a7RII+Meikon Case+ST-100 Strobe

I just received all the items to assemble my a7RII inside the case and connect to their ST-100 strobe.

ST-100 cycle time:  I measured the cycle time with a 20 ns risetime detector and oscilloscope shown below.  Camera set to multiple exposure, jpeg plus raw images. Strobe set on M, SD card 95 MB/s speed class, Recycle Rate=3.16 fps.  Cycle rate for camera alone=5 fps.  No difference for format set to fine jpeg only.  For strobe set to Full, recharge time=7 sec.  I'm not able to get the TTL setting to work consistently, probably requires more work on my part.  If I can't figure this out, I may return the strobe.

Meikon Case:  I was pleased to find a double o-ring seal on the rear cover.  I hadn't seen this listed in specs in their literature.  The face seal o-ring in the case is a little too small, so it must be stretched to get it to lay in the groove, then the case must be closed quickly and left in that position for an hour to seat the o-ring.  I measured buoyancy with a calibrated water column for the case and camera with 24-70 mm f/4 lens.  Weight of camera, lens, and case 4.8 lbs.  Case displacement 3234 cc.  Net buoyancy 2.3 lbs positive.  The camera top mode dial cannot be actuated through the case, the case knob misses it completely.

Delivery Times to LA:  Case from Meikon 3 days.  Strobe from Sea Frogs 8 days.  Cable from Japan 11 days, $45 from ebay including shipping compared to $125 from the usual camera outlets.

Cycle time measurement setup.  White arrows show positions (316 msec) of sequential flashes.

Left,  face seal o-ring; right perimeter seal o-ring.

Internal view of camera top mode dial and case actuator.  They do not engage.

daveco2 wrote:

I just received all the items to assemble my a7RII inside the case and connect to their ST-100 strobe.

ST-100 cycle time: I measured the cycle time with a 20 ns risetime detector and oscilloscope shown below. Camera set to multiple exposure, jpeg plus raw images. Strobe set on M, SD card 95 MB/s speed class, Recycle Rate=3.16 fps. Cycle rate for camera alone=5 fps. No difference for format set to fine jpeg only. For strobe set to Full, recharge time=7 sec. I'm not able to get the TTL setting to work consistently, probably requires more work on my part. If I can't figure this out, I may return the strobe.

Thank you for the detailed info. Am I correct in assuming that 316ms is recharge time at minimum power, as opposed to 7sec at maximum power?

Meikon Case: I was pleased to find a double o-ring seal on the rear cover. I hadn't seen this listed in specs in their literature.

It's kind of unintuitive, but they have a list of o-ring sizes for all of their housings here: https://meikon.com.hk/collections/spare-o-rings

From this, you can see which housings have single o-rings, and which ones have double seals.

The camera top mode dial cannot be actuated through the case, the case knob misses it completely.

Interesting, so it's not just the lock... do you think that maybe a rubber cap on top of the mode dial could keep the lock button depressed and increase the dial diameter to engage the knob? Or is there insufficient clearance from the other parts around it?

That's right, 316 ms recycle time at minimum strobe power and 7 sec at full strobe power.

Yes, if the button could be kept depressed with tape, then a round rubber bumper attached to the mode selector rotator could work. Arrow 1 indicates a backup tab that would keep pressure on the bumper at the end of the rotator stem. Arrow 2 indicates the section of the rotator that could engage the mode dial. The small double arrow indicates the space between the rotator and camera housing which is larger than the space to the mode dial, so a bumper could engage the dial without interfering with the case. There is sufficient room.

I still have not gotten the strobe to fire on TTL. It should be straightforward according to the instructions and camera settings. On Manual, and 2 ft from the target, there is too much intensity even at the lowest output setting. I sent a message to Sea Frogs and expect a reply shortly. They've been very good about response time.

Thanks for information on the O-rings. The one in the case keeps popping out of the groove. Although it doesn't appear to get pinched if I leave it slightly out of the groove and close the case on it, I would rather have it lay flat to begin with. Meikon shows the same 155 mm for both the lid and case O-rings which is probably for convenience, but in reality the case O-ring should be slightly bigger.  Meikon's next stock size up is 165 mm which would be too big.

daveco2 wrote:

That's right, 316 ms recycle time at minimum strobe power and 7 sec at full strobe power.

Thanks, that's good to know. 7sec is, unfortunately, quite a lot, but for one third of the competition's (Inon/Sea&Sea/Ikelite) cost, complaining about that one point would be... excessive. Hopefully, with a pair of strobes, I won't need the full output too often.

Yes, if the button could be kept depressed with tape, then a round rubber bumper attached to the mode selector rotator could work. Arrow 1 indicates a backup tab that would keep pressure on the bumper at the end of the rotator stem. Arrow 2 indicates the section of the rotator that could engage the mode dial. The small double arrow indicates the space between the rotator and camera housing which is larger than the space to the mode dial, so a bumper could engage the dial without interfering with the case. There is sufficient room.

It's an odd oversight on Meikon's part that they don't have an A7R II/A7S II kit to enable mode dial operation, but then again, they've got quite a few of those. I don't know how stiff that center lock button is, but it's possible that flexible tape won't hold it - you may need a solid disc with an adhesive surface. I was thinking about a rubber bumper to go over the mode dial, but there's clearly insufficient space to clear the EVF hump.

I still have not gotten the strobe to fire on TTL. It should be straightforward according to the instructions and camera settings. On Manual, and 2 ft from the target, there is too much intensity even at the lowest output setting. I sent a message to Sea Frogs and expect a reply shortly. They've been very good about response time.

Does it not fire at all, or does it fire and overwhelm the camera? If the lowest manual setting is too much, I doubt TTL can be below that - maybe you need to put more distance between the strobe and target, or close down the aperture, or use an ND filter, or all three of the above.

I ordered a pair on July 6th, tracking number went live yesterday - a few more weeks and they should get here, along with 16 Eneloop Pro batteries and a bunch of other accessories (arms, clamps, carrying handle, trigger extension, blue gel filter sheet, etc).  Cost was $461 for the pair - I'm patient enough to wait a few weeks when it represents $200 worth of savings

The strobe doesn't fire at all on the TTL setting through the Meikon case and 5 pin cable to the A7RII.

However, with the strobe fiber optic connector attached to my Fantasea case and RX100iv, the TTL setting on the ST-100 works fine. And the exposures are good, even close up. As usual, with the RX100iv and fiberoptic connection, the strobe puts out two rapid pulses separated by 77 ms. I assume the first pulse is for exposure test and the second is for the photo.

I checked the TTL compatibility for the Sea and Sea YS-D2 and Inon Z-240 which the ST-100 seems to be modeled after and they do not list the A7RII as compatible; however, they do list the RX100iv (and a6xxx) series as TTL compatible with an optical cable. Sea and Sea also says that a converter may be needed to convert electrical to optical trigger for TTL with other than the RX100 and a6xxx types.

In conclusion, it looks like my ST-100 all works as intended, which does not include TTL with the A7RII. Also, returning the ST-100 and buying a $700 Sea and Sea or Inon would not solve the A7RII TTL compatibility problem. I suppose I could buy an a6300 and the Sea Frog case for it in order to get TTL, but I'd rather have the high cropability of the A7RII. Considering price and my frequency of use, I think I'll stick with the ST-100 and use it in manual mode. Besides, I usually shoot under ambient and do adjustment in post.

If anyone has other information, I would appreciate hearing about it.

daveco2 wrote:

The strobe doesn't fire at all on the TTL setting through the Meikon case and 5 pin cable to the A7RII.

Bummer; has SeaFrogs support responded to clarify that?

In conclusion, it looks like my ST-100 all works as intended, which does not include TTL with the A7RII. Also, returning the ST-100 and buying a $700 Sea and Sea or Inon would not solve the A7RII TTL compatibility problem. I suppose I could buy an a6300 and the Sea Frog case for it in order to get TTL, but I'd rather have the high cropability of the A7RII. Considering price and my frequency of use, I think I'll stick with the ST-100 and use it in manual mode. Besides, I usually shoot under ambient and do adjustment in post.

If anyone has other information, I would appreciate hearing about it.

If ST-100 doesn't do TTL with electrical triggering then your alternatives are Ikelite ($1695 housing, $375 TTL kit, $799 per DS-160 strobe) or Nauticam ($2850 housing, €349 s-Turtle LED trigger - Nauticam's own trigger doesn't do TTL) with fiber optic strobes of your choice. Compared to Meikon, both options are prohibitively expensive - besides, from what I understand, many people shoot their strobes manually even when they do have TTL as an option, as in underwater conditions, TTL accuracy can be iffy.

Still, I'm kind of glad I picked A6300 as the camera system to invest myself in - I couldn't know it at the time, but it turned out to be the system that the manufacturer of the best value housings and accessories on the market decided to give their best effort to.

I wonder, what is the eventual successor to A6500 going to be like - an entry level offering to replace A6000? An 'A5' APS-C sports camera to complement the A9? An A6500R with a high-res sensor? Hopefully they'll keep the same body and control layout so that it will fit into existing housings...

Right, I was real close to getting an A6300 and Meikon case; and if I had known about the TTL issue a month ago, that's the route I would have taken.  But I already had the a7RII.  Now we'll see if I can live with that huge housing.

I relayed my findings to Sea Frogs and they replied with the message below, which is in agreement.

We were about to tell you the same information.

Basically for TTL to work with SYNC cable, there needs to be a TTL converter, which we don’t have, but the strobe will work in Manual mode without any problems. When using this strobe via fiber-optic cable the TTL function is available.

You’re absolutely right about other brands of strobe, they work on the same principal – they also need a TTL converter if used via SYNC cable.

File under 'crazy ideas': get a handle like this one and use it to mount your RX100 over the A7RII. Configure the A7RII for macro with FE90 and RX100 for wide-angle with a wet lens. Connect the strobe(s) to A7RII with sync cable and to RX100 with fiber optics. Fire the strobe(s) in manual mode for macro (where your aperture is tiny anyway, so ambient exposure doesn't matter) and in TTL mode for wing-angle.

For the reference, I have seen one guy diving with a similar setup - Olympus mirrorless set up for macro, Fuji compact on top of it with wet wide lens, and a GoPro on top of that.

That's a good one, and I'll give it some thought.  But I'm 75 years old, 5'5" tall, and weigh 150.  If I had to handle all that equipment, I would risk drowning.

Another possible (but dangerous and somewhat expensive) way to get TTL working would be to buy a TRT s-TURTLE mobile LED trigger and DIY a couple of light transmission ports on the housing, then use fiber optics for sync. Maybe stick the LEDs and the fiber optic cable ends onto the the rear window to avoid drilling through the plastic.

Edit: Actually, I just downloaded the user manual for that trigger, and it has a wired sync option in addition to optical triggering with an LED board, so it's highly likely that it can function as a TTL converter which Meikon support said they don't have.

Very interesting. I have a message to Turtle with a diagram asking for alternatives. The unit is a little pricey, but depending on the comments from Turtle, I just may go for it.

One question:  The optical TTL strobe trigger works because it uses the two light pulses from the flashes on the RX100iv and a6xxx.  Is it true that the sync cable does not work for TTL because two pulses are not emitted at the hot shoe connection?

Thank you,

Dave

daveco2 wrote:

Very interesting. I have a message to Turtle with a diagram asking for alternatives. The unit is a little pricey, but depending on the comments from Turtle, I just may go for it.

Yeah, it's kind of mind-boggling how that tiny box costs more than the whole housing, or the strobe for that matter.

One question: The optical TTL strobe trigger works because it uses the two light pulses from the flashes on the RX100iv and a6xxx. Is it true that the sync cable does not work for TTL because two pulses are not emitted at the hot shoe connection?

Thank you,

Dave

No idea, I'm far from an expert on the subject matter. You might want to ask Pavel Kolpakov over at Wetpixel forums - he's bound to know. Also, a quick Google search coughed up this document describing various underwater strobe TTL sync protocols: http://g3ynh.info/photography/articles/ttl_flash_connexions.pdf

I got a reply from Turtle, which I couldn't interpret.  I think my question may have been misunderstood.  In any case, I don't have the energy to pursue that inquiry to get all the answers I would need before a purchase, which I would probably not make anyway.  I'll ask the question at the Wetpixel site just to clarify the workings of the optical and synch TTL approaches, and I'll post it here if I get all the answers.  Bottom line - I'll go with the strobe on Manual.

Thanks again for all the good information.

Quick question - did the strobe that you received directly from Meikon include a YS-to-ball adapter? I just got my pair of strobes from Cameraman's Store on Aliexpress and each package included a strobe, two diffusers, spare o-rings, a cleaning cloth, a tube of o-ring grease and a user manual - but no ball adapter, and no obvious place in the package where one might have been. It's no big deal, I already ordered two for $9 each, but I'm wondering if that makes up part of the difference between $329 direct from Meikon and $230 that I paid.

Yes, I did get the ball adapter, in addition to all the items you mentioned.

Dave

Thank you; I will keep this in mind next time I'm offering unsolicited advice on strobe purchasing

Barmaglot_07 wrote:

Quick question - did the strobe that you received directly from Meikon include a YS-to-ball adapter? I just got my pair of strobes from Cameraman's Store on Aliexpress and each package included a strobe, two diffusers, spare o-rings, a cleaning cloth, a tube of o-ring grease and a user manual - but no ball adapter, and no obvious place in the package where one might have been. It's no big deal, I already ordered two for $9 each, but I'm wondering if that makes up part of the difference between $329 direct from Meikon and $230 that I paid.

Yeah buying from third party dealers can save some money but can be problematic.  I bought a Meikon housing for a Nikon J5 from a third party about a year ago.  It came with only one o-ring despite the Meikon site specifying two.  I ordered an extra o-ring, but it would not fit into the housing's second o-ring groove.  Meikon refused to provide support of any kind, instead referring me to the third party, who was no help whatsoever.  I am actually able to use the housing with only one o-ring, but I'd feel better if I could get the second one in.  It's a nice housing otherwise.

A few more notes:

The ST-100 has a nice feature in the flashlight mode that helps in pointing it.

I can't get the strobe pin-outs so hooking up the Turtle sync cable for TTL would be risky.  Besides, the 5-pin Sea&Sea cable from Meikon a7RII case has only two connections and Turtle specifies three, which means I would have to buy connectors and make my own cable.

Turtle sells a fiber optic bulkhead adapter that would solve the interface problem, but I can't get the dimensions from Turtle to determine if it would fit in the clear space I have on the Meikon case.  I've given up this approach.

Vivid Housings makes a vacuum bulkhead adapter for a pump test port, but its questionable if a flat spot on the case is large enough.

The ball adapter I received with the strobe was not seated in the box, rather it was thrown in.  If the adapter is missing, I would suspect that the shipping person just forgot to reach over to the parts bin.  If the strobe description mentioned a ball adapter, and it was not included, I would ask for it.  Why not?

daveco2 wrote:

The ball adapter I received with the strobe was not seated in the box, rather it was thrown in. If the adapter is missing, I would suspect that the shipping person just forgot to reach over to the parts bin. If the strobe description mentioned a ball adapter, and it was not included, I would ask for it. Why not?

The listing on Aliexpress that I bought them from (link) doesn't actually mention the adapters, so I don't really have a leg to stand on here. Besides, I already ordered two, at $8.99 apiece, so whatever - I just need to wait 2-3 weeks for them to get here.

The more distressing part is that one of my two strobes died during testing At first it was fine, then it started firing intermittently, and then it just stopped firing. I swapped the fiber cables and the batteries, but the problem is in the strobe. Its LED light works, but the tubes won't fire, although there is no visible discoloration or smell or anything suspicious. Let's see how their warranty holds up.

Edit: Hmm, I let it sit for a couple hours, and now it's firing again? Going to recharge the batteries and proceed with testing in a bucket of water just to be sure; maybe it overheated or something.