Could someone please explain this?

In article ,
Alan Browne wrote:

I don't know either camera, but answer these first:

Are you sure the apertures were the same when the shot was made?
Are you sure the shutter speed was at sync speed (or slower)?
Does the manual/auto slider affect aperture setting?

Can you post the results?

Cheers,
Alan

I wonder why I have yet to see anyone bring up the issue that few
shutters are ever completely accurate and it's relatively easy to
imagine one or both being off. Yet you would not see the difference
unless doing the kind of test that was done.
--
Reality-Is finding that perfect picture
and never looking back.

www.gregblankphoto.com

"Alan Browne" wrote in message
...
joe mama wrote:
Two cameras...both with the same film, from the same lot numbers.
developed at the same time in the same tank with the same chemicals. the
difference is, one came out fine, the othe came out as if way
underexposed.

the scenario:

one camera was a nikon fe-2 with a 105mm 2.5 lens. these are the pics
that came out fine. the other camera was an older pentax spotmatic with a
55mm 1.8 lens. this camera yielded the softer results. now, these were
also done with a studio lighting setup, so there was no difference in
lighting conditions.

now that i am typing this, i can only think of one thing. the spotmatic
had two pc connections on it. i used the top one. i don't have an old
manual for this camera, so maybe it was synced differently or something.
i still don't know how that would explain the overall underexposed look.
the lens also has a manual/auto slider that may have been in auto,
instead of manual. would that have mattered?

the lens looks fine. it is very clear. i doubt that it is the problem.
the flash sync speed was only 1/60 of a second on it, but i don't know
how a slower sync speed could account for underexposure. you'd think the
opposite.

any help would be great.....

I don't know either camera, but answer these first:

Are you sure the apertures were the same when the shot was made?
Are you sure the shutter speed was at sync speed (or slower)?
Does the manual/auto slider affect aperture setting?

Can you post the results?

Cheers,
Alan

Another thing you could check is whether the two cameras perform the same
without flash...Take a photo with the Nikon, and record the speed and
aperture when you take it. then, set that exact same speed and aperture into
the Pentax, and retake the same photo (with the same film speed/type) in
manual mode. Then see if the photos are approximately the same......

On Sun, 06 Aug 2006 17:45:27 GMT, "Richard Knoppow"
wrote:

"j" wrote in message
...
http://course1.winona.edu/jstafford/fp.jpg

[snip]
Class FP bulbs take about as long as Class-M to come up
to full brightness but they have a very long dwell time,
enough to cover the total travel time of small focal plane
shutters.
The minimum shutter speed that can be used with a
Class-FP bulb depends on the size and type of focal plane
shutter. For instance, the FP shutter in most 35mm cameras,
for instance Leica, has a total travel time which is
independant of shutter speed. The exposure time is varied by
controlling the width of the slit. In a Speed Graphic or
Graflex camera the curtain has a series of slits of varying
width but also variable tension. The tension, and therefore
the speed of the curtain as it travels across the film plane
varies with both the slit setting (the curtain must be wound
up to the slit desired) and with the tension setting. On a
4x5 Speed Graphic the _only_ speed that can be used with a
flash bulb is 1/1000 because the travel time is shortest at
that setting. In principle a 35mm FP shutter should be
usable at all speeds, so I don't quite understand the limits
shown unless the shutter on this camera is of a type where
the total travel time _does_ vary with speed.

Isn't it because the FP shutter must open _and_ _close_ while the
flash is burning to obtain an even exposure with an FP bulb? The
chart shows that each curtain has a travel time between 1/60s and
1/125s. If the second curtain hasn't completed its journey by the
time the flash dies then one side of the frame will have received
up to 1/60s more exposure than the other.

--
Matthew Winn
[If replying by mail remove the "r" from "urk"]

Greg "_" wrote:
In article ,
Alan Browne wrote:

I don't know either camera, but answer these first:

Are you sure the apertures were the same when the shot was made?
Are you sure the shutter speed was at sync speed (or slower)?
Does the manual/auto slider affect aperture setting?

Can you post the results?

Cheers,
Alan


I wonder why I have yet to see anyone bring up the issue that few
shutters are ever completely accurate and it's relatively easy to
imagine one or both being off. Yet you would not see the difference
unless doing the kind of test that was done.

It's a good point, but unlikely (IMO) ... a mechanical shutter is more
likely to be slow than terribly over fast. And even if over fast,
there's some margin.

With my Minolta's I can shoot sync at 1/350 (Maxxum 9) and 1/200 (Maxxum
7D) which is at least 1/3 stop faster than rated in both cases (1/300
and 1/160). Not that I would depend on it at -20°C.

Cheers,
Alan.

--
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-- e-meil: Remove FreeLunch.

William Graham wrote:


Another thing you could check is whether the two cameras perform the same
without flash...Take a photo with the Nikon, and record the speed and
aperture when you take it. then, set that exact same speed and aperture into
the Pentax, and retake the same photo (with the same film speed/type) in
manual mode. Then see if the photos are approximately the same......

Better use slide film to be less than aproximate.

Cheers,
Alan




--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.

"Alan Browne" wrote in message
.. .
William Graham wrote:


Another thing you could check is whether the two cameras perform the same
without flash...Take a photo with the Nikon, and record the speed and
aperture when you take it. then, set that exact same speed and aperture
into the Pentax, and retake the same photo (with the same film
speed/type) in manual mode. Then see if the photos are approximately the
same......

Better use slide film to be less than aproximate.

Cheers,
Alan

Indubitably......Or, at least, inspect the negatives......

"Richard Knoppow" wrote in message news:XUpBg.383

The chart shows what I was talking about. Note that electronic flash can
be used at slower speeds up to 1/60th. For 35mm cameras with focal plane
shutters and a top speed of 1/1000 this speed is usually the fastest where
the entire frame is exposed at once.
Note that this camera has only two flash settings; X and FP. For some
reason they chose to use X synch for the standard type bulbs. These have a
long delay between applying the power and reaching full brightness.
Because the bulb is being fired when the shutter is wide open the shutter
speed has to be slow enough to allow the bulb to come up to full
brightness and also to remain open for a time. Class F bulbs come up
faster and mostly have a very short dwell time so a faster speed can be
used. I suspect that Class-M bulbs could be used with the FP setting at
somewhat higher speeds.
Class FP bulbs take about as long as Class-M to come up to full
brightness but they have a very long dwell time, enough to cover the total
travel time of small focal plane shutters.
The minimum shutter speed that can be used with a Class-FP bulb depends
on the size and type of focal plane shutter. For instance, the FP shutter
in most 35mm cameras, for instance Leica, has a total travel time which is
independant of shutter speed. The exposure time is varied by controlling
the width of the slit. In a Speed Graphic or Graflex camera the curtain
has a series of slits of varying width but also variable tension. The
tension, and therefore the speed of the curtain as it travels across the
film plane varies with both the slit setting (the curtain must be wound up
to the slit desired) and with the tension setting. On a 4x5 Speed Graphic
the _only_ speed that can be used with a flash bulb is 1/1000 because the
travel time is shortest at that setting. In principle a 35mm FP shutter
should be usable at all speeds, so I don't quite understand the limits
shown unless the shutter on this camera is of a type where the total
travel time _does_ vary with speed.




Those old flash bulbs surely aren't available anymore, are they? Honeywell
"Tilt-A-Mite" flash units must be one Honeywell item most often sold on eBay
these days. I vaguely remember those spent flashbulbs being so hot that
they could cause severe burns. Many venues banned flash bulbs.

I can't say that I miss them.

"jeremy" wrote in message
news:tERBg.5154$rd1.577@trnddc01...
"Richard Knoppow" wrote in message news:XUpBg.383

The chart shows what I was talking about. Note that electronic flash
can be used at slower speeds up to 1/60th. For 35mm cameras with focal
plane shutters and a top speed of 1/1000 this speed is usually the
fastest where the entire frame is exposed at once.
Note that this camera has only two flash settings; X and FP. For some
reason they chose to use X synch for the standard type bulbs. These have
a long delay between applying the power and reaching full brightness.
Because the bulb is being fired when the shutter is wide open the shutter
speed has to be slow enough to allow the bulb to come up to full
brightness and also to remain open for a time. Class F bulbs come up
faster and mostly have a very short dwell time so a faster speed can be
used. I suspect that Class-M bulbs could be used with the FP setting at
somewhat higher speeds.
Class FP bulbs take about as long as Class-M to come up to full
brightness but they have a very long dwell time, enough to cover the
total travel time of small focal plane shutters.
The minimum shutter speed that can be used with a Class-FP bulb depends
on the size and type of focal plane shutter. For instance, the FP shutter
in most 35mm cameras, for instance Leica, has a total travel time which
is independant of shutter speed. The exposure time is varied by
controlling the width of the slit. In a Speed Graphic or Graflex camera
the curtain has a series of slits of varying width but also variable
tension. The tension, and therefore the speed of the curtain as it
travels across the film plane varies with both the slit setting (the
curtain must be wound up to the slit desired) and with the tension
setting. On a 4x5 Speed Graphic the _only_ speed that can be used with a
flash bulb is 1/1000 because the travel time is shortest at that setting.
In principle a 35mm FP shutter should be usable at all speeds, so I don't
quite understand the limits shown unless the shutter on this camera is of
a type where the total travel time _does_ vary with speed.




Those old flash bulbs surely aren't available anymore, are they?
Honeywell "Tilt-A-Mite" flash units must be one Honeywell item most often
sold on eBay these days. I vaguely remember those spent flashbulbs being
so hot that they could cause severe burns. Many venues banned flash
bulbs.

I can't say that I miss them.

The old press cameras had spring loaded flash bulb sockets, so you could
remove the old bulb without touching them.....In those days, they just
popped them out onto the street....Today, they would get a ticket for
littering.......:^)

"William Graham" wrote:

The old press cameras had spring loaded flash bulb sockets, so you could
remove the old bulb without touching them [...]

Not really. We as often than not had to pluck them out of the flash-holder.
That's why so many had either numbed-due-to-burned fingers or wore a glove
on the hand.

My finger-tips are very numb thanks to fifty years of using them as tools.

My finger-tips are very numb thanks to fifty years of using them as tools.

4 Butt scratching and nose picking no doubt.

--
Would thou choose to meet a rat eating dragon, or
a dragon, eating rat? The answer of: I am somewhere
in the middle. "Me who is part taoist and part Christian".