View topic - Is Manual better than TTL setting?

Is Manual better than TTL setting?

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Postby DigitalDiver » Wed Mar 09, 2011 8:13 pm

Hi all,
in the subject my question, because in this days i was reading in a review that Inons Z240 on a DX, where shooting more ''slowly'' in TTL mode... Is it real?
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Postby James » Wed Mar 09, 2011 8:47 pm

Please rephrase your question as it is difficult to understand.

Swim down, swim around, swim back up

Canon S90 with FIX90 housing, 2X Inon D2000 strobes, DIY tray, Inon UFL165AD, Inon UCL165AD, Inon UWL100-67 with dome kit, ordered Fisheye UWL-04
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Postby TomR1 » Wed Mar 23, 2011 10:47 am

I am shooting Z-240s on a D-300.
You actually asked two questions.

1.Is there delay?

In ttl both the internal flash and the external strobes use a preflash. In most cases the light from the internal flash does not reach the subject (being inside the housing) but the light from the external flash preflash does. The camera sees the light from the preflash through-the-lens (ttl) and adjusts the lengeth of time that the internal flash fires.

With fibre optic cables the camera does not directly control the external flash The camera fires the internal flash and the external flash mimics it, turning on when it sees ligh from the internal flash through the fibreoptic connection and turning off when the internal flash turns off.

Ikelite ttl works somewhat differently. The external strobes are connected to the hot shoe. The camera knows that an external flash is present and controls the external strobe directly. Circuitry either in the ikelite housing or the Ikelite cable provide the electronics for an Ikelite strobe to work as the camera expects.

In either case there is a slight delay due to the preflash. It has never been a problem for me.

2. Which is better?

With ttl you will get proper exposure as long as you are close enough to the subject. I shoot my d-300/af-105-vr from anywhere between 2 inches (using a +10 diopter) to 30 inches (in clear water) and get proper exposure. With an INON z-240 you can vary the ttl exposure somewhat but can't get the kind of lighting creativity that you can in manual.

For example, in manual one process is to set a key strobe to light a desired area (usually the subject) from a particulay angle, then set the second strobe, at a much lower power, as a fill-in strobe, to gently light the area not lit by the key strobe.

In clear, well lit water you can get the same effect in ttl by simply turning off the second strobe, decrease shutter speed, and allow the ambient light to light the background.

My experience:
I shoot exclusively macro and always use ttl. My subjects are almost always skittish and/or non-stationary. What I am trying to do is catch the subject in an interesting pose so, at my level of experience, carefully setting up manual strobes is task loading I can't afford.

The attached photo would be greatly enhanced if the shadow of the lobster against the barrel sponge was enhanced. I should have turned off the right strobe.
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Postby Weiry » Wed Jun 01, 2011 4:55 am

So TomR1 arent you saying that you could get more creative shots using manual strobe settings?? great shot by the way!!
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Postby bvanant » Thu Jun 02, 2011 11:45 am

The original question asked about delay. Using Inon strobes in TTL mode via an optical fiber means that the Camera flash must fire at full power. Shooting fast moving subjects then is more difficult in TTL mode than in manual mode. In manual mode, you can set the Camera flash at say 1/128 power and the camera can fire as rapidly as you will need and you will be limited only by the strobe recycle time.

As to which is better? Some situations TTL is better, some situations manual is better, most situations either will work the same.

Bill Van Antwerp Canon/Nauticam/Subal/Inon Lots of glass

Technical Advisor to Bluewater Photo

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Postby TomR1 » Sat Jun 04, 2011 7:51 pm

Sometimes one strobe is better than two. The shadow caused by the subject often give greater depth to the shot. This is true of both ttl and manual.

In general TTL gives the same lighting every time. This can be good and bad.

I admit to not being a great lighting expert. Generally I focus mostly on getting myself in the proper position to get an interesting shot of the subject and getting the subject tack sharp. Therefore I shoot in ttl and don't worry about it.

However, if you are shooting wide-angle as opposed to macro lighting can be everything. In many cases one needs to vary each strobe's intensity independently in order to spotlight the area of interest.

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