Wrong and different readings with same wein peanut slaves (PN)!!!!

Hello everyone let me make this as short as possible. Two vivitar

283 flashes, one connected to radio slave and one to wein peanut

slave (PN). Both are on one light stand with a 45� translucent

umbrella. The output reading on the light meter (sekonic L-558)

should be f-8. Now when light meter�s shutter is on 1/60 it gives me

a reading of f-8. On 1/125 or 1/250 gives me f-5.6. I have four wein

slaves which out of all just one give me the right and close reading

on 1/125 or 1/250 (5.6 8/10). And lately I got one of those new

don�t remember which one. So those that mean if a wein peanut (PN)

gets older it act wrong. Did anyone have the same problem too?

I don't get it.

 

The Wein Peanut just triggers the flash. Why would it change the intensity reading of your flashes?

It�s a mystery to me too

But Etan I am telling you if I set the speed of light meter on 1/60th of second, the reading of f-stops comes out the same for four wein PN on the same vivitar flash. But changing it to a faster speed such as 1/125 or 1/250 it gives me readings like 5.6 or less. But out of four wein peanut PN one would give me the same reading or close to it (5.6 8/10) on 1/125 or 1/250 speeds.

I'm not sure what the full-power flash duration of the 283 is, but it's not insignificant.

 

It's quite possible that a delay in triggering, or long flash duration (or both) may cause the total time that both flashes are active to exceed 1/125 or 1/250 by some small amount. Perhaps the one slave you have responds faster than the others. At 1/60, you wouldn't notice, but at 1/125 or 1/250, it might be what's making the difference.

Then in a word with my equipment, just to make sure that I get the right exposure on the film I have to set up the speed on the camera (Mamiya C330 pro S) to 1/60. Am I right?

Well, I don't have any clue about your equipment, but I think you should use what works consistently for you.

'Am I right?'

 

I would say that you can use any shutter speed, all the way up to 1/500, as long as you set

the aperture according to the meter.

 

From your experiments it sounds as if you'll be clipping into the flash exposure when

using higher shutter speeds - but I don't think this will have a detrimental effect to the

image....

 

However, someone might correct me re. the mechanics of a leaf shutter and the output

curve of a Vivitar flash. Maybe the light coverage will be slightly uneven (centre vs.

corners)?

 

Best to ditch the slaves, and wire the Vivitars directly.

The light meter doesn't have a shutter. You are probably measuring ambient light in addition to the flash, which would diminish as the shutter speed SETTING is faster.

The daisy-chained sync system may introduce some lags that would affect the actual exposure on film or digital. However, you say the reading is different on your flash meter and say nothing about the actual exposure.

Edward I did say the actual exposure should be f-8 and one out of four slaves that I have when the speed of light meter goes higher such as 1/125 and 1/250 the reading for F stop become 5.6 or less. But one slave gives me right and almost right exposure. Meaning at 1/125 is f-8 and on 1/250 is 5.6 8/10. And for the records the ambient light was so low the meter reads the 100% or flash output.

Do you have each of the flashes set to manual?

William,

 

The L-558 is gated to ignore ambient light when used to measure flash intensity. Perhaps the length of the gate is affected by the indicated shutter speed. Each link in the sync chain adds a certain amount of delay. Perhaps the second flash falls near or beyond the end of the gating period. Wein Peanuts are simple, inexpensive devices which may vary in sensitivity or time lag, and may be subject to aging.

Yes James it�s set to Manual and Edward is there any other cheap peanut slaves better then the one I have ( wein PN) to use with my vivitar 283ez

You should be guided by results from your camera. Here's what I think is happening:

 

The meter has some built in assumptions about the kind of shutter you are using. When you use a shutter speed that is at a fast max X sync, the shutter behaviour depends on the kind of shutter. With a focal plane shutter, a good portion of the total exposure time is taken with the shutter curtains opening and closing, so the actual time when the shutter is completely open is only a fraction of the total time. With a diaphragm/Copal shutter (in lens), you effectively get a reduced aperture while the shutter is opening and closing. The meter is making a possibly conservative estimate of the time for which the shutter is fully open during exposure (this will obviously depend on the body or lens shutter you are using in practice), and warning you of potential light loss when using high shutter speeds.

 

Usually with optical slave triggers, the response speed is pretty rapid, effectively closing the contacts in a few microseconds at most. In practice, when actually shooting you are probably at more risk of extra delay from the radio slave.