Rx100 ys01 ttl

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alta5

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How is the TTL supposed to function with the RX100 and YS01? From my understanding if the strobe is set to TTL the strobe adjusts the power depending on the camera TTL to get a standard exposure.
When I test this out on land I'm pretty sure the strobe is giving me a full dump every single time. I tried shooting a macro shot on land at f11/2000/iso100 and the photo is overexposed. The flash is set to fill and I'm shooting in M (also tried PAS and auto w/ same results). Is there a camera setting on the RX100 that needs to be set?

I was also wondering about securely closing the YS01 battery compartment. The manual says to close until you hear a click, which works when there are no batteries. However with batteries inside the sound is more of a thud. Is this ok?
 
Check that you get a green light on the YS-01 after shooting to confirm it did get TTL. If you do take into account that the Sea and Sea TTL is not as precise and at close range you may need to dim the strobe intensity anyway
 
After doing some more reading and testing I'm still not sure if TTL is working properly, but this is what I've found. Just curious if someone has a link or can explain exactly how TTL works with RX100 and YS-01. All my testing is done indoors.

From my understanding the way TTL works by the TTL sensor averaging to 18% grey. RX100 pre-flashes allowing the TTL sensor to determine how much light is in the scene and when to quench the flash. The camera flash flashes into the optical cable, which passes light to the YS01 and the YS01 quenches based off of the camera TTL.

Does the YS01 also pre-fire when the RX100 flash pre-fires? (meaning does strobe position affect TTL)

Does the YS01 modelling light change the measurement of light from the TTL? (I assume it doesn't because the modelling light turns off when strobe fires, but it's so fast I cannot tell).

How does the YS01 know when to quench? Is it just based of how quickly the light travels through the optical cable and stops? Does the YS01 just start and quench the flash synchronously with the RX100's flash through the light that travels via the optical cable?
Also does the YS01 have a sync range for the shutter speed? Does the shutter speed need to be between 60-160?

If I set the YS01 to TTL do the manual dials still affect the exposure? For example, let's say I set strobe to TTL and have the manual controls on full dump. Do I always get a TTL bright exposure vs a consistent darker exposure if I set manual controls to half dump.

I also usually shooting in either center focus/manual focus and usually have metering set to multi. However, I'm not sure what the optimal settings are. I assume metering type will change TTL, but I would think focus is completely separate from how the TTL sensor captures light.

SIDE NOTE: I'm not sure why, but on the Nauticam cover for the flash there are 2 vertical pin holes that allow the camera flash to shine through. If you have the strobe off and fire the camera flash you'll get horizontal lines that look like the sensor captured an image between curtains.

To Interceptor: Thanks. I got the green light when shooting with some light, but I don't believe the green light went off when shooting at night at f11/2000/iso100. I guess the TTL sensor would sense it's really dark with those settings even if there was indoor lighting.

---------- Post added April 23rd, 2014 at 04:45 PM ----------

After some further testing I think I have a better grasp on how this works, but my previous questions still stand.
Basically I think what's happening in this scenario is that when the RX100's flash is on, the LCD output is brightened up to show what the image would look like post flash. However, if your EV is really low like -2, then it may be in a range where the strobe overcompensates thinking the scene is pitch black. Generally if EV is near 0 TTL behaves normally.

I also noticed there's a plug for the secondary optic cable. I'm not sure if this plug should NOT be covering the secondary optic cable hole. If the camera's preflash is necessary to correctly judge the exposure needed for TTL then the plug may be adversely affecting the TTL sensor. However, not covering the secondary optic hole creates cross lighting if the strobe power is not high.
 
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It's not the strobe doing TTL is the camera that sends the start and stop signal. In order for TTL to work you need to aim directly at the subject so that you have a reflection back in the lens. The strobe going green tells you a strobe return has been detected. When you are really close you can still get an overexposure so you can turn the power knob down. The little hole on the housing should be covered or the camera internal flash leaks. This however at close range is very little and is not significant. This system syncs at any speed all the way to 1/2000 as there is an electronic not mechanical shutter. Just try to dim the strobe down. When I shoot my inon I use another mode called sttl-low for macro (another reason why inon are superior) and works fine
 
Thanks Interceptor. So from what I gather the way TTL works is the strobe mimics the camera pre-flash and flash. The TTL sensor is in the camera so the camera determines when to quench the flash. So for TTL to work properly the strobe must be pointed at subject to illuminate it because the strobe mimics the preflash, which allows the camera TTL to determine the flash duration.

From doing some more reading and following other threads with similar issues it seems that:
1) TTL works primarily for Macro where subject is about 50% of frame.
2) Strobe should be pointed directly at subject.
3) TTL is somewhat unreliable or hard to predict outside of these circumstances.

From my tests on land it seems that on top of number 1 the background of the scene plays a significant role in how TTL is metered. When taking shots where subject was 50% of frame and background was light TTL was mostly reliable. However, on darker backgrounds like dark wood or if there was a reflective surface TTL would behave more erratically usually resulting in a full dump especially when the Exposure Value is low (-2 or less). It didn't seem like changing the metering from multi to center or spot made a difference to TTL metering. However, I can correct EV to 0 and get TTL to function properly. What's interesting though is that the shot will come out looking pretty much like the LCD preview where the scene is evenly illuminated. In contrast when shooting manual at same settings, even on the lowest strobe power, the shots will come out dramatic with the subject well lit and the background dark.

It also appears that at least with the RX100 and YS01 there seems to be certain syncs or cycles between the strobe and shutter speed. For example if I shoot between 60 and 250 shots can get progressively darker, but at 500 everything gets a little brighter.

These observations are on land and may not apply underwater, but I'm curious if this is common behavior for TTL or specifically the RX100 and YS01.
 
I think there are some misconceptions here or maybe I am just confused reading this stuff. In the dim ancient historical days of film, TTL worked by having a light meter/sensor on the pentaprism. The pentaprism is the device that let light from the scene go to the finder and when the mirror flipped up the light went to the film. The strobe power was set by this light meter on the pentaprism. In a housing the same system worked, and instead of a strobe on the camera it is now external but worked the same, the sensor on the pentaprism set the power/duration of the flash.
In digital you could do the same thing but Canon/Nikon/everyone else made proprietary systems that worked by sending out a small pulse then looking at the return light then adjusting the real strobe power. This is great but since Canon and Nikon and the rest want to sell their own strobes they don't publish the secret to strobe setting in e or i TTL.
In the case of S&S or Inon they emulate TTL by allowing an on-board strobe send out the little pulse and that goes down the fiber and triggers the external strobe to send out a little pulse. The camera brains figures out how to light the scene and sends that light pulse out. But since it is in the housing it goes through the fiber and out to the external strobe that then lights the scene. What you have happening is that S&S and Inon are trying to mimic the internal strobe on the camera. If the software and electronics guys did their job right then you get good exposure.

Bill
 
Good info above. Can some one clarify the s&s ttl green light?

My prior understanding of ttl stobe operation matches the descriptions above: the strobe simply acts as a remote optical slave to the camera on board flash. The camera flash turns the strobe on and off via the fibre cable. This means the strobe does not need any "ttl smarts". It is just a slave. It does exactly what the camera tells it to.

So what is the point of the green ttl light? What does it really mean? How does it work? Is it simply a "I did not do a full dump" indicator?
 
The green lights indicates return detected. Which means the camera sent a stop signal. The strobe fires a preflash, this bounces on the subject and goes back into the lens. The camera then sets it's internal strobe to start and stop and communicates accordingly. If the return is not detected the camera sends only a start signal which results in a full dump
 
Thanks. So in layman terms: when using fibre optic sync cable, the green light now simply indicates the strobe did not do a full dump. No guarantee that camera ttl was successful.

In the old days, a camera could send a separate start (x pin) and stop (q pin) signal via the wired synch cable. If ttl is not achieved the stop signal will never be sent by the camera. Lack of the q signal from the camera can be used by the strobe to indicate ttl failure. There were 2 communication channels for 2 separate signals.

With fibre cable there is only 1 communication channel, so the stop signal becomes ambiguous. It either means ttl has been achieved or it means the onboard flash has performed a full dump before ttl being achieved. Fibre does not have the ability to omit the stop signal since the inboard flash will always turn off, even if ttl was not achieved. So the strobe can now only "guess" that ttl worked if it did not do a full dump. This reduces the green light to being a "not full dump" indicator.
 
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