Hi Dawid, Ken, Chuck, Moose and all,
From: Dawid Loubser <dawidl@xxxxxxxxxxx>
>I just wanted to comment that I think the 20mm f/3.5 that I received
>from Clay is an incredibly early (and, consequently, rare?) version.
>It's not multicoated (i.e. no "MC" marking).
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
>Without regard to the 20mm in particular, not all MC Zuikos are marked
>as MC.
The Zooms, Macros and some special lenses didn't follow the x.Zuiko/Zuiko
MC/Zuiko markings... The latest scheme can be recognized by the order of
focal length and aperture: these late lenses have the focal lenght alone
first, and then the aperture (e.g. '24mm 1:2') whereas the older lenses (MC
or not) have them reversed, with a 'f=' before focal length (e.g. 1:2
f=24mm)
Please note that this late lettering does NOT guarantee the presence of
multicoating, although most are -- AFAIK, the 135/3.5 was NEVER multicoated,
even when marked 'Zuiko Auto-T 135mm 1:3.5'. Of course, when a lens is
marked MC, it _is_ multicoated.
From: Dawid Loubser <dawidl@xxxxxxxxxxx>
>My OM-1 manual, which dates from 1974 or so (i.e. it pre-dates the
>existence of the 21/2.0 and 50/1.2 lenses) already refers to the
>20/3.5 "MC" Macro (along with the 80/4.0 MC macro, also manual
>diaphragm) lenses. So - this means that only from about 1972 - 1974
>were these very very early single-coated Macro lenses made?
Can't say about this, I've never seen 'in person' those macro lenses. Some
lenses were MC from the start, like the fast wides -- except the 21/2,
introduced later.
The 50/1.2 (always MC, marked or not) appeared much later than the early
G.Zuiko 55/1.2 -- always single coated, if I'm not mistaken.
From: Dawid Loubser <dawidl@xxxxxxxxxxx>
>Quite special indeed... I also love single-coated lenses for B&W work,
>and I must say, the quality of the 20/3.5 (on all aspects of image
>quality) is stupendously good,
Some lenses are great even in single-coated version -- even in flare
resistance. The unrelated 28/3.5 comes to my mind, I have used it
successfully in either B&W, colour film or digital. OTOH, the 135/3.5 would
definitely improve from multicoating... but never had it :-(
>as long as you use the lens
>at relatively wide apertures. Have not done scientific testing, but
>from images I actually get the impression that wide open it's already
>at peak performance.
From: Moose <olymoose@xxxxxxxxx>
>The diffraction mavens have previously opined that the 20/3.5 is indeed
>already slightly diffraction limited at f3.5 and gets progressively
>softer as it is stopped down. As I recall, speculation was that the
>20/2 replaced the f3.5 in part to avoid diffraction limiting, but
>only wide open.
That makes a lot of sense. As a funny note, the older 20/3.5 Macro is like a
reversed Tessar (4 elements, 3 groups => highly flare resistant), wheras the
later 20/2 is a classic Planar/double-Gauss design (6 elements, 4 groups)
From: Dawid Loubser <dawidl@xxxxxxxxxxx>
>Oh, and another question - what do you guys do to tame vibrations from
>an OM-1 when using a lens like this for natural-light work? (i.e.
>shutter speeds anything from 0.5 to 20 seconds) ? I thought my
>old Linhof tripod was reasonably solid, but even with mirror lockup,
>at these high magnifications the image is jumping all over the show,
>almost impossible. Thus, am generally using flash for the moment.
From: Ken Norton <ken@xxxxxxxxxxx>
>The short answer is to NOT use the OM-1. The OM-1 has that little >issue
with the aperture stop-down mechanism that shakes the camera
>(even with mirror lockup) like it's coming off of a high.
From: Dawid Loubser <dawidl@xxxxxxxxxxx>
>That really sucks, I love my OM-1n, but I am happy to perhaps relegate
>all Macro shooting to the OM-2n (which, I must admit, does appear to
>be a lot smoother).
Shouldn't be that way. However, I have the impression that the oldest OM-1
(pre-MD) and OM-2 (older, uneven mettering pattern) feel smoother than later
OM-1 and OM-2, including the -n series...
>Hmm - my OM-1n must have bad internal bumpers then, because it really
>does vibrate a bit more than the OM-2n.
Most likely. The foam at the mirror isn't really intended for light sealing,
but mostly for damping.
From: Ken Norton <ken@xxxxxxxxxxx>
>An OM-2, 3 or 4 series body (even the OM-2000) will be much smoother in
>this circumstance.
I don't think a 2/2n would make things better. (Nearly) all OM cameras
suffer from the aperture issue, but some models have a workaround...
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
>An OM-2S, OM-4x or OM-2000 will pre-fire the mirror and stop down
>mechanism when used with the selftimer.
...this is it. The OM-3 doesn't have a self timer, so I'm afraid it won't
help -- I've never handled one, though.
>The mirror and stop down will
>fire after about 2 seconds thus giving about 8 seconds for the
>vibrations to damp down before the shutter fires.
Never seen that behaviour... mine do pre-fire both mirror and aperture when
pressing the release button, so they have the full 10? seconds for the
vibration to extingish.
>Actually, I'm not
>100% sure the 2S also pre-fires the aperture along with the mirror but
>I'm not at home to check it out. But the stop down mechanism is the
>major vibration culprit so be sure to check.
Yes, it does prefire. BTW, the 2S and the PC/40 have another measure against
vibration: the aperture mechanism bears a delayed action (because of Program
capabilities) which smoothens things quite a bit.
Wonderbricks and other 'modern' cameras have no springs at all, everything
is motor driven. They _are_ much smoother, but at the cost of an increased
shutter lag -- and I'm not talking about AF, I discarded the (manual focus)
Contax Aria because of this.
From: Moose <olymoose@xxxxxxxxx>
>Others have already weighed in with excellent advice. To make it
>perfectly clear, an OM-2 or OM-2n is no improvement on the OM-1(n) for
>vibration.
Amen to that. As already said, I don't think the OM-3 is any better,
although the added inertia of the secondary mirror _may_ improve things a
little bit...
>You must go to an OM-2s (why it's called an OM-2_ is a
>mystery to me),
I agree, I think something like 'OM-4 Lite' should have been much more
appropriate...
>OM-4 series, OMPC (OM-40) or OM2000 body and use the
>self timer to pre-fire mirror and aperture to reduce camera induced
>vibration.
Quite effective, indeed.
From: Dawid Loubser <dawidl@xxxxxxxxxxx>
>But as I said, my main issue is vibration not from the mirror, but
>when the shutter opens (and thus, the notorious aperture stop-down
>mechanism).
Even when the mirror and aperture pre-fire, the opening shutter does induce
a bit of vibration...
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
>Other means of vibration reduction is to place your hand heavily on the
>camera during exposure or use a bean or shot bag.
From: Moose <olymoose@xxxxxxxxx>
>Also, a bag filled with lead shot (coated for your health) will be more
>effective than light things like lentils, rice, etc. When used on a
>tripod mounted, i.e. horizontal, camera, be sure to have it resting on
>both body and lens.
Always recommended for high resolution and/or high magnification work --
ESSENTIAL with some lenses (e.g. 200/4)
From: Dawid Loubser <dawidl@xxxxxxxxxxx>
>It is amazing how well a human being damps vibrations, no? The OM-1 is
>the only camera I've used with which I can get tack sharp 1/15s
>exposures hand-held (say, with a 24mm lens) but which absolutely sucks
>on a tripod for similar exposure durations.
Have you ever tried rangefinders?
From: Ken Norton <ken@xxxxxxxxxxx>
>Long answer is to use a LONGER shutter speed. As a general rule, you
>should avoid 1/4 to 1/30 second with all OM bodies, but especially
>the OM-1. When you use a longer shutter speed than 1/4 second, the
>percentage of the exposure that is affected by vibration is greatly
>reduced. With a 2-second exposure, for example, you will have no
>shutter-vibration blurring.
There is the well-known 'hat' method -- put a black cardboard in front of
the lens, release shutter, wait several seconds for the vibration to
disappear, and _start_ actual exposure by lifting the black cardboard.
Commonly used in astrophotography, it seems however tougher to implement for
macro, where things are much closer...
From: Dawid Loubser <dawidl@xxxxxxxxxxx>
>Anyway, my plan B is to potentially think of building a leaf shutter
>(like from an old busted Mamiya RB lens, those shutters induce an
>effectively zero moment of inertia to the system when they fire) in
>between the lens, bellows, and camera somewhere. That might be an
>all-round better solution, I have found leaf shutters to be much
>superior for delicate Macro work
Seems quite interesting, but rather difficult... please let us know if you
experiment about this!
>For example, this shot I posted previously was with the 20/3.5 with
>natural light, ~4 seconds exposure at f/16 (massively diffaction
>limited, but needed the DOF).
>It came out fine with the OM-2n (auto tube + bellows), not sure that
>my OM-1 would have settled down enough by then.
<
http://fc01.deviantart.com/fs46/f/2009/236/9/d/Seedling_by_philosomatographer.jpg
>
Nice result anayway!
Cheers,
--
Carlos J. Santisteban Salinas
IES Turaniana (Roquetas de Mar, Almeria)
<http://cjss.sytes.net/>
--
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