I've searched the forums but with no answer to my question. My question isn't about sync speeds or stopping motion blur. I'm knowledgeable about that. I also have no reason to need a higher sync speed than 1/250 myself but I'm still curious as to why the high end cameras (D2x, D2h,1DMKII, 1DsMKII etc)use mechanical shutters instead of electronic ones. If that's the case. Something about the design is keeping them from being able to use a faster sync speed. But what is it? I'm assuming it has something to do with the sensors performance and not cost. Although, I'm not sure. Is there anyone who understands this so that I too, might understand.
I imagine it's because nothing electronic actually turn on/off instantly so a well adjusted mechanical shutter is better especially for faster shutter speeds. (Just an educated guess, prepared to learn otherwise )
My guess is that it has to due with their choice of sensor. In the D1 series and D70 cameras they utlized a CCD chip whilst on the newer D50, D2x and D200, they use a CMOS sensor and lowered the x-synch back to 1/250th.
Something to do with the design and operational difference between CCDs and CMOS?
Yes, but Devin listed cameras with only mechanical shutters so I think the question was not about the choice of speed but why a mechanical shutter at all. (The D50 has a "combined mechanical and CCD electronic shutter" like the D70/D70s.)
>My guess is that it has to due with their choice of sensor. >In the D1 series and D70 cameras they utlized a CCD chip >whilst on the newer D50, D2x and D200, they use a CMOS >sensor and lowered the x-synch back to 1/250th.
As far as I know, the D200 and D50 have CCD sensors, not CMOS.
I'm afraid I don't know the answer to Devin's original question
Probably the sensors in those cameras don't "settle" electronically in less than 1/250th of a second, meaning that they the enable-expose-readout can't be safely accomplished in less time. So the sensor takes its 1/250th or so, but does so behind a mechanical shutter that closes in potentially much less time.
Of course, the problem with mechanical shutters is that it takes a certain amount of time to run the curtains from top to bottom. I haven't done the calculations, but I'd guess that it's pretty darn hard to move the curtains fast enough to have the shutter fully open for 1/500th.
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The D70 actually has a combined elecronic and mechanical shutter I believe.One takes over from the other at higher speeds. This is why it does 1/500 sync. Why other cameras including those from Canon (1/200 BTW) only have mechanical I dont know - I assume it has to do with electonic timings and CMOS sensors.
1/250 is the high speed limit for Nikon's focal plane shutters.
The higher end Nikons don't use electronic shuttering for high speeds. The D70 and similar cameras produces a rather nasty "plaid" pattern at speeds of 1/4000 and up. The noise that produces just becomes obvious at those speeds, it probably lurks at lower speeds. The D70 and siblings also has a tendency to hard-edge horizontal blooming that has been linked by some folks to using speeds where the electronic shutter is in effect.
I have no doubt that Nikon would offer a higher speed electronic shutter flash sync if there weren't image artifact problems they considered to be more important.
Shooting in FP will alow one to shoot past 1/250th without the banding issues. I can't remember if Nikon achievs this via the standard FP mode where the flash fires a flash equal or longer than the shutter speed or fires small pulses at precise intervals to compensate for focal plane movement.
Either way, using FP will drasticly reduces the flash's range as it requires more energy to complete.
Thank you everyone for trying to help figure this out. So far we have a bunch of assumptions but no solid answer to the question. The D1 series synced at 1/500th and seemed to be fine. Those cameras used an electronic shutter. Therefore, theoretically could of synced at any speed. But electronic shutters are not being used with the newer D2 and Canon 1D series cameras. There must be a logical answer to this. Does anyone know a tech at Nikon who they can ask. I know it has to be a simple answer. But What?
It all has to do with ability to perform uniform shuttering while maintaining image quality at reasonable sensor cost and performance. CCDs have high uniformity and high uniform shuttering compared to CMOS. That is, CCDs can be rapidly turned off electronically.
1/500th and faster flash sync can be obtained on the older D1/D1x/D1h in manual mode because the CCD is turned off electronically -- electronic shuttering.
CMOS can't be turned off electronically without tradeoffs in design. So they're stuck at no faster than 1/250th shutter sync.
For CMOS and new cameras, high speed shutter sync (FP) is achieved by pulsing the flash throughout the exposure. So while one can theoretically achieve 1/8000th second flash sync, the pulse is still there in such a way that you can get some blur during imaging -- stroboscopic effect.
The reason nikon uses 250th of a second sync speeds is because there is no mechanical shutter out there that can sync faster. The Nikon D1-series and and Canon 1D both synced at a 500th because with the early CCD sensors the sensor itself controled exposure, not the shutter, even though it still had one it didnt control the shutter speed. With the new and more complex CMOS (ID markII) and LBCAST (D2h) I guess they take longer to cool down before shots and arent as accurate at controlling exposure so they had to go back to the mechanical shutters that only sync at 1/250th. As far as why the D2x with its CCD isn't 1/500th.....beats me, maybe they didnt want it to be faster than the D2h. hope that makes sense. cheers, Trevor
1. Mechanical shuttering -- fastest sync speed with the vertical plane mechanical shutters is 1/250th.
2. Electronic shuttering (electronically turning off the sensor)
2. a. CCD sensors can be turned off at any time arbitrarily and they maintain high uniformity of the image. Thus high sync speeds at 1/5000 to 1/16000 can be achieved in the D1/D1x/D1h by using manual mode and having the camera electronically turn off the shutter at the right time.
2. b. CMOS sensors cannot perform electronic shuttering and maintain image uniformity unless special hardware is placed immediately adjacent to the individual sensor wells (pixels). The placement of hardware in the image field leads to loss of imaging area and would compromise signal to noise ratio and image resolution but also cost more to make. Apparently, image uniformity can be maintained at up to 1/250th of a second (the maximal sync speed of the vertical plane mechanical shutter). Hence Canons dSLRs, D2h, and D2x are restricted to 1/250th of a second.
3. Faster "sync" speeds on all the newer cameras can be achieved using FP mode in which the flash continually pulses during the shutter movement. The problem with this technique is it will use up the flash battery a little faster and heat up the flash head faster (for some rapid continuous event shooting, some have melted the flash head) and could result in a stroboscopic blur in some situations.