EOS Flash Photography System

EOS Flash Photography System

 

I'm a newcomer to flash photography, just wanna know more about fill-

flash. What would be the effect if the shutter speed is longer than

the flash sync speed? Shallow depth-of-field always means using a

very fast shutter speed, say 1/500 and 1/1000th second. How to set

the flash in conditions like portrait photography?

 

I have also heard that the flash unit usually gives out light that is

too much to be used as a fill flash. How much negative flash exposure

compensation is suitable?

 

Any reference to introductory materials on the web would be welcome.

 

Many thanks.

Try the search button - top right corner

A photo master asking for introductory materials? Just kidding

 

photonotes.org has very good information I think you will be interested in reading

http://photonotes.org/articles/eos-flash/

Focus you attention on "high speed sync".

Aha ! Finally someone already a "Photo Guru" who needs more information on "photography" :-)

 

More seriously, try the EOS Doc website:

http://www.eosdoc.com/

 

- Harman

Yeah, I clicked on this thread expecting to be enlightened.

Hi Folks,

 

Thank you for your contributions.

 

I specialize in LANDSCAPE PHOTOGRAPHY and is going to extend my photographic realm to flash photography. That's why I have asked elementary questions even I am a `photo guru`. One good at one particular field may not be doing equally well in all others.

 

I guess many of you are doing general photography. Aren't you? You all may not be familiar with, have knowledge of, macrophotography and wildlife photography at all. Am I correct?

 

Photo Guru

Greetings,

I always respect those who dare to ask, thats the only way to improve. Try this website. It has a very good article on canon flash. Enjoy

http://photography-on-the.net/forum/forumdisplay.php?f=35

Ha! Wrong! I specialize in macro but I suck at more general types of photos (portraits etc.) So much for generalizations Mr Guru type person! :)

No, photo guru, you are not. Not correct.

Not to jump on you, but a couple of statements jumped out at me.

 

>I'm a newcomer to flash photography, just wanna know more about fill- flash. What would be the effect if the shutter speed is longer than the flash sync speed?

 

Setting the shutter speed lower than the flash output duration is called slow-sync flash. Used properly, it can give good results when you wish to expose for the background as well as the subject, but it often requires a tripod to avoid ghosting from camera shake. Not that that's a bad thing in some cases. Most modern cameras will not allow you to set a shutter speed faster than the camera's max sync speed.

 

> Shallow depth-of-field always means using a very fast shutter speed, say 1/500 and 1/1000th second.

 

DOF is a function of aperture, not shutter speed. A photo guru would know that. Only high-end bodies offer mechanical flash sync as high as 1/500. Canon has a system called "High Speed Sync," but it is not the same as if you had a true higher sync speed and is dependant upon support of the flash unit used. It puts the flash into a strobe mode in order to achieve the higher flash sync. Unfortunately, this results in the flash range being reduced significantly. It does work well for fill-flash situations, though.

 

> How to set the flash in conditions like portrait photography?

 

Direct flash (on-camera or hot-shoe mounted) is generally the worst kind of flash for portraits. It often results in harsh, flat lighting that obliterates features and distracting causes shadows. Side and back lighting with a bit of frontal fill-flash usually result in better portraits. Most portrait photogs find a setup through experimentation that works best and then stick to it.

 

>I have also heard that the flash unit usually gives out light that

is too much to be used as a fill flash. How much negative flash exposure compensation is suitable?

 

There is no set value for such photos. Some camera systems handle fill-flash better than others and certain situations may even need positive FEC rather than negative. Canon's ETTL-II system is pretty good with fill-flash, but any system requires some trial and error rather than a standard setting that fits all situations.

Flash only reaches a short distance and then falls off rapidly (doubling the distance decreases the light by 4x). In a studio type environment where everything is close this doesn't matter much especially if all of the light is coming from the flash but outdoors in the daytime where you have a lot of ambient light an exposure slower (longer) than the flash sync can overexpose the subject and produce a ghosting effect from subject movement. It can also be used to vary the background illumination as standard exposure rules still apply to anything beyond the reach of the flash. Setting the shutter to a speed faster than the flash sync will result in a partially exposed frame if you have a focal plane shutter (this is why many portrait photographers tend to have leaf shutter lenses as they will sync at all speeds giving them greater control over foreground vs background illumination).