i am just curious on how it works and what i shud do ...if i cna set my WB to the DOT on the SPOT then i dont have to PP la hha

eh, ya woh..if sync at 1/900 isnt it COOL? I am curious too....since the slowest is 1/900....

great debate on flash...
too bad I'm no master in this area... PP for White Balance is my thing...

I learned my lesson somehow...no matter how I pp, sometimes, when the color wasnt captured properly, no matter how I pp also i cant get the right result.

extreme case, shooting in tungsten and set my WB to 8000k....
most of the colors may not be captured in this case and the histogram might be heavy towards one channel (blue i pressume) i might be wrong,

Correct me if im wrong.

Deleted.....

This post has been edited by wufei: Aug 19 2009, 11:01 AM

of course, extreme cases may be difficult... but i'm using the cobra+a900+dome diffuser its quite reliable in AWB.. some minor white balancing only..

hmmm...dome diffuser with COLOR?I doubt that a uncolored/white color dome may help in WB....

the flash is on the cam or off the cam ?

on camera... only have 1 cobra at the moment...

i beg to defer, it's just merely some finding out and knowledge sharing happening, no debate, no insult and no offence enjoy your day

oops same here...i just wana find out more..

its good though... probably every1 who uses off cam flashes & multiple flashes are thinking about this now...

The variance between full power and low power flash certainly is not very drastic. You can try it yourself between 1/1 power F22 ISO100 and 1/32 power F4.0 ISO100. I would say it is in 100 Kelvins variance, but this is a good experiment to do with RAW and a custom WB color picker.

I have used off-camera flash in tungsten and flourescent light on the A700. In both cases, the AWB certainly did not go down to tungsten (giving me blue-ish flash) or flourescent (giving me magenta-ish flash). It stayed at Flash WB or 5500K.

Could something be wrong with Seng_Kiat's A700? Maybe.

Flash sync speed depends on the camera shutter. It is determined by how fast the shutter blades can move. Shutter blades travel at a fixed speed.

Flash duration depends on the flash head. You're the audio guy, you know your capacitors lah.

Even though the flash duration for a SB-600 is 1/900s at 1/1 output, your shutter curtains are not fast enough to run from one end of the frame to the other. If you were to hook a SB-600 to a camera via PC Sync or a camera without a Nikon TTL hotshoe, and you shot at 1/900s, you would see a stripe of light! It would be fixed in position relative to the frame.

At shutter speeds slower than the flash sync speed, the first curtain goes up, and the entire frame is exposed, before the second curtain goes up. Thus, one pulse from the flash is enough to light the whole frame.

At shutter speeds faster than the flash sync speed, the first curtain goes up... and the second curtain follows behind it without ever exposing the entire frame. The delay/distance between the first and second curtain is smaller for faster shutter speeds so there is a smaller 'stripe' of the exposed frame at any time.

If you put the SB-600 on a Nikon TTL hotshoe, the camera recognizes that there is a flash attached (and prevents the shutter speed from going faster than the camera's flash sync speed if the flash is in bounce mode) and the flash recognizes that it is attached to a camera. So when the flash is pointed straight, the camera allows HSS, and the flash goes into HSS mode.

The flash, in HSS mode, will fire a few pulses, to 'fill in' the stripes to illuminate a full frame. Because it fires a few pulses its power is reduced.

* HSS = High Speed Sync, same as Canon's FP Flash

If you hooked a SB-600 up to a point-and-shoot which doesn't use a mechanical shutter, shooting at 1/1800s would thus get 1/2 output even though the flash is 1/1 output.

Seng_Kiat: "Ambient&flash" means that when you change EV, your flash EV changes also. "Flash only" means that when you change EV, flash EV does not change.

SpOOkY: AWB will default to Flash WB when the camera knows that a flash was used so there is no need to change to Flash WB.

in fact, im concern about on-camera flash too......imagine if the cam adjust the WB based on the signal passed from the flash...then there is no need in using custom wb/flash wb....unless the signal is only to tell the camera to + or - the current WB temp

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Added on August 19, 2009, 11:42 amthanks for the explanation....

How do we do this? a bit lost....

Oh great..means that hen camera is attached, WB is set automatically..i shall try if flash is off camera and what the AWB will act as.
Then, what is the flash WB for? Which means it is pointless to set custom WB also right? Assuming that each manufacturer will set their AWB to the color temp of the flash of the same make.

IINM, SB600 allows HSS mode even in bounce mode...

This post has been edited by Sp00kY: Aug 19 2009, 11:42 AM

even though it doesn't use mechanical shutter, the speed 1/1800s should be too fast and it should miss the flash. It should have finished capturing b4 the flash fire. No ?

For your information


Attached thumbnail(s)

i think what he is trying to say is that
if the shutter is at 1/1800 (faster)and the flash is at 1/900 (slower)
the cam only manages to capture 1/2 of the flash instead of full...

a more extreme example will be shutter at 1 sec and flash at 2 sec...

did i misunderstand ur question?

But i still dont get why cant x-sync set at 1/900. what bro albnok said was because
your shutter curtains are not fast enough to run from one end of the frame to the other
so when i shoot at 1/4000? how is it like? hmm..

interesting...albnok free tonight? TT on knowledge sharing, teh tarik on me

This post has been edited by Sp00kY: Aug 19 2009, 12:12 PM

You mean need to buy 230 or 330 1st, then get all below items for RM 699 ?

Thanks

oh god.. A230 & A330 is a disgrace to current alpha users.. very dissapointed with them... cost-cutting models... but the savings not passed to the customers..

grab the older A200/300/350 while you still can..

The SB-600 at 1/1 output, is ON for 1/900th of a second. So if you shot at 1/1800th of a second you would only get half the flash duration effectively making it 1/2 output. It's not like the flash is an instantaneous burst that happens at the end of the 1/900th of a second - it's continuously lit for that 1/900th of a second. SpOOkY has got it right.

This Youtube video might make it clear:



Ah, better diagrams!

http://www.planetneil.com/tangents/2008/12/13/max-it-out/

And an animation:

http://www.mhohner.de/essays/myths.php#shutter

SpOOkY: The "exp.comp.set" function in the A100/A700/A900 can switch between "Ambient&flash" or "Flash only".

On the A200-A380 it is "Ambient&flash" by default behavior and there is no option in the menu. On Nikons it is "Flash only" and there is no option (on the D700).

Oops my bad, the SB-600 does allow HSS and bounce (though it is quite pointless because you lose so much power bouncing and using HSS.)

Flash WB is for when you want to fix the WB as 5500K even when there is no flash attached. This retains rich color for stage lighting, for example. With AWB and no flash, it can go down or up.

MemorableStudios: I see you've got the FA-EB1AM battery pack. Congratulations!

This post has been edited by albnok: Aug 19 2009, 12:27 PM

The poster is very misleading....

At 1st glance I thought A330 sells at RM699 with flash, extra lens and bag.

Dont misjudge with the word PWP (Purchase with purchase)

You need to top up of your purchase in order to get those.