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Re: [OM] Using adapted manual lenses, was: Kirk Tuck on micro 4/3

Subject: Re: [OM] Using adapted manual lenses, was: Kirk Tuck on micro 4/3
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Thu, 12 Jan 2012 05:56:52 -0500
Thanks for the explanation.  I'll have a closer look with a magnifier... 
er.. my 24/2.8 is the best "magnifier" I have around here.  I'll also 
consider "whittling" with some fine emery paper since the chipped 
adapter seems to be unusable as is.

I don't have a problem spending more than $20.  I just have a problem 
spending more than $20 if the more expensive adapter doesn't fit any 
better.  I was just looking at the FotoDiox adapters.  Unchipped cheap 
ones are $20.  Unchipped "Pro" models are $80.  Material of the cheap 
one is unspecified (possibly aluminum as some ebay models?).  The 
expensive one is brass, not stainless steel.

Chuck Norcutt

On 1/11/2012 11:18 PM, Moose wrote:
> On 1/11/2012 3:34 PM, Chuck Norcutt wrote:
>> No, I don't see the problem the makers have.  All of these lenses fit
>> all of my OM bodies perfectly.  The maker only need make the mating lens
>> flanges to the same specification as OM bodies.  They're probably off by
>> 0.001-0.002 inches.  A large error for a good machine shop.
>
> OK, let me revise what I said.
>
> "You can see the problem the makers have without raising the price 
> considerably. The same adapter is a good fit for
> Zuikos, too tight on a Vivitar and too loose on a Tokina."
>
> Now get out your flashlight and magnifying glass. Look closely at the inside 
> of the mount on an OM body. See those
> separate little springs screwed to the mount? Stainless steel mount with 
> spring steel springs to hold the lens flanges.
>
> To sell an adapter for under $20 (your previous stated limit), with chip, the 
> adapter is made of one solid piece of
> brass, with two screws in it, a lens stop and an aperture stop down. The 
> flanges that hold the lens flanges have a kerf
> cut in them to allow them to flex and provide tension to hold the lens from 
> turning.
>
> Such a design simply doesn't have the spring range to accommodate as wide a 
> range of lens flange widths and depths as
> the more complex one on OM bodies. The design is nothing new. Inexpensive 
> teleconverters and extension tubes from the
> old days are made the same way. The Oly teleconverters and extension tubes 
> use the same, far better, but more expensive,
> design as the bodies.
>
> The focus confirmation chips used to be available separately, with a little 
> jig for mounting them correctly. Perhaps you
> might separate the purchase of adapter and chips. You already have one 
> adapter that fits all the lenses.
>
> As you have said you would be happy with dedicated adapter/ship combos for 
> each lens, how about custom modifying
> adapters you already have? As long as the problem is that they are too tight, 
> simply reduce the mating flange surfaces a
> little. You don't need a shop to sand/file/dremel/whatever each one just a 
> little, test fit, repeat as necessary. Sort
> of like exposure determination by chimping. :-)
>
> My first adapter was a home made brass one with no plating. This was at the 
> beginning, and all adapters were quite
> pricy. Home made and used brought down the price of the experiment of trying 
> OMs on a D60 borrowed from a former list
> member before springing for a 300D. the results convinced me.
> <http://galleries.moosemystic.net/D60/>  I wonder what I could do now with 
> those images with such better tools and
> greater experience.
>
> The brass was a bit too soft. Worked fine with small lenses. A big, heavy one 
> would soon feel loose on the camera. Twist
> a small screwdriver in the kerfs, and it would be fine until I used another 
> heavy lens. I cut and stuffed tiny pieces of
> sheet aluminum into the kerfs. Worked like a charm. Still works, although I 
> have other, better looking adapters now.
>
> I can just see Chuck, sitting in a rocker on the front porch of his trailer, 
> whittling' away at his adapters. :-P
>
> Sittin' on the porch, retellin' old lies,
>      Moose
>
-- 
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