Basics Course Session 6
Pop Up Flash
Pop up flash usually produces HORRIBLE HORRIBLE pictures that:
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Give little modelling of the face
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Have harsh shadows
If a large lens is used it will often leave a shadow
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If subject is against a wall it gives a tell tale shadow and
reflects anything shiny
If not against a backdrop it gives a black background and
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bleaches out the face (and you loose your glasses!)
Red Eye
(some have pre flashes to reduce this)
You can use a Diffuser to soften the shadows (poor focus down to
me!)
There are proprietary diffusers or you can make your own
You can Bounce flash off the ceiling
There are proprietary mirrors to bounce flash, but I used a vanity mirror.
You can bounce flash off the wall ( you have to improvise)
Compare the five results,
Uhm!!
Use flash in Backlit situations
Or as Fill In flash
Courtesy Amateur Photographer
External Flash
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Doesn’t take power from camera battery
Much more powerful than camera pop up
Swivel head makes bouncing flash easier
Zoom the flash 24 – 105 ml with your lens
Control flash output from the camera menu
Guide Number e.g. GN 56 (56 meters at ISO 100)
Devide the GN by the distance to get the f stop i.e. GN 56 at 10mtrs = f5.6
Maximum Shutter Sync Speed
Flash fires when the sensor is completely uncovered
Max shutter sync speed is usually about 1/200th
Above this the sensor is never completely uncovered
This is what happens when you use a shutter speed which is too
fast – part of the picture is blacked out. The rear shutter
curtain (2nd Curtain) is already moving.
Heidi
External Flash Modes
Manual
ETTL
Multi
HSS
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Set everything yourself
Evaluative Through The Lens
Strobe
Second Curtain Sync
High Speed Sync
Modes - ETTL (evaluative through the lens)
When the shutter is released the flash fires a test shot and camera assesses the
amount of light reaching it. The flash then fires a corrected amount of light for the
actual photograph. You don’t see two flashes as it happens so quickly.
Just press the shutter button and the camera does it
for you!!
The swivel head makes bouncing flash off the walls easy.
Use the Reflection Panel to give your subjects catchlights in
the eyes.
Use the diffuser to soften the light.
If there is no suitable wall or ceiling to bounce the flash
there are proprietory bounce attatchments available.
Moving objects:
Use LOW power on the flash to freeze
fast action to avoid ghosting around the
edge
Modes – Multi (strobe)
It is possible to make a speedlight strobe and set
how fast it flashes. It might be too limited in power
for many uses.
Here Manuel has used a powerful strobe on each side.
Courtesy: Manuel Cafini
When doing portraits without the benefit of a Modelling
Light, press the Depth of Field Preview button and this
will cause the speedlight to give a burst of strobe so you
can see where the ligt is falling on your subject. Use very
sparingly for the sake of your model. Maybe better to
tape a small LED torch to the top of the flash instead.
Add Radio Remote Triggers and the flash will do everything
away from the camera – even ETTL
I’m showing Yongnuo equipment because that is what I have. I guess they wont mind
me pubicising their kit.
A second speedlight can be controlled
by the first using Slave mode. You
probably have two slave settings- use
S2 as this disables the preflash
(remember in ETTL) and the flash
only fires for the actual picture
capture.
With a more sophisticated trigger you can group your
flashes and control them independently.
Add Gels to give extra colour
to your image
Colouring the backdrop is easier if you start with
grey one rather than white.
If you wish to balance flash with the background set your camera so that it exposes
the background correctly, then set your flash to match, or put it on ETTL
When balancing the flash with the
ambient light the golden rule is that
the shutter regulates the Ambient,
and the aperture regulates the
flash.
Modes – 2nd Curtain Flash
‘Dragging the Shutter’
Sometimes a shutter speed well below the max sync speed
is used to allow some movement ‘ghosting’ to occur. Here
the ghosted cue ball shows movement but it is in front of
the movement not behind it!
Courtesy: Exposure Guide
Courtesy: Exposure Guide
Normally the flash fires when the front curtain (1st curtain) opens
But in this case you want the flash synced with the rear curtain (2nd curtain)
This gives the ghost trail behind the movement, which we
see as natural (reading too many comics I guess).
Modes - High Speed Sync HSS
Joel Grimes
This picture fascinated me - bright sunny day, but dark background – needs detective work!
Lens
Aperture
ISO
Filter
Light modifier
Post production
24 – 70 ml zoom set at 24 ml
f2.8 to put the background out of focus
100
Neutral Density (6 stop) to darken the background in full sunshine
Softbox, 36 x 48 inch set on left hand side
Right hand side stretched to move subject off centre
With this it is possible to calculate the settings,
Exposure based on the Sunny Sixteen Rule, which says if sun is shining and you set aperture
at f16 the shutter speed will be the inverse of the ISO e.g. f16 – ISO 100 – shutter 1/100th
To underexpose the sky by 2 stops = shutter speed now 1/400th.
Open up to f2.8 (5 stops more light) needs faster shutter at 1/12800th (5 stops less light).
But the shutter speed only goes up to 1/8000th!
A 6 x stop neutral density filter (camera sun glasses) brings down shutter speed to 1/200
Now set the flash for f2.8 plus six stops = f22
easy as that!!!!
th
A 6 stop ND Filter is very difficult to see through,
and using narrow depth of field can lead to poor
focus results.
To do the same thing without the ND filter use HSS
Frances
(1/5000th, f1.4, ISO 50, silver brolly)
(The judge gave this picture 6 ½ !! – when
concentrating on your lighting don’t forget the
‘life light’ in your model’s eye!)
Courtesy: Exposure Guide
The shutter achieves faster speeds not by moving quicker but by the 2nd curtain moving
sooner, which means that the sensor is never fully exposed. The flash fires repeatedly like
‘painting the slats on the fence’. This appears as one flash, but the multiple firing creates a
complete image!!
HSS is quite hard work for the flash, which will use up
the batteries and it may get hot. The answer is to raise
your ISO and run the flash on lower output. This will also
help your Recycle Time.
These images are from the same session with Frances taken a couple of minutes apart. It has
now clouded over and to avoid difficult shadows under the eyes caused by all the light coming
from above, we moved into a handy fireplace. In the first picture the flash fired, but the
batteries were struggling, and after 30 seconds recycle time there was so little power it’s
difficult to see the flash at all. The second picture had 50 seconds recycle time, which was
sufficient to light the picture. I think I prefer the first picture anyway!!
HSS Trick 1
I discovered that if you have some speedlights which don’t have HSS mode and one that
does, it is possible to run them all on HSS! Set the non-HSS flash(es) to slave mode
(remember S2 setting disables the preflash) and they will fire with the HSS one, giving you
extra power. This means you can run the set on lower power settings and get better recycle
times, (2 x ½ = 1).
Courtesy: The Slanted Lens
HSS Trick 2
Speedlights are great, but they lack the power of studio lights even if you use multiples as
above. Cheaper /old studio lights will not operate on HSS and they have the lower maximum
sync speed of around 1/160th. However you can put studio lights on to slave mode and then
trigger them using a speedlight on HSS. The dwell time of the studio light (the duration of
the flash) is long enough to light the subject evenly over the high shutter speed. Now you
have studio lights working on HSS.
The Angel above was created in this way.
The studio lights were triggered by a speedlight angled away from the subject and towards
the studio light.
Location – swimming pool
Décor – some plants and plastic rocks
Extras – smoke machines x 3
Lighting – studio lights x 3
Reflectors – silver x 2
Post production – remove seat!