Leica LTM IIIf Understanding slow speeds

[mike goldberg]

My IIIf RD has arrived, and I'll be picking it up in Tel Aviv in a few days. For slow speeds, I'm told that I set the dial on the top plate at 1/25... and then choose
slow speeds via the small dial on the front of the camera.

QUESTIONS:

How does thie work, i.e., what is happening inside the IIIf?

Let's say that I'm shooting at 1/250. Does it matter what the slow speed is set on?

Thanks,

 

[burninfilm]

Hello Mike,
If you have the slow speed dial set to 1 second, but the main shutter speed dial is set to anything except 1/25 (or whatever speed a LTM Leica, Canon, etc. uses for the slow speeds), there will be no effect on your shutter speed. The 1/25 or 1/30 speed on the main dial is used to engage the slow speed escapement inside the camera, which enables the slower speeds. Now, if you intend to use 1/25 or 1/30 on a LTM Leica/Canon, be sure you have the slow speed dial at the corresponding speed! Otherwise, you'll be shooting at 1, 1/2, 1/5, 1/10, etc.!

 

[mike goldberg]

Thanks burninfilm, and I like your Avatar.

 

[John Shriver]

Basically, the closing curtain latch has to wait until the timing gear train at the bottom of the camera releases. How far it has to travel is set by a cam on the rear of the slow speed dial.

 

[aad]

Hmm-my IIIf manual says it is "very important" that the slow speed dial be set to "25" while using the high speed settings, and the slow speed dial has a hard detent to assure you are in the right place.

 

[colyn]

By setting the main speed dial to 1/25th <red dial or 1/30th black dial> you are properly positioning the opening curtain cam lever to engage the upper retard lever for proper slow speed operation.

 

[wolves3012]

On my IIIC if you have the slow speed dial set away from 1/30 and the main dial on "B", then shutter doesn't close immediately after releasing the button, it's held back by the time set on the front dial. Worth knowing, although up to an extra second on "B" is often not going to be an issue.