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newbie question: manual and auto flash advantages?

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tenggiri10

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hi there,

I think this a stupid question. But till now i cant differentiate between manual and auto flash. For beginner like me, both seems like same. BTW i'm using 580EXii.

can i know the use (advantage) of both mode (manual and auto)
 
Here's a silly reason for using manual flash - I shoot speedway, and I can't get it through the heads of some of the drivers/car owners that putting reflective material on the left side of the car makes the photographer unhappy.

If I use the flash on auto, I get to see the reflective material and nothing else. If I use manual (usually set to 1/4 power) I get a blowout of the reflective material but I can actually see the rest of the car - what a concept!

The other time that I use manual is when track workers in their nice reflective safety gear are in the way...

Apart from that, I pretty much use auto but it's nice to know that the manual option is there when required.

G
--
http://www.gordong.com
 
tenggiri10 said:
But till now i cant differentiate between manual and auto flash. For beginner like me, both seems like same.
Click to expand...
Auto = camera sets the flash strength
Manual = YOU set the flash strength

Think of an automatic door compared to a 'normal' door - which one opens for you? Which one does not?

I don't know how to put it any simpler - if you still can't tell the difference, then I give up!

--
Bannor

'Political Correctness is doctrine fostered by a delusional minority and the media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
D.I.L.L.I.G.A.F.'
 
Hi, You may not have got your head around the speed of electronic flash - this has a bearing on how Auto flash works. It's not like your ambient Auto modes which vary SS Ap etc.

Electronic flash is quick - generally far quicker than your shutter speed (SS). (HSS is an exception.)

Auto flash started when light sensors were developed that were even quicker. They could measure flash return during the flash burn - as flash illumination accumulated, they decided when enough (given Ap & iso) had been reflected from the subject, and then - in real time - quenched the flash burn.

Initially the sensors were on the flashgun (1) then in the film era they were in cam measuring flash return off the film surface (while the shutter was open & the exposure actually occuring) - now they are still in cam but 'pre-flash' based, measuring 'thru' the lens'.
There are dozens of pages on the sites near this one;
http://cpn.canon-europe.com/content/education/infobank/flash/flash_basics.do
Happy reading!
Cheers, Donald

PS Note (1) Separately (& confusingly) your 580(11) has one of these too (p 30) but learn ETTL(11) first!
 
You should certainly be able to see the difference between using Manual and Auto modes!

Auto mode will calculate the strength of the flash output based upon the scene and Manual will just throw out the amount of light it is set for regardless of the ambient lighting. I use Manua when I want a consistent amount of lighting when taking portraits. I can take 10-20 pics in a row and know that the lighting will be the same for each pic regardless of how I reframe the picture. That doesn't always happen when the flash is set in Auto mode......

John
--

Feel free to use any of these additional letters to correct the spelling of words found in the above post: a-e-t-n-d-i-o-s-m-l-u-y-h-c If you find any extra letters, please place them here for future use...
 
the most troublesome thing of auto flash is that it needs to send out a pre flash to determine the power of the flash needed to get a good exposure. That happens fairly quickly, but if you want to precisely photgraph something, the time difference can cause a failed photo. Manual flash fires as you press the shutter and photo is taken as normal. (useful for macros as small amount of time can mean moved subject or focus)

As well as mentioned above, choosing what part of the picture you want to expose.
--
http://www.flickr.com/photos/41942460@N04/sets/
 
how do we determine the power by just send out a pre flash??
its too fast
Fabian628 said:
the most troublesome thing of auto flash is that it needs to send out a pre flash to determine the power of the flash needed to get a good exposure. That happens fairly quickly, but if you want to precisely photgraph something, the time difference can cause a failed photo. Manual flash fires as you press the shutter and photo is taken as normal. (useful for macros as small amount of time can mean moved subject or focus)

As well as mentioned above, choosing what part of the picture you want to expose.
--
http://www.flickr.com/photos/41942460@N04/sets/
Click to expand...
 
ScratchDisk said:
Hi, You may not have got your head around the speed of electronic flash - this has a bearing on how Auto flash works. It's not like your ambient Auto modes which vary SS Ap etc.

Electronic flash is quick - generally far quicker than your shutter speed (SS). (HSS is an exception.)

Auto flash started when light sensors were developed that were even quicker. They could measure flash return during the flash burn - as flash illumination accumulated, they decided when enough (given Ap & iso) had been reflected from the subject, and then - in real time - quenched the flash burn.

Initially the sensors were on the flashgun (1) then in the film era they were in cam measuring flash return off the film surface (while the shutter was open & the exposure actually occuring) - now they are still in cam but 'pre-flash' based, measuring 'thru' the lens'.
There are dozens of pages on the sites near this one;
http://cpn.canon-europe.com/content/education/infobank/flash/flash_basics.do
Happy reading!
Cheers, Donald

PS Note (1) Separately (& confusingly) your 580(11) has one of these too (p 30) but learn ETTL(11) first!
Click to expand...
thanks for the website,,,... I got along way to go :)
 
balloonchasers said:
You should certainly be able to see the difference between using Manual and Auto modes!

Auto mode will calculate the strength of the flash output based upon the scene and Manual will just throw out the amount of light it is set for regardless of the ambient lighting. I use Manua when I want a consistent amount of lighting when taking portraits. I can take 10-20 pics in a row and know that the lighting will be the same for each pic regardless of how I reframe the picture. That doesn't always happen when the flash is set in Auto mode......
Click to expand...
I always set at auto mode.... no wonder I always get a different lighting.
balloonchasers said:
John
--

Feel free to use any of these additional letters to correct the spelling of words found in the above post: a-e-t-n-d-i-o-s-m-l-u-y-h-c If you find any extra letters, please place them here for future use...
Click to expand...
 
tenggiri10 said:
how do we determine the power by just send out a pre flash??
its too fast
Click to expand...
You don't determine the power required, the camera does. It measures the exposure with the pre-flash and adjusts the length of the flash to give the required subject exposure.

--
Chris R
 
tenggiri10 said:
..... I use Manual when I want a consistent amount of lighting when taking portraits. I can take 10-20 pics in a row and know that the lighting will be the same for each pic regardless of how I reframe the picture. That doesn't always happen when the flash is set in Auto mode......
tenggiri10 said:
I always set at auto mode.... no wonder I always get a different lighting.
Click to expand...
Click to expand...
You certainly can get different amounts of flash when using Auto! Reframing the picture just a little can cause the flash to calculate a complety different setting. With Manual you are going to get the same amount of flash regardless of where you move the camera. In other words you are no longer allowing the camera to make a guess for your. Being able to set the flash's output level becomes a big advantage when you progress in your flash photography exploration. http://strobist.blogspot.com/ is all about getting the flash off the camera and taking control of the flash output.

Right now I think you just need to experiment with both modes and learn the functions of your flash as you settle into flash photography.

Remember to have fun!

John

--

Feel free to use any of these additional letters to correct the spelling of words found in the above post: a-e-t-n-d-i-o-s-m-l-u-y-h-c If you find any extra letters, please place them here for future use...
 
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