TTL Synch Issues with D7100 and YS-D1

Asking for a friend who is "computer" challenged ....

Shooting Nikon D7100 in Nauticam housing with dual S&S YS-D1 strobes and fiber optic cables. Random pictures over the last year have dark band across bottom when shooting in TTL mode (see below/attached).

All 3 pictures shot with Nikon 105mm lens, f 1/13, ISO 160, TTL, Spot metering

1st picture is 1/320 shutter speed, 2nd one is 1/250, and last one is 1/200

Purchased second D7100 camera and D7200 camera and problems persisted - so not the camera.

Synch speeds set to 320 AP, 250 AP, 250, and problems are still there.

Today we put camera on tripod and replicated problems on land (same setup used as when diving).

Any thoughts ????

You are having sync problems. Press the flash button and rotate the dial and watch the top lcd display. make sure that you don't have red eye reduction on and it probably should say (Rear) with a lighting bolt only. Also just for fun try a slower speed like 1/250, 1/200, 1/160. you can not use 1/320 s (Auto FP) or 1/250 s (Auto FP) with those external fiber optic strobes.

Thx for the reply. I agree that it is probably a synch problem, but we haven’t found any resolution yet. Fill flash is on, red eye reduction is off, rear curtain is off. We’ve also tried with rear curtain on and off - and no real answers there either.

Also tried numerous shutter speeds as you suggested. The dark band appears to be more pronouncd (larger) at 1/320 and less as the shutter speed is reduced (1/250 and 1/200). Did not try 1/160 yet, but that kinda defeats the purpose of a DSLR if one can only shoot at 1/160 or slower.

Sea&Sea YS-D1/YS-D2 Not Designed For High Speed Sync - Lights ...

sorry but here is another link

http://wetpixel.com/forums/index.php?showtopic=56787

Thank you. That seems to make the most sense. Shooting manual can use shutter speeds up to 1/320, but when shooting TTL use max shutter speed of 1/200. Will try both of these tomorrow.

Thanks again.

Dark strip on images is shutter 2-nd curtain. It became visible in shutter window at the moment of flash, because of inconsistent flash sync speed setting in your camera menu.

Nikon D7100 has mechanical shutter, which makes fully open window at max fast speed 1/250. If you set faster speed (1/320 or faster, or FP speeds), then camera mechanism does not make fully open window at all, but just an open strip which moves along the window (2-nd curtain goes after 1-st curtain faster), the more fast speeds cause more narrow open strip.

Regarding "FP" flash sync speeds in camera menu *

Nikon FP is fast shutter speed shooting method, when camera initiates Nikon land strobe to burst 40khz multi-pulses.

But underwater strobe cannot burst 40 khz FP light, underwater strobe burns only continuously in a single pulse. That is why underwater strobe must burn only at the moment when camera shutter window is fully open, to light the full shot. Such shutter speed, when window is fully open, was named as "X-sync speed" in photography technics.

The maximum x-sync speed which you can set in D7100 menu is 1/250: Bracketing/Flash--->Flash sync speed--->1/250. But, without "FP" !! Only this case underwater strobe will light the full shot.

By the way, If you would use any old DSLR camera, like Nikon D50 for example, (it has electronic-mechanical shutter with x-sync speed up to 1/500), then underwater strobe can work even at 1/500. I tested my strobes with Nikon D50 and #11031 UWTechnics TTL-converter, - all strobes worked perfect in TTL at 1/500 s shutter speed.

Regarding Sea&Sea YS-D1**

The 1/200 restriction in User's Manual, - it is a mistake. This strobe works with all available x-sync speeds (without FP of course), the same as other uw strobes. Believe me, YS-D1 works at 1/250 (without FP), i have just tested it again now. You can set 1/250 flash sync speed in D7100 menu and use YS-D1.

I can only assume that Sea&Sea put 1/200 restriction into User's Manual to avoid any consultations about flash sync speeds, because 1/200 works as x-sync speed for all modern cameras.

Thank you for the very detailed answer ! On today’s dive we will set Flash Synch Speed to 1/250 and TTL.

If the 2nd curtain problems persist (dark strip), any ideas on other likely culprits ? Old strobes (4 years), worn out fiber optic cables, batteries, other ???

The dark strips is a relatively new problem. For the first few years there were no issues. For the last 12-18 months the dark strips show up on occassion, sometimes several shots on a dive, and sometimes not at all.

The probelm is also independent of the camera, as we have used 3 different camera bodies - two D7100s and a D7200.

Thanks again.

If the 2nd curtain problems persist (dark strip), any ideas on other likely culprits ? Old strobes (4 years), worn out fiber optic cables, batteries, other ???

I don't think that old strobes or fiber cables can cause such effect of dark strip. This is exactly looks like wrong synchronization (2-nd curtain is lighted).

Anyway, better solve it step by step. The initial step, - right settings in camera menu (Flash sync speed), then everything will be more clear or totally solved. Easy to check it on land. You have to set 1/200 or 1/250 flash sync speed (without "FP") in camera menu.

Thank you again.

Short dive today in Cozumel - very stong currents arrived during the shore dive forcing us to call the dive.

Took about 15-20 pictures, flash synch speed set at 1/200, TTL, and there were NO issues. Will dive more in the next few days. Hopefully this has resolved the problem.