how fast do the curtains travel?

[h_s1]

Does somebody know how fast do the curtains travel in Canon FTb and in the A-1? Note that is not regarding the shutter speed for the camera, it is regarding the speed of each curtain as it moves from one side to another. Can't find this from the basic google search I did.

 

Thanks.

[jim_bielecki1]

FTb curtain speed is between 14.0-15.5 millisecond.

 

No idea for A-1.

[h_s1]

FTb curtain speed is between 14.0-15.5 millisecond.

 

No idea for A-1.

 

Did you mean travel time instead of speed?

 

With 36 mm being traveled in 14 ms, it gives the faster end of the curtain travel speed as 2.57 m/s. Did I interpret that correctly?

 

Thanks.

[jim_bielecki1]

This is from the factory FTb repair manual. Several ways to adjust the shutter. They suggest:

 

1). Adjust curtain speed with a PA-16 transistor shutter tester.

2). The curtain speed when using a "34mm slit-4" is 13.0 - 14.5 ms.

3). Using a different slit will result in different curtain speeds.

[steve_gallimore1]

Did you mean travel time instead of speed?

 

With 36 mm being traveled in 14 ms, it gives the faster end of the curtain travel speed as 2.57 m/s. Did I interpret that correctly?

 

Thanks.

Looks right to me. The curtains won't necessarily travel at a constant speed though.

 

It's fairly safe to assume that the curtain transit time will be only very slightly shorter than the shutter's x-sync, 14-15.5 milliseconds is 1/65 to 1/70 second, which would fit nicely with 1/60 x-sync, leaving a small margin.

Edited December 21, 2021 by steve_gallimore|1

[glen_h]

Did you mean travel time instead of speed?

 

 

(snip)

 

I suppose, but note that photographers have this wrong since forever.

 

Shutter "speeds" are commonly indicated as time, though the dial normally

has reciprocal time which is closer to a speed.

 

(Speed should, at least, increase when something gets faster.)

 

In any case about (1/60)s, or maybe better 60/s, is usual for horizontal travel

focal plane shutters.

 

The vertical travel Nikon FM is 125/s, and the FM2 200/s or 250/s.

 

The Mercury II, with a rotating metal disk, is likely slower.

[h_s1]

I suppose, but note that photographers have this wrong since forever.

 

Shutter "speeds" are commonly indicated as time, though the dial normally

has reciprocal time which is closer to a speed.

 

(Speed should, at least, increase when something gets faster.)

 

In any case about (1/60)s, or maybe better 60/s, is usual for horizontal travel

focal plane shutters.

 

The vertical travel Nikon FM is 125/s, and the FM2 200/s or 250/s.

 

The Mercury II, with a rotating metal disk, is likely slower.

 

That is good to know. I wasn't aware of this nomenclature of stating time while describing speed. This was helpful.

 

Thanks.

[steve_gallimore1]

I suppose, but note that photographers have this wrong since forever

Hence why I edited my post 3 times, to remove any time/speed confusion ;)

 

The cameras don't help any, when 1/60th second is abbreviated to just 60, or when the only difference between 1/2 sec and 2 seconds is their location on the dial

[glen_h]

In any case, it is 60/s for the FTb. The easy way to find this is the speed that is used for X sync.

 

The shutter has to be completely open for X, which is marked in orange to remind you.

It might be M sync on all other settings.

 

I am not sure about the A1, but 60/s is a good guess.