D700 only 1/250s Sync....will nikon ever learn?!

Started Jul 1, 2008 | Discussions thread
Doctor_No Junior Member • Posts: 36
Mechnical vs electronic shutter (sacrifice IQ for flash syncspeed)
1

The limiting factor in modern DSLRs is the mechanical shutter. The maximum sync speed is the fastest speed at which the shutter opening is completely open. In a focal plane shutter, a slit moves across the film/sensor plane, and the fastest sync speed is governed by the fastest shutter speed at which the entire frame is exposed.

A lot of the medium-format digitals use a leaf shutter (the shutter is bladed and opens and closes). Hence there is always an moment that the shutter is entirely open regardless of the shutter speed. Leaf shutters also have their downsides and hence aren't used commonly in dSLRs.

However, the D1/D1X/D1H and D70 used a hybrid-shutter/ 'electrical shutter' on their interline transfer CCD sensors to accomplish flash sync speeds of 1/500s. Theoretically speaking, these older Nikons should have had an unlimited sync speed much like a P&S but was likely limited due to the shortcomings of the speedlights (I think there were flashes that went faster with the D70)

In the case of the D70 had the exposure timed electronically and the shutter would only serve to in providing darkness for clearing and readout of the CCD sensor at high sync speeds (the sensor requires darkness before/after the exposure for best results). Beyond that the electronic shutter also had some downsides, critics complained that the electronic shutter speeds (1/500 to 1/8000) seem to produce curious grid-like patterns in plain tonal areas in bright light.

Also, the problem with these 'electrical shutter' is that it takes valuable sensor real estate to have circuitry to incorporate the feature. Circuitry that can be used to improve image quality and light sensitivity. I'm also unaware if the feature could be incorporated with the modern CMOS sensor without sacrifice.

Regardless, there are trade-offs to every technical feature, and it would be unreasonable to ask Nikon or Canon to move to leaf shutters for their dSLRs or sacrifice IQ. Perhaps there is new technology being developed with these new live-view modes, but at this point there is a good niche with medium-format digitals that serve folks that require high-sync speeds.

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pdw
pdw
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