Sync speed and the 40D!

So I'm reading the manual on my 40D and the manual refers to the sync speed of 1/250 for compact flashes. Then it says for studio strobes that its 1/60.

I'm a bit confused because from everything I've known that it was 1/250 on any flash. Is the manual correct. I haven't had a chance to test in the studio yet to see how a photograph is impacted with the ambient light at that slow of a shutter speed.

If anyone can give me some insight that would be awesome.

Anyone?

I know radio triggers vary widely in terms of sync speed and that must be due to the time it takes the electronics to respond. I the time it takes for the radio signal to get to the remote flash is negligible...

I know the manual says 1/60 but i would advise you to do a test with your specific gear. start at 1/60 and work your way towards 1/250. Use something that will show the contrast well such as a white wall. Watch out for the diffuse shadow at the bottom of the frame. In the film days sync failure was a crisp line right along the frame... but DSLRs generally have more space between the shutter and the sensor, therefore the line is diffuse.

majin tcz wrote in post #9973997
So I'm reading the manual on my 40D and the manual refers to the sync speed of 1/250 for compact flashes. Then it says for studio strobes that its 1/60.

I'm a bit confused because from everything I've known that it was 1/250 on any flash. Is the manual correct. I haven't had a chance to test in the studio yet to see how a photograph is impacted with the ambient light at that slow of a shutter speed.

If anyone can give me some insight that would be awesome.

Try and find out; some camera bodies have defied their publish specs and sync at speeds faster than what their literature entails. You may find yourself lucky in this front or you may find that it performs as documented. It won't to try for yourself and see as it can be rather dependent on your method of syncing your camera with your off-camera lighting (whether it be a studio strobe or a speedlight(or lite).

I just sold my Leica D-LUX 4 and one of the great things about it was that it synced via GI triggers at 1/2000th of a second without any black barring whatsoever on the frame and did it without fail consistently.

Pretty impressive for a compact camera if I do say so myself.

An electronic flash has a 'rise time' as well as a 'duration'. During the rise time, the output is increasing to its peak, and the 'duration' is the time interval during which the shutter needs to be fully open in order to capture the output of light. For speedlights, they generally have a fast rise time and fast output duration, as they generally are limited in total output. Studio flash units, typically being more powerful than speedlights, have somewhat slower rise times and long durations in order to output all the light. Think of fire hoses...it takes a bit of time to open the valve fully and for the max output to be achieved.

So a fast shutter speed like 1/250 works with a speedlight or most of the lower power studio flash units, while the slower shutter speed is needed for really powerful studio flash units. (note: Some studio flash unit designs do not follow the generality about longest duration = max power output.)

Back when i had a 40D, it would sync at a max speed of 1/250 with AB's triggered with Cybersyncs or a sync cord...any faster and the shutter would make an appearance in the frame.

Same goes for a 580EXii triggered with the same means.

Both of my 40D's sync nicely at 1/200 with the 602 rf triggers firng Alienbees.

Stuart Leslie wrote in post #9974940
Both of my 40D's sync nicely at 1/200 with the 602 rf triggers firng Alienbees.

yup same here, no worries. Same set up using AB400's

It depends on the flash equipment you are using (not the radio triggers as virtually all of them are designed to allow maximum flash sync anyway). YOU have to test it for your own camera/lighting and see what works. It doesn't matter what works on some one elses camera and flash.

JJ

I suspect that is to cover themseves in case someone is using the longest duration flash one could imagine. Manufacturers tend to be conservative in that respect. For what it's worth, I can remember when 1/60 was the fastest shutter speed you could sync with any kind of flash when using focal plain shutters. We thought it was a miracle when 1/120 sync speeds were available on a few select cameras. The improvement in shutter curtains has been phenomenal.

I get 1/320 using Calumet Genesis and Skyports with the 40D if everything has fresh batteries/charge. it drops as the batteries do but stays consistent at 1/200th until the batteries are on their death bed.

Yea I just found it extremely weird that they had it rated so low. I'm currently using Alien Bees B800's and at 1/250 I dont get any of the shutters in the frame. Definitely to cover their butts just incase.

rigshots wrote in post #9976609
It depends on the flash equipment you are using (not the radio triggers as virtually all of them are designed to allow maximum flash sync anyway). YOU have to test it for your own camera/lighting and see what works. It doesn't matter what works on some one elses camera and flash.

JJ

Again, not true. You cannot disregard the variable that in which triggers your flash via frequency because you think they all adhere to a phantom standard. Not all radio triggers are created equal -- just as all flash and cameras are not. Take a look at the additional examples of some ABs syncing faster than the ones contested for earlier in this thread with the same camera body but what was the variable that changed? The choice of radio triggers.

Luminodio wrote in post #9982018
Again, not true. You cannot disregard the variable that in which triggers your flash via frequency because you think they all adhere to a phantom standard. Not all radio triggers are created equal -- just as all flash and cameras are not. Take a look at the additional examples of some ABs syncing faster than the ones contested for earlier in this thread with the same camera body but what was the variable that changed? The choice of radio triggers.

I'm assuming reasonable quality triggers here. If you use gear that costs you 20cents on evilbay then you do get what you pay for but I suspect most are designed to sync at 1/250th. In any case, you need to test YOUR specific equipment/setup and not worry about how it works on some one elses camera.

For example, my Pocketwizard Plus (the old ones, not Pocketwizard Plus II) trigger correctly at 1/500th on a leaf shutter (on a view camera) with hotshoe strobes yet I only get 1/125th when using studio strobes using the same radio triggers.

JJ