Minolta SSM lenses, 300/2.8 & 70-200/2.8

AnOvercomer 02 wrote:

(Alan Browne) wrote:
IS has no improving effect on resolution. (and possibly reduces the
resolution of the lens if it is incorporated in a lens element that
otherwise would not be in the lens system.)
method or the IS lens tested.
==========================

In the case of the EF 300 f4 lenses on Photodo, the IS lens scored 9
points lower than the non IS version and I don't think IS has much
effect on resolution, not that much anyway.

IS and resolution are not related items.

Loss of resolution comes from the inability of glass to transmit shorter
wavelenghts of light. More glass generally results in less resolution as your
statment above suggests: the non-IS lens scored a bit higher.

IS (image stbilization) is a means of compensating for physically moving the
lens in pitch and yaw __during__ the exposure period. IOW it reduces blurring
due to movement. Blurring indeed reduces resolution of an image but it's due to
movement not basic optical quality.

The presence of the glass elements that are used to perform IS (or VR for the
Nikon folks) adds glass which reduces resolution. But in cases where movement
is expected the improvement from IS is better than the best lens in that class
can do without IS in the presence of movement. Blur is blur.

If it were (or is) the case that the glass element used to correct for movement
was a lens element that was already required in any case, then there would be no
loss of resolution and only the benefit of IS would remain.

Is that better?

"My expectations were reduced to zero when I was 21. Everything since then has
been a bonus." --Stephen Hawking replies to 'how do you keep your spirits up?'

in NYT 12 Dec 2004.

Cheers,
Alan.
--
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-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.

(Alan Browne) wrote:
Is that better?
====================

Yes, very well put.
Thank you.



Cody,

http://community-2.webtv.net/AnOverc...otographyLinks

(Alan Browne) wrote:
Is that better?
====================

Yes, very well put.
Thank you.



Cody,

http://community-2.webtv.net/AnOverc...otographyLinks

Alan Browne wrote:

Loss of resolution comes from the inability of glass to transmit shorter
wavelenghts of light. More glass generally results in less resolution

not "wavelengths" but higher line spatial frequencies. Sorry.

--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.

Alan Browne wrote:

Loss of resolution comes from the inability of glass to transmit shorter
wavelenghts of light. More glass generally results in less resolution

not "wavelengths" but higher line spatial frequencies. Sorry.

--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.