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Pl help me to understand TTL Flash

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Sravan V

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Hello -

I will be getting a promaster 5750dx for my E-20 in two days. I have never used an external flash before but I am comfortable with SLR technology. Can any one please provide some info or links to know how to control and how to make use of the setting for this flash (or any similar flash in general). I have downloaded the instruction manual for 5750 and read once but I believe I need to know the basics first.

Thanks in advance!

Sravan
 
I just got my e10 and having fun learning all the other mode besides P. Correct if I am wrong guys, but TTL Flash communicate with the camera thru the lens to meter the proper exposure all the time. I have the vivitar 285hv and just got tired of adjusting in the manual mode in terms of F stop and iso. Received my fl40 the other day, all my indoor shots are just perfect. I thought about Promaster but I believe somewhere you have to adjust the tele mode if you zoom in. Other wise both work fine as ttl flash
Sravan V said:
Hello -

I will be getting a promaster 5750dx for my E-20 in two days. I
have never used an external flash before but I am comfortable with
SLR technology. Can any one please provide some info or links to
know how to control and how to make use of the setting for this
flash (or any similar flash in general). I have downloaded the
instruction manual for 5750 and read once but I believe I need to
know the basics first.

Thanks in advance!

Sravan
Click to expand...
 
Sravan V said:
Hello -

I will be getting a promaster 5750dx for my E-20 in two days. I
have never used an external flash before but I am comfortable with
SLR technology. Can any one please provide some info or links to
know how to control and how to make use of the setting for this
flash (or any similar flash in general). I have downloaded the
instruction manual for 5750 and read once but I believe I need to
know the basics first.

Thanks in advance!

Sravan
Click to expand...
If your E-20 instruction manual explains use of the Oly fl-40 flash with your camera much of this info is applicable to the Promaster flash units, assuming you also purchased an appropriate adapter to connect to your camera. The camera will control the output of the flash according to your menu selections. It will provide most of the functions of the Oly flash except the zooming flash head which has to be set manually on the Promaster.

Just hook it up and play with it! That's the beauty of virtual "free film" that digital photography provides us. Have fun!
--
Lili's Dad
 
Sravan V said:
Hello -

I will be getting a promaster 5750dx for my E-20 in two days. I
have never used an external flash before but I am comfortable with
SLR technology. Can any one please provide some info or links to
know how to control and how to make use of the setting for this
flash (or any similar flash in general). I have downloaded the
instruction manual for 5750 and read once but I believe I need to
know the basics first.

Thanks in advance!

Sravan
Click to expand...
Sravan - with TTL flash, as stated above, the meter that the camera uses to determine proper exposure in all situations which is read TTL (through the lens) is used to control the flash output to achieve proper exposure for the distance and lighting at time of exposure. I do not have a promaster, but understand that if you have the right module for the oly, it will work ttl like the fl40 unit except for zooming the head. With the fl40 in ttl mode, you can essentially turn on the flash, set the camera in any mode p, s, a, m, and fire away with the camera doing the control of the light output just as the camera would normally control the camera settings without flash. TTL flash metering is normally considered to be the most accurate, as it measures the light coming through the lens that strikes the sensor and essentially controls the flash to provide just the amount of light that is required to produce proper exposure.
 
Sravan V said:
Hello -

I will be getting a promaster 5750dx for my E-20 in two days. I
have never used an external flash before but I am comfortable with
SLR technology. Can any one please provide some info or links to
know how to control and how to make use of the setting for this
flash (or any similar flash in general). I have downloaded the
instruction manual for 5750 and read once but I believe I need to
know the basics first.

Thanks in advance!

Sravan
Click to expand...
Read this report, it may help:
http://www.molon.de/imaging/TTL_Principles.html

Moshe
 
pbleic said:
Moshe:

Thank you! This is such a clear and useful report. I only wish it
would continue and discuss the more sophisticated uses of the flash
where shutter speed is reduced and you are balancing ambient and
flash light.

Paul
Click to expand...
Now that I'm retired, I may consider it for a Ph.D. thesis subject...

Moshe
 
pbleic said:
Moshe:

Thank you! This is such a clear and useful report. I only wish it
would continue and discuss the more sophisticated uses of the flash
where shutter speed is reduced and you are balancing ambient and
flash light.
Click to expand...
It's pretty simple if you are using a thyristor flash (Vivitar etc.) rather than a TTL, such as the FL40.

I mount my Vivitar 265 on a Stroboframe bracket, connect the PC cord, and determine which range I want to use, with associated f-stop. Then I set the camera (E20) to aperture priority mode, with the aperture required by the flash. Now, the camera's meter will set the shutter speed according to the ambient light, and the flash will fill and expose correctly according to the thyristor's metering action. The flash exposure will be correct because the f-stop is correct, and the ambient will be correct because of the camera's automatic metering. Just watch that the shutter speed doesn't get too slow for hand held shots or subject movement. If it does, just go to full manual and shoot a faster shutter speed. Flash exposure will then dominate.

Gary Eickmeier
 
I have also read an article that recommended controlling the flash with the shutter speed and NOT the aperture. Basically, the faster shutter speed the more the direct subject is bright and the background is dark. By reducing the shutter speed you get more ambient light. This allows you to get anything from a spotlight effect to a fully lit effect.

Thoughts?

Paul
Moshe Ronen said:
Gary Eickmeier said:
It's pretty simple if you are using a thyristor flash (Vivitar
etc.) rather than a TTL, such as the FL40.
Click to expand...
You can use Gary's method with the FL-40, if you trick it into AUTO
instead of TTL AUTO mode.

Moshe
Click to expand...
 
When I bought a flash unit in 1983, it was a TTL one. Advertised as TTL, total transistor logic. Trouble is, some people think TTL means through the lens. Which is right? I do not know!

ˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇ

--
Ian Yates
 
I think it is thyristor, not transistor.

Older flashes were only able to fire at full power, you had to restrict the amount of light with the aperture setting.

Thyristor flashes come with their own sensor( or use the TTL sensor of the camera)- they fire and measure at the same time- once the amount of light was enough they shut the lamp imediately down and recycle the power(faster recharge times, if the full charge was not nescessary).

The FL40 has a sensor as well, but it only uses it, when used on a non Oly camera or if the extra contacts on the flash shoe are blocked.
 
Reminds me of how NCR paper (produced by the National Cash Register company) became "No Carbon Required" paper.
Ian Yates said:
When I bought a flash unit in 1983, it was a TTL one. Advertised as
TTL, total transistor logic. Trouble is, some people think TTL
means through the lens. Which is right? I do not know!

ˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇˆˇ

--
Ian Yates
Click to expand...
 
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