Stepless shutter in Zeiss Ikon?

[Andrew Sowerby]

Hi all,

Seeing as the Zeiss Ikon has an electronically-controlled shutter, I figured it's not limited to full stops. I checked the specs on the Zeiss site and discovered that "Shutter speed: speeds with 1/12 f-stop resolution between 1/2000 s to 8 s in AE mode". I think this confirms my suspicion, but "resolution" is throwing me off a bit. Am I reading this right? The camera will select a shutter speed within 1/12 of an f-stop in AE mode?

Here's the link: http://www.zeiss.com/zeissikon

Best,
-Andrew

 

[pvdhaar]

Apparently, between the full stop shutter speeds, the camera is able to select one of 11 intermediate ones. So it's not entirely stepless, but the steps are so small it doesn't matter in practice.

 

[mervynyan]

"stepless" is misleading concept in both aperture and shutter. The metering is only as good as camera's built-in meter. If the built-in meter has a small interval, e.g. 1/10 stop, the shutter can use aperture setting to derive shutter speed to 1/10 sec.

In reality, I have not seem any handheld meter can go beyond 1/10 stops, so in pratice 1/3 stop is good enough.

 

[Andrew Sowerby]

Yeah, not really "stepless" but close enough! I wonder why they went with 1/12 of a stop increments. Maybe because the aperture on the Zeiss lenses (and AE compensation) is in 1/3 stops?

 

[ampguy]

Interesting, are the Bessa RxA's also using 12 step increments?

I wonder how many steps the Yashica GSN has?

 

[MartinP]

The "trapped needle", selenium-meter on my prehistoric Pen-EE (and the Trip etc) really is stepless. Of course, that is just an accidental function of the design, rather than actually meaning very much.

I also seem to recall reading a description from a large maker that their film-batches were consistent to a fifth of a stop, presumably when "seasoned" and ready for packaging, so (nearly)stepless will have little benefit especially in a reflectance-meter based system !