Problem with DS-50: inconsistant exposure

[MagnaRyder2]

I'm not convinced that this is an Oly problem, so "The Oly Corner" may not be right, but MRM brought the topic up on
4/29. His problem, as mine, is inconsistent illumination of
a frame using the D-50 with TTL sensor.

I'm shooting with a 3020 in a PT-010 housing, DS-50 strobe
with the TTL Slave Sensor.
My problem is inconsistent exposures. 1/4 to 1/2 the time, the
exposure is poor to unuseable.
I set up a static test in my office. In this
particular test, I fired off ten frames changing nothing.

Distance to image: 19 inches
Camera mode: Auto
Flash: Auto
Slave sensor sensitivity: Mid-point
Slave sensor switch: ignore pre-flash.
Camera set to timed shutter release.
Internal flash blocked off to limit its influence.
( card trimmed and inserted behind housing diffuser)
Time between frames: 15 seconds


I'm attaching three photos. The first is my test bed.
The other two are best and worst. "Best" is salvageable
but still a little dark. "Worst" is almost totally black with little
detail to work with. EXIF info indicated that
the two exposure frames were both exposed at ISO 100,
F7 @ 1/30 second.

An article on Digital diver mentions the same problem, but with
a DS-125
(www.digitaldiver.net/images/strobearticle/strobearticlescrn2.pdf)
- quote -
"I was less enthusiastic about using the DS-125 with the DS
Slave Sensor. Exposures ranged from perfect to radically
underexposed, with no apparent rhyme or reason. Two
exposures taken just a few moments apart would rarely
achieve the same results. "........

"Why the DS-50 Slave Sensor worked so well with the DS-50
and so inconsistently with the DS-125, I cannot say ..."

I'm wondering if Ikelite has a problem with their DS Slave
sensors.

I'd like to get this resolved before I take the camera/strobe
out again. I'm leaning toward the manual sensor and full
manual mode on the camera.

JimC

 

[ike]

MagnaRyder2: We will be glad to test the strobe and sensor if you want to return to us, or will exchange the TTL Sensor for EV Manual Controller.............

 

[MagnaRyder2]

Thank you for the offer. I may send the unit back for testing.
What would be the turn-around time? We were considering
a trip in early-mid July and I'd hate to be without the unit.



As for swapping the TTL Sensor for a Manual one, I ordered
an EV Manual Controller last night. I do appreciate the offer.

MagnaRyder2: We will be glad to test the strobe and sensor if you want to return to us, or will exchange the TTL Sensor for EV Manual Controller.............

 

[ike]

We only need for a few days. Indicate a date needed and we will be sure to have done by then............

 

[MagnaRyder2]

IKE, the strobe is on the way.
You should see it on Thursday, June 3.
Thanks again.

JimC

We only need for a few days. Indicate a date needed and we will be sure to have done by then............

 

[saholz]

My C-5050 is set up with a single DS-50 and a manual sensor. While this setup may require bracketting your exposures in some situations, I've had very good results with it. The DS-50 has a somewhat limited range compared to larger strobes, but it is certainly adequate for most shots. I use the diffusor to widen the coverage and this seems to work out fine. I will, however, add an aiming light in the near future. I'd be curious to see how you like the strobe after you switch over to the manual sensor.

Stan

 

[MagnaRyder2]

I don't mind bracketing, as long as the camera/strobe give
me a consistent baseline. Right now I don't feel that I have that.
The two attached photos were taken seconds apart (darker one
first), F2.8 @ 1/60 second.

For an aiming light, I used an Ikelite Mini C with the reflector
diffused with foil, mounted low on the strobe bracket.
It put out a soft circle of light with no hot spots and gave
enough light to aim and focus.

We're trying to book a trip mid-July. I'll report back how it
worked out.

Later.
JimC