In some cases, you're "correcting" (ie shooting daylight film under
artificial light) but in other cases you are altering for effect...
Eric Goldstein
On Sat, Aug 21, 2021 at 8:04 PM `Richard Knoppow <dickburk@xxxxxxxxxxxxx>
wrote:
Well, it does and each film has filter factors for each
filter. But, the question is what is being corrected? To me it
would make sense to correct for the spectrum the filter is
passing. The spectral transmission charts should show this. A red
filter will hold back some red light, not as much as other
colors, it might pass very little blue light. What I want is to
get a "normal" exposure for red objects in the picture. Same
exposure as if there were not a filter. However, if I put the
filter over an exposure meter the reading will depend on the
relative spectrum of the light striking it. If its a red light,
in the range the filter passes, the meter may show very little
reduction.
I think I used to understand this stuff better.
On 8/21/2021 4:26 PM, Eric Goldstein wrote:
It kinda depends on the spectral sensitivity of the film,
doesn’t it? Kinda weird to have a generalized version stamped
on a filter or a camera…
Eric Goldstein
On Saturday, August 21, 2021, `Richard Knoppow
<dickburk@xxxxxxxxxxxxx <mailto:dickburk@xxxxxxxxxxxxx>> wrote:
Filter factors always puzzle me. They make sense if they
are compensating for reduction of the colors that are
transmitted. i.e. a red filter may hold back some red light
but just increasing exposure for the overall spectrum does
not make sense to me since that, in a way, undoes the
effect of the filter or would result in overexposure of the
colors transmitted. I am not sure I am being clear about
this. If you have, say, a red filter, it holds back blue
and some green. The idea is that these colors should be
reproduced darker than without the filter. If the exposure
is increased enough you get normal exposure for these
colors and overexposure for red.
I have never used filters much so don't have a practical
knowledge of them.
On 8/21/2021 3:52 PM, CarlosMFreaza wrote:
RolleiMagic I and II have a interesting mechanism to
compensate the filter factor for the exposure in the
Automatic mode. There is a little window beside the
taking lens, when you attach a Rollei filter on the
taking lens according you turn it, the little window
shows the numbers 1 and 5 and 2, this way you stop the
movement when you see your filter factor number in the
window or the closest filter factor number. It looks
like a inner rim rotates with the filter, pressing
something to change the exposure value. It's not useful
if the light meter doesn't work, of course.
Carlos
El sáb., 21 de ago. de 2021 07:26, CarlosMFreaza
<cmfreaza@xxxxxxxxx <mailto:cmfreaza@xxxxxxxxx>
<mailto:cmfreaza@xxxxxxxxx
<mailto:cmfreaza@xxxxxxxxx>>> escribió:
The sun and the water; a bird and a tree and its
shadow:
https://flic.kr/p/2mi5UhD ;<https://flic.kr/p/2mi5UhD>
<https://flic.kr/p/2mi5UhD ;<https://flic.kr/p/2mi5UhD>>
Carlos
El sáb, 14 ago 2021 a las 6:30, CarlosMFreaza
(<cmfreaza@xxxxxxxxx <mailto:cmfreaza@xxxxxxxxx>
<mailto:cmfreaza@xxxxxxxxx
<mailto:cmfreaza@xxxxxxxxx>>>) escribió:
A further comparison with other 3,5/75 Rollei
cameras
(F, T, 'cord IV) allowed me to establish the
fixed "A"
mode exposure at 1/125 sec f11
This frame was taken at this "A" mode:
https://flic.kr/p/2mh31mB ;<https://flic.kr/p/2mh31mB>
<https://flic.kr/p/2mh31mB ;<https://flic.kr/p/2mh31mB>>
Carlos
El mié, 11 ago 2021 a las 5:29, CarlosMFreaza
(<cmfreaza@xxxxxxxxx
<mailto:cmfreaza@xxxxxxxxx> <mailto:cmfreaza@xxxxxxxxx
<mailto:cmfreaza@xxxxxxxxx>>>)
escribió:
The Rolleimagic has a shutter release lever
on the
right side; this lever has a movment up-down to
release the shutter and it requires to hold the
camera a bit different regarding the 'flex;
I dd
not use tripod for this film, all the
frames were
taken camera hand held.
This street shot was the first frame of
the film,
it was taken at 1/30 f5,6;
https://flic.kr/p/2mgeD1a ;<https://flic.kr/p/2mgeD1a>
<https://flic.kr/p/2mgeD1a ;<https://flic.kr/p/2mgeD1a>>
Carlos
El dom, 8 ago 2021 a las 7:35, CarlosMFreaza
(<cmfreaza@xxxxxxxxx
<mailto:cmfreaza@xxxxxxxxx> <mailto:cmfreaza@xxxxxxxxx
<mailto:cmfreaza@xxxxxxxxx>>>)
escribió:
Yesterday I loaded a roll of Tmax 100
film into
the Rolleimagic (model I, see the story
below)
and tested its working taking in mind the
lightmeter does not work and the camera
has an
unknown fixed f stop and an unknown fixed
shutter speed for the A ``automatic
mode . I
took photographs using the "Flash (orange)
mode" fixed 1/30 sec shutter speed and
different f stops and I also used the
unknown
fixed f stop and shutter speed for the non
working" A "mode; the" B "green mode
needn't a
test, it works for any photograph
requiring the
"B" shutter speed. I think, according my
results, the "A" exposure is f11 and 1
/ 300sec
shutter speed and the 1/30 for the
Flash mode
is working fine; this si a still usable
camera,
however it is limited for several
situations,
of course; the Xenar lens is in very good
condition and it's the most valuable
item for
this Rolleimagic.
This one was taken at 1/30 sec f5,6 ,
the sun
is included in the frame:
https://flic.kr/p/2mfS4JD ;<https://flic.kr/p/2mfS4JD>
<https://flic.kr/p/2mfS4JD
<https://flic.kr/p/2mfS4JD>>
Carlos
El mié, 21 jul 2021 a las 11:40,
CarlosMFreaza
(<cmfreaza@xxxxxxxxx
<mailto:cmfreaza@xxxxxxxxx>
<mailto:cmfreaza@xxxxxxxxx
<mailto:cmfreaza@xxxxxxxxx>>>) escribió:
I had a Rolleimagic camera
several years
ago; it was given to me as a present,
almost unused; the lightmeter worked
perfect and the camera worked fine
after a
CLA., this first version was called
Rolleimagic "I" when F&H introduced the
second version, the"Rolleimagic
II", this
name is engraved on the camera
front panel;
however the "I" is "Rolleimagic"
only. The
Rolleimagic has three modes you can
select
with the right wheel pressing a
button on
the left side to release each one
of them.
The "green" mode is a manual "B"
shutter
speed and within this mode you can
select f
stops from f3,5 to f22. "The "A"is
the full
automatic mode,, the Prontor
shutter works
from 1/30 sec to 1/300 sec choosing
speed
and f stop according a internal needle
position linked to the lightmeter via a
mechanism, there is an upper button
and a
scale to select the film speed and
a window
with a needle, if this needle is
between
two red marks the exposure is right to
release the shutter. The "orange"
mode is
the manual flash mode, the shutter
speed is
about 1/30 and you can select the f
stops
from f 3,5 to f22, you can also use
this
flash mode like a sort of fixed shutter
speed manual mode. Focusing is made
via the
left wheel, the mechanism moves
both Xenar
3,5/75 lenses first element to
focus the
subject (yes, the Heidosmat is also
a Xenar
lens). The camera has a little hole to
attach a shutter cable release and
it can
use the Rolleiflex T masks for 16
exposures, if the big Rolleimagic
Gossen
selenium lightmeter does not work,
you only
have the B and Flash modes.The
"Rolleimagic
II" camera is almost the same,
however it
has a improved Prontor automatic
shutter,
the speeds are from 1/30 to 1/500
and it
offers a full manual mode from 1/30 to
1/500sec.I took very nice color
photographs
with the Rolleimagic in the Auto
mode, I
liked to use it, the exposure was
right,
but I lost most of them in a
moving; Icould
save only one; I also lost this
Roleimagic
in a divorce agreement...(but I
kept the
best 'flexes).
Last year I saw a pretty cheap
Rolleimagic
in a local auction site. The seller
showed
photographs about a "Rolleimagic
II" saying
it was in good condition and it was
working
fine, it looked nice indeed. It was my
surprise when I received it, it was
not a
"Rolleimagic II" with the full
manual mode
option, it was a "Rolleimagic", the
version
I. The lightmeter did not work as I
suspected immediately, but the camera
worked fine for the B and Flash
modes and
had a fixed quick shutter speed and
a small
fixed f stop at the "A" mode. The
seller
offered to return my money, she did not
know the difference between the
"Rolleimagic" and the "Rolleimagic
II" and
uploaded some images from the
internet and
she thought the camera worked fine
because
she could cock and release the
shutter. I
saw the lenses were very clean, the
focusing screen was clean , the
transport
mechanism worked fine, the focusing
mechanism worked fine and the
camera had a
very good shape in general and I
decided to
keep it, taking in mind the price
too. I
"discovered" the "A" fixed f stop
is f11
and the shutter speed is between
1/125 and
1/300 by comparing the f stop size
at the B
mode and the 1/30 shutter speed
at the
Flash mode.
I'll try it with a roll of film
some day...
Carlos.
;
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx <mailto:dickburk@xxxxxxxxxxxxx>
WB6KBL
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WB6KBL
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