of manual power setting; and no noticeable change in light output by eye. Vertical peak amplitude same in all cases.


A7Rii in Meikon housing, sync cable trigger, ST-100 strobe manual.


A7Rii in Meikon housing, sync cable trigger, ST-100 strobe manual.


RX100iv in Fantasea housing, fiberoptic trigger, ST-100 strobe manual or TTL.

 

[Barmaglot_07]

Thank you, this is just as I suspected - in optical trigger mode, it just blindly mimics the driving light source, pre-flash and all, and the manual power adjustment only comes in play for wired triggering. Also, if power level 8 results in a ~1ms pulse, then it stands to reason that a full dump would take ~4ms, beyond the capability of the on-camera flash to drive it.

By the way, with the RX100IV, you could probably modify the pulse length using flash compensation mode in the camera (I tested it with my A6300 and it does result in a noticeable difference in the resulting exposure), and probably get the maximum strength pulse that it's capable of by covering the lens to trick its TTL logic into a maximum-strength mode.

 

[daveco2]

You're right about flash compensation on the RX100 and ST-100 output. ST-100 output: Top trace, zero flash compensation; Bottom trace, +3 flash compensation. About 23% increase. I'm thinking I may need a wired flash TTL, but that would lead me to a higher end enclosure. I checked the pinouts for the Meikon case and strobe cable and there are only two connections. the Turtle shows three connections needed for TTL; so this may not be an option for the Meikon case and strobe. In the meantime, I'll stick with manual wired flash on my next trip and see if I really need TTL.

increase.

 

[Barmaglot_07]

Yep, this pretty much aligns with my empirical findings. The difference between -3, +0 and +3 flash compensation was noticeable, but not orders of magnitude noticeable.

If I get an s-TURTLE trigger (€390 shipped to Israel, unless they waive the EU VAT), and its LED board is sufficiently strong to trigger the ST-100s, then I'll have TTL capability across the entire power range of ST-100, but still no manual mode, and adjustments will be possible only via the camera menu, not via the strobes themselves. If I get a pair of used YS-D1s or Z-240s ($600 or so) and trigger off the camera flash, the TTL mode will still be limited to the lower end of their power range, but I'll be able to use manual mode for extracting more power. Same goes for a pair of new YS-D2s or Z-330s ($1300-1400), with the extra $600-700 buying me more power and manufacturer's warranty.

On the other hand, so long as I don't try to light up a whole wreck at once, the part of ST-100's power range that is currently accessible to me works reasonably well. Considering that I plan to expand my photography into macro rather than more wide-angle, I might be better off saving my money towards a 90mm FE macro lens and a trip to Anilao.

 

[fplanglois]

Hello everybody. I had to prove the malfunction of this strobe by a video for AliExpress. I did not see this thread when I realized this test on Youtube. My English is approximate, but I think you will understand and my conclusions are the same as yours :

 

[daveco2]

Interesting series of tests you did.

When I bought the ST-100, I naively expected to get TTL with the sync cable. When that failed, I began to search for more information (which I should have done before the purchase), and found that most cases with sync cable strobe connections do not provide TTL, the exception being Ikelite which provides TTL via sync cable and a $375 TTL converter, which works only with their brand of strobe.

An after market solution for the Meikon a7Rii case could be the so-called Turtle. The Turtle can provide an output to fiber optic link, but the case would have to be modified for a transparent window, or perhaps modified to emit through the clear screen view window, but space in that area is very tight. The Turtle could also be wired to provide TTL via sync cable; but according to the Turtle manual, that requires three wires. The cable connecting the case Meikon case to their strobe has two wires.

Bottom line in my case: The ST-100 can be triggered via the sync cable and its output can be controlled manually. TTL does not work. The Turtle will not work because a third wire is missing from the cable. There is no easy way to modify the cable, and even doing so, there would be risk in determining which pins on the strobe to connect to. Lastly, is TTL really necessary? Many say it is not. But I would certainly like the option, especially for macro.

 

[fplanglois]

When I bought the ST-100, I naively expected to get TTL with the sync cable. When that failed, I began to search for more information (which I should have done before the purchase), and found >>that most cases with sync cable strobe connections do not provide TTL,

Indeed, even Inon does not make TTL with the electrical connection. Except the old TTL protocol of argentic strobe for old Nikonos. It's probably the same for the Seafrogs.

the exception being Ikelite which provides TTL via sync cable and a $37>>5 TTL converter, which works only with their brand of strobe.

Other brands do it but it's much more expensive than Ikelite.

An after market solution for the Meikon a7Rii case could be the so-called Turtle.

Exactly not, because the seaFrogs do not know how to exploit the optical signals. He will have the same behavior.

The easiest way will be to buy an Inon flash when they become available again. In France at the moment, it is in the dropper.

 

[kelpdiver]

How far out were the strobe arms?

The water was very clear, so on close-focus shots, I tucked them all the way in, while for larger objects, I spread them maybe 20cm out from tray handles. With 10-18mm lens, I had them pointed forward or even slightly inward; with 7.5mm fisheye, I pointed them well outward to cover its near-hemisphere FoV. Diffuser plates helped a lot. Never needed to even come close to utilizing the full spread of my strobe arms (2x8" on each side) - only time I needed that was on Koh Tao, when full moon tides kicked up a bunch of silt, and I was night diving with video lights which were blinding me with backscatter otherwise.

you rarely, if ever, want to point the strobes inward, regardless of water clarity. The better light (color) comes from the edges of the strobe, not the center.

 

[Barmaglot_07]

Without diffusers, at close range (5-10cm from dome to subject), I found that with strobes facing directly forward, I was risking having an unlit area in the middle of the frame. Turning the strobes slightly inward helped, as did fitting diffuser plates.