Flash problem D300

On Feb 1, 2:54 pm, "Sosumi" wrote:
"Rita Berkowitz" wrote in message

...

Pete D wrote:

Damn, what a bust. With this level of equipment it probably means you
have to actually know what you are doing and adjust accordingly.

All he need do is turn BL off on the SB800 and he'll back in business.

Is there some problem with taking a test shot or two and make
adjustments as needed?

No need to.

I think it's not quite clear: I made a shot of my car at night, being stuck
in the mud, waiting for the auto club ;-)
I took a few shots, without the BL, from the left front at about 4 or 5
yards. The front is well lit, but the back of the car is far too dark. I
remember taking shots like this with the D40x (same SB 800) without this
being an issue.

The other day I was shooting a party and the sun was from the left back. I
used the flash at standard TTL, but most pictures were a bit too bright. I
guess it's just lack of experience. Like I said: most pictures I take
without flash, so now I'll have to learn again ;-)

I'll show some stuff one of these days. 6 days of carnaval.... I'm getting
too old for this **** ;-)

--
Sosumi


light dissipates at the square of the distance, so if you use the
flash in the dark, photographing a big object like a car, the front
will be well lit the back 2 stops or so under exposed. This is why you
have more than one flash, use the second to illuminate the back. Be
careful of distance and flash power ratios. Then you should be fine.
BTW a flash like the SB800 can only illuminate up to 20-30 ft before
your camera runs out of aperture. Taking a picture in a large room or
outside and the light dissipates over a shorter distance. Read the
flash specs carefully and you find the flash distance is for a room
with 8ft ceilings.

Tom

In article , Sosumi
wrote:

Most picture I make are without flash, but now we have a six day crazy
carnaval here in my city of Torres Vedras, Portugal. So I want to make some
good pictures with flash. I have the D300, 18-135 lens, 50 mm 1.8, SB 800
and 2 x SB 600.
When I set the camera to Aperture priority or Manual, the SB 800 to TTL or
TTL BL, it seems it constantly over exposes in the front and hardly or
nothing in the back, while the flash indicates a range from 1-17 meters.
I get this whenever I use matrix or centre weighed average. If I use spot
metering it's much better.
Does this mean you always have to use spot metering with flash to get the
right results? Seems a little odd to me, because they don't mention anything
about it in the manual of either the D300 or the SB 800.
I would think with all this expensive computerized equipment, it would
automatically give better results then this.

Sosumi, I am using similar equipment. Here's what I do...

1. Start with P mode, and set the SB 800 for TTL. I don't know what
happens in A or M. Notice what happens with the shutter speed.

2. Flash only works well (gives similar illumination) to objects that
are similar distance. Anything further back will not be lit by the
flash.

3. Vary the exposure comp (+/-) and the flash exposure comp (same
symbol but with the lightning bolt).

4. For fill flash in daylight, set the 800 to TTL BL.

5. For flash indoors or at night, try Slow Sync and Rear Curtain.
Notice what happens to the shutter speed (it will go to perhaps 1/8 or
something slow). Indoors you'll get the room lighting for the
background and a combination of flash and blurred room lighting for the
subject. Unpredictable results if people move, pictures of dancing are
really wild. But, I get some keepers this way.

Write if more problems... Or post a sample exposure.

-=- Rick

--
Richard Karash
Richard "at" Karash "dot" com

Richard Karash wrote:
In article , Sosumi
wrote:

Most picture I make are without flash, but now we have a six day crazy
carnaval here in my city of Torres Vedras, Portugal. So I want to make some
good pictures with flash. I have the D300, 18-135 lens, 50 mm 1.8, SB 800
and 2 x SB 600.
When I set the camera to Aperture priority or Manual, the SB 800 to TTL or
TTL BL, it seems it constantly over exposes in the front and hardly or
nothing in the back, while the flash indicates a range from 1-17 meters.
I get this whenever I use matrix or centre weighed average. If I use spot
metering it's much better.
Does this mean you always have to use spot metering with flash to get the
right results? Seems a little odd to me, because they don't mention anything
about it in the manual of either the D300 or the SB 800.
I would think with all this expensive computerized equipment, it would
automatically give better results then this.

Sosumi, I am using similar equipment. Here's what I do...

1. Start with P mode, and set the SB 800 for TTL. I don't know what
happens in A or M. Notice what happens with the shutter speed.

2. Flash only works well (gives similar illumination) to objects that
are similar distance. Anything further back will not be lit by the
flash.

3. Vary the exposure comp (+/-) and the flash exposure comp (same
symbol but with the lightning bolt).

4. For fill flash in daylight, set the 800 to TTL BL.

5. For flash indoors or at night, try Slow Sync and Rear Curtain.
Notice what happens to the shutter speed (it will go to perhaps 1/8 or
something slow). Indoors you'll get the room lighting for the
background and a combination of flash and blurred room lighting for the
subject. Unpredictable results if people move, pictures of dancing are
really wild. But, I get some keepers this way.

Write if more problems... Or post a sample exposure.

The problems arise because of the inverse square law by which
radiation intensity (illumination) falls off as the square of
distance. So something 3 metres away will get less than half the light
of something 2 metres away. We don't have this problem with the sun
because it's millions of miles away. So a way of lessening this
problem with flash is to move it further away. This is most easily
done if it isn't attached to the camera, e.g. if you had an assistant
standing a few feet behind you holding your flash up high and pointing
a bit down. That would also result in much better looking photographs
quite apart from better exposure.

If you're stuck with on-camera flash, then what you've observed is
that if you use a flash mode which decides the flash power based on
camera focus distance, that getting the distance past the nearest
subjects helps a bit, because instead of having correctly lit
foreground and the rest too dark, you have the better compromise of
overexposed foreground, correct mid, and dark background. Rather like
choosing your focus point as an average between the nearest and the
farthest detail you want.

They often omit details like this from camera and flash manuals
because it helps mass sales of complicated devices to pretend that
they're simpler than they really are :-)

--
Chris Malcolm DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

I used to do night shooting with film (F3 and vivitar 283)

I always shot manual. At night I'd look at the calculated exposure on
the flash and add 2 stops. Given that your effective distance with a
flash a night goes way down (but with digital you could jack up your
sensitivity)

Guide numbers and flash scale were created for use in a well lighted
about 10x10 with an 8 foot ceiling all painted white. Anything less
well lighted start adding light. Any larger room start adding light.

I have a couple flash meters that work great.

At night any subjects at a distance equal to the camera to subject
distance are not visible (I used to also do lots of night macro shooting).

Why not shoot with available light? During christmas I took some really
fun night shots with my D200 while my wife drove on our way to pick up a
kid that was down town for a concert. If you wanted to still use the
flash, I'd use it as a fill for the foreground. That way you would
still see the background and the fill would correct the color of the
available light.


Sosumi wrote:
Most picture I make are without flash, but now we have a six day crazy
carnaval here in my city of Torres Vedras, Portugal. So I want to make some
good pictures with flash. I have the D300, 18-135 lens, 50 mm 1.8, SB 800
and 2 x SB 600.
When I set the camera to Aperture priority or Manual, the SB 800 to TTL or
TTL BL, it seems it constantly over exposes in the front and hardly or
nothing in the back, while the flash indicates a range from 1-17 meters.
I get this whenever I use matrix or centre weighed average. If I use spot
metering it's much better.
Does this mean you always have to use spot metering with flash to get the
right results? Seems a little odd to me, because they don't mention anything
about it in the manual of either the D300 or the SB 800.
I would think with all this expensive computerized equipment, it would
automatically give better results then this.

Chris Malcolm wrote:

The problems arise because of the inverse square law by which
radiation intensity (illumination) falls off as the square of
distance.

.... from the flash to the subject, but *not* from the subject to
the lens.

So something 3 metres away will get less than half the light
of something 2 metres away.

~44%, a bit over a stop difference overall.
± ½ stop ... I understand even slide film can tolerate that much.

We don't have this problem with the sun because it's millions of miles
away. So a way of lessening this problem with flash is to move it
further away.

The real solution is going towards _equalizing_ the distance
to the flash(es). Moving farther away is just one way of
doing this.

This is most easily done if it isn't attached to the camera, e.g. if
you had an assistant standing a few feet behind you holding your flash
up high and pointing a bit down. That would also result in much better
looking photographs quite apart from better exposure.

Except that then the flash is farther away and thus even more a
point source of light ... whch gives harsh light.

-Wolfgang

On 2008-02-01 09:48:02 -0800, "Sosumi" said:

Most picture I make are without flash, but now we have a six day crazy
carnaval here in my city of Torres Vedras, Portugal. So I want to make some
good pictures with flash. I have the D300, 18-135 lens, 50 mm 1.8, SB 800
and 2 x SB 600.
When I set the camera to Aperture priority or Manual, the SB 800 to TTL or
TTL BL, it seems it constantly over exposes in the front and hardly or
nothing in the back, while the flash indicates a range from 1-17 meters.
I get this whenever I use matrix or centre weighed average. If I use spot
metering it's much better.
Does this mean you always have to use spot metering with flash to get the
right results? Seems a little odd to me, because they don't mention anything
about it in the manual of either the D300 or the SB 800.
I would think with all this expensive computerized equipment, it would
automatically give better results then this.

I use slow sync and rear curtain in situations like that. You need a
tripod or monopod, though. You can also use rear curtain and shutter
priority or manual mode if you want the background less blurred or you
want more control over how bright the background is.

--
Waddling Eagle
World Famous Flight Instructor

In article , ozcvgtt02
@sneakemail.com says...
-Chris Malcolm wrote:
-
- The problems arise because of the inverse square law by which
- radiation intensity (illumination) falls off as the square of
- distance.
-
-... from the flash to the subject, but *not* from the subject to
-the lens.
-
- So something 3 metres away will get less than half the light
- of something 2 metres away.
-
-~44%, a bit over a stop difference overall.
-± ½ stop ... I understand even slide film can tolerate that much.

yes. But, if you are being critical,
4x5 ektachrome, +- 1/3 stop is excessive,
FROM one part of the chrome to another.


-The real solution is going towards _equalizing_ the distance
-to the flash(es). Moving farther away is just one way of
-doing this.
-
- This is most easily done if it isn't attached to the camera, e.g. if
- you had an assistant standing a few feet behind you holding your flash
- up high and pointing a bit down. That would also result in much better
- looking photographs quite apart from better exposure.
-
-Except that then the flash is farther away and thus even more a
-point source of light ... whch gives harsh light.

no one" by three" flashhead gives anything but harsh light,
unless it is reflected off something much larger.

Also, after equal distances, increasing the distance
helps make them closer to equal
when you compare front of scene to back of scene.

the distance ratio is better.

-
--Wolfgang
-

--
Bob Crownfield

crownfield wrote:
In article , ozcvgtt02
-Chris Malcolm wrote:

-~44%, a bit over a stop difference overall.
-± ½ stop ... I understand even slide film can tolerate that much.

yes. But, if you are being critical,
4x5 ektachrome, +- 1/3 stop is excessive,
FROM one part of the chrome to another.

If you are being critical, you use a studio with proper studio
lighting.

-Except that then the flash is farther away and thus even more a
-point source of light ... whch gives harsh light.

no one" by three" flashhead gives anything but harsh light,
unless it is reflected off something much larger.

.... or re-transmitted (see softbox). Yep.

Also, after equal distances, increasing the distance helps make them
closer to equal when you compare front of scene to back of scene.

Ah, but if you move the flash to the side of the subject
(i.e. in front of the camera, though outside your field of
view) ...

-Wolfgang

In article , ozcvgtt02
@sneakemail.com says...
-crownfield wrote:
- In article , ozcvgtt02
- -Chris Malcolm wrote:
-
- -~44%, a bit over a stop difference overall.
- -± ½ stop ... I understand even slide film can tolerate that much.
-
- yes. But, if you are being critical,
- 4x5 ektachrome, +- 1/3 stop is excessive,
- FROM one part of the chrome to another.
-
-If you are being critical, you use a studio with proper studio
-lighting.

as I do.

-
- -Except that then the flash is farther away and thus even more a
- -point source of light ... whch gives harsh light.
-
- no one" by three" flashhead gives anything but harsh light,
- unless it is reflected off something much larger.
-
-... or re-transmitted (see softbox). Yep.
-
- Also, after equal distances, increasing the distance helps make them
- closer to equal when you compare front of scene to back of scene.
-
-Ah, but if you move the flash to the side of the subject
-(i.e. in front of the camera, though outside your field of
-view) ...



the ratio (DisToRearOfScene / DisToFrontOfScene)
is a good measure of lighting difference.


-
--Wolfgang
-

--
Bob Crownfield