Re: [OM] Vision problem?

Subject: Re: [OM] Vision problem?
From: Jim Brokaw <jbrokaw@xxxxxxxxxxx>
Date: Sat, 22 Nov 2003 17:34:50 -0800
on 11/22/03 2:48 PM, Lars Bundesen at lars.bundesen@xxxxxxxxxx wrote:

> Hi,
> I am 45 and getting close to the time I need reading glasses, I am afraid.
> I am shortsighted and use contact lenses.

Lars, I'm slightly older, use contact lenses, and I'm nearsighted and often
shortsighted as well... I liked your turn of phrase there <g>.
> I normally have no problem focusing with my Om cameras, except in low light
> conditions, especially with a zoom. I normally use the 1-14 screen with an
> OM 4 T.

1-14 screen is my personal favorite, although I only have one... I sure wish
Olympus had seen fit to make a 2-14, that would be heaven!
> This summer I have taken an embarassing number of photos that were unsharp.
> Many were taken with a Sigma 50-200 mm zoom around 200 mm, and that
> particular lens might be to blame, I am not quite sure. It is a lenbs I
> haven't used before.

Could be the lens - are the 200mm pictures taken at infinity (of very
distant objects) sharp? Zoom lenses sometimes need the focus set/adjusted at
both the short and long end of the zoom, and its often done in two different
ways. So the lens could be sharp at the shorter focal lengths, then shift
focus or be unable to be brought to sharpness at certain distances at the
longest focal length. But if its not sharp at infinity at 200mm, that would
be a strong clue to mis-adjustment (for most zoom lenses a relatively easy
> But I'd like to know if deteriorating ability to focus on close things
> affects your ability to focus with a camera?

The focus screen image (and surrounding exposure scales, numbers, etc) is at
a 'virtual distance' of something like 3-6 feet, depending on the diopter
setting. So this should not be a huge problem even for nearsighted people...
and if your contacts correct you to 'normal' 20-20 vision then you should be
able to get a sharp viewfinder image using the diopter adjustment (or the
eyecup with inserted lenses). The way to do this is remove the lens, look in
the finder at a bright light or window, then turn the diopter screw until
the focus screen's circles and the meter LCD are their sharpest. This sets
the finder, then when you reinstall the lens and focus, you should be
focusing to the sharpest image, which should then be correct. This is
assuming you know that your focus screen is correctly set to match the
actual camera body focus
> Then I'd even more strongly consider going digital and AF, at least as a
> supplement.
> Lars

Jim Brokaw
OM-'s of all sorts, and no OM-oney...

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