Mamiya 645 1000s - slow shutter

[bence8810]

Hello,

I acquired an 80mm 2.8 lens for a Mamiya 645 so I now need to get a body. I went into a few stores and only was available, a 1000s, which is exactly what I was after.

Trying the camera I noticed the shutter was slow. Exactly 1.5 times slower. 1second was 1.5, 2 seconds was 3, etc... I measured with an app on my iphone, but also as the shutter does 2/4/8 seconds, it was easy to measure with a wall clock. I measured up to 1/15th and all were exactly 1.5x delayed.

It was a bargain too, at 100USD, but I left it there. I don't want to buy an old camera like this from auctions, for this specific reason.

I left it with a heavy heart and just now as I got home, I remembered that the 645's use a batter for their shutter.

I know it's a long shot, but could the speed of the shutter be in relation with an outgoing battery?

If so, what battery do I need to buy? I'd go back today and try again with a fresh battery.

Thanks,
Ben

 

[RichC]

More likely the mechanism's drifted out of spec. over the years. However, the fix is easy. You need to take the (left?) side off by peeling back the leatherette and undoing a few screws. You'll see a circuit board with a potentiometer - adjust this until the shutter speed is spot on. If you search the web you'll find instructions with photos - sorry, I don't have any links to hand.

 

[bence8810]

More likely the mechanism's drifted out of spec. over the years. However, the fix is easy. You need to take the (left?) side off by peeling back the leatherette and undoing a few screws. You'll see a circuit board with a potentiometer - adjust this until the shutter speed is spot on. If you search the web you'll find instructions with photos - sorry, I don't have any links to hand.

Hi Rich,

Saw this online as well yesterday and this went back and got the camera. It's in perfect state minus the shutter lag.

I will need to adjust it at the 1/60 stage. Wonder how will I measure at that high speed....

Cheers,
Ben

 

[nikon_sam]

I also have a spare body or two that need the shutter speeds tuned up...the 8 second setting is actually 15 seconds, the 1 second comes out to 1.5 seconds...
I discovered that with the metered prism (CDS) the shutter speed is set through it not the body but I would prefer to use the WLF instead...
When I get the time I just might crack one open and look for that Pot...Thanks...

 

[RichC]

Saw this online as well yesterday and this went back and got the camera. It's in perfect state minus the shutter lag.

I will need to adjust it at the 1/60 stage. Wonder how will I measure at that high speed....

Like this: http://www.rangefinderforum.com/forums/showpost.php?p=2262098&postcount=23

Using a digital camera was very quick, easy and cheap - and, importantly, accurate. Everyone has or can borrow a suitable digital camera.

 

[nikon_sam]

Like this: http://www.rangefinderforum.com/forums/showpost.php?p=2262098&postcount=23

Using a digital camera was very quick, easy and cheap - and, importantly, accurate. Everyone has or can borrow a suitable digital camera.

Interesting...Thanks for the info...🙂

 

[bence8810]

I ordered a photo plug. Have any of you used it before? Wonder how well it'll work...

Ben

 

[bence8810]

Also, I found this online:

http://jabcam.wordpress.com/2012/04/16/setting-shutter-speed-on-a-mamiya-645/

I have two questions.

1. Where do I find that screw that needs adjusting? On the picture at the above link there's no notation of that.

2. Have you guys ever used the Shutter Tester app? I ordered the Photo plug for it but was trying to test even before that arrives, with the built in mic. I get a crazy curve with about 5 peaks for every shutter actuation and I don't know which to look for as the opening and closing of the shutter. Any suggestions?


Thanks a lot! The photo plug arrives on the 8th of May so I have a lot of time prior to that.

Thanks
Ben

 

[bence8810]

The photoplug arrived and I've taken the cover of the cam off to play with the pot meter. Set the camera at 1/60 and took some readings. Photoplug metered 1/49 for 1/60 so I had the pot adjusted until I got it right on target and then measured a few more sets. Attached is the outcome of where my speeds are at the moment. It isn't perfect but good enough I hope. The 1/500 and 1/1000 I can't accurately measure with the photoplug so I only have up to 1/250. I see the camera is gradually slowing at the higher speeds, hope those two stops at the far end are somewhat ok too!

Greetings,
Ben

 

[bence8810]

Actually I had the feeling that as I tested the times weren't consistent, perhaps the fact that I fired the shutter 100 times in an hour didn't help. So having the first roll through since the speed adjustment I now retested the speeds that were off (1sec / 1/125 and 1/250) and this is how we are doing right now. 1 sec is still slightly off which is ok, I'll never use it. I can't afford a tripod that would handle this mirror slap 🙂

The 1/125 and 1/250 peacefully got aligned to where they should be.

20USD well spent on this photoplug!
Ben