Re: slide vs neg (lp/mm)

[P3D John Ohrt <johrt@xxxxxxx>]

P3D Grant Campos wrote:
> Also, someone in the archives said that the lens should have twice the
> resolution of the film.

Actually 3x to 5x the resolving power are more common rules of thumb.

But for discussion purposes, the lens having much greater RP that the
film will do.

>  If the Custom is truly 300 lp/m then you would have
> to use Velvia to get the maximum benefit from the Custom lenses.

I think you should be more clear here.  If your lens has 300 lpm,
presumablely measured at 1000:1 contrast ratio,  then any film having an
RP more than 150 lpm at the same contrast may have unusably high
resolution for your application.

> In other words it is not necessary to use these high resolution films in your
> regular Realist, because your lenses aren't sharp enough to take advantage of
> the extra resolving power.  So, if you have a regular Realist, Save your money
> and don't bother with high res professional film; use a regular ASA 100 slide
> film, like a Fuji Sensia or Kodak Elite II.

A most important aspect of color technology is color rendition.  There
are people who buy Kodachrome 25 for just that reason.  Please note that
in the area of resolving power Sensia 100 has higher resolution that
Kodachrome 25 at 1000:1!  Do not confuse grain size as a measure of
resolution!  No lens affects grain size.


The best advice I can offer is:

Like anything else, a particular film has particular properties.  Until
you select your application, they remain properties. Only when you have
specified the characteristics of your application, can the properties be
evaluated into advantages and disadvantages.

This is a fundamental philosophy of life for engineers.  I wish I could
state it better.  Many engineers never understand it, but outstanding
design engineers always work that way.  We of lesser skills, should pay
heed.  Prejudice exhibited by believing a particular product has
inherent advantages and disadvantages, clouds your creative processes
and consequently diminishes the quality of your work sooner or later.

But when you select a film, consider what you want to do.  If you want
to do still life, then film speed is not an issue, but cost per frame,
resolution, and other considerations may be.  Conversely, if you want to
shoot sports events with a real 3D camera, speed assumes much greater
weighting!  

If you are not really sure, well there are a whole lot of happy campers
who just shoot the cheapest 400 speed they can lay their hands on.  I
love this techy stuff, but good advice from experienced pros is a whole
lot better than a spec sheet.

Remember, good composition is necessary to get people to truly look at a
photo.

No composition, no one cares, except for technical photography.

--
John Ohrt,  Regina, SK, Canada
johrt@xxxxxxx



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