High Speed Flash Sync: 5D2 + 580 EX II

[Jay Gould]

5D2 + 580 EX

P.17 of the 580 Manual says to press the "lightning H" (hereinafter LH) button so that the icon appears on the screen. That is supposed to allow a sync at all speeds up to the camera's maximum flash sync speed (1/200 for the 5D2)

and that the LH icon is supposed to appear in the viewfinder.


On p.19 of the 5D2 Manual, the Viewfinder Information, it specifically shows that when high speed sync is set on the flash, the LH icon should appear in the viewfinder.

My 5D2 is only showing the L icon without the H.


In the 5D2 Manual is specifically says "High Speed Sync 'FP Flash'". I do not know what the FP means.

When I am in Tv and set the speed at, for example, 1/160, and the flash is in LH mode, when I press the shutter the speed drops to significantly.

Your thoughts/help greatly appreciated.

[John Chardine]

Hi Jay-

1. H-sync on Canon flashes allows use of flash above, not "up to", the native flash sync shutter speed which on most modern focal plain shutters is 1/250s or 1/300s. It does this by producing multiple flashes as the shutter curtain slit (it's a slit above the sync speed) moves across the sensor. I imagine the "up to" refers to flash sync up-to the maximum shutter speed of the camera, not the flash sync shutter speed.
2. As long as the flash shows the H-sync icon you should be fine. The universal flash icon (lightening) in the viewfinder means the flash is on and/or it's ready- can't remember exactly.
3. Nikon calls their H-sync FP high-speed sync. I assume the FP stands for focal plain.

[Jay Gould]

Thanks John; however, something is missing.

There is an icon for the viewfinder when you are in high speed sync; and, my speed while set at 1/200, in a dark area is being automatically reduced to 1/4 or less.

[John Chardine]

Jay- The H doesn't show in the viewfinder if you have set a shutter speed below the sync speed. I haven't the foggiest what you mean by the last bit of the post (starting .... my speed while set at ......).

[Roger Clark]

Hi Jay,
See:
http://cpn.canon-europe.com/content/...s_explained.do

C.Fn I -7 – Flash sync speed in Av mode

By default, Av mode will try to produce a balanced fill flash result. In low light this can mean the shutter speed becomes quite long and you are at risk of camera shake. This Custom Function will stop that. The default setting, or 0, will allow any shutter speed to be set between 1/200sec and 30sec. Setting 1 will choose shutter speeds from 1/200-1/60sec, so you’re unlikely to get camera shake, and setting 2 will lock the shutter speed to 1/200sec.

http://www.rpphoto.com/howto/view.asp?articleID=1026

Canon's High Speed Sync is turned on from the flash. On the 580EX there is a single button on the back of the flash which cycles among Standard, High-Speed Sync, and Second Curtain Sync.

Hope this helps

Roger

[Jay Gould]

Roger, in Paonessa's article, in the Canon High Speed Sync Section, he has an image of the viewfinder and in that image you see red "H" for his 1D2. I used to get the red H; I am no longer seeing the red H and I am unable to cause my camera to sync at high speeds even though I have set HSS on the 580EXII.

[John Chardine]

Jay- With respect, look at panel 4. The H will not show if you have shutter speeds set below the sync speed. In the previous panel you say you have the speed set at 1/200s. At that speed, the H will not show. If you have H-synch set on the flash, then watch the view finder as you increase the SS above the sync speed. As soon as you go above you should see the H. If you don't there's something wrong.

[Jay Gould]

Bingo!! I found my problem!!!

John, I am slow; I do not give up!

The H is off at 1/200 and comes on at 1/250.

C.Fn I-6 is the Safety Shift setting which I normally have enabled.

However, C.Fn I 6 overrides the flash settings. If you have enabled the Safety Shift so that the camera overrides your settings in changing light circumstances, when you are using your flash in a dark location, the fact that you have set the flash to HSS is ignored if you enable the Safety Shift.

In Tv I set the speed to 1/250 and that set the Av to 4.0.

The flash in on in HSS and I have set the flash output to +1 to compensate for the loss of light due to HSS.

With Safety Shift enabled the speed dropped to 1/40 and the image was not quite bright enough.

With Safety Shift disabled, the speed remained at 1/250 and the image was sufficiently exposed and the issue of camera shake removed.

Thanks John and Roger for hanging in there with a slow learner.

Cheers,



PS: The moral: disable Safety Shift with flash.

[John Chardine]

Bingo!! I found my problem!!!

John, I am slow; I do not give up!

The H is off at 1/200 and comes on at 1/250.

C.Fn I-6 is the Safety Shift setting which I normally have enabled.

snip

Exactly! The H appears with shutter speeds above the sync speed, and disappears below it. This makes perfect sense. Even if you have H-sync set on the flash, if the SS is slower than the sync speed the flash works as if H-sync was turned off, hence the H disappears. On my 1DIV, this happens regardless of the Safety Shift setting, which I never have turned on.

I don't give up easily either!!!