MF & Technical Pan, looking for optimum sharpness

Hello,

The last few weeks I've been shooting landscapes with a Hasselblad 503CW,
using a CFE 2.8/80 mm- lens and TMX. Now that I've finally decided on how to
build my compositions, I'm considering to start all over again using
Technical Pan. For most pictures, the lens is stopped down to f11 or more.

As you probably suspect from the combination medium-format / Technical Pan,
I'll be trying to get the most out of my camera/film combination in terms of
detail, sharpness, ...

The technical data-sheet of my lens states that Depth Of Field data are
'calculated for a blur circle of 60 µm and do nog include the effect of lens
aberrations. For very critical photography and great enlargements this blur
will be visible.'
(http://www.hasselblad.se/Archive/doc...oductsheets/CF
E80.pdf). Further ause of DOF-data for apertures of 2 f-stops larger is
suggested.

Kodak claims that ther Technical Pan film
(http://www.kodak.com/global/en/profe...p255/p255.jhtm
l?id=0.1.18.14.21.22.16&lc=en) has an RMS-granularity of 5 (developed in
Technidol, of which I have a few bottles craving for film in the darkroom).
As far as I can figure out, the RMS-granularity is a standard deviation
(been confronted with rms-values more then a few times throughout my
education), but I don't know of what. There must be a link to the size of
film-grain, but to me it's still a missing link.

My question is not so much wether, for my specific case, I should take in
account the 2-stop correction for DOF-data Hasselblad recommends. Most of
all I would like to understand why (of maybe why not) I should consider this
correction.

Thx to all (and please accept my excuses for cross-posting),

Philippe

, I should take in
account the 2-stop correction for DOF-data Hasselblad recommends. Most of
all I would like to understand why (of maybe why not) I should consider this
correction.

Thx to all (and please accept my excuses for cross-posting),

Philippe

Your biggest problem with high resolution and Hasselblad will be film set. You
see, the film takes on a "set" in the cassette. This will alway be on the
second shot right after the first one. It's hard to see without resolution
targets but it is there. If your using a 80mm lens and Tech Pan, your first
shot at about f-8 will be about 100 lines per mm. The second shot will have a
band of 40 line per mm detail right through the middle of the frame.

With wedding photography using 160 film and 8x loupe you will not see this but
with Tech Pan and a very good 20x loupe you will.

Larry

"Hemi4268" schreef in bericht
...
, I should take in
account the 2-stop correction for DOF-data Hasselblad recommends. Most of
all I would like to understand why (of maybe why not) I should consider
this
correction.

Thx to all (and please accept my excuses for cross-posting),

Philippe

Your biggest problem with high resolution and Hasselblad will be film set.
You
see, the film takes on a "set" in the cassette. This will alway be on the
second shot right after the first one. It's hard to see without
resolution
targets but it is there. If your using a 80mm lens and Tech Pan, your
first
shot at about f-8 will be about 100 lines per mm. The second shot will
have a
band of 40 line per mm detail right through the middle of the frame.

With wedding photography using 160 film and 8x loupe you will not see this
but
with Tech Pan and a very good 20x loupe you will.

Larry

And what exactly is this 'film set' ? I suppose my not being a native
speaker is the reason why I don't completely understand.

Philippe

"Philippe Lauwers" schreef in bericht
i.nl...
Hello,

The last few weeks I've been shooting landscapes with a Hasselblad 503CW,
using a CFE 2.8/80 mm- lens and TMX. Now that I've finally decided on how
to
build my compositions, I'm considering to start all over again using
Technical Pan. For most pictures, the lens is stopped down to f11 or more.

As you probably suspect from the combination medium-format / Technical
Pan,
I'll be trying to get the most out of my camera/film combination in terms
of
detail, sharpness, ...

The technical data-sheet of my lens states that Depth Of Field data are
'calculated for a blur circle of 60 µm and do nog include the effect of
lens
aberrations. For very critical photography and great enlargements this
blur
will be visible.'

(http://www.hasselblad.se/Archive/doc...oductsheets/CF
E80.pdf). Further ause of DOF-data for apertures of 2 f-stops larger is
suggested.

Kodak claims that ther Technical Pan film

(http://www.kodak.com/global/en/profe...p255/p255.jhtm
l?id=0.1.18.14.21.22.16&lc=en) has an RMS-granularity of 5 (developed in
Technidol, of which I have a few bottles craving for film in the
darkroom).
As far as I can figure out, the RMS-granularity is a standard deviation
(been confronted with rms-values more then a few times throughout my
education), but I don't know of what. There must be a link to the size of
film-grain, but to me it's still a missing link.

My question is not so much wether, for my specific case, I should take in
account the 2-stop correction for DOF-data Hasselblad recommends. Most of
all I would like to understand why (of maybe why not) I should consider
this
correction.

Thx to all (and please accept my excuses for cross-posting),

Philippe




Some more thoughts ... my intuition tells me that, as long as this blur
circle is smaller than the average silver-particle in the film used, the
piece of the image can be considered as 'sharp'.
Is there a relationship between the RMS-granularity and the size of
silver-particles in the emulsion (I suppose so, but don't have a clue on
what this law could be) ? Is there a rule of thumb that gives an estimation
for the grain-size based on RMS-granularity ? Are there any other elements
that I should consider ?

"Philippe Lauwers" wrote

Hasselblad 503CW ... CFE 2.8/80 ... Technical Pan ... get the most

Shoot at optimum aperture, about f5.6.
Use a 25A filter.
Use a tripod (goes without saying).

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

"Philippe Lauwers" wrote in message
i.nl...
Hello,

The last few weeks I've been shooting landscapes with a Hasselblad 503CW,
using a CFE 2.8/80 mm- lens and TMX. Now that I've finally decided on how
to
build my compositions, I'm considering to start all over again using
Technical Pan. For most pictures, the lens is stopped down to f11 or more.

As you probably suspect from the combination medium-format / Technical
Pan,
I'll be trying to get the most out of my camera/film combination in terms
of
detail, sharpness, ...

I'm not convinced it's all that much better than Provia or Velvia 100F.
Maybe slightly. It scans really ugly (gritty) and dust is really obnoxious.
YMMV if you are projection printing.

But it's very much worth the time experimenting.

The technical data-sheet of my lens states that Depth Of Field data are
'calculated for a blur circle of 60 µm and do nog include the effect of
lens
aberrations. For very critical photography and great enlargements this
blur
will be visible.'

(http://www.hasselblad.se/Archive/doc...oductsheets/CF
E80.pdf). Further ause of DOF-data for apertures of 2 f-stops larger is
suggested.

My experience is that hyperfocal focusing is usually a bad idea: any loss of
sharpness at infinity hurts. For landscapes, leave your lens at infinity
focus except in rare cases.

Remember that DOF tables were all created in the days when medium format was
the format used by the masses for snapshots and small prints. Things are
different in this day of 4000 dpi scans and 13x19s from 645. Even two stops
may not be enough. With my 35/3.5 lens on my Mamiya 645, I get lots of DOF.
The DOF on all my other lenses (55, 110, 150) is esssentially zero for
practical purposes.

Kodak claims that ther Technical Pan film

(http://www.kodak.com/global/en/profe...p255/p255.jhtm
l?id=0.1.18.14.21.22.16&lc=en) has an RMS-granularity of 5 (developed in
Technidol, of which I have a few bottles craving for film in the
darkroom).
As far as I can figure out, the RMS-granularity is a standard deviation
(been confronted with rms-values more then a few times throughout my
education), but I don't know of what. There must be a link to the size of
film-grain, but to me it's still a missing link.

Stop thinking and go shoot some frames.

My question is not so much wether, for my specific case, I should take in
account the 2-stop correction for DOF-data Hasselblad recommends. Most of
all I would like to understand why (of maybe why not) I should consider
this
correction.

See above. It's your art and your eye: decide for yourself.

David J. Littleboy
Tokyo, Japan

In article , "Philippe
Lauwers" wrote:

My question is not so much wether, for my specific case, I should take in
account the 2-stop correction for DOF-data Hasselblad recommends. Most of
all I would like to understand why (of maybe why not) I should consider this
correction.

Hasselblad's article seems to make it clear: when closely scrutinizing the
outcome or making large prints, the hyperfocal table does not work because
it presumes a modest enlargement - a generous COC. Big prints or more
strident standards requires a smaller COC.

Benchracers. Sheesh.

In rec.photo.darkroom Philippe Lauwers wrote:
Hello,

The last few weeks I've been shooting landscapes with a Hasselblad 503CW,
using a CFE 2.8/80 mm- lens and TMX. Now that I've finally decided on how to
build my compositions, I'm considering to start all over again using
Technical Pan. For most pictures, the lens is stopped down to f11 or more.

My experience with Techpan is that it's very fine grain, but not optimum sharpness.

There is a thing like "visible sharpness", and this isn't reflected in RMS
values. I ususally shoot Delta 100 in medium format (mostly SL66 and Mamiya 7)
and occasionally use Efke 25 in Beutler developer. These two films give
very good visible sharpness, my test films with Techpan and Neofin Doku
had finer grain, but less sharpness. Both cameras were used with a
large Linhof tripod and MLU at the SL66. Both Delta 100 and Efke 25 are
good enough for enlargements to 1mx1m, and even then smallest details
of 1mm are easily visible. Good enough for me, if I want more, I use 13x18.

Martin

Philippe Lauwers writes:

And what exactly is this 'film set' ?

The film is slightly curved from its passage over rollers in the film
back. This causes it to be less than perfectly flat against the
backplate when the film is exposed. In most cases this is not an issue,
but if you really need the highest possible resolution, it becomes a
concern.

--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.

"Philippe Lauwers" wrote

'calculated for a blur circle of 60 µm and do nog include the
effect of lens aberrations. For very critical photography and great
enlargements this blur will be visible.

You might look at it this way. Tech Pan is for two dimensional
subjects. That was the reason for it's creation. No three dimensional
subject will do Tech Pan justice.
Minox and 35mm users love the stuff because big grainless
enlargements can be made. With a very carefull selection of subject
and superb optics they can produce large sharp prints. Dan