[rollei_list] Re: Rolleiflex 35 SL lenses QBM IV (3-Pin)
- From: James Richard Tyrer <tyrerj@xxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Wed, 18 Aug 2010 14:11:17 -0700
On 08/10/10 04:33, John Wild wrote:
James,
Belatedly responding to your query; from memory (I do not have any of my
3000 lenses in front of me), the QBM IV lenses have a groove around the
circumference of the mount. The groove depth gives the maximum lens aperture
information to the camera metering system. You can experiment by pressing
the camera pin in gently and the aperture displayed in the viewfinder will
change. Some lenses do not have an actual groove, because the depth of the
groove is in effect zero. However, the early lenses did not have the groove
either but the protrusion of this ring on the lens mount is such that the
meter knows that the lens is not fully compatible with the camera and so you
have to revert to open aperture metering. Hence if the camera pin is not
depressed at all or it is depressed too far, the meter aperture display does
not show. The first pin is the stop down pin, the second is the 'set
aperture' information.
The difficulty checking a lens from a photograph can arise when an older
lens has been converted to the later mount.
The German Rolleinar at:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280540109557&ssPageName=A
DME:B:SS:US:1123#ht_4262wt_1139
Shows the slight groove and the two pins in the shot of the rear of the
lens. Also in the photograph of the 'Made in Germany' inscription.
Hi John:
Yes, in the photo showing "Lens made in West Germany" you can clearly
see a step in the outer retaining ring (which I presume is the retaining
ring that holds the aperture ring on).
So, am I correct that that step would indicate a QBM IV?
If so, a caliper would be the easiest way to determine if a lens was QBM
III or QBM IV.
--
James Tyrer
Linux (mostly) From Scratch
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