Why are flash sync shutter speeds getting worse?

[paul13walnut5]

Has anyone given any thought to my throwaway idea about "Faking" a fast synch speed by taking a 1/1000 sec sample of a 1/200 exposure.   Now granted it would do nothing for those using a strobe to fill in foreground illumination when shooting outdoors and other advanced fill flash work, but I could be an interesting tool for wedding/event photographers.

If you are lighting a scene purely by flash, then essentially your exposure duration is not your shutter speed, but the duration of the actual flash of light.  Which is a lot faster than 1/200th or 1/250th.

And as you say, such an idea wouldn't do much where fill flash is being used, which is were the problem actually is: at fast shutters in bright ambient light.

Your sample would also need to take place at the exact same 1/1000th of a second that the flash actually flashes at...

Maybe Canon will come up with a portrait lens with a leaf shutter?  That would be another way of solving the problem.

And your idea of multiple samples would only really work with multiple flash bursts, which is kind of what HSS mode already does, except that each sample occours over a different portion of the sensor as the shutter curtain moves.

The issue with this mode is of course, reduced output.

[Jeffrey]

Leaf shutters make all the difference in shutter speeds, but then you need to be careful that the lights will synch at speeds faster than 1/250. Surprisingly many lights won't synch at faster speeds including some models of the most popular pro level lights. Oddly enough, the Paul Buff brand Einstein model light packs do synch at very fast shutter speeds and they cost a fraction of the higher end pro level lights.

Having been lucky enough to shoot with a camera and lights that synch at 1/1600, the image captures of a model in motion in the studio are wonderful. 

[KyleSTL]

I understand the limitations everyone is bring up about killing higher levels of ambient light with a faster SS, however, the 6D (which is what prompted this thread) is a consumer level camera (i.e. and 'entry-level' full frame DSLR).  For more advanced users that would have the need for a strobist setup and more complicated techniques, higher end cameras fulfill the need for a fast sync speed.  I would say the majority of 6D owners would not be limited by the lower spec.  I think we all need to compare apples-to-apples though, as far as sensor size is concerned.  Here's how I see it:

Full Frame

1/300 - Nikon F5
1/250 - Canon 1Ds series, 1Dx, and highest-end film cameras (EOS 620, EOS 1, 1N, 1V), Nikon D3, D4, D700, D800, F4, F6, F100, F90, F801 (N8008)
1/200 - Canon 5D series, prosumer film cameras (EOS 3, 5), Nikon D600
1/180 - Canon 6D
1/125 - lots of Canon and Nikon middle-to-low-end film cameras
1/90 -    "

APS-H

1/500 - 1D
1/300 - 1D Mark III, IV
1/250 - 1D Mark II
1/200 - EOS IX (APS film SLR)
1/180 - Nikon Pronea 6i (APS film SLR)
1/125 - EOS IX Lite, Nikon Pronea S (APS film SLR)

APS-C

1/500 - Nikon D1 series, D70, D70s, D50, D40
1/250 - Canon 20D through 60D, 7D, Nikon D2 series, D200, D300, D300S, D7000
1/200 - Canon D30, D60, 10D, Rebels, EOS M, Nikon D90, D80, D60, D40x, Dxxxx
1/180 - Nikon D100

One cannot compare sync speeds between cameras when sensor size is different.  Look up at the full frame section and notice where the highest-end film cameras ever made are, and also where the EOS 3 and EOS 5 were.  The industry does not look like they have made huge steps back as the forums seem to indicate (especially with regards to prices and other available technologies included in the cameras and flashes).  Prior to the AF era sync speeds were even worse (T50, T60 = 1/60, T80 = 1/80, T70 = 1/90), except for T90 (1/250).

I'm still a little baffled by the 1/500 sync speed on the oldest Nikon APS-C DSLRs, but clearly Nikon hasn't gone back to that since.

EDIT:  Added APS Film SLRs just for comparison.

[KyleSTL]

I was hoping my breakdown would add to the discussion, but it seems to have died.  I think that organizing them by image size shows that the overall distance travelled affects sync speed.

If I remember correctly from my Art Photography classes the vertical plane shutters at their highest speeds (1/1000+) never have the entire frame exposed at the same time.  Essential what happens is a slit between the upper and lower blades travels down the frame.  That is what affects the sync speed because the entire frame needs to be exposed during the short burst of light provided by the flash.  I would assume that the sync speeds listed above are the shortest intervals each camera is able to have the whole frame exposed prior to the dropping of the upper blade.  Someone with more intimate knowledge about shutter design may be able to backup or refute my statements.

[neuroanatomist]

That is what affects the sync speed because the entire frame needs to be exposed during the short burst of light provided by the flash.  I would assume that the sync speeds listed above are the shortest intervals each camera is able to have the whole frame exposed prior to the dropping of the upper blade.

Absolutely correct. 

[DB]

Here's what Ken Rockwell has to say on the subject. He debunks the myth that new camera models with better ISO can compensate for slower shutter sync

http://www.kenrockwell.com/tech/syncspeed.htm