[LargeFormat] Winter oil change

[philip lambert]

I would use S Grimes but the freight to and from USA and the possibilities
of Customs charges when landed back here makes it uneconomic. PL
----- Original Message ----- 
From: "Richard Knoppow" <dickburk@ix.netcom.com>
To: <largeformat@f32.net>
Sent: Sunday, January 18, 2004 4:01 PM
Subject: Re: [LargeFormat] Winter oil change


>
> ----- Original Message ----- 
> From: "philip lambert" <philip.lambert@ntlworld.com>
> To: <largeformat@f32.net>
> Sent: Sunday, January 18, 2004 4:57 AM
> Subject: Re: [LargeFormat] Winter oil change
>
>
> > Cautionary tale:
> >
> > I am replacing my 180mm TeleArton f5.6 with a 180mm Symmar
> as I no longer
> > need the short back focus and welcome the wider field of
> the Symmar.
> > However this came in a Synchro-Compur shutter that is
> slow, sometimes by
> > half a stop or more  and some speeds aren't the same twice
> in succession. I
> > put the  shutter for three hours in a petrol-vapour
> atmosphere  (having
> > taken the glass out). Hitherto this has softened up
> coagulated lubricant to
> > good effect but on this occasion had adverse results.
> > The speeds 1sec 1/2sec, 1/5 sec stopped working or were
> unpredictable.
> > Higher speeds worked but 1/100 was timed at 1/90 to 1/120,
> 1/200 was nearer
> > to 1/125 and 1/400 was approx 1/200 or worse.
> >
> > These odd effects were temporary, as a day later as the
> slow speeds were
> > working again and most speeds were more or less a half
> stop slow. I can live
> > with this if speeds are consistent by putting a small
> correction table or
> > note  on the lensboard. Over-exposure doesn't bother me on
> negative film
> > (although it would on 'chromes) but unpredictable speeds
> are a bother.  I
> > suppose a professional overhaul would be good. Regrettably
> the firm I used
> > for my 203mm Ektar didn't do much of a job.  Philip
> >
> >
>    The shutter needs a real cleaning. I think the reason it
> behaved so oddly after the vapor treatment is that the
> solvent hadn't completely evaporated and was causing the
> shutter blades to stick together. The Syncho-Compur is a
> good shutter, as good as any made now, but it needs a
> thorough cleaning and lubrication with the proper
> lubricants. Once cleaned the speeds will be consistent.
>    Note that the top speeds are calibrated in terms of
> _effective_ exposure time for the full aperture of the
> shutter. Measured for total open time (open time at the
> center) they will be about 20% slow. The spec for the #1
> Synchro-Compur is about 1/380th at the marked speed of
> 1/500th.  All blade shutters are calibrated this way. The
> slow speeds should be quite accurate up to perhaps 1/100th.
>    Try Steve Grimes shop for the shutter work,
> http://www.skgrimes.com
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@ix.netcom.com
>
>
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