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Author Topic: Flash Newbie: Flash Photography Concept  (Read 3863 times)

eninja

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Flash Newbie: Flash Photography Concept
« on: June 16, 2013, 10:03:13 PM »
Can someone enlighten me, I acquired 430ex ii for my 6D recently.

I am using 6D for six months, its my first dslr. I am used to Av mode, auto ISO, minimum shutter speed set.
The camera will meter properly and under or overexpose accordingly base from exposure compensation.

My concept of having a flash is that. The camera will meter the scene automatically as if it wasn't using flash. According to settings. Then the function of a flash is just an addon light to the scene.

But I don't understand what is actually happening when using flash in Av mode:

In Av mode with flash. My shutter speed goes less than the min shutter speed set in the camera.
ISO stuck to 400 (why is this?). I can not control my ambient light.


I know I can use manual, but what I want is the camera is able to meter on the scene automatically, basically use only exposure compensation for ambient and FEC for flash add on. How can I do this.
 

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Flash Newbie: Flash Photography Concept
« on: June 16, 2013, 10:03:13 PM »

RAKAMRAK

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Re: Flash Newbie: Flash Photography Concept
« Reply #1 on: June 17, 2013, 01:31:46 AM »
If you put your flash on top of your camera (or attach the flash with the camera using an ETTL cable) the camera will recognize the flash fix the shutter speed at 1/200 sec. You can go for a slower shutter speed if you use M or Tv, without any problem. But if you try to go for a faster shutter speed than 1/200th sec (1/250sec in other cameras than 6D) in M or Tv mode you will get a black unexposed part on the frame. To just use your flash as a fill flash you need to reduce the flash power in the flash (or with flash menu in camera). If you want to go for a faster shutter speed than the limiting flash sync speed (1/200) then you need to go for High Speed Sync (HSS) capable flash. There may be other ways of doing it, I do not know. Someone else will probably point you to those directions soon.
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digital paradise

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Re: Flash Newbie: Flash Photography Concept
« Reply #2 on: June 17, 2013, 01:36:39 AM »
The problem is shooting in AV mode in a dark venue. Your camera does not care if there is a flash on your camera or not. The light cameras light meter will continue to meter ambient light the same way. Take the flash off or turn it off and the meter will read the same and your shutter speed will be very slow slow unless you crank the ISO way up and/or open up the aperture. Based on your ISO AV mode will protect the aperture you selected and will take the shutter to 1/15 or lower if it needs to. It will keep the light meter in the middle no matter what. 

Most pros set the camera to manual when shooting with flash. Now you are bound to the cameras light meter. You can your shutter, aperture and ISO to meter the ambient and flash output via manual or ETTL for subject exposure. Like I said your camera does not care about what your flash is doing and the flash does not care about what your camera is doing. Both have distinct jobs.

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Re: Flash Newbie: Flash Photography Concept
« Reply #3 on: June 17, 2013, 01:40:28 AM »
If you put your flash on top of your camera (or attach the flash with the camera using an ETTL cable) the camera will recognize the flash fix the shutter speed at 1/200 sec. You can go for a slower shutter speed if you use M or Tv, without any problem. But if you try to go for a faster shutter speed than 1/200th sec (1/250sec in other cameras than 6D) in M or Tv mode you will get a black unexposed part on the frame. To just use your flash as a fill flash you need to reduce the flash power in the flash (or with flash menu in camera). If you want to go for a faster shutter speed than the limiting flash sync speed (1/200) then you need to go for High Speed Sync (HSS) capable flash. There may be other ways of doing it, I do not know. Someone else will probably point you to those directions soon.


Correct. Here a a good video on HSS. It is a PW ad and you do not need PW to make it work when the flash is on the  camera. After about 6 minutes it gets into stuff you don't really need to yet unless you are interested.

 http://www.pocketwizard.com/inspirations/tutorials/pocketwizard_controltl_optimiz/

RAKAMRAK

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Re: Flash Newbie: Flash Photography Concept
« Reply #4 on: June 17, 2013, 01:47:12 AM »
If you put your flash on top of your camera (or attach the flash with the camera using an ETTL cable) the camera will recognize the flash fix the shutter speed at 1/200 sec. You can go for a slower shutter speed if you use M or Tv, without any problem. But if you try to go for a faster shutter speed than 1/200th sec (1/250sec in other cameras than 6D) in M or Tv mode you will get a black unexposed part on the frame. To just use your flash as a fill flash you need to reduce the flash power in the flash (or with flash menu in camera). If you want to go for a faster shutter speed than the limiting flash sync speed (1/200) then you need to go for High Speed Sync (HSS) capable flash. There may be other ways of doing it, I do not know. Someone else will probably point you to those directions soon.


Correct. Here a a good video on HSS. It is a PW ad and you do not need PW to make it work when the flash is on the  camera. After about 6 minutes it gets into stuff you don't really need to yet unless you are interested.

 http://www.pocketwizard.com/inspirations/tutorials/pocketwizard_controltl_optimiz/


Good video. thanks for the link.
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eninja

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Re: Flash Newbie: Flash Photography Concept
« Reply #5 on: June 17, 2013, 03:40:37 AM »
So in conclusion, if flash is mounted, there is no way to automatically get standard exposure in Av mode.
Also it is undesireable to use Av mode, simply because there is no way I can make my Min shutter speed to 1/90 or 1/125. Also Auto ISO is Clipped to 400.

My intention is, I want the camera to automatically get exposure of ambient light 1 stop below standard exposure exposure (given min shutter speed and auto ISO), in different lighting condition. And be able adjust FEC as necessary.

As conclusion There is No Way to do this.
« Last Edit: June 17, 2013, 03:48:28 AM by eninja »

RAKAMRAK

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Re: Flash Newbie: Flash Photography Concept
« Reply #6 on: June 17, 2013, 06:17:25 AM »
I do not have either your camera or the flash you are talking about - so take my word with a grain of salt. Have you tried putting the flash in full manual mode? - mount it on camera (or with a cable) and then put the flash into manual mode. The camera will meter the scene disregarding the flash, then manually change the power of the flash (i do not know whether your flash can be fully manually controlled or not). Then shoot. The camera will use its own metering to determine ISO (since you are keeping it at Auto) and shutter speed (since you are in Av). But the flash will fire at whatever power you manually set it to. Just now I tried this technique (assuming I understood your last post correctly) with my Canon 40D (ISO 100, f/4.5, -2/3 EC) and Nikon SB 28DX (set at 1/32 power with ISO 100 and f/5.6) - the camera metered the scene at  0.5 sec disregarding the flash. I took two photos of the same scene - one with and one without the flash firing. Both has the exif (ISO 100, f/4.5, -2/3 EC 0.5 sec). But one has only ambient light and the other has flash plus ambient light. This is probably what you are looking for.
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Re: Flash Newbie: Flash Photography Concept
« Reply #6 on: June 17, 2013, 06:17:25 AM »

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Re: Flash Newbie: Flash Photography Concept
« Reply #7 on: June 17, 2013, 07:16:32 AM »
So in conclusion, if flash is mounted, there is no way to automatically get standard exposure in Av mode.
Also it is undesireable to use Av mode, simply because there is no way I can make my Min shutter speed to 1/90 or 1/125. Also Auto ISO is Clipped to 400.

My intention is, I want the camera to automatically get exposure of ambient light 1 stop below standard exposure exposure (given min shutter speed and auto ISO), in different lighting condition. And be able adjust FEC as necessary.

As conclusion There is No Way to do this.

I often use Av mode for flash stuff for candids, etc, because it does meter for the ambient.  I'll typically set the meter to -1 and then adjust FEC accordingly.  Set the ISO manually high enough so that the ambient is about 1/100-1/200.  Enable HSS on the flash in case you walk into a brighter area and the shutter speed goes past the sync speed of the camera.

It might be worth checking out the manual to see if you can override the max iso of 400 constraint.  Is it only with flash attached, etc?  Perhaps there is a setting to remove it. 

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Re: Flash Newbie: Flash Photography Concept
« Reply #8 on: June 17, 2013, 07:46:17 AM »

I often use Av mode for flash stuff for candids, etc, because it does meter for the ambient.  I'll typically set the meter to -1 and then adjust FEC accordingly.  Set the ISO manually high enough so that the ambient is about 1/100-1/200.  Enable HSS on the flash in case you walk into a brighter area and the shutter speed goes past the sync speed of the camera.

It might be worth checking out the manual to see if you can override the max iso of 400 constraint.  Is it only with flash attached, etc?  Perhaps there is a setting to remove it.

Will HSS be required if the shooter walks into brighter area? The "bright" ambient light will take care of the black bars when shutter speed goes past the sync speed of the camera - won't it?

And yes, adjusting the ISO manually is the best bet, instead of letting it stay on auto.
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Re: Flash Newbie: Flash Photography Concept
« Reply #9 on: June 17, 2013, 08:50:16 AM »

I often use Av mode for flash stuff for candids, etc, because it does meter for the ambient.  I'll typically set the meter to -1 and then adjust FEC accordingly.  Set the ISO manually high enough so that the ambient is about 1/100-1/200.  Enable HSS on the flash in case you walk into a brighter area and the shutter speed goes past the sync speed of the camera.

It might be worth checking out the manual to see if you can override the max iso of 400 constraint.  Is it only with flash attached, etc?  Perhaps there is a setting to remove it.

Will HSS be required if the shooter walks into brighter area? The "bright" ambient light will take care of the black bars when shutter speed goes past the sync speed of the camera - won't it?

And yes, adjusting the ISO manually is the best bet, instead of letting it stay on auto.

Depends....  The situtation I was talking about is more appropriate when the light levels change a lot.  For example, ISO is set to 2000 and shutter speed of about 1/100 is achieved for indoor work.  You walk outside where there is a lot more light and you want to use the flash for fill.  The fastest shutter speed is the sync speed and not the 1/4000 that is more appropriate, so the shot will be horribly overexposed (if the camera is capped to the sync speed with flash is attached).

Unless I need 2nd curtain sync, I leave it in HSS.  If the shutter speed is less than the sync speed than HSS does not apply and everything operates normally.  If the shutter speed is faster than the sync speed, then HSS does what it is intended to do.  Basically, it's a hedge against a fixed ISO like auto ISO would be.  Otherwise, the bars might not be black, but any linear delineation between "exposure" zones might be annoying.

privatebydesign

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Re: Flash Newbie: Flash Photography Concept
« Reply #10 on: June 17, 2013, 09:28:11 AM »

I know I can use manual, but what I want is the camera is able to meter on the scene automatically, basically use only exposure compensation for ambient and FEC for flash add on. How can I do this.

That is exactly what your 6D does in Av Mode with a flash in ETTL. EC only alters the ambient exposure, FEC only alters the subject exposure.

My concept of having a flash is that. The camera will meter the scene automatically as if it wasn't using flash. According to settings. Then the function of a flash is just an addon light to the scene.

Your concept is wrong. The when you push the shutter button the camera sends out a small low powered pre flash, it meters that and decides what your subject exposure needs, the subject is illuminated by the flash the flash duration normally being very short, around 1/1500 sec depending on power needed, this means your subject is getting an exposure of your set aperture, the cameras set shutter speed and the cameras calculated flash power. But before the exposure the camera also meters the ambient and this is exposed with a combination of your set aperture and the cameras metered shutter speed. There are two completely separate exposures metered and calculated between pushing the shutter button and exposure.
« Last Edit: June 17, 2013, 10:51:42 AM by privatebydesign »
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Re: Flash Newbie: Flash Photography Concept
« Reply #11 on: June 17, 2013, 09:39:12 AM »
So in conclusion, if flash is mounted, there is no way to automatically get standard exposure in Av mode.
Also it is undesireable to use Av mode, simply because there is no way I can make my Min shutter speed to 1/90 or 1/125. Also Auto ISO is Clipped to 400.

My intention is, I want the camera to automatically get exposure of ambient light 1 stop below standard exposure exposure (given min shutter speed and auto ISO), in different lighting condition. And be able adjust FEC as necessary.

As conclusion There is No Way to do this.

As I said, Av Mode does exactly that for you. Just dial in -1EV compensation and your background is one stop underexposed, in ETTL your subject is correctly exposed as metered for 18% grey. To change subject exposure move FEC, to change ambient exposure change EC.
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Re: Flash Newbie: Flash Photography Concept
« Reply #12 on: June 17, 2013, 12:29:47 PM »
As a flash noob myself, I can recommend The Speedliter's Handbook

http://www.amazon.com/Speedliters-Handbook-Learning-Craft-Speedlites/dp/032171105X/ref=sr_1_1?ie=UTF8&qid=1371486499&sr=8-1&keywords=speedlite+handbook

The author has a talent for explaining the things you need to know in simple easy to learn ways.
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Re: Flash Newbie: Flash Photography Concept
« Reply #12 on: June 17, 2013, 12:29:47 PM »

cayenne

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Re: Flash Newbie: Flash Photography Concept
« Reply #13 on: June 17, 2013, 01:06:16 PM »
As a flash noob myself, I can recommend The Speedliter's Handbook

http://www.amazon.com/Speedliters-Handbook-Learning-Craft-Speedlites/dp/032171105X/ref=sr_1_1?ie=UTF8&qid=1371486499&sr=8-1&keywords=speedlite+handbook

The author has a talent for explaining the things you need to know in simple easy to learn ways.


I second this.

Also, they just over the past 5x days, had free classes on lighting and speedliting on CreativeLive.com

Today is it a series starting on LR5, but do keep an eye there and go through their calendar for classes that interest you. Shown free during the day, free rebroacasts that evening (sometimes longer), and then you have to pay if you want to download or stream the classes after that.

I've found that to be a great resource for all things photography.

C

Zv

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Re: Flash Newbie: Flash Photography Concept
« Reply #14 on: June 17, 2013, 08:41:41 PM »
+1 for speedlighter's handbook.

Av mode with ettl flash in a darker environment doesn't work well. Sounds like you want to drag the shutter. This is what I would do.

Switch your flash off for a second.
Then in Av mode take a picture.
Make any EV adjustments you need to get the amount of ambient right.
Make a mental note your shutter speed and aperture and ISO.
Switch the camera to M mode and dial in those settings.
Now switch on your flash on ettl and take a picture.
Now you have some options - if you want more ambient / background light then decrease shutter speed. And if you want more or less flash power just change FEC to suit.
If the subject is stationary you may want to use manual flash too, that way you get shot to shot consistency.

Hope that helps.

Forgot to add - never use auto ISO. It is fixed at 400 when using flash.
« Last Edit: June 17, 2013, 08:46:28 PM by Zv »
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Re: Flash Newbie: Flash Photography Concept
« Reply #14 on: June 17, 2013, 08:41:41 PM »