At 15:02 4/14/02, Charles Sdunek wrote:
Speaking of Konica film, who's used it? I see it for sale but I dont know
anyone who has used any.
How does it perform? how dies it differ from kodak and fuji?
I haven't used it . . . so I cannot remark about its color rendition.
And specifically, what about this konica impressa 25 that's been talked
about recently? I'd be interested in hearing some comments from those who
have used it.
It's Impressa 50, not 25, and is AFIK it's the sole surviving C-41 still
camera color negative film. Extremely fine grained, but not nearly so as
Ektar (Royal Gold) 25 was. The other recently departed C-41, ISO < 100,
Agfa Ultra, was noted for its very high saturation and extremely fine
grain, making it quite unique.
Judging from its MTF curves, which show _above_ 100% through the low-medium
lppmm numbers, it should show high apparent sharpness. The human eye and
brain perceives apparent "sharpness" (or accutance) from extremely fine,
high-contrast edge definition. Diffuse rms granularity only plays a
supporting role in accutance. Films with MTF curves that start at 100% and
taper off with values under 100 0n the low-medium lppmm numbers, before
falling off rapidly at grainularity limits, are typically perceived as
having lower sharpness (accutance) than those with over 100% through the
medium lppmm numbers.
An example of this is Fuji's Provia 100F and Velvia. Provia 100F has lower
diffuse rms granularity (finer grain). OTOH, Velvia's MTF curve is higher
in the medium lppmm numbers. In addition, the chart contrast figures for
for Provia are 60 and 140 lppmm (1.6:1 and 1000:1 contrast) compared to 80
and 160 lppmm for Velvia. Velvia is perceived as having greater sharpness
even though it has a higher diffuse rms granularity. MTF curves tell more
about both perceived sharpness (accutance) and resolving power than rms
diffuse granularity numbers.
A look at Konica's Impressa 50 data does not give its rms diffuse
granularity (I couldn't find it) but its MTF curve and chart contrast
figures are more telling. 63 lppmm @ 1.6:1 contrast and 160 lppmm @ 1000:1
contrast. It falls between Provia and Velvia's figures. Based on this
(notably the 160lppmm @ 1000:1), and the MTF curve hump over 100% through
the middle lppmm numbers, Konica Impressa 50 should exhibit exceptional
sharpness (if printed well on ultra high gloss materials suitable to show
it). The data sheet for it is here:
http://www.konica.co.jp/pdfe/IMP50.PDF
-- John
Obviously there are other criteria important about color films: archival
life, color rendition, saturation, etc. It depends on how important these
are relative to the need for exceptional sharpness in deciding whether to
use Impressa 50 or a different film.
-- John
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