Good day to all of you who entered - much to my surprise and joy - into the
lively dialogue that my inital letter brought forth some three weeks ago
(beginning on June 19th) . Sorry for not being able to do this little report
earlier but in the meantime I had some other things on my mind. Hope you
remember the thread.

First:
It seems that the matter about how to measure colour differences between
'lens families' (Canon FD and Pentax SMC) turns out to be a LITTLE too
complicated for me to be able to reach final conclusions - at least not in
the more scientific sense. The variables that (among others) William put
into perspective were a few too many to have them all controlled for.
However, the whole shutter-reliance matter is noted (that is: the shorter
times used for exposures, the more probable it is that between two camera's
there might be unwanted differences). Longer times are easier to control
for.

Second:
On second scrutiny of the slides made in the Hardanger Vidda I observed some
important aspects that led to different colour-presentations:
1. I used more often the 'wrong' moments for photographing (pouring rain,
water on lens and oculair etc. while my friend refrained from pushing
buttons at this moments).
2. My friend extensively used his 17 mm/3.5 - thereby having actually less
distance to subjects (that do seem to be farther away) which means less air
and humidity, fog and rain between lens and subject, resulting in more
saturation in colour in comparison to my slides which were taken for the
greatest part with 85/1.8 which meant much more distance to the subjects
(people in environment).

On our experiment:
The slides shot side by side were deliberately NOT taken in an absolute
controlled environment like proposed. Personally I prefer to work from out
of a pragmatic "Good is that what works out well" stance. That means that we
chose to go citywards with both camera's (Canon EF and Pentax MX) and
shooting same things (very diverse in themes and content and colours) from
the same perspective. What we did is:
1. coming to an exposure combination which we agreed upon (independently we
measured much of the time one and the same exposure - when not we averaged
both);
2. Having films (Velvia, taken from the same emulsion number = the same
batch) developed at the same lab;
3. Subjectively give opinions about results of the colour, warmth (and light
fall-off or lack of it) on the basis of viewing the slides on a standard
evenly lit light table through a viewer and later when projecting the slides
(Leitz Pradovit 153 with 90/2.5 Colorplan lens).


Conclusions Part I (28mm/f2.0 FD versus 28mm/2.8A SMC):

1.
First check was on the light-table. The SMC slides seemed to present more
brighter colours. Overall the saturation looked pretty much the same between
the Canon and Pentax shots giving a rough indication that the exposure was
at about the same.

2.
Striking difference was the absence of light fall-off of the Canon FD lens.
There was a remarkable homogenious projection without any unevenness in
projecting the slides. Of course the SMC lost most of his (or her) light
fall-of when stopping down but in general it remained more visible in the
pictures of the SMC. Actually I feel the SMC has to be stopped down towards
5.6 (better still 8.0!) to begin to resemble the same 'egality' of the FD
ones. To be honest 2.8 should be avoided at all costs in my opinion (unless
there is no alternative of course).

3.
Sharpness was also noticable higher in case of the FD lens. Details were
just a bit more defined. Also the sharpness towards the corners was better
with the FD. It seemed to me that the FD maintained a more flat field of
focus than my SMC-A.

4.
Colours were brighter with the SMC. The colours of the FD slides were
somewhat subdued in comparison - the SMC slides had more brightness and
turned out to be warmer in colour-presentation. Those who remember my
previous observations will know that this concerned my original question and
as such this is a strange result. It has to be mentioned that I did not use
my 28mm in Norway while my friend did. But I don't think that there will be
much difference between colour-presentations within the Pentax range of
lenses (I have never felt the 28mm did different colours than the other
lenses I own). We think it will be fun to compare our 50/1.4 (FD and SMC-A)
lenses with each other too, as well as our 135/(2.8 and 2.5) etc., so if
there are some of you interested in this experiment, please let me know, in
that case I'll bother to do a little report of our own subjective
evaluation - we will do the shooting anyway.

For now it's unsure if there are slight differences in exposure between our
camera's resulting in differences in saturation (which can be small but - as
I appreciate by now (I did learn a lot from this experiment) - causing
important differences in colour-brightness). At least lab differences are
ruled out as well as film variation differences for both our films were
taken from the same batch that has been stored in one and the same way (same
carton box with 5 films in it).

The results are useful I think, at least from an 'everyday practice
perspective'. If it does (or does not) work in practice what good then is a
thoroughly controlled lab-report that states the contrary? Interesting note:
I presented  a number of people the slides mixing randomly the FD and SMC
versions and asked which of them appealed most to them. Far more slides
taken with the SMC were prefered over the slides taken with FD than the
other way around, light fall-off or not and slightly less sharp or not. So
do people in general tend to judge a picture more on the basis of colours
than on
other aspects like sharpness?
I personally think the 28/2.0 FD is the better lens but then it was a lens a
lot more expensive than the 2.8 version. So it's probably not completely
fair a comparison.

As a personal side-note: uncertainty has ended, I'm happy again with lenses
I use -well, never stopped being happy. I learned when (not) to use slide
film. I bought a digital incident meter yesterday and will use it the coming
time in search of better exposures.

Thanks for thinking with me.



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