Last week we watched this video explaining the difference between TTL, ETTL and ETTL II which is very helpful in understanding how all versions of TTL flash work and the differences between them.
To begin we worked with the Canon 580EX-II in ETTL mode, mounted on the hot shoe of the camera.
We first shot in P or Program mode. In Program mode the camera decides the aperture and shutter speed for you and with ETTL mode the speedlight and camera communicate with each other to choose a power setting for the flash.
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| ISO 1600, f4, 1/60 second; Camera in P / Program shooting mode Canon 580 EX-II on hot shoe in ETTL mode |
The result is a decent exposure for the subject but still a little underexposed and the background is quite dark. If we wanted to make adjustments to the overall exposure in this setting we could use exposure compensation (adjusts aperture, shutter or ISO to let more light into the camera) or flash compensation (set on speedlight unit, will use higher power on flash), but more on that later.
Next we next tried Av and Tv settings. These are both semi-automatic camera settings that also allow the use of exposure compensation, but in addition will take ambient light into consideration.
First Tv, in this shooting mode you choose the shutter speed but the camera chooses the aperture. In this case since we were shooting with the flash in ETTL the flash and camera are still deciding on the power setting for the flash.
With Tv setting we chose a long shutter speed (2 seconds) to let in more ambient light.
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| ISO 1600, f8, 2 seconds; Camera in Tv shooting mode Canon 580 EX-II on hot shoe in ETTL mode |
Then we shot in Av mode. Av is the counterpart mode to Tv - now we choose the aperture and the camera chooses the shutter (based on information from the light meter and ETTL flash).
With Av selected we chose f4 because we knew it was dark in the room without much ambient light and the camera chose a shutter speed of 1/2 second so we see more ambient light and a bit of movement in this one.
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| ISO 1600, f4, 1/2 second; Camera in Av shooting mode Canon 580 EX-II on hot shoe in ETTL mode |
Next we moved on to using the built-in flash. The Canon 70D has a small, built-in flash unit that can also operate in ETTL or Manual mode. Today we worked with it in ETTL mode.
First we shot with the built-in flash in P mode.
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| ISO 1600, f4, 1/60 second; Camera in P mode Built in flash fired in ETTL |
Then we experimented with exposure compensation and flash compensation.
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| ISO 1600, f4, 1/60 second; Camera in P mode, Exposure Compensation +1 Built in flash fired in ETTL |
Unfortunately when we were shooting in class this didn't have quite the effect we wanted, which was that with exposure compensation +1 the subject and the background should both appear slightly brighter. My guess as to why this did not work so well was because the camera would use aperture for this (hence making both subject lit with flash and any background/ambient light brighter) BUT we were at the limit of our aperture which was as wide as it could go for this focal length so both images appear the same.
So we moved on to flash compensation.
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| ISO 1600, f4, 1/60 second; Camera in P mode Built in flash in ETTL with flash compensation |
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| ISO 1600, f4, 1/60 second; Camera in P mode Built in flash in ETTL with flash compensation +2 |
As you can see, with flash compensation the subject becomes brighter because the flash power is increasing. We do see some spill onto the background but if the subject were further from the background we'd see even less of a change of brightness on the background.
Next we tried using the built-in flash as a fill light.
Setup: Jaclyn is silhouetted by light from outside the studio.
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| ISO 1600, f4, 1/60 second, camera in Manual mode No flash |
Problem: we see no detail in Jaclyn's face.
Solution: add built-in flash as fill
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| ISO 1600, f4, 1/60 second, camera in M Built-in flash fired in ETTL mode |
Now we see the detail in Jaclyn's face thanks to fill flash.
But now we have a new problem: mixed light. (I.e. the color temperature of the light outside the studio is different than the light coming from the built in flash.)
Solution: add a gel to the flash to make it the same color as light from the classroom beyond the studio.
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| ISO 1600, f4, 1/60 sec; camera in M Built-in flash fired in ETTL Orange gel added to built-in flash White balance set to daylight |
Now both lights are the same color but we need to make sure that the camera is balanced for that color.
Solution: Change white balance setting to tungsten (adjusts for lighting with orange/yellow color cast)
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| ISO 1600, f4, 1/60 sec; Camera in M Built-in flash fired in ETTL mode Orange gel on built-in flash White balance set to tungsten |
Here we have the final result with Jaclyn lit in equal proportion to the background.
We can also control the lighting ratio of Jaclyn to the background by adjusting the flash compensation which will adjust the flash power.
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| ISO 1600, f4, 1/60 sec; camera in M Built-in flash fired in ETTL with flash compensation in -1 Orange gel over built-in flash White balance set to tungsten |
In this last one we see Jaclyn is slightly darker but the background is the same brightness. That's because only the power of the flash has changed, which will only effect the lighting on the subject in this case. If we wanted to make Jaclyn brighter we could also increase the flash compensation.
Then we experimented with what I like to call "Party Mode." Many digital cameras have different modes or scenes which are like presets that will create a certain effect. If I could design one for a camera it would be called "Party Mode" and the settings would be: slow shutter speed, built-in flash on and possibly high ISO and shooting in black and white. Note: if shooting in RAW your image will still appear on your computer in color, you will have to convert in post-production (if shooting in JPG images shot in black and white will appear in black and white).
Here is one result that uses all four of the above mentioned settings:
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| ISO 1600, f4, 1/2 second Built-in flash fired Converted to black and white in post |
As we can see the appearance of movement caused by the slow shutter gives the effect of a fun, festive mood, but the flash adds a little bit of sharpness to the image so we see some details of people and faces.
One caveat with working with this method is that often background/ambient light at parties can often be a different color, usually an orangey-yellow color caused by tungsten light.
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| ISO 1600, f4, 1/60 second Built-in flash fired |
This orange color cast doesn't bother everyone but if it does there are a couple ways to deal with it. One cheat is using the method I have outlined above - shoot in black and white (or turn it black and white in post production) so you avoid the problem altogether. Another approach is to put an orange corrective filter gel on the flash to make it match the background/ambient light.
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| ISO 1600, f4, 1/60 sec Built-in flash fired with orange corrective gel White balance set to tungsten |
This gives a more natural look.
Or you can take it in the opposite direction; for an additional fun kick we also tried adding a purple gel to the scene instead of the corrective orange.
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| ISO 1600, f4, 1/60 Built-in flash fired with purple gel White balance set to daylight |
Next we experimented with 1st (Front) and 2nd (Rear) curtain sync. When the camera's shutter opens there are actually two parts or curtains that raise and lower to let light into the camera. As we discussed in a previous class that is why sync speed is important when shooting with flash otherwise we will see the effect of part of the shutter blocking light from part of the photo.
The first (or front) curtain opens from bottom to top to let light in and then the second curtain comes in from bottom to top after it to stop light from entering the camera. For a visual of how this works, check out this youtube video and skip to around 1:38 to see the inside of the camera and the two parts of the shutter move up and down.
So when does the flash fire?
In the above illustration we see the flash occurring just as the shutter is fully open. This is called 1st or front curtain sync.
The problem with first curtain sync is that the direction of motion looks "backwards" because the flash fires first and then more light collects on the sensor while the shutter remains open so we see a motion smear in front of the moving object rather than behind, which causes the moving object to appear as though it is moving in the opposite direction.
Take this image we created in the studio in which Reilly is throwing a football to Cody. Even though Reilly threw the ball and Cody was the one to catch it this image makes it appear as though Cody was throwing it to Reilly.
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| ISO 400, f22, 1 second Built-in flash fired 1st curtain sync |
We then changed the flash setting to 2nd curtain sync and then the ball appeared to be moving in the proper direction.
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| ISO 400, f22, 1 second Built-in flash fired 2nd curtain sync |
Though faint we can see a light green streak behind the ball which more accurately represents that Reilly threw it to Cody.
Lastly we experimented with bounce flash. Bouncing flash can be a great technique to use when you are forced to shoot with the flash on the camera. By bouncing the light off a ceiling or wall you can create a bigger light source which gives a more diffused look.
For this exercise we once again turned to our speedlight in ETTL mode and shot with the camera in P.
Here is an image shot with the flash pointing at the subject for comparison:
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| ISO 800, f4, 1/60 second; camera in P Canon 580 EX-II in ETTL mode, mounted in hot shoe, pointing a subject |
In this image you can see the slight vignetting (darkening at corners) of the image. If you are shooting this wide you can use the wide angle diffusion panel to cause the light to spread out even further.
The wide angle panel is built-in to the Canon 580EX-II and many other flash units. It looks like this and can be pulled out and over the flash to spread out the light.
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| ISO 800, f4, 1/60 second; camera in P Canon 580 EX-II in ETTL mode, mounted in hot shoe With wide angle panel |
Then, still using ETTL flash in P mode we bounced the flash from the ceiling
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| ISO 800, f4, 1/60 sec; camera in P Canon 580 EX-II in ETTL mode, mounted in hot shoe Pointed at ceiling to create bounce diffusion and change direction of light |
You can see this has a much more flattering look because it spreads out/diffuses the light (think of bouncing a flashlight from the ceiling in a dark room) and also we see it coming from a different direction - from above rather than that frontal light which creates the flat mug-shot look.
We can also bounce the light off the wall which is also has a better look than straight-on camera flash because it is diffused and not coming from the front, but it will also create uneven light on the face and a quick fall-off of light to one side of the subject.
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| ISO 800, f4, 1/60 sec; camera in P Canon 580 EX-II in ETTL, mounted in hot shoe Bounce-flash pointed at wall |
A reflector can be added to the opposite side of the subject to fill in the light a bit on the shadowed side.
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| ISO 800, f4, 1/60 sec, camera in P Canon 580 EX-II in ETTL, mounted in hot shoe Bounce flash pointed at wall Silver reflector to subject's right to fill in shadows |
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| Production stills by Tiancong "Jacob" Huang |
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