Sekonic corded reading

[swmcl]

Hi all,

I am trying to do some portraits on my 4x5. I am in shade and I have one white diffuser and one silver reflector. I'm trying to use an L-358 on corded flash mode.
It gives me a reading of f16 80% 1/8th second for one flash and the other is f16 50% 1/6th second.

I am clearly not shooting at these shutter speeds ...

So what is this percentage thing? Assuming I'm shooting at say 1/60th and f16.

I'm not in a hurry to completely waste film so any help getting close would be good.

I should mention that the meter just gives a aperture when there is no ambient light.

Rgds,

Steve

[Archphoto]

Forgive me for asking but:

Have you set your filmspeed and shutter-speed on your Sekonic ?

Peter

Edit: did you set your meter for flash only or flash+ambient ?

[Nick_3536]

The percentage is the amount of flash versus ambient light. Yes you should have set shutter speed.

[swmcl]

Thanks guys,

Yes the ISO is set.

I have noticed that I can turn the dial wheel to a point of f14. At this point the meter says 100%. So. I assume that if I shoot at 1/60th at f16 I will get underexposure because the meter says 80%. If I shoot at f14 I can have correct exposure. But what with the other flash? It is showing 60% at f14. How many stops is 60% ??

I think I wish the meter would just give me an EV number for each sample.

BTW - The Sekonic manual is quite useless.

Do other Sekonic meters give this percentage information? I find it irritating to be honest.

Cheers,

[swmcl]

Sorry - I should answer the question - the corded flash mode must be a "flash + ambient" mode.

There is another mode that allows me to manually trigger the flash. Should I use this mode instead?

It is now later in the evening here at present so I'll need to set up again later.

Rgds,

[Nick_3536]

You're missing some points I think.

The 80% [or whatever the meter shows] is the ratio of flash to ambient light in the total exposure. If you have a low power flash or are using a slow shutter speed this can be an issue. You may want this. Or you might not. You need to understand the things that can happen to colour balance with colour film and various types of light. Or how backgrounds etc will show up. The percentage in the end is an artistic choice.

The shutter speed isn't a big issue unless you want to control the amount of ambient light. Go fast enough and the whole exposure will come from the flash. If the flash is powerful enough.

When you turn the dial and it switches from F/16 to F/14 what are you changing? Shutter speed?

[Lee Christopher]

Have a peek at Pg #27 of the manual. It might help.

What your meter sounds like it's doing is analyze the ratio of existing light to flash output.

http://www.cameramanuals.org/flashes...lash_l-358.pdf

[swmcl]

Hi Nick and Lee,

Turning the dial changes the aperture setting I think and this then changes the percentage reading.

I'm really very hopeful trying to use camera flashes in large format aren't I?!

I need more flash power. The SB-24s are too underpowered to allow me to change settings.

p27. does seem to indicate that twiddling the 'jog wheel' changes the shutter speed setting rather than the aperture... I'll set up again and give it another try.

I think I get the physics now I just need to marry those thoughts with the lightmeter. It is very clear to me that I need more light. Both flashes are running flat out - and they are very close to the subject!

Many thanks for your help. I am very much a learner as you can see.

Cheers,

[Gordon Moat]

I run a set-up that sometimes uses an SB-25 and SB-26. Basically, you run them at cull manual power setting, then you meter with the Sekonic. If you are expecting to so this in a dark room, then you need at least two Speedlights. If you are only using it for fil in daylight, then you might get away with one Speedlight. Bottom line, it is possible, but the set-up is not simple.

Meter the ambient only, without flash first. Then remember that reading. Next take a flash only reading, but with the Speedlight at full power on manual setting. Do not set Automatic mode on the Speedlight, because it will vary the power output. Compare the two readings.

Flash to Ambient means that the flash is responsible for the exposure when your reading is greater than 50%. If you get a 100% reading, then the flash is the only exposure, or think of it as the only light. In other words, once it is at 100%, then it doesn't matter how fast your shutter is set, because the flash duration controls the exposure. As you slow the shutter speed, the ambient light continues to expose the film after the flash has popped. As an example, you could fire the flash, and have a 1 second shutter speed; the flash is likely 1/1000 or shorter, and exposes the film, then the shutter being open continue to expose the film.



This shot was a two light set-up plus ambient room light. The short flash duration stopped the action, and then the longer shutter duration captured the room light. If I recall correctly on this, the shutter speed was 1/8 second. Since the flash stopped the action, all the model had to do was stand fairly still, and I would avoid ghosting.

Ciao!

Gordon Moat Photography

[swmcl]

Thanks Gordon,

I have made a section of the shed as a photographic area. I painted it black! I am now thinking that was a little silly.

My light sources are being sucked up. I have no reflections available to me. The power is such that I will be limited to large apertures and hence drastically small DOF.

I'd prefer to have something like a theoretical DOF of some 20cm or more for head and shoulders portraits and this means at least f22 and even perhaps as short a lens as my 180mm.

A lovely photo by the way ..

Cheers,