Olympus OM-1 and Metz 45CT1 flash sync issue: Electronic Flash / MF?

Buzz-01

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Hi all,

My first post on this form after reading for quite a while. Short introduction:
I have been shooting film with some basic point-and-shoot cameras in the 1990s and early 2000s and when things became affordable I switched to shooting digital somewhere in the early 2000s.
Recently I started shooting with film again, using my late father's Olympus OM-1 camera and Metz 45CT1 flash.
I have replaced the light seals of the camera and made an adapter ring to be able to use a hearing-aid battery, ordered a new battery basket for the flash and put in some fresh NiMH cells.
All (except flash) appears to work perfectly fine.

Until now I have been using the camera without flash exclusively for shooting available light and I thought it would be nice to also be able to use the flash with this camera. Especially since it's winter time again.

Because I never really shot with this type of auto electronic flash before, I made an adapter cable with optical isolation to the hot-shoe adapter, so I could use this High Voltage flash safely on my Canon EOS 50D.
So I set up a scene with a subject on a small table and used my 50D to test-shoot the scene. The 50D can sync up to 1/250th sec, but exposure-wise things should be the same.

My OM-1 was loaded with ISO200 film, so I set up:
- The Metz flash to match ISO200 and f/8.
- The EOS 50D to ISO200, shutter 1/60 and f/8.
- In both cases, the flash is connected using a hot-shoe adapter, so not directly on pc-sync port of the cameras.
- Not really relevant for the issue, Focal length on 50D lens set to approx. 35mm to match my 50mm Zuiko lens.

With the 50D I got a perfectly fine exposure, so I dialed in the same parameters on my OM-1 and took the same shot with the flash:


Clearly something went wrong here, to me this looks like some sort of sync problem.
My first thought would be:
- Either I did not set shutter speed slow enough (<= 1/60th sec)
- or the fp/x switch could have been set to fp
- or there is something wrong with my OM-1

When browsing through my dad's old negatives, I found several shots taken in the late 1970s / early 1980s with the same sync issues. Therefore, it's also quite well possible that something's wrong with my camera or flash.

I specifically made sure that shutter speed was set to 1/60th and that fp/x was set to x before I took the shot.
Also, I remember reading somewhere online that fp/x switch would only be applicable to pc-socket, and that hot shoe would always be x-sync. Unfortunately I can't remember where I read that.

On this web page (and in the user manual), they explain something about Electronic flash being synced at 1/60th or slower and MF / MF:FP being synced at 1/15th or slower.

But what is the difference between Electronic Flash and MF / MF:FP in regard to my Metz flash?
I always assumed that the Metz is an Electronic Flash and that I should dial in 1/60th or slower.
Anyone who can point me in the right direction here? Thanks in advance!
 

MattKing

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Welcome to Photrio.
Your result resembles the results of using electronic flash with the OM-1 set to something like 1/250 second shutter speed.
Most likely, that was what happened with those old examples from your father's photographs - there are no automatic safeguards built into the OM-1 to prevent the user from forgetting to set an appropriate for synch shutter speed.
As for your results, the shutter on the camera may need some service - particularly if it has been unused for a long time.
With the OM-1, you can open the back and release the shutter while observing the effect of setting the different speeds. If 1/60 seems the same as 1/250, then there is a problem.
One final concern - is there any chance that your adapter cable is adding a delay into the circuit? That would explain the result. Try a flash exposure with the shutter set to something like 1/4 of a second. You can do that with no film in the camera and looking through from the back - large problems with synch can usually be detected that way.
 

shutterfinger

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With the camera pointed at a light colored wall, back open, shutter speed set to 1/60, flash selector switch set to X, lens aperture wide open, flash connected and pointed at the wall trip the shutter while looking at/through the image plane of the camera.
You should see bright white light through the shutter when open. If you see the flash go off then the shutter open the fp/x switch is not functioning properly. Operate from position to position several times as that may clean the contacts sufficiently to get it to work correctly.
Set the shutter to 1/30 and repeat. Continue with slower speeds until you see the flash through the open shutter.
Try both the hot shoe and PC connectors on the camera. Flash voltage at the sync cable connection is not that high and will not be a problem on the OM1.
Recommended shutter speed for flash bulbs is 1/30 second or slower.
 

ciniframe

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With the OM-1 (not the OM-1n) even with the flash on the hot shoe make sure you have the switch on the PC terminal set to 'X' and not 'FP'. Just something easy to check.
 

wiltw

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If it were synch setting issue,
  1. the FP synch setting fires immediately so that the bulb has an opportunity to come up to full brightness, THEN after brief delay the shutter captures the peak of bulb brightness while shutter is fully open. If you use electronic flash instead of FP bulb, the light will have already peaked before the shutter opens and the frame will be only dimly illuminated by the residual output of the xenon tube.
  2. the X synch setting opens the first shutter curtain then fires the flash, and if the shutter is not fully open because it is a slit (faster than 1/60) the correctly exposed fragment of frame is at the beginning and the sharp edge of curtain 1 prevents the rest of the frame from capturing the flash
The portion of your shot which is exposed properly is indicative of the fact that the flash is firing 'late': The flash is occurring at the end of horizontal shutter curtain's right-to-left travel across the frame over the focal plane's reversed optical image of the subject.

However, the curtain really should be fully opened at the time of flash, but it is apparently only a slit opening. That might indicate either
  1. shutter speed >1/60, so it is moving as a slit across the frame
  2. flash is firing really late, when the fully open curtains have already mostly closed themselves at the end of exposure
...but if it were #1, the bright part of the frame should be at the Beginning of shutter travel across the frame, not at the end of its travel! So #1 seems not likely.
 
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AgX

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ciniframe said:
With the OM-1 (not the OM-1n) even with the flash on the hot shoe make sure you have the switch on the PC terminal set to 'X' and not 'FP'. Just something easy to check.
Click to expand...

You are both off:

At FP-setting the flash is fired a fixed time before the first curtain starts opening.

In case of an electronic flash being triggerd erroneously at FP synch-setting it would be triggered when the shutter is still closed and thus it will not show on film.

The fault the OP experienced is caused by

-) the shutter being set (or faulty working) at shutter speed above sync speed
or
-) the optocoupler circuit he built retared the ingnition to a moment in time when the second curtain already had started and even nearly closed.
 

AgX

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Of course, it takes a delay for the bulb to develop brightness, but thus it needs to be fired before shutter opening starts.
And you said, it would be fired immediately.
That you did not not mean "immediately with pressing the shutter release button, and then the start of the shutter action proper being delayed.", I concluded from your " ...but if it were #1, the bright part of the frame should be at the beginning of shutter travel across the frame".
Which as I pointed out above is not true. There would be no bright part at all.
 

shutterfinger

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Type M flash bulbs take 15 to 17 millisecond to reach 2/3 of their peak light output, burn another 10 to 15 milliseconds before light output drops below 2/3 of the peak light output.
FP (focal plane) flash bulbs burn for 45 to 50 milliseconds allowing the slit in focal plane shutters to travel the image frame of large format cameras.
The standard delay on cameras for type M flash bulbs is 17 milliseconds. On pressing the shutter release the flash bulb is fired (power applied to it) then the shutter is released to operate ensuring the shutter is open when the bulb output is between 2/3 of peak on both the rise to peak and fall from peak. The fastest sync for flash bulbs is 1/30 second. 1/30 is 26 to 40 milliseconds with 33 milliseconds nominal; 1/60 is 13 to 20 milliseconds with 16.6 milliseconds nominal.
The image in camera is flipped both vertically and horizontally when the film is at the film plane therefore the image in post 1 shows the left edge of the film being exposed by the flash ie a millisecond or two before the second curtain fully closed. Shutter curtain travel in 35mm horizontal travel focal plane shutters is about 1.5mm per millisecond.
 
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OP
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Buzz-01

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Thanks for all of your replies! Nice to see there's a lot of help available here.
What got me confused from the start was the fact that I'm only familiar with electronic flash equipment, while back in the day when the OM-1 came to market, lots of people were probably still using bulb-style flashes.
I did not know/notice that MF / MF:FP flashes were also bulb-type, I assumed they were something in-between of FP bulbs and electronic flash and perhaps my 45CT1 would fall in that in-between category. This was all probably mainstream stuff back when I was still a toddler... ;-)

What also got me confused, was that I read somewhere that with the newer OM-2 camera, flash sync speed would be 1/30 with any (Non-Olympus) flash other than Olympus T-type electronic flash.
As I did not understand why, I thought there might have been something like this applicable to my OM-1 being undocumented in the User Manual.
Last night I read somewhere that sync speed for OM-2 is also 1/60, but Olympus would advise to use 1/30 because of the OM-2's auto exposure mode being able to increase the shutter speed by 1 stop just before taking the shot and therefore disabling the flash activation inside the OM-2 if that automatic adjustment would cause shutter speed to go faster than 1/60. By choosing 1/30 you would allow the camera to make that change while still making sure that the flash would fire.

Summary on equipment / note-to-self:
- OM1 sync speed should indeed be 1/60
- My Metz 45CT1 is definitely an Electronic Flash and should be able to sync at 1/60 with my OM-1

As for the photo in the OP and the questons follwing up:
- I am 100% sure I took the photo at 1/60, f/8 with FP/X switch set to X. I did toggle the FP/X switch a couple of times before taking the shot, but scientifically that says nothing.
- I did use my homemade optocoupler safety circuit on both 50D and OM-1, while indeed it is not needed with the OM-1. (My 45CT1 has a confirmed trigger voltage of 300V DC, I measured it in the past)
- The camera had been unused for about two decades in the past and the last period of time I have taken about 150-ish photos with the camera using mostly the range of 1/30 - 1/250 shutter speeds.
- I did not yet do any calibration/lubrication on the camera, I only replaced the light seals and removed the prism foam.

Next I will need to figure out what's going wrong.
At this point, I think that it could be either:
- Flash fires too soon
- Flash fires too late
- Shutter speed of the camera is actually a lot faster than the selected 1/60
- Optocoupler circuit delays the trigger signal by too much

The tips as described above will definitely help me with this!
Somewhere else I read the tip of putting a piece of white paper inside the camera instead of film and then removing the lens.

My plan will be something like this:
- Put a piece of white paper inside the camera and close the lid
- Connect the flash to the camera and set the OM-1 to 1/60 sync, FP/X to X.
- Point the flash towards the OM-1's mirror box from some distance (I have some cable length) because it needs to light the scene from the 50D's point of view
- Set up my 50D to take a photo of the shutter curtain / white paper area with a long shutter speed (several seconds) giving me some room to operate the OM-1
- Darken the room, then press shutter button on 50D and when the 50D's shutter is open then press shutter button on OM-1.
- Test with and without the optocoupler circuit and try to find a setting where the white paper will be fully visible on the photo.

This should allow me to figure out at which setting the flash would fully cover the film inside the OM-1, and perhaps it can tell me more about where the problem lies exactly.
Hopefully I will find some time to do this testing somewhere this weekend!
 

AgX

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I think that was a matter of market. Here electronic flashes were well spread amongst more serious photographers.
However bulbs set a lot of energy free and thus they can be more practical if only one or two flashes are needed.

There are practically only two groups of flashes: incandescant (bulb) and electronic (tube)
Nothing inbetween. What has evolved is the degree of exposure control achieved with electronic flashes.

In the long past there even were true fire (flashpowder) and true incandescants lamps (used heavily overated for a fraction of as second).
 
OP
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Buzz-01

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Just got around to do some extensive testing, and it appears as if nothing's wrong with my camera.
When I select X and 1/60 shutter speed, the full image area is correctly exposed, both with and without the optocoupler safety circuit.

Shutter 1/30 and 1/60 (image actually of 1/60):


Shutter 1/125:


Shutter 1/250:


Shutter 1/500:


Shutter 1/1000:


As you can see I tested every shutter speed from 1/30 to 1/1000 to figure out where sync would start to go bad and what shutter speed would match my faulty image the most. When measuring the images on my computer screen using a ruler, 1/500 seems to match the faulty image the most. And I'm 100% sure I did not dial in 1/500 when taking the picture in the OP!

Lastly, when I select FP, the image/shutter area is always fully black, at any shutter speed. So the FP/X switch is most likely also not the problem here.

The last thing I can think of is that the camera has not been used with a flash for a very long time (>30 years) and perhaps the flash trigger switch inside the camera got slightly corroded after years of not being used and then after that only switching current-less for possiby a couple hundred times at most.
Using the optical isolator, there only is a very small amount of current flowing through the switch (it runs on two button cells, so 6V and the circuit is designed at only 2-5mA switching current).
This low voltage/current could create the need for some extra time to build up the path for triggering the flash when the switch is closed and therefore firing it too late.
Perhaps the contacts got burned "clean"ish by using the flash (without the isolator) at high voltage a couple of times during my tests.
I just measured the trigger voltage again, it's 205-208V DC. When I operate the flash by short-circuiting the center pin of the connector to its shield I can see a small spark, which could make this theory plausible.

I have put the original negative back in the camera to compare horizontal/vertical orientation and whether it would match the 1/500 scenario and it does. The exposed area is in the exact same position as in the 1/500 shot of white paper.
What do you guys think, does this corroded switch story make any sense at all?
 

Chan Tran

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I think it's still a mystery because if the contact gave you problem then why when you do the test it didn't.
 
OP
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Buzz-01

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Well, I started the test by firing the camera without the isolator to just see if it would fire the flash. So the very first flash of my tests was with high voltage over the trigger switching mechanism.
This very first flash could have burnt away the corrosion/oxidization, allowing the isolator to also trigger correctly on lower current from here on.
I think from an electrical standpoint it makes sense and could be a possible valid explanation.


Before this moment, I've been using the camera almost entirely without flash, except for a couple of test fires without film and this photo on my last roll of film. Those flash shots were all taken with the isolator connected, so low voltage and low current triggering.
 

AgX

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But I wonder about your explanation about the low voltage at the optocoupler and that may causing a retarding. It would make sense to me if large capacitators would have to be charged.
 

shutterfinger

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The flash sync in the camera only connects the center post to ground. The common failure is higher trigger voltages arc and cause a carbon build up.
Another possibility is the connector on the camera was lightly corroded and the cable did not make good contact. The common is the outer shield gets expanded and does not fit snugly on the connector.
PC sync connector conditioners at the bottom of the page: https://www.paramountcords.com/product-category/accessories/
 

cooltouch

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A brief comment about the Metz flash -- or any electronic flash for that matter. The actual duration of the flash pulse is very fast. Sometimes as brief as 1/20,000 of a second. So the flash isn't the issue. And looking at the photo shown, it sure looks like the camera was set to a higher shutter speed. But your pics of the shutter tossed that out the window. So it had to have been a connection. Personally, I'd remove that gizmo used to protect your digital, and use a fresh PC cord, or at least one known to work properly, and I'd use the PC connector, since you're shooting with a handle-mount flash. But wait a sec. I have a couple of Metz 45s -- a CT4 and a CT5. Both have dedicated cords that plug into the side of the flash with PC connectors on the other end. So, I'd just use one of these cords meant for your flash and plug it into the PC connector.

Let us know when you finally solve this puzzle what the culprit was.
 
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Buzz-01

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Thanks for all the new input.
I do know that PC-sync connectors are not the most durable connectors out there. I had already slightly bent the outer ring of the Metz cable's PC-connector when I built the Optical Isolator, because I didn't trust it. My extension cords are brand new and (still) feel fine.
On my 50D and also via my wireless triggers the 45CT1 had always worked perfectly fine with the Metz cable. I simply had never used it on the OM-1 before.

First I'd like to fully explain what I've been doing, as reading back the story I might have cut some corners in explaining things here and there:
- The first test-shot was taken with: 50D -> Hot Shoe -> Hot Shoe adapter -> Optical Isolator -> 45CT1.
- The shot in OP was taken with: OM-1 -> Hot Shoe -> Hot Shoe adapter -> Optical Isolator -> 45CT1 as well.

Then I started testing before I took the shutter images:
- OM-1 -> Hot Shoe -> Hot Shoe adapter -> 45CT1. Flashed once or twice to make sure that all worked. So WITHOUT optical isolator.
- OM-1 -> PC-Port -> extension cord -> 45CT1. Flashed once or twice to make sure this worked as well. Also NO optical isolator used here.

With this last set-up (using PC-port directly on the OM-1) I did the shutter speed tests and all seemed to work as expected.

Then I did the shutter speed tests again, but then with the hot shoe adapter:
- OM-1 -> Hot Shoe -> Hot Shoe adapter -> 45CT1.

All results were the same as my previous test where I used the PC-port, everything worked as expected.
Then I tested with hot shoe adapter and Optical Isolator and that worked fine as well.

Now this morning I got curious about the FP/X setting and hot shoe, because I read somewhere online that the hot shoe would always be X-sync.
So I tested this, using FP-sync:
- OM-1 -> Hot Shoe -> Hot Shoe adapter -> 45CT1.

And with the switch on FP, there was absolutely no sync at 1/60, flash fired but fully black shutter area, same as FP-sync on PC-port. X-Sync worked as expected again.

However, testing this back and forth, I found out that my aluminum hot shoe adapter is a bit loosely connected when I insert it into the OM-1's hot shoe.
A bad connection as a result is quite well possile here.
So I tested the hot shoe adapter with the 45CT1 and my Optical Isolator on my 50D. On my 50D it fits just as loosely as on the OM-1.
Result of testing with the 50D was hit and miss; about 50% of the time the flash did not fire at all.
Then I removed the hot shoe adapter and connected the 45CT1 and Optical Isolator directly to my 50D's PC-port and tested again.
Without the hot shoe adapter the flash would fire 100% of the time.

My latest conclusion would therefore be that my hot shoe adapter is sketchy at best.
I would have expected this loose connection it to either work or not work, like my 50D tests showed: A percentage of images where the flash would just not fire at all.
A delay in flash sync because of this loose connection wasn't something I'd expected. (For anyone interested: the 45CT1 with Optical Isolator syncs to my 50D's shutter up to 1/320! )

For now I'll just put a roll of film in the OM-1 and start shooting flash using the PC-port, leaving out the Optical Isolator and hot shoe adapter. Perhaps all will work just fine like that!
 
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OP
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Buzz-01

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Just wanted to finally update on this topic, as I've finally finished the roll and got it developed last week.
With the flash connected via PC-port, FP/X-switch set to X and shutter speed 1/60, all seems to work perfectly fine:



I've also taken some off-camera flash photos using a set of wireless triggers and manual flashes which I normally use with digital, those came out perfectly fine as well. Those were taken with the wireless transmitter connected directly to the OM-1's hot shoe.
So I guess it's safe to say that most likely the root cause was the faulty hot shoe / pc-sync adapter.
 
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