Flash N00b! Need help understanding these things!

Ok guys so I am quite the seasoned photographer, all but in one aspect and that aspect is flashes.

I have gone ETTL for quite a while now with my 430 EX II and today I got myself a 580...

An easy explanation of how it works and how I can play around with manual and slave flashes would be extremely appreciated.

Cheers

// Bang Bang

There is no easy explanation of a subject that has over 34,000 threads and 427,000 posts on this forum alone.

However, there is a place to start. Click on the flash-related links in my signature.

Then when you have specific questions from what you have read, feel free to ask.

Thanks, yeah I figured it wouldn't be easy! Thought there might be a thread like this on POTN. Thanks for sharing!

Check for the "Canon wireless flash" link in my signature.

Cheers Tiberius! Extremely useful! Good thing I am a fast learner when it comes to photography.

Since you are a previous owner of the 430, you might simply explain what is it about the 580 which you do not understand? The 580 can be Master in wireless flash, whereas the 430 cannot. Apart from power and wireless, the two flash units are conceptually quite similar. Your OP is too open ended, and you need to advise what information you need, not merely "Please explain the meaning of Life".

In ETTL, the camera tells the 580 how much light to put out, after the preflash. The 580 tells the 430 how much light to put out, based upon the amount of light commanded by the camera and also based upon the flash intensity ratio which the photographer had established. In manual, the relative output of the two flash units based upon the Manual power setting of the Master and flash intensity ratio which the photographer had established.

subbing to read!

Wilt wrote in post #12838399
Since you are a previous owner of the 430, you might simply explain what is it about the 580 which you do not understand? The 580 can be Master in wireless flash, whereas the 430 cannot. Apart from power and wireless, the two flash units are conceptually quite similar. Your OP is too open ended, and you need to advise what information you need, not merely "Please explain the meaning of Life".

In ETTL, the camera tells the 580 how much light to put out, after the preflash. The 580 tells the 430 how much light to put out, based upon the amount of light commanded by the camera and also based upon the flash intensity ratio which the photographer had established. In manual, the relative output of the two flash units based upon the Manual power setting of the Master and flash intensity ratio which the photographer had established.

Hey yes you are absolutely correct and I have realized this now. For me the flash has always been last resort, basically when I max out the ISO and f/1.4 aint cutting it anymore. So I have always used the 430 on ETTL and basically adjusted the flash exposure compensation whilst shooting M.

I figured since I know how awesome a camera is when you know how it works I should try to understand how a flash works and what benefits there is with manual flash settings.
Basically I have always trusted luck when it comes to flashes, now I wan't to be able to control them.

Sorry this might be different topic, in the 60D and 7D there is a wireless function that you can control the FLASH 580EXII, I was wondering do you guys know what is the range?

Because When I tried to shot with my 60D with wireless function, sometimes the flash didn't fire.

I thought it was the range, but sometimes when it's close, it didn't fire as well.

Hey Tefu I have no idea but I hope someone will respond!

Primer:

• When you shoot with electronic flash, unless you use HSS flash you MUST use the X-synch shutter speed (or slower), which fully opens the entire frame area to the flash (i.e., both shutter curtains are fully clear of the frame area)
  
• Guide Number = distance * f/stop. So GN100 flash = 25' to subject at f/4, or 12.5' to subject at f/8, or 50' to subject at f/2.
  
• Light from a flash head falls off in intensity with distance, and follows the Inverse Square law of intensity drop...2x the distance = 1/4 the intensity (-2EV)...that is, if you move flash from 4' to 8', it is -2EV lower in intensity; same applies when moving light from 8' to 16', it is again -2EV in intensity.
  
• Light from a relatively large source (subject distance < 2x the largest dimension of the source) falls off less rapidly...Inverse Linear, or 2x the distance = 1/2 the light (-1EV)
  
• Manual flash outputs a fixed amount of light. You must adjust your aperture to suit the Guide Number.
  
• 'Manual on flash' is not the same as 'Manual on camera'
  
• ETTL flash outputs a preflash (upon camera command), camera reads returning light and then commands ETTL flash to output a specified amount of light; the flash ouput is varied to suit your aperture.
  
• To have ETTL control you need either direct hotshoe mount, or use of an off-camera cord which preserves connectivity of the 6 electrical contact in the hotshoe...a PC cord or a non-ETTL radio control only does two of the six contacts to trigger the flash!
  
• Canon ETTL wireless uses optical signals, not radio signals
  
• HSS with fast shutter speed will cause very severe reduction in the intensity of light from the flash
  

tefu wrote in post #12840064
Sorry this might be different topic, in the 60D and 7D there is a wireless function that you can control the FLASH 580EXII, I was wondering do you guys know what is the range?

Because When I tried to shot with my 60D with wireless function, sometimes the flash didn't fire.

I thought it was the range, but sometimes when it's close, it didn't fire as well.

Were you outside?

Page 119 of the 7D manual says you are good for about 7 meters outdoors and 10 meters indoors. (less if off to the sides)

Indoors, the light signals bounce off the walls and ceiling, so it is very reliable. Outdoors can be a problem. You need to take extra care to make sure you have line of sight between the flashes.

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Hope this is a good place to ask this in relation to the threads above - will ETTL work over wireless triggers? Do you have to use certain triggers?

Brules wrote in post #12848213
Hope this is a good place to ask this in relation to the threads above - will ETTL work over wireless triggers? Do you have to use certain triggers?

As I stated in Post 11,
To have ETTL control you need either direct hotshoe mount, or use of an off-camera cord (added: or a wireless ETTL compatible trigger system) which preserves connectivity of the 6 electrical contact in the hotshoe...a PC cord or a non-ETTL radio control only does two of the six contacts to trigger the flash!