Is this due to the shutter being too fast?

[zanxion72]

Could you please help me identify the problem? Is this a shutter sync issue? If it was due to a shutter speed been too fast shouldn't it be at the lower part of the frame?
This was shot with a Nikon FM at 1/125 (the flash sync speed of the camera) and an Nikon SB-27 tilted left or right.

Edit: I did a small test with the film door of the camera open against a wall and I can see the lower part of the frame shaded at 1/125s but not at 1/60. Does that mean that the 1/125 setting on the speed dial runs actually faster than 1/125? Does this call for a CLA?

 

[RalphLambrecht]

Could you please help me identify the problem? Is this a shutter sync issue? If it was due to a shutter speed been too fast shouldn't it be at the lower part of the frame?
This was shot with a Nikon FM at 1/125 (the flash sync speed of the camera) and an Nikon SB-27 tilted left or right.

Edit: I did a small test with the film door of the camera open against a wall and I can see the lower part of the frame shaded at 1/125s but not at 1/60. Does that mean that the 1/125 setting on the speed dial runs actually faster than 1/125? Does this call for a CLA?

could be one of several things:
1. camera sync speed is sloer than 1/125th s
2. sync not set to 2st curtain
3. flash reaching peak too fast
3.shutter bounce
setting the shutter speed to 1/60th s, to be on the safe side, should fix the issue.

 

[zanxion72]

could be one of several things:
1. camera sync speed is sloer than 1/125th s
2. sync not set to 2st curtain
3. flash reaching peak too fast
3.shutter bounce
setting the shutter speed to 1/60th s, to be on the safe side, should fix the issue.

Thanks Ralph,
It seems that 1/60s is what I should use regardless of the camera manual giving it a 1/125 top flash shutter sync. Could it be that due to age the 1/125 of the camera stated to run faster, or the manual being too optimistic with 1/125 being the top flash sync speed for the FM?

 

[bdial]

If the spec for the top sync speed is 125, you shouldn’t see a cut off like that, so the camera may likely need a tuneup.
But, you you really only need that sort of speed if you’re trying to fill shadows in daylight or some similar situation.
For indoors where the ambient light isn’t strong 1/60 is fine. If the camera is working correctly and consistently otherwise, you could just live with it, and not use flash at 1/125.

 

[Chan Tran]

Thanks Ralph,
It seems that 1/60s is what I should use regardless of the camera manual giving it a 1/125 top flash shutter sync. Could it be that due to age the 1/125 of the camera stated to run faster, or the manual being too optimistic with 1/125 being the top flash sync speed for the FM?

It means the shutter needs some adjustment primarily the shutter curtain travel time. It could be too long

 

[zanxion72]

It means the shutter needs some adjustment primarily the shutter curtain travel time. It could be too long

Does that mean that one of the curtains travels slower than it should?

 

[Chan Tran]

Does that mean that one of the curtains travels slower than it should?

I think the first curtain travels slower than it should. Basically the camera releases the first curtain and after the exposure time it releases the second curtain. The curtain should be fast enough to open fully before the second curtain is released. When it's was correct at 1/125 it would open fully slightly before the second curtain is released. Now it open fully slightly after the the second curtain is release. You can increase the spring tension on the first curtain and fix the problem. However, it's not the correct way. One should have a shutter tester that can measure the speed of the shutter curtain to verify that before making adjustment. Because as you said the second curtain may be got released slightly earlier.

 

[wiltw]

The real definition of X-sync speed on a focal plane shutter is 'the shutter speed at which both curtains of the focal plane shutter are both OPEN FULLY'
if the shutter is not 'fully open' when it should, that is 'not X-sync speed'. But the camera was designed so that the curtains both SHOULD be open!

Because the curtains are not open fully, the net effect of that is 'exposure is not for the indicated time', because the second curtain is closing too soon. But as also indicated, the first curtain could be moving too slow,so it does not get to its fully open position before the second curtain starts moving across the opening.

 

[zanxion72]

I think the first curtain travels slower than it should. Basically the camera releases the first curtain and after the exposure time it releases the second curtain. The curtain should be fast enough to open fully before the second curtain is released. When it's was correct at 1/125 it would open fully slightly before the second curtain is released. Now it open fully slightly after the the second curtain is release. You can increase the spring tension on the first curtain and fix the problem. However, it's not the correct way. One should have a shutter tester that can measure the speed of the shutter curtain to verify that before making adjustment. Because as you said the second curtain may be got released slightly earlier.

Thank you for the great explanation! I guess that my trusty FM should be on its way to CLA. As soon as I finish the current roll (at least this does not show up on daylight shots) it is off for CLA.

 

[RalphLambrecht]

Thanks Ralph,
It seems that 1/60s is what I should use regardless of the camera manual giving it a 1/125 top flash shutter sync. Could it be that due to age the 1/125 of the camera stated to run faster, or the manual being too optimistic with 1/125 being the top flash sync speed for the FM?

well, the flash sync speed of your FM is apparently not 1/125. That may be repairable but the repair man costume more than another used Nikon FM.

 

[Huss]

All this curtain talk when the Fm does not have shutter curtains.

 

[wiltw]

All this curtain talk when the Fm does not have shutter curtains.

The FM uses the Copal Square S shutter, and it has five metal blades in front, three at the back), which traverse the film gate vertically, rather than horizontally.
Much similar on concept to modern shutters found in dSLRs.

 

[wiltw]

well, the flash sync speed of your FM is apparently not 1/125. That may be repairable but the repair man costume more than another used Nikon FM.

The Copal Square shutter had the fastest X-sync speed for its time, 1/125. Something is ailing the OP camera.

 

[Chan Tran]

All this curtain talk when the Fm does not have shutter curtains.

They still use the term curtain for current DSLR and Mirrorless with bladed shutter. Even when there is no physical shutter they still use the term curtain for the electronic shutter.

 

[RalphLambrecht]

All this curtain talk when the Fm does not have shutter curtains.

Every focal plane shutter has a first and the second curtain! How else would it adjust the timing?

 

[wiltw]

Every focal plane shutter has a first and the second curtain! How else would it adjust the timing?

Here is a photo of the FM shutter
https://www.mir.com.my/rb/photography/hardwares/classics/nikonfmseries/fm/part5.htm

Same Copal Square, seen from the other side, in a Ricoh
https://www.flickr.com/photos/casualcameracollector/15363103078

You can see a modern Canon shutter in extremely slow motion here

 

[Huss]

Every focal plane shutter has a first and the second curtain! How else would it adjust the timing?

Shutter curtains - two - are used in horizontal travel shutters. Two cloth type curtains, hence the name.

Vertical travel shutters tend to be made out of multiple blades. With two sets of them.

I am curious though - is there a metal bladed horizontal shutter? The Nikon SP used titanium cloth, but it was still cloth, and still just two pieces.
And also, are there vertical travel shutter curtains? In 35mm cameras? I'd guess in medium format there is as the configuration is more symmetrical with the SLR type cameras.
Many medium format cameras have leaf shutters in the lenses.

 

[Mackinaw]

.......The Nikon SP used titanium cloth, but it was still cloth,......

It's not cloth but titanium foil. Just 0.02 mm thick.

https://imaging.nikon.com/history/chronicle/rhnc10shut-e/index.htm

Jim B.

 

[shutterfinger]

Nikon FM service manual https://learncamerarepair.com/downloads/pdf/Nikon-FM-Repair.pdf comes up blank pages online but opens fine in Adobe reader once downloaded on my computer.
Shutter pages pdf 195 to 198.
Revised version for production changes in the FM https://learncamerarepair.com/downloads/pdf/Nikon-FM-Revised-Service-Manual.pdf
Shutter pdf pages 191 , 192.
The shutter charge may be at fault and is part of the speed dial/winding mechanisms.

 

[zanxion72]

well, the flash sync speed of your FM is apparently not 1/125. That may be repairable but the repair man costume more than another used Nikon FM.

Not big deal, I will try using 1/60. Some friend of mine had the same problem with his FM and he said that the flash is not triggered at the proper moment. He said that he fixed it and he could fix mine too, but I'd prefer having it professionally CLA'ed (or buy another one ).

 

[RalphLambrecht]

Here is a photo of the FM shutter
https://www.mir.com.my/rb/photography/hardwares/classics/nikonfmseries/fm/part5.htm

Same Copal Square, seen from the other side, in a Ricoh
https://www.flickr.com/photos/casualcameracollector/15363103078
thank you. the video clarifies th motion of first and second curtain very well.

You can see a modern Canon shutter in extremely slow motion here

 

[Chan Tran]

Shutter curtains - two - are used in horizontal travel shutters. Two cloth type curtains, hence the name.

Vertical travel shutters tend to be made out of multiple blades. With two sets of them.

I am curious though - is there a metal bladed horizontal shutter? The Nikon SP used titanium cloth, but it was still cloth, and still just two pieces.
And also, are there vertical travel shutter curtains? In 35mm cameras? I'd guess in medium format there is as the configuration is more symmetrical with the SLR type cameras.
Many medium format cameras have leaf shutters in the lenses.

The Nikon F2 and F3 for sure. I am not sure about the Nikon F. Also the Hasselblad 2000FC has metal shutter too. Which got damaged easily if you're not careful.
My mistake there is no metal bladed shutter that I know off. The bladed shutter is needed for vertical because there is no room for the full curtain but vertical has advantage of shorter distance.

 

[zanxion72]

I found the culprit! On the shutter blades there was a point of dirt, sticky dirt. That single spot was slowing down the upper curtain in such a way that on every speed above 1/125 there was not enough time for the shutter to open completely. I didn't see that, because you must wind the shutter to see the upper curtain come down. I cleaned it with benzene and then again with a cotton bud moistened with just a tad of water and now everything is back to normal. It puzzles me where that spot came from. The seals are fresh and still new, the mirror bumper as well.
It is not an expensive camera to die for, but I hate owing things that partially work.

 

[RalphLambrecht]

I found the culprit! On the shutter blades there was a point of dirt, sticky dirt. That single spot was slowing down the upper curtain in such a way that on every speed above 1/125 there was not enough time for the shutter to open completely. I didn't see that, because you must wind the shutter to see the upper curtain come down. I cleaned it with benzene and then again with a cotton bud moistened with just a tad of water and now everything is back to normal. It puzzles me where that spot came from. The seals are fresh and still new, the mirror bumper as well.
It is not an expensive camera to die for, but I hate owing things that partially work.

good for you. How are you can enjoy it again.

 

[zanxion72]

good for you. How are you can enjoy it again.

Although I love my more expensive cameras, I enjoy this one quite a bit as due to being cheap, I focus more on taking photos than caring about the external looks of my camera.