Flash photography help


Status
Not open for further replies.

mfbatzap

New Member
Jan 24, 2007
363
0
0
Tampines
#1
I was asked to take pictures at a convocation ceremony lately and I decided to rent flash equipments along with some lenses (since I was only using the Canon kit lens). That was my first time doing flash photography and the I can say 60-70% of the pictures turned out right (exposure levels were acceptable).

Those which turn out bad were either overexposed, underexposed or faced weird lighting problems (especially vertical body group shots where the one nearest to the flash is exposed correctly while the one at the farthest end turned out darker). I was using a 580EX with the inbuilt bounce card.

I have a few questions..

1. What's the difference between flash exposure (on the flash) and flash exposure option in the camera? I tried reading on it but got quite confused.

2. How come there are people who were taking photos with me using a hot shoe flash didn't need to change their exposure settings? I kept changing mine because of overexposed/underexposed problems when shooting location changes.

3. Bounce card or omnibounce? Saw quite a number of photographers that day using omnibounce.

4. What mode should I use for indoor shots with flash? I kept using manual mode with shutter speed of about 80-120 and constant AP of f5.6. Used ISO 200 for the indoor shots. When I metered the ambient lighting, the shutter speed was metered to be about 20-30. How to gauge what shutter speed should I use?

5. Lastly, I changed my white balance to flash (even for outdoors). Is this a correct WB or should I just leave it to AWB?

Hope you guys can help a noob like me. hurhur.. I was using a 350D with a rented 24-105mm f4L.
 

westwest2

New Member
Jun 6, 2007
535
0
0
#2
I was asked to take pictures at a convocation ceremony lately and I decided to rent flash equipments along with some lenses (since I was only using the Canon kit lens). That was my first time doing flash photography and the I can say 60-70% of the pictures turned out right (exposure levels were acceptable).

Those which turn out bad were either overexposed, underexposed or faced weird lighting problems (especially vertical body group shots where the one nearest to the flash is exposed correctly while the one at the farthest end turned out darker). I was using a 580EX with the inbuilt bounce card.

I have a few questions..

1. What's the difference between flash exposure (on the flash) and flash exposure option in the camera? I tried reading on it but got quite confused.

2. How come there are people who were taking photos with me using a hot shoe flash didn't need to change their exposure settings? I kept changing mine because of overexposed/underexposed problems when shooting location changes.

3. Bounce card or omnibounce? Saw quite a number of photographers that day using omnibounce.

4. What mode should I use for indoor shots with flash? I kept using manual mode with shutter speed of about 80-120 and constant AP of f5.6. Used ISO 200 for the indoor shots. When I metered the ambient lighting, the shutter speed was metered to be about 20-30. How to gauge what shutter speed should I use?

5. Lastly, I changed my white balance to flash (even for outdoors). Is this a correct WB or should I just leave it to AWB?

Hope you guys can help a noob like me. hurhur.. I was using a 350D with a rented 24-105mm f4L.

1. Cause one is for your inbuilt flash and the other for your external flash

2. You sure they nv change? and what mode did they use...and what did you used?

3. Its preferences

4. Is your location so dim?

5. did you take a shot to see which WB is correct? you did not mentioned what lighting is on that day...cannot expect us to guess ya...best to shoot raw...
 

cantaresg

New Member
Feb 23, 2007
765
0
0
Woodlands
#3
In using flash, the light fall-off observes the inverse-square law. The subject nearest to the flash receives the maximum flash output but the subject furthest may receive 1 stop less light compared to the nearest subject (details require more calculations).

1. If I'm not wrong, the flash compensation on the flash overwrites the reading on the camera.
2. Are you using manual mode? Other photographers probably used Av mode, or perhaps they changed their exposure settings without you noticing it, since they never took their eyes off the viewfinder.
3.It depends on what you want to achieve. I had heard that omnibounce results in a harsher lighting as compared to a bounce flash. I have not tried it though I have an omnibounce.
4. For a beginner, perhaps you should just leave it to evaluative metering, and compensate for the exposure as necessary. When you are used to the basic controls, do read up more on the different types of metering.
http://en.wikipedia.org/wiki/Metering_mode
5.I used raw and AWB. If the colour is wrong, change it on a computer.
 

grantyale

Senior Member
Oct 4, 2004
1,798
0
36
Bedok
#4
0. Those closer to the flash are naturally brighter as the light intensity decreases propotionally with the square of the distance. The flash exposure metering may tend to protect subjects from washing-out thus the person further away is underexposed so that the one closer to you is exposed correctly. This is less pronounced with bounce flash as the relative difference in distance is smaller - try tilting the flash head towards the far end of the group a bit.

1. They do the same thing, but if both are set to a nonzero value, the setting on the flash unit is used (flash overrides body).

2. There's some difference in the camera's flash metering. Some may be better than others. Or it's simply that the other person didn't chimp at the screen and didn't bother to change FEC - or he's shooting with manual flash control in a bounced setting.

3. Bounce card is fine especially in a larger room. Omnibounce sends more light to the sides and the back - if you have white walls nearby, it will results in a softer lighting - otherwise it's mostly a waste of the flash power.

4. Depends on how much ambient light you want in the exposure. For better balance - If the scene and subjects are relatively still and you have a good support, you can lower the shutter speed for more ambient exposure; alternatively you can raise the ISO setting to 800 and keep the shutter speed reasonably high. However, if you're bouncing off the ceiling in a small room, you can kill ambient light if you like without getting dark backgrounds.

5. Depends on 4 - how is the flash and ambient balanced. The color temperature of Indoor lighting is seldom close to daylight - while light from flash is. If the ambient light is pretty much killed - underexposed by about 2 stops - you can use flash WB for accurate color reproduction. Otherwise, if the ambient and flash is mixed in similar amounts, one may use auto WB as flash WB may be overly yellow/green depending on the ambient lighting. It is generally not advisable to use flash WB outdoors as the flash only acts as a fill most of the time, assuming daytime. The photos may turn out a bit bluish if the sky isn't clear.
 

mfbatzap

New Member
Jan 24, 2007
363
0
0
Tampines
#5
4. Is your location so dim?
Yes, it was quite dim. And outside was kinda bright, hence I needed the flash to fill in the shadows.

5. did you take a shot to see which WB is correct? you did not mentioned what lighting is on that day...cannot expect us to guess ya...best to shoot raw...
it was those kinda yellow/orange kinda lamp lighting. I shot the pics in raw, but how do I go about changing the WB?

Thanks for the replies! Really appreciate them =)
 

mfbatzap

New Member
Jan 24, 2007
363
0
0
Tampines
#6
In using flash, the light fall-off observes the inverse-square law. The subject nearest to the flash receives the maximum flash output but the subject furthest may receive 1 stop less light compared to the nearest subject (details require more calculations).

1. If I'm not wrong, the flash compensation on the flash overwrites the reading on the camera.
2. Are you using manual mode? Other photographers probably used Av mode, or perhaps they changed their exposure settings without you noticing it, since they never took their eyes off the viewfinder.
3.It depends on what you want to achieve. I had heard that omnibounce results in a harsher lighting as compared to a bounce flash. I have not tried it though I have an omnibounce.
4. For a beginner, perhaps you should just leave it to evaluative metering, and compensate for the exposure as necessary. When you are used to the basic controls, do read up more on the different types of metering.
http://en.wikipedia.org/wiki/Metering_mode
5.I used raw and AWB. If the colour is wrong, change it on a computer.
Yes I was using manual mode. When I use AP priority, my shutter speed goes very slow and the pictures will turn out super overexposed. Any ideas why? haha.. I was hoping to use something more "auto" that day. Almost wanted to use P-mode.
 

cantaresg

New Member
Feb 23, 2007
765
0
0
Woodlands
#7
What was the metering mode you used that day? You might have used the partial metering mode, and if you aimed at the convocation gown, the in-built light meter may assume that the scene is too dark and opt for a slower shutter speed. That will cause the scene to be over-exposed.
 

Nov 6, 2006
54
0
6
Sembawang
#8
Well, I am not expert.. but my 2 cents..

I have tried using AV Mode but I find the picture is more shakier if the object is moving. Later I switched to Programme Mode (P) {I know it is a layman mode, but results are much better}.

Yes, Centre weighted average metering is good if you are taking a group photo.

Also, use E-TTL mode in Flash. (this is a crucial)

Take it in RAW, you can correct the exposure later on if you desire changing.
 

cantaresg

New Member
Feb 23, 2007
765
0
0
Woodlands
#9
Actually the image is not shakier. When you use the Av mode, you need to watch your shutter speed. As a rule of thumb, if you use a shutter speed slower than 1/X, where X is your focal length, the picture may blur due to handshake. For eg, if you use 100mm, you should use a shutter speed at least 1/100s to avoid handshake.
 

mfbatzap

New Member
Jan 24, 2007
363
0
0
Tampines
#10
0. Those closer to the flash are naturally brighter as the light intensity decreases propotionally with the square of the distance. The flash exposure metering may tend to protect subjects from washing-out thus the person further away is underexposed so that the one closer to you is exposed correctly. This is less pronounced with bounce flash as the relative difference in distance is smaller - try tilting the flash head towards the far end of the group a bit.

1. They do the same thing, but if both are set to a nonzero value, the setting on the flash unit is used (flash overrides body).

2. There's some difference in the camera's flash metering. Some may be better than others. Or it's simply that the other person didn't chimp at the screen and didn't bother to change FEC - or he's shooting with manual flash control in a bounced setting.

3. Bounce card is fine especially in a larger room. Omnibounce sends more light to the sides and the back - if you have white walls nearby, it will results in a softer lighting - otherwise it's mostly a waste of the flash power.

4. Depends on how much ambient light you want in the exposure. For better balance - If the scene and subjects are relatively still and you have a good support, you can lower the shutter speed for more ambient exposure; alternatively you can raise the ISO setting to 800 and keep the shutter speed reasonably high. However, if you're bouncing off the ceiling in a small room, you can kill ambient light if you like without getting dark backgrounds.

5. Depends on 4 - how is the flash and ambient balanced. The color temperature of Indoor lighting is seldom close to daylight - while light from flash is. If the ambient light is pretty much killed - underexposed by about 2 stops - you can use flash WB for accurate color reproduction. Otherwise, if the ambient and flash is mixed in similar amounts, one may use auto WB as flash WB may be overly yellow/green depending on the ambient lighting. It is generally not advisable to use flash WB outdoors as the flash only acts as a fill most of the time, assuming daytime. The photos may turn out a bit bluish if the sky isn't clear.
Thanks bro! So I should have just used AWB la. I used flash WB that day
 

westwest2

New Member
Jun 6, 2007
535
0
0
#11
Yes, it was quite dim. And outside was kinda bright, hence I needed the flash to fill in the shadows.
u need to learn how to take in very low light condition

it was those kinda yellow/orange kinda lamp lighting. I shot the pics in raw, but how do I go about changing the WB?

Thanks for the replies! Really appreciate them =)
Tungsten lighting i believe...

change the WB with the software that comes with your camera...adjust the temp yourself...to obtain the best result...

Yes I was using manual mode. When I use AP priority, my shutter speed goes very slow and the pictures will turn out super overexposed. Any ideas why? haha.. I was hoping to use something more "auto" that day. Almost wanted to use P-mode.
its most likely that the camera metered something very bright in the frame...you must be pointed to a strong light source...and also use your EV lock to help u maintance the correct exposure...if all else fail...use M...
 

Status
Not open for further replies.
Top Bottom