Whether or not you need correction in order to properly focus will depend
more on your age than anything else. As the focusing screen appears to be at
arm's length, the real question is your ability to focus at 36-40". This will
be neither your distance prescription nor your reading prescription (if
wearing bifocals), but rather, your mid-range prescription. If you already
wear trifocals, this will be easily determined as it is your "middle"
prescription. For bifocal wearers, you must select a setting slightly
stronger than your bifocal and weaker than your distance IF you need the
correction. Olympus "builds in" 1/2 diopter of magnification in the system,
so if you only need a little "oomph" it's already there....but if you are in
middle age or older, you may well need more.
It may help if you understand why you need bifocals as you age. In youth the
eye has elasticity and can re-shape itself (with the aide of the muscles) in
order to focus on near objects. As we age we lose this elasticity and must
(usually between the ages of 35 and 45) have "help" with a "near"
prescription ground into the lower edges of the glass lens. The degree of the
loss of this elasticity varies greatly between individuals, therefore the
mid-range correction will also vary greatly. Those who also lose the ability
to focus in the mid-range must also use either trifocals or a "progressive"
lens so that they will have a mid-range correction to help them with tasks at
arm's length, i.e. computer scerens, pianos, gardening, etc.
Having a dial to adjust the dioptric correction such as that of the OM4, 4T,
and assume the 3T is very convenient (OM content) as you can sample and
arrive at the correct degree of correction by trial-and-error. I have
dioptric-correction lenses with eyecups and have used them with the OM1 and
OM2 for 25 years even tho my distance correction was only a -1.00 in one eye
and -1.50 in the other. I find I like a little over-correction.It's a hassle
to take down the sunglasses or even regular glasses, but I feel the nearness
to the viewfinder and the blockage of light with the eyecup is well worth it.
So take heed you youngn's..it's comin'..I have fit bifocals upon the faces of
those as young as 29!!
Susan
Heart of Va, USA
Who has a red nose from yard work on a gorgeous, sunny Saturday!
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