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Re: [Rollei] Rolleiphot - Iris diaphram
- Subject: Re: [Rollei] Rolleiphot - Iris diaphram
- From: Jerry Lehrer <jerryleh >
- Date: Fri, 09 Nov 2001 18:41:01 -0800
- References: <200111090858.fA98wGA12149 >
For a moment I thought that you had gone 'round the bend!
Problem is, some of the newbies would believe you.
> Using mirrors, light coming through the viewing lens was compared to light
> that was falling on a mirror on the front of the Rolleiphot. This
> difference in light was translated into a small movement of a bimetallic
> strip that bent a lever to show the amount of light falling. There was a
> mechanical linkage that automatically changed the shutter dial when the
> iris diaphragm was turned to the f-stops as listed on the table on the
> Rolleiflex back. Different film speeds could be set on the Rolleiphot outer
> rim which had a dial set ring to compensate for different ISO film in the
> linkage...... okay, I'm lying.
> All you were supposed to do was stop down the iris diaphragm until you
> could no longer see detail in the darkest shadows. Then you were supposed
> to read off the shutter / f-stop combination from numbers around the rim of
> the Rolleiphot. Viola! Exposure determination.
> Rich Lahrson wrote:
> > Hi Todd!
> > How was this used to set exposures?
> > Rich
> > > You can always get one of those old Rolleiphots made from about 1933 to
> > > 1941. Originally used for determining exposure, it fits over the viewing
> > > lens via bayonet and has an iris that can be closed down thus offering
> > > depth of field preview. Being an early accessory, it fits only to bay one.
> > > todd