bypass flash max shutter speed

[pikar]

Hi,

I just bought a non HSS 3rd party flash (the YN-565EX) for my 550D and, similarly to the built-in flash, I cannot go faster than 1/200s on the shutter speed  , Canon blocks it whenever the flash is plugged.
I tried ML's exposure override but it doesn't change anything.
I believe a non HSS flash can be used at faster shutter speed (1/250 or maybe 1/400) and that would help me a lot in outdoor shooting.

Is there any way to bypass Canon's limit here?

Thanks

[Francis]

Disable under Canon C.Fns menu. Not sure if the option is there for every model but most likely. You have it backwards though. Non-HSS flashes can NOT be used at faster shutter speeds. You might have luck syncing at 1/250s if you have a particularly long duration flash, but that speedlight is not going to fit that category.

X-sync speed is a mechanical limitation, not a software limit. 1/200s is the shortest shutter speed that the entire sensor is exposed. Anything above that and the rear shutter curtain starts traveling across the sensor before the front curtain has fully exposed the sensor. You can shoot at higher speeds but you are going to get a black bar of underexposed image. Also historically Canons have slower shutter curtains and thus lower sync speeds than say Nikons, where most models can sync reliably at 1/250s and some even higher. I think the D50 had an hybrid mechanical/electronic shutter, something I would like to see become a standard feature. I do a lot of portraiture and being able to use wider apertures and still syncing flash in more outdoor situations would be wonderful.

Edit: The C.Fn option I was thinking of was in regards to Av mode only. Real answer: Use M. You can pick any shutter speed you want. If you are using flash, you should be shooting in M anyways. Set aperture in relation to flash output and shutter to balance in ambient.

[pikar]

I am using M mode already, but Canon also limits this mode to 1/200 for the max shutter speed.

I was not sure HSS was a purely mechanical feature and hoped to be able to figure out the limitations of my own flash with some kind of tweaks from ML. You might be right though, I'll probably won't get good picture at faster shutter speeds.

I guess the best I can do now is to buy a ND filter, I'll lose few stops on the ambient exposure and I'll set more power to the flash to compensate.

[Francis]

I'm guessing this is because of the e-TTL compatibility of this flash. Have you tried putting the flash in manual power mode as well? You will have to set it to the appropriate exposure (which is going to have to be 1/1 or close to it if you are shooting outside and competing with daylight) but it should let you set whatever shutter speed you want. If it is in manual and the camera still doesn't let you select over 1/200, you can cover all the metal pins on bottom of the flash's foot except the center one with electrical or gaffer tape. That should stop the camera from "seeing" the flash but it will still fire the flash. Again the flash and camera is going to have to be in manual.

NDs do help get below the sync speed, but you still need to get a power output from the flash close to the ambient, as the ND is cutting that light down as well.

[pikar]

Alright, Manual mode on the flash does not change anything to the shutter speed limitations.
I guess the flash is still recognized as non-HSS by the 550D.
But I covered the 4 e-TTL pins as you suggested and there you go, the shutter speed limit is gone  !

FYI, I can go up to 1/320s without any issues, I then see a black strip on the bottom of the picture at 1/400, and past this it is just unusable.

Thanks for the advise!

I'll buy a HSS wireless transmitter/receiver soon, and I think no matter what flash you put on it on one end, the camera will be fooled on the other end and believe it can do HSS. I might be wrong though, time will tell.