- see also:
- on the net:
- basics of using flash off the camera:
- Quantum wireless-enabled flashes for Nikon/Canon/Olympus/etc:
- Metz flash
- flash photography with Canon EOS cameras:
- flash photography with Olympus digital cameras:
- flash light meters:
- safety of legacy flash units - the issue of high trigger voltages
potentially damaging your camera:
- concert photography when flash is allowed:
- polariser film to put on your flash:
Flash exposure basics:
There are only 3 main ways to modify the flash exposure effect for a given
- the amount of light hitting a subject from a flash decreases by the square
of the distance, THUS if you double the distance, you reduce the light
hitting the subject to a 1/4 which is 2 f stops less light.
- if you bounce a flash off a white wall, you must use the total distance of
flash to wall PLUS wall to subject as your flash to subject distance AND
THEN allow for light loss of about 1 f stop (ie 50% light loss) from
bouncing off the wall.
- similarly, shooting through a white translucent material such as a flash
umbrella will lose perhaps 1 f stop of light depending on material used.
- a flash unit can output a variable amount of light up to its maximum
output which is measured by its Guide Number (GN).
- BUT beware, with modern "zoom" flashes, their stated GN only
applies to maximum zoom, thus if using a wide angle or normal lens, the
broader coverage required will result in a lower GN.
- the Guide Number allows you to determine either:
- the maximal range of the flash to subject for a given aperture and ASA/ISO
- the appropriate aperture to use on full output for a given flash to
subject distance and ASA/ISO.
- thus a GN of 45m at 100ISO means that at maximal output using ASA 100 film
or ISO 100 setting on your digital camera:
- at f/4.5, the correct exposure should occur when the flash to subject
distance is 45/4.5 = 10m
- most built-in flashes on cameras have a GN of about 12m at 100ISO which is
very limiting but still useful.
1. change the aperture (includes putting a filter on your lens such as a ND
2. change the ISO
3. change the flash output (includes putting diffusers over the flash or
bouncing flash off walls, etc)
- changing shutter speed mainly effects the ambient lighting mix, although
at shorter speeds, it may impact on flash output if the duration is shorter
than the flash duration (see below) and there may be some issues with flash
- that changing shutter speed will have NO EFFECT unless you choose a
shutter speed faster than the X-sync of the camera which is about
1/180th sec (ie. avoid using shutter speeds like 1/500th sec with flash
as results will be less predictable)
- You can use this to your great advantage by adjusting the shutter
speed you can determine how light or dark the scene is as lit by ambient
light and not the flash light. If you want to see outdoors on a sunny
day as you would normally expose it and you are using your flash, then
just set shutter speed so that it will expose correctly for sunny day
when using your set ISO and aperture values.
- your effective maximum GN is drastically reduced if you forget that
your polarising filter is on - this cuts exposure by 2-2.5 stops and can
really confuse you!!!
There are 3 main ways to get correct flash exposure:
- camera controls the flash:
- analog TTL - camera has a sensor which detects light bouncing
off the film then tells flash to turn off when it is enough
- digital TTL - camera instructs flash to fire pre-flashes then
determines the correct output for the main flash exposure
- some systems may include AF setting to make this more accurate (eg.
Canon's eTTL II), but these only work if flash is on the camera and
not being bounced, and the lens provides distance information to the
- when in a hurry, this is usually the best way to go
- great for fill-in flash outdoors to reduce shadows in portaits,
etc as camera will meter for ambient light and automatically
determine exposure settings and flash output.
- nb. TTL = Through-The-Lens metering and thus takes into account any
filters used in case you forgot!
- flash has an inbuilt light meter sensor:
- flash sensor must point at subject and user sets an aperture and ASA/ISO
on the flash to match the camera's settings
- works well but being a reflective light meter, can be fooled by
bright/reflective surfaces, dark backgrounds or nearby objects
- don't forget to allow for any filters on the lens.
- great when you do not have TTL functionality or flash is incompatible
- many modern flashes do not have this functionality
- the Canon 580EX II has it but most other Canon flashes do not
including the 580EX
- manual flash:
- user sets a manual flash output level (eg. full, 1/2, 1/4, etc), each
setting will have their own GN value.
- user determines camera aperture & ISO by either:
- trial & error
- calculations using GN, or,
- preferably an incident flash meter placed at the subject and
pointing at the flash
- favorites include the Minolta IV F or VF light meters, or even
a 1degree spot meter if you can't put yourself in the subject's
position and you have to use reflective metering with meter
aimed at subject.
- flash meters can be set to 3 main modes:
- ambient - just measures ambient light levels
- corded flash - connect a PC sync cord from flash to light
meter and press button on meter to trigger flash.
- uncorded flash - flash will automatically detect flash
firing and display exposure BUT may be tricked by digital
flash pre-flashes when using TTL modes.
- for set situations, manual flash can in the end be the least confusing
as it removes flash output variability as a source of error when things
just don't seem to be going right, then you can check for other causes
- filter on the lens you forgot to account for
- camera shutter speed to fast for sync and thus not getting all the
Using your in-built flash on your camera:
So how do we go about changing these settings?
- the built-in flash in most cameras has a maximum output measured by Guide
Number (GN) of 11-13 metres at ISO 100 and can be used for:
- main flash (although results usually won't be too flattering for
- fill-in flash
- as an optical trigger for other flash units (helps if you can power
the built-in flash down)
- to provide catchlights in eyes when the main light won't do this (also
helps if you can power the built-in flash down)
- what this means is that if you are using ISO 100 and f/5.6 then 11/5.6 =
about 2m and so only subjects at 2m will be able to be exposed adequately
when it is on full power. Subjects beyond this distance will be
progressively darker, while subjects closer than this will be lighter.
- My favourite is to go fully manual and check the histogram afterwards
- if I need more light then I manually adjust them (use M exposure mode on
the dial and manual flash mode on the menu). One of the great features with
the Oly's which is not often found elsewhere is that you can manually reduce
the built-in flash output on the menu system. NB. the flash +/- setting is
not functional here as this is only for auto flash.
- if you really want to calculate these yourself rather than use trial and
- the correct aperture to use will be (approx) = GN of manual flash
setting x ISO sensitivity / subject distance in metres.
- here ISO sensitivity is your selected ISO related to ISO 100 so ISO
200 = 1.4, ISO 400 = 2, ISO 800 = 2.8, ISO 1600 = 4
and on the Olympus E330 (think it is same for E500), the GN in metres at
ISO 100 for various manual settings are:
- full = 13, 1/4 = 6, 1/16 = 3, 1/64 = 1.5.
- Next, you can just use the camera's auto exposure modes eg. A or P
but avoid S.
Here you will be responsible for setting the ISO and in A mode also the
aperture, the camera will try to control the flash output for you. You can
use exposure compensation to tell camera to adjust the exposure.
- NB. if the Olympus menu function flash+/- and +/- is set to ON, then
any flash +/- compensation you select in the menu will be ADDED to the
+/- main exposure compensation that you have selected.
- BUT if the subject is too far away for maximum flash output to work at the
settings you have used, then the subject will turn out dark no matter what
exposure compensation you tell the camera to use.
- Now, although the built-in flash is really handy, for best photos, you
should get a 2nd flash that you can use off the camera to give different
lighting effects such as more flattering bounce lighting, etc, but this is
quite a bit more difficult for most to get their heads around. But if you
need more flash output then you may need to resort to this.
- the Olympus E330 and E500 cameras have a menu setting which allows flash
compensation (flash +/-) to be ADDED to the general exposure compensation
- If you have the flash +/- and +/- setting set to ON, then the camera
will ADD the exposure compensations in BOTH the flash +/- setting AND
the main exposure +/- setting.
- eg. if for example, each was set to minus 1 EV then the exposure
will be minus 2 EV as they are added.
- If you have the flash +/- and +/- setting set to OFF, then the camera
will ONLY use the exposure compensations in the flash +/- setting AND
IGNORE the main exposure +/- setting when it determines the auto flash
- The auto flash works even when dial is set to M (manual exposure) as
long as the flash mode is set to a non-manual flash mode (eg. AUTO,
redeye or Slow), but when dial is set to M mode, the main +/- exposure
compensation is not available and thus whatever setting you have the
flash +/- and +/- setting set to, it behaves as if this is set to OFF.
- One advantage of having the flash +/- and +/- setting set to ON is
that you can rapidly change your flash exposure using the +/- button
when using an exposure mode that is not M on the dial.
- Thus say you take you pic in Aperture priority mode (A on the dial)
and flash set to AUTO and the picture turns out too dark, you can check
the histogram and see where the right edge is, then go back to picture
tqking mode and adjust the +/- button (by rotating dial while holding it
down) to a + value (eg. +1 EV) and re-take the photo.
- If the histogram on the second photo has not moved more to the Right,
then you can assume the flash is not powerful enough for your aperture,
ISO settings and subject distance, THUS you need to change these (or
remove that damn polarising filter).
Flash photography technology:
- using electronic flash in your photography involves consideration of the
following main issues:
- amount of light or exposure:
- there are a number of ways to get the desired amount of light from
a flash unit:
- manual calculation:
- this is handy if the subject is very light or dark or
dominated by background that would fool light sensors, but
requires a bit of thinking.
- you need to set the aperture on the camera according to
the flash guide number for your ISO setting divided by the
distance from the flash to subject.
- if you are bouncing the flash then you must use the total
distance of the light path and then adjust your aperture to
open it from the calculated amount by 1-2 stops depending on
the loss of light from the surface used to bounce the light.
- it helps if there is a range of manual output levels you
can select, for instance, older flashes like the Metz CT-1
has only one manual setting, the Metz 45CL-4 has M, M/2, M/4
& M/40, while newer flash guns may have up to 25 output
- distance priority manual flash:
- you set aperture and distance on camera which relays this
info to flash which sets output, great for weddings,
products where metering may be fooled by white or black
- Nikon SB-800
- flash auto sensor:
- you set the camera aperture according to the flash auto
setting & the flash will attempt to deliver the correct
amount of light as it detects in its sensor.
- if subject is too far away, flash will fire its maximum
output but image will be dark and hopefully flash will tell
you there was a problem. In this case you need to either
increase your ISO or open your aperture setting or both.
- TTL flash:
- camera controls light output of flash.
- see below
- too much light:
- check the flash unit's minimum GN because this may be too high
for fill-in flash for subjects closer than 2m with wide
apertures that are desirable for portrait work.
- for example, using a 85mm f/1.4 lens at ISO 400 for
ambient light with subject at 2m and using flash to fill-in
under-exposing by 1EV requires an effective GN at 100 ISO of
about 0.5-1 in metres.
- duration of flash:
- this is mainly important when trying to stop subject movement or
camera shake (see below)
- full output flash is about 1/200th sec on most units, and as you
halve the output, you generally shorten the flash exposure by half.
- relative amounts of light between various flash units used and
- assuming each flash is simultaneously triggered, either by cord,
slave trigger device or manually if long exposure allows this, this
can be achieved in a number of ways:
- NB. existing light contribution to exposure may need
consideration and is usually altered by changing shutter speed
as this does not effect flash contribution unless it becomes
faster than the X-sync of the camera in which case the flash
will not light the whole frame or will not work.
- it is helpful if the flash unit has a modeling light to
visually check likely result, but if this is not available then
either review of a digital image or use Polaroid film is handy
to confirm the result is what you desire.
- manual calculation:
- knowing the GN for each flash, set its distance from
subject to get desired effect, the accuracy of doing this
can be aided by use of an accurate flash light meter, which
requires each flash to be fired separately and its light on
the subject measured either by incident (with meter aimed at
flash unit) or reflected (meter aimed at subject), and then
adjusting flash distance or manual output setting
- Obviously this is cumbersome but may be suitable for
static situations such as studio work.
- flash auto sensor:
- set each flash unit to its auto setting and use the f-stop
setting on the flash to create relative differences in
- flash sensor must be pointed at subject
- wireless-TTL flash: see
- quality of light:
- the small area of the flash results in hard, sharply-defined
shadows which may not be suitable for many subjects.
- the quality of light can be modified by diffusers, filters and by
bouncing the light off surfaces to give a larger effective area and
thus less sharply defined shadows and less specular highlights.
- see flash modifiers.
- shape of the light:
- most flash guns are designed to output a rectangular shape over a
reasonably wide coverage area to allow lens as wide as 28mm to have
adequate light coverage
- older flash units may allow addition of wide angle or telephoto
lens to control the spread of light
- some newer flash guns have a motorised auto "zoom"
function which sets the coverage according to the camera's lens
focal length, which enables output to be conserved and faster
recycling times and higher maximum GN at telephoto.
- eg. Metz MZ series; Olympus FL36/50; Nikon SB-800/600;
- macrophotography and beauty photographers often prefer circular
- Olympus OM ring flash system but unfortunately does not work
in TTL mode on digital cameras.
- Olympus Digital ring flash system
- Alien Bees ABR800
ring flash - an AC-powered studio flash
- in studio settings, it is nice to be able to shape the light
- restrict light to certain parts of frame by use of snoots,
barn-doors, etc, although these are generally not available to
electronic flashguns, but are widely used with the larger
- to create a desirable catchlight shape for the eyes by use of
umbrellas or soft-boxes, etc.
- additional features & issues:
- red-eye reduction:
- if a light source is close to the camera lens axis, then it will
light up a subject's retina resulting in red pupil in the photo.
- this can be minimised by:
- turning the subject away from the camera
- placing the flash as far from the lens axis as possible whilst
still retaining the desired modeling effect
- constricting the subject's pupil to minimise amount of light
being reflected from the retina, this can be achieved by
shooting in bright light with light behind you (but this may
make subject squint) or most camera flashes and some external
flashes can be set to pre-fire a flash to constrict the
- The pre-flash may incorrectly trigger any slave triggered
- this can be repaired by either:
- in-camera red-eye removal (some cameras from late 2004 such as
- in computer red-eye removal - many programs available to help
you edit out the red eyes.
- AF assist illuminator light:
- some flash gun-camera combinations utilise the flash to provide
extra light (usually via an infrared beam) to allow faster auto
focus in dim light situations
- need to ensure compatibility, eg. wide AF illuminator needed
for Nikon D2H's 11 AF sensors.
- most modern Metz flashes are capable
- for use off the camera, some flash manufacturers have an
on-camera TTL AF module to provide the illuminator beam whilst
connecting to the flash for TTL flash, eg. Nikon's SC-29
Off-Camera TTL cord.
- some cameras have the AF assist light built-in to the camera eg.
Olympus C8080, Nikon D70
- slow sync / rear curtain sync modes:
- usually a flash is set off at the start of the exposure, but this
means for longer exposures of moving subjects, the subject is frozen
at the start position and then there is motion blurred for
- rear curtain sync (2nd curtain) fires the flash at the end of the
exposure and thus allows subject to appear sharp from the flash at
the end of the blurred motion trail which is more natural.
- slow sync allows one to set long exposure times (otherwise many
cameras will default to 1/60-1/180thsec shutter speed when using
flash) and can usually be combined with either front curtain
or rear curtain sync.
- high FP sync modes:
- while most digital cameras have a X-sync of 1/180th (Nikon D70 has
1/500th!), some cameras have a high FP sync mode (pioneered by
Olympus) that allows flash sync at very fast shutter speeds which
may be useful for fill-in flash in sunlight:
- Olympus E-1 camera with Olympus FP50 flash: 1/4000th sec (n/a
on Metz adapter yet)
- Nikon D2H, D2X & ?D70 with Nikon SB-800/SB-600/Metz MZ
- Canon e-TTL capable combos eg. Metz MZ series:
primary drawback is that pulsing the light causes a reduction in
overall light output and thus range. When you have FP mode engaged
you typically get about a third less range than you would if you
were shooting with normal flash.
- rapid sequence capability:
- this determines the shortest interval between successive photos
and is dependent upon:
- flash gun recycling capabilities for given power supply &
state of batteries
- many flash guns have a recycling time of 5 sec after a
full discharge on fully charged batteries which deteriorates
as the battery charge falls.
- some flash guns have faster recycle times
- rapid sequence flash gun mode availability:
- eg. Metz
CL-4 has a "winder" mode that is a
manual mode at 1/40th output and allows 2fps shooting
- how much residual charge is left after each flash, the more
the shorter the recycle time
- stroboscopic flash:
- this is rapid sequence flash outputs in the one exposure to allow
stroboscopic action photos
- only some flash gun-camera combinations have this capability:
54MZ-4, 70MZ-5; Olympus FL-50 (with E-1 camera);
EF 500 DG Super SA-N: The multi pulse flash features enable
reduced power setting from 1/4 to 1/128 in 6 steps and the pulse
frequency of the flash can be set from 1Hz to 199Hz.
- Speedlite 420EZ: 1-5 Hz.
Speedlite 430EZ: 1-10 Hz.
Speedlite 540EZ: 1-100 Hz.
Speedlite 550EX: 1-199 Hz.
- modeling light:
- some flashes (eg. high end Metz) allow you to fire the flash for a
few seconds so you can see the effect of the light on the subject,
but this consumes considerable battery power.
Using flash to "stop" the action:
TTL flash systems
- this requires dedicated connections between flash & the camera, unless
the flash is in-built into the camera
- 1st developed by Olympus on its OM-2 camera of 1976, with film SLR
cameras, light passed through the lens and reflected by the film is
continually measured by the flash sensor during exposure until the
correct exposure has been achieved.
- TTL for digital cameras works a little differently as you cannot use light
reflected of the "film" or sensor anymore so alternative metering
is used via a pre-flash measurement of a lower power flash burst prior to
the main flash.
- current best, least complex TTL system appears to be Nikon's i-TTL.
- accurate TTL fill-in flash for daylight photos is best on Nikon's i-TTL or
Canon's ETTL II. Olympus does not seem to support it yet.
- standard TTL flash:
- user sets ISO, aperture or shutter speed with option to set exposure
compensation for ambient light levels separate to flash exposure
compensation, and camera sets TTL flash output to give even illumination
but not fill-in.
- camera detects when sufficient light has reached camera after shutter
has opened & then turns off the flash output.
- to achieve fill in, user may be able to set flash exposure to minus 1
stop for example so that ambient light is exposed properly while flash
is under-exposed 1 stop but enough to fill in the shadows.
- Olympus OM TTL-auto:
- no pre-flash; analog system for OM film cameras;
- Olympus T20, T32 flash
SCA 300 with SCA 321 adapter
- Canon A-TTL:
- Canon's 1st attempt (with T90 film & EOS cameras) but very
poor and no longer used as it really only determined if subject
was out of range, the pre-flash didn't actually meter the exposure.
- fires pre-flash when half press shutter release, unfortunately if
flash is tilted or swiveled, the main flash fires as the pre-flash
which is very distracting
- auto-aperture TTL:
- camera determines best aperture as well as TTL flash metering
- eg. Nikon D70 + Nikon SB-800/600 + CPU lens
- balanced TTL fill-in flash:
- camera attempts to set flash output to fill in the shadows but not
overpowering the ambient light, most use pre-flashes to determine
exposures needed but these have problems:
- may cause subject to blink & be caught in mid-blink
- may falsely trigger normal optical flash slave trigger units
- can confuse handheld flash light meters
- Nikon matrix-balanced TTL fill-flash:
- camera adjusts ambient light exposure via its matrix sensor and
adjusts TTL flash so that flash is not over-powering for the ambient
light and provides fill in of the shadow areas.
- Nikon allows either spot or CW metering.
- Nikon 3D Multi-Sensor Balanced Fill-Flash (D-TTL):
- DX camera analyses likely subject distance from its AF sensors and
using its 3D matrix metering system via 18 preflash pulses,
determines the correct flash output to create a natural balance
between main subject and ambient background lighting.
- DX master flash must be on camera for D-TTL to work, in this case
camera should be set for spot metered TTL as camera will not know
where flash is in relation to camera-subject.
- with type G or D CPU lens: full 3D functionality
- other CPU lenses: distance information not included thus not 3D
- non-CPU lenses or in spot-metering: standard TTL only
- Nikon D70 / D100/ D1 series with SB-50DX, SB-80DX, SB-600, SB-800,
500 DG Super SA-N
- Nikon i-TTL (see below)
- an evolution of D-TTL that incorporates more accurate systems
for pre-flash. The pre-flash fired is much stronger and of much
shorter duration than D-TTL to achieve greater accuracy
using the flash sensor. Forms part of Nikon's Creative Lighting
- Canon evaluative TTL (e-TTL):
- introduced 1995 with Canon Elan II/50 camera
- fires a low-power preflash of known brightness from the main bulb
to determine correct flash exposure. It measures the reflectance of
the scene with the preflash just before the shutter opens using
usual light metering, then calculates proper flash output to achieve
a midtoned subject, based on that data.
is also generally superior to TTL and A-TTL when it comes to fill
flash. The E-TTL algorithms are usually better at applying subtle
and natural fill flash light to daylight photographs. E-TTL exposure
is also linked to the current AF focus point, which in theory
results in finer-grained exposure biasing than most multiple-zone
TTL flash sensor systems.
abstractly, E-TTL is a very automated system and isn’t well
documented for the user. For instance, Canon have never published
details on the E-TTL auto fill reduction algorithm. It takes a bit
of experimenting to figure out how the system is likely to respond.
And there’s relatively little user selection or choice in
operation modes. Most flash units don’t, for instance, let you
manually choose TTL, A-TTL or E-TTL flash metering at will.
current Canon digital cameras with hotshoes - both the
interchangeable-lens SLR cameras and the point and shoot digital
cameras - support E-TTL (or both E-TTL and E-TTL II) and do not
support either TTL or A-TTL. Even Canon digital cameras with
internal popup flashes are E-TTL only. This means that only
Canon EX flash units or third-party flash units with E-TTL support
can be used with Canon’s current lineup of digital cameras. Older
E and EZ flash units will not work correctly - no automatic
through the lens metering is possible. You can get manual-capable EZ
flash units like the 540EZ to fire in manual flash mode but this
requires external flash metering.
E-TTL has been a particular problem for digital EOS users. Many
users report serious problems with wildly varying exposure when
using an E-TTL flash unit with their Canon DSLRs. The main problem
appears to stem from the way in which E-TTL on these bodies biases
flash exposure heavily to the focus point. For this reason some
digital EOS users have given up on E-TTL and gone back to the
old-style autoflash units. Others routinely set their lens to manual
focus once focus has been achieved, since the camera uses a centre-weighted
average metering pattern for flash metering when in manual focus.
The EOS 10D has revised E-TTL algorithms which rely on centre-weighted
average metering for E-TTL flash, even if the lens is set to
are times when TTL metering may be more desirable than E-TTL. A
common example is a studio setting where analogue optical
slave units can be fooled by the E-TTL preflash. The 550EX,
MR-14EX and MT-24EX let you disable E-TTL via a custom function, but
they’re the only Canon Speedlites with this ability. All other EX
flash units (220EX, 380EX, 420EX) will always operate in E-TTL mode
when mounted to an E-TTL-capable camera, even if the camera is also
capable of supporting TTL and even though they’ll work in TTL mode
just fine on a type B camera."
- see flash
photography with Canon EOS
- complex to use with multiple flashes
- cameras: all type A EOS cameras;
- flash guns:
- all EX series Canon speedlights; Sigma
EF 500 DG Super SA-N;
- offers features that Canon do not - such as flash units
with memory settings, built-in secondary reflectors, clip-on
coloured filters and audio warning signals.
- later Metz models (54MZ 3/4/4i or 45CL4dig or 76MZ5 or
later) + require SCA 3103 M3
- BUT e-TTL will not work with a Metz gun if either:
- filters attached to flash head of Metz 54MZ
- 2nd reflector used (unless you have the 45CL4 digital,
76MZ-5 or later)
- wireless remote TTL
- with e-TTL, Canon also incorporated technology pioneered by
Olympus to provide synch at fast shutter speeds:
- focal plane (FP) or high-speed sync mode which allows
fast shutter speeds by having the flash pulse at 50Hz to
simulate continuous light sources, but the compromise is much
reduced GN (more than a 1/3rd loss).
- Canon e-TTL II (2004 see below)
with the EOS 1D Mark II then 20D/350D to remedy the problems of the
- E-TTL II does not require any changes to either the flash units or
lenses used with an E-TTL II camera - the changes are all basically
internal to the camera body, hence an e-TTL compatible flash should
be compatible with e-TTL II.
- the biggest benefit of E-TTL II is that flash exposure is no longer
linked to the active focus point.
- it analyzes all metering zones before and after the
preflash for improved flash metering:
the presence of highly reflective objects and excludes them from
- the 1D Mark II has two main modes:
- C.Fn 14-0 on a Mark II allows E-TTL II flash metering to
be subject-based, so it can use anywhere from 1 to 17
metering segments depending on the camera's analysis of the
pre-flash information. This is not a spot meter reading,
unless the camera determines that the subject is so small
that it occupies only one of the 17 metering segments. Most
subjects will cover a larger area than that. =>
- C.Fn 14-1 on a Mark II applies the E-TTL II flash metering
algorithm equally to all 17 metering segments within the
Area AF ellipse => averaged metering
- NB. the Mark II never falls back to e-TTL I metering.
addition it may use distance information if available
data is not used by E-TTL II if either:
- the distance information adds only marginal change to the
exposure so will not be missed by most people.
guns: all Canon EX series - see above under e-TTL.
- cameras which support E-TTL II:
1D mark II, EOS 30V/33V/7S/Elan 7N/Elan 7EN, EOS 20D/20Da, EOS
350D/Rebel X Digital/Kiss N Digital, EOS 400D/Rebel XTi
Digital/Kiss X Digital, 1D mark IIN, 1Ds mark II, 1D/1Ds mark III,
- Olympus digital TTL-auto:
- not compatible with film-based OM TTL auto
- uses pre-flash in either spot-metered, CW or iESP exposure modes
- does not appear to use AF-measured mode
flashes require SCA 3202 adapter (M3 for the E-1, and M4 version for E-300)
AND a digital-enabled Metz flash such as Metz 54MZ4i, 45CL4 digital,
- Minolta P-TTL - Sigma
EF 500 DG Super SA-N flash
- Sigma S-TTL - Sigma
EF 500 DG Super SA-N flash
- Minolta ADI:
- used in their 7D DSLR
- calculates distance to subject in the flash calculation but flash
must be on camera facing at subject
- wireless TTL flash:
- i-TTL balanced fill-in flash:
- arguably the best, and simplest TTL system available, is an
advanced form of D-TTL
- introduced Jan 2004 with the Nikon SB-800 flash and Nikon D2H
camera, can b used on D70, D2X, and some functionality on Coolpix
8800 & 8400.
- allows a master i-TTL flash to wirelessly control flash output of
up to 3 other i-TTL flash groups (each group may have more than one
flash), by setting exposure compensation for each group. A pre-flash
is used to set the light outputs of each group & this can be
locked ("FV lock") so that one can zoom out and still get
same exposure on the subject.
- 4 wireless frequency channels to minimise conflict with other
- modeling lights can be remotely turned on/off
- i-TTL compatible flash units:
- Nikon SB-800; SB-600; Sigma
EF 500 DG Super SA-N;
54MZ-4i with SCA 3402 M3 adapter
- Quantum QTTL flash
- Nikon D-TTL:
- precursor to i-TTL but problematic in wireless usage
- The main D-TTL pre-flash contains 18 discrete pulses arranged in a
wireless flash tries to match what the camera is doing with the main
flash. It starts firing with the first pulse and stops with the
last. Then starts up again when the main flash occurs, as long as
its recycle time can cope
guns: SB-28DX / SB-50DX / SB-80DX / SB-800 / SB-600; Sigma EF 500 DG
Nikon D1 series; Kodak DCS Pro 14n;
- Nikon's older wireless TTL:
- e-TTL II:
- Canon 20D, 350D cameras with EX flash guns (esp. 550/580EX; 420EX
only as slave; MR14/MT24 only as master).
- allows slave control of up to 3 groups, supporting flash output
ratio control, flash exposure bracketing (FEB), & modeling flash
with flash output ratio.
- e-TTL II compatible flash units:
- e-TTL II wireless Speedlite transmitter ST-E2:
- IR line of sight transmitter
- Olympus wireless TTL:
- Olympus finally stepped up to the plate and introduced wireless
TTL in 2007 but you will need the latest cameras (eg. Olympus E3/
and the R versions of the Olympus FL flashes.
- 3rd party flashes do not yet support Olympus remote TTL but
hopefully will d so late in 2008.
- Sony wireless TTL:
- Metz sell a digital
slave trigger SCA-3083 which allows light-triggered wireless TTL
control of other compatible Metz units such as the 54MZ-3, 70MZ-5,
70MZ-4. This is not compatible with Canon's wireless system.
- Quantum QTTL flash
- modular system supports Nikon's i-TTL, Canon's e-TTL II
- separate radio transmitters & receivers to control wireless
- Radio Poppers:
- wireless (not IR) transmitters and receivers for flash units which
retain TTL functionality for i-TTL (ie. Nikon) and e-TTL (ie.
- each unit attaches via velcro to your flash and your IR wireless
transmitter and converts IR signals to radio signals and vice versa,
thus you still will need a IR transmitter from your camera as well (eg.
Canon ST-E2 or Nikon SU-800).
- not weatherproof though.
- no longer stuck with IR line of sight restrictions as with
Powering your flash:
- see also:
- most flashes are powered by 4-6 1.5V AA batteries which usually give a
5sec recycle time
- these can usually be replaced with cheap, rechargeable NiMH batteries but
these have problems:
- unpredictable, shorter life than NiCd, a single cell failing will stop
the whole pack
- ideally, should remain as sets and not mixed with different brands,
age of battery, etc.
- some manufacturers (eg. Metz) have their own AA rechargeable battery packs
- alternatively, you can purchase separate generic lead acid power packs
which reduce recycle time to 50%, and provide more shots:
- Al Jacob's
- Al doesn't like AA batteries, NiMH or Li ion batteries.
- He has made a lead acid black box for wedding photographers, etc
using Canon/Nikon/Vivitar flashes;
- recycle 3sec, 800-1000 shots; 90 days at 90% charge off a charger;
- designed to be on a charger all the time when not in use.
- two outputs; 6.4V peak; 2.7lbs;
- eg. power a Canon 580EXII via a Quantum MB-2 cable which leaves
the battery door open for the cable.
- for 9V flashes (eg. Metz 45 series);
- lead acid battery with fuel gauge; 2 output jacks for separate
- holds it charge for months
- 300 full shots per charge, recycle time 3-5sec
- standard recharge 12hrs; fast charger 2hrs;
- with the advent of AA NiMH batteries, these heavy packs are losing
favour but are safer for your flash.
- high voltage packs via AC port (usually need AA's in to power LCD, etc
- most manufacturers also have their own high voltage power packs to
give faster recycle times:
- 3rd party accelerated packs via AC port:
- if you want fastest performance and prepared to live dangerously
in terms of strobe life, try an accelerated pack which supplies
power via the strobe's AC port:
- risk of damage to strobe as strobe electronics are being pushed
beyond their design and may void warranty - see Al
- Quantum Turbo SC Slim battery pack:
- use AC port of most recent Canon, Nikon, Metz (incl. 45
series) flashes, Olympus FL-50
- high voltage NiMH pack; 1.5Hr charge; 400 shoe mount flashes
per charge; fuel gauge; recycle time to less than 2secs;
- warnings when using with Canon 580EXII:
- Be careful how you plug the cord into the flash - if it
isn't lined up correctly you can push the flash socket in
and it's off to Canon for repair.
- plus see special note here
- low voltage NiMH power packs via strobe's battery terminal:
- with 16 NiMH AAs in the QUICK-RECYCLE Module, the BVS PULSAR is
about 1.6X as fast (1/3 to 1/2 LESS recycle time) as the Canon CP-E4
with 12 NiMH AAs (8 + 4 in the flash helping to drive external
- "The QUICK-RECYCLE module in the BVS PULSAR uses two
proprietary techniques to accelerate current flow beyond what is
possible with a large high resistance HV battery. Plus it does this
through the flash battery port, so the flash internals are removed
as a limiting factor. This is not the case using HV port which is
slowed by normal AA power flow to the flash."
- "it compensates for the lower voltage of NiMH batteries,
pushing the pack voltage slightly higher than a lithium AA battery.