[clackers]

Something curious I also learned, is that at high shutter speeds only a sliver of the sensor is exposed (from top to bottom I believe?)

Watch your video again, Michael, you'll see the sliver.

[stevebrot]

My understanding is the fastest actual shutter speed is the flash sync speed and after that it's done by the width of the slit.
I've been known to be wrong though.

In one sense, true; for exposures longer than X-sync, the slit (timewise) is broader than the opening being traversed, but the curtains themselves are traveling the same speed as before. The same is true for exposures X-sync and shorter where the slit (timewise) is narrower that the opening.

That said, the event span (moment start first curtain motion to moment end second curtain motion) varies through the entire range of exposure times. On many cameras lacking mirror noise, there is an audible change in tone through the entire range of "fast" exposures. (This is particularly true with cameras such as Barnack-body Leica and their clones* and also true of my Canon P.)


Steve

* How this is become immediately obvious on tear-down and hinted by direct observation of the number placement on the "fast" shutter dial. The same is true for the Pentax AP, S, and K models.

[Wheatfield]

In one sense, true; for exposures longer than X-sync, the slit (timewise) is broader than the opening being traversed, but the curtains themselves are traveling the same speed as before. The same is true for exposures X-sync and shorter where the slit (timewise) is narrower that the opening.

That said, the event span (moment start first curtain motion to moment end second curtain motion) varies through the entire range of exposure times. On many cameras lacking mirror noise, there is an audible change in tone through the entire range of "fast" exposures. (This is particularly true with cameras such as Barnack-body Leica and their clones* and also true of my Canon P.)


Steve

* How this is become immediately obvious on tear-down and hinted by direct observation of the number placement on the "fast" shutter dial. The same is true for the Pentax AP, S, and K models.

My response was in relation to the poster saying that the speed of the shutter curtain increased from just over 11KPH at 1/180th sec to 33kph at 1/500th sec. Curtain speed is what it is. I don't know what the actual speed is, but it doesn't change based on exposure duration, at least not for modern focal plane shutters.

[othar]

My response was in relation to the poster saying that the speed of the shutter curtain increased from just over 11KPH at 1/180th sec to 33kph at 1/500th sec. Curtain speed is what it is. I don't know what the actual speed is, but it doesn't change based on exposure duration, at least not for modern focal plane shutters.

True, the only thing changing is the delay time of the second curtain.

[swanlefitte]

If Synch speed were 1/500 the blade WOULD have to move at 33km/h. It moves at about 11km/h. Because that takes 1/180s to move 18mm. To be fully open the second shutter can't start until the first shutter is done and must be closed 1/180s later. Because it moves no faster the second shutter must start sooner. If it moved faster the synch speed would be faster.
The k1 has a 1/200 synch and has to move 24mm so it moves faster, around 16-17 km/s.

[othar]

If Synch speed were 1/500 the blade WOULD have to move at 33km/h. It moves at about 11km/h. Because that takes 1/180s to move 18mm. To be fully open the second shutter can't start until the first shutter is done and must be closed 1/180s later. Because it moves no faster the second shutter must start sooner. If it moved faster the synch speed would be faster.
The k1 has a 1/200 synch and has to move 24mm so it moves faster, around 16-17 km/s.

Ah, you are comparing the speed of the blades for different cameras with different sync speeds, in that case your assertion is correct too.