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[OM] Re: Q: re 2x converters

Subject: [OM] Re: Q: re 2x converters
From: Moose <olymoose@xxxxxxxxxxxxxxx>
Date: Sun, 20 Feb 2005 16:09:51 -0800
Gene Wilburn wrote:

>As I only use the Vivitar 2x occasionally, it doesn't sound as if an
>upgrade to the Oly 2X-A would get me much. I prefer not using one at
>all, but they're handy in a lightweight travel kit.
>
If you are going to carry one at all, and don't want the expense of the 
Oly, I recommend finding one of the 7 element 3rd party ones cheap and 
carrying that. They are only a tiny bit bigger than the 4 element ones 
and perform much better. You should be able to find a nice one for $30, 
maybe less, if you take your time.

>Looking through Gary's tests I was struck at how much worse many of
>the lenses fared on the OM-1 as opposed to the OM-4T. Would that apply
>only to controlled, tripod shooting with mirror and aperture prefire
>on the 4T? 
>
Yes, no effect on hand held. Gary did us all an incredible service with 
those tests. No other line of lenses is nearly so well tested and 
documented. On the other hand, his methodology left out an important 
factor. He went to extremes to give the camera/lens combos solid 
support, even freezing tripod legs into the ice of a rink. What he 
didn't do is damp the camera/lens itself.

In the instructions for EVERY lens over 55mm it says:

 "Also, to prevent camera shake: When using a tripod, hold the camera 
steady with both hands and press the shutter release with the ball of 
finger, not with the cable release."

Gary didn't do this, as he didn't see any way to maintain consistency 
between shots, let alone different tests. He is scientifically correct, 
but his tests can lead to misleading conclusions if not carefully read 
and considered. I believe that including in the tests a solution like 
Walt uses, a heavy bag of discrete, inert particles (Lead bird shot in 
his case, but sand, etc. would do.) draped over the camera and lens 
would have lead to clearer conclusions.

I believe a correct conclusion from his results is that sympathetic 
vibrations in the camera, lens, tripod and head and in their 
combinations and parts are a very significant contributor to unsharpness 
in all tele lenses. A further conclusion may be logically proposed based 
on the results:

1. There are three significant sources of vibration in an SLR, mirror, 
aperture and shutter.
2. Elimination of the effects of two of those sources significantly 
improves results.
3. Elimination or mitigation of the third source may be expected to 
further improve results.
4. Mitigation is possible through damping that absorbs part of the 
initial movements and damps the various vibrations is initiates.

The OM bodies and many of the Zuiko lenses are light. Their response to 
the release and landing of shutter curtains will be greater than that of 
more massive cameras and lenses. Adding mass, especially mass that 
absorbs, rather than responds to, movement and vibration, significantly 
decreases movement of the whole and its parts.

My belief, based on experience, but no rigorous testing, is that the use 
of the "wetware", hands-on practice or draped damping material is at 
least as good as, and possibly better than, ANY unmediated camera/tripod 
setup, including mirror and aperture prefire. Prefire with damping is 
logically the best. At least in the early heyday of development of the 
OM system, Oly did major real world testing of lens designs, rather than 
just rely on theory and lab testing. I think that's why some of their 
lenses test OK, but not great, but are loved as wonderful performers by 
serious picture takers. I suspect that the advice in favor of damping 
the camera with both hands came from that kind of practical testing.

I have also come to two closely related conclusions about tripod use. 
The first is that Oly left out one aspect of damping; some of the weight 
of hands and body should exert firm, gentle downward pressure on the 
camera/lens/tripod. This further eliminates vibration in tripod and head 
and engages more of the body in the damping process. It also can make a 
soudnly designed, but light tripod preform above expectation. I also 
think that the popular idea of using a weight hanging from the tripod 
center post is not going to be much help, as it doesn't do anything for 
head, body and lens.

>Should I give some serious consideration to trading up my OM-1 to an OM-4T? (a 
>friend of mine has one for sale). Most of my shooting is handheld.
>
Well, I really like the 4 series, and would recommend giving one a try 
for its other characteristics. Spot and multi-spot metering, shutter 
speeds visible in the viewfinder, the option of auto operation, etc. are 
all useful in various ways. But I don't see any compelling reason to do 
so for vibration reduction, especially as most of your shooting is hand 
held. On the other hand, I hadn't used an OM-1 for some time until the 
recent TOPE Simplicity theme. I went out with OM-1 and simple primes, 
had a lot of fun and got several shots I really like. The '4' viewfinder 
image is smaller than the '1', which doesn't matter to me, but may to you.

By the way, if your OM-1 bodies haven't been serviced in many years, or 
ever, a CLA could be in order, even if exposures are still correct. The 
difference in feel and sound is wonderful. Suddenly they are the smoooth 
cameras they were when new.

Sorry you asked? :-)

Moose



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