[rollei_list] Re: Rolleiflex 35 SL lenses QBM IV (3-Pin)
- From: John Wild <JWild@xxxxxxxxxxxxxxxxxxxxxx>
- To: "'rollei_list@xxxxxxxxxxxxx'" <rollei_list@xxxxxxxxxxxxx>
- Date: Mon, 23 Aug 2010 09:48:07 +0100
James,
Your lens must be a QBM III (as it has the rubber rings), which will still have
the two pins. One for stop down, one for relaying the set aperture information
to the camera. QBM IV has the additional groove. It would have been made for
the SL35M, SL35ME or SL35E.
Obviously the 0.5mm depth is not enough to trigger the QBM IV 'factor'. If it
does unscrew... Now, having started to type this, I thought I would go and have
another look... On another lens I have just looked at, the ring unscrewed
easily - not so easy to get it out without tipping upside down! Underneath
there is the ring which holds the aperture transfer pin with a small spring - I
did not remove this. On initial reassembly, the aperture ring would not turn
so, on subsequent removal, I took out the lower ring and I saw that there is a
locating pin on this ring, which must sit in a hole in the aperture ring, this
being held with locked screws - all now works fine. So, actually with a bit of
care, no problems in removing it. The outer ring could be removed and
half-a-mil machined off the top outer face to let the camera pin sit deeper.
Spanner lots could be cut at the same time... I can send photos or a sketch
with measurements if you are interested.
John
-----Original Message-----
From: rollei_list-bounce@xxxxxxxxxxxxx
[mailto:rollei_list-bounce@xxxxxxxxxxxxx] On Behalf Of James Richard Tyrer
Sent: 22 August 2010 18:38
To: rollei_list@xxxxxxxxxxxxx
Subject: [rollei_list] Re: Rolleiflex 35 SL lenses QBM IV (3-Pin)
On 08/21/10 03:29, John Wild wrote:
> James,
>
> I am sure you will experience 'the wrath of the gods' for posting
> images on the list
Usually it is only a size limit on lists so I posted a small image.
But, if images are not allowed, I will avoid it in the future.
> ;-) but, yes the recessed ring with the two spanner key slots in it. The
> depth of that ring determines the maximum aperture of the lens which the
> camera picks up...
I am presuming here that there would be no reason to put a step in the
retaining ring if it weren't to provide the QBM IV aperture information.
> I have measured my lenses, using the matt step of the mount - assuming this
> is the reference register face - to the bottom of the groove using a digital
> vernier caliper.
The reference surface would be the ring that has Pin-2 in it.
> A dial gauge would be more accurate but there should be a reasonable
> tolerence and I expect that the depth when plotted on a graph will be linear,
> so discrepencies can be adjusted...
>
> F1.4 - 1.15mm
> F1.8 - 1.4mm
> F2.8 - 1.9mm
> F4.0 - 2.2mm
While I agree with 2.8, my f/1.4 lens is only 0.5mm so it would appear that it
is the lens that is the problem. This would mean that the theory that all
Planar 50mm f/1.4 2-Pins lenses will fully function on a 2000/3000 series
camera is not correct.
Still not certain of this since measured on the camera, +/- 0.5mm should work
for f/1.4.
This would mean that I need a new retaining ring, if it is a retaining ring
since it does not have any notches or holes in it for a spanner wrench like the
Japanese or Singapore lenses have. Would this still be a retaining ring but
require a rubber device to remove like the front retaining rings.
Nikkors are much easier to take apart. At least to the point of removing the
aperture ring (to replace it with an AI aperture ring); the whole rear of the
lens on most modern manual focus Nikkors is held on with screws.
So, I now have a collectors item since most of these lenses were made by Rollei
Singapore, but I would like to use it. So, if conversion is needed how would I
go about this. With Nikkors to convert to AI, it was necessary to purchase the
correct new aperture ring, but I have seen no indications that Rollei sold the
retaining rings. Can you recommend a repair shop that could take care of this?
--
James Tyrer
Linux (mostly) From Scratch
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