Bad eyes, diopter?

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AAvK - 20 Sep 2006 09:27 GMT

I have diabetic neuropathy in my optic nerves, which is sugar crystals in there
and that messes-up eyesight. But glasses do work fine to correct my vision.

I seem to notice that my images (35 slides) look sharp under a loupe, then I
scan them and they come up fuzzy! My older 6x7 positives are alright, but not
my recent 35s, and I take time focusing.

Maybe I am getting bloom in scanning from overdone settings in Vuescan?
Overworking the CCD? Settings too intense?

Or maybe I am focusing the lens to the wrong length, using the lens as like my
eye glasses, or in another term; focusing to the same prescription of my
glasses, and therefore the images are a bit fuzzy? Is that exactly what diopters
are for?

If so I need a -1.25 for my Pentax K2 and I don't know where to find one.
I would appreciate any positive advise, please.

TIA,

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Stephen - 20 Sep 2006 09:39 GMT

> I have diabetic neuropathy in my optic nerves, which is sugar crystals
> in there
> and that messes-up eyesight. But glasses do work fine to correct my
> vision.

That's because you have other eyesight problems than the neuropathy,
although if your blood sugar is too high it does affect the focal length
of your eye temporarily - the neuropathy has different symptoms though.

> I seem to notice that my images (35 slides) look sharp under a loupe,
> then I scan them and they come up fuzzy! My older 6x7 positives are
> alright, but not my recent 35s, and I take time focusing.

This suggests to me that your scanner is out of focus - although it
depends on what scale you're looking at the image - ALL digital images
have a point where they look "fuzzy" when you're approaching the
resolution of the scanner. 35mm film should support better than 3000 dpi
- what are you scanning at?

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AAvK - 20 Sep 2006 10:20 GMT

>> I have diabetic neuropathy in my optic nerves, which is sugar crystals
>> in there
[quoted text clipped - 4 lines]
> although if your blood sugar is too high it does affect the focal length
> of your eye temporarily - the neuropathy has different symptoms though.

That makes sense, because I know the neuropathy goes up and down, as
sugar levels goes up and down. Therefore levels of fuzzy eyesight does
go up and down.

>> I seem to notice that my images (35 slides) look sharp under a loupe,
>> then I scan them and they come up fuzzy! My older 6x7 positives are
[quoted text clipped - 5 lines]
> resolution of the scanner. 35mm film should support better than 3000 dpi
> - what are you scanning at?

In Vuescan it's whatever gives me a final 300ppi, though I think I should
try for 400ppi, but that can be done in Genuine Fractals which has got to be
a much better up-sizer.

I use the slider to set "scan dpi" related to final dimension settings. The
scanner's highest is 2700 ppi, though it will interpolate to higher. It is a
35mm only scanner, the old 2720s by Acer/BenQ, now owned by Umax.

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Stephen - 21 Sep 2006 10:05 GMT

>>> I have diabetic neuropathy in my optic nerves, which is sugar
>>> crystals in there
[quoted text clipped - 9 lines]
> sugar levels goes up and down. Therefore levels of fuzzy eyesight does
> go up and down.

That's not the neuropathy - means dead nerves from the Latin or Greek -
it's a one-way process. Eyesight doesn't usually go fuzzy until your
blood sugar is way too high.

>>> I seem to notice that my images (35 slides) look sharp under a loupe,
>>> then I scan them and they come up fuzzy! My older 6x7 positives are
[quoted text clipped - 15 lines]
> higher. It is a 35mm only scanner, the old 2720s by Acer/BenQ, now
> owned by Umax.

2700 should capture standard 35mm film adequately so maybe the scanner
is out of focus - can you fix that?

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AAvK - 23 Sep 2006 11:51 GMT

>>>> I have diabetic neuropathy in my optic nerves, which is sugar
>>>> crystals in there
[quoted text clipped - 13 lines]
> it's a one-way process. Eyesight doesn't usually go fuzzy until your
> blood sugar is way too high.

Never listen to a nurse. Only the doctor.

>>>> I seem to notice that my images (35 slides) look sharp under a loupe,
>>>> then I scan them and they come up fuzzy! My older 6x7 positives are
[quoted text clipped - 18 lines]
> 2700 should capture standard 35mm film adequately so maybe the scanner
> is out of focus - can you fix that?

Nope.
AAvK

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Alan Browne - 20 Sep 2006 13:45 GMT

> Or maybe I am focusing the lens to the wrong length, using the lens as
> like my eye glasses, or in another term; focusing to the same
[quoted text clipped - 3 lines]
> If so I need a -1.25 for my Pentax K2 and I don't know where to find one.
> I would appreciate any positive advise, please.

If you're manually focusssing with glasses (-1.25) and get good results
and getting fuzzy results w/o glasses, then yes, a diopter is the thing
to add to the VF. Shooting with glasses sucks.

As an exercise, focus on something w/o glasses. Then put them on and
look through the VF... that should tell you the story quite quickly.

Try b&h photo.

Most new mid to high end cameras have a diopter setting built in (-3 to
+1 is typical).

G'luck,
Alan

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AAvK - 23 Sep 2006 11:54 GMT

>> Or maybe I am focusing the lens to the wrong length, using the lens as
>> like my eye glasses, or in another term; focusing to the same
[quoted text clipped - 18 lines]
> G'luck,
> Alan

Thanks Mr. Browne, I will order one from the local shop. Wish they had
my exact prescript though.
AAvK

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