Max Sync Speed w/Alien Bees

[Todd]

Greetings All-
Using (4) B1600's and the LG4X remote wired to a -1D the maximum shutter I could run was 1/3200. It would sync at 1/4000 about 30% of the time. The same set-up plugged into my -10D and I was catching the curtain each time from 1/500 thru 1/2000. I have not tried moving the sync cord to a head instead of the remote yet, though I don't think it will matter.
I'm wanting to get to 1/16000 shutter sync, and I know many people live on this shutter speed using studio flashes, is it that the Bees aren't up the the sync speed or something else? For the money the bees seem to be a very good value thus far....I may be expecting too much on the sync speeds.

Thanks
Todd Asher

[DocFrankenstein]

I'm confused

[CyberDyneSystems]

... er

O-kay.. the max synch speed of the 1D was the fastest of any SLR camera in history.. it was 1/500.

The 10D max sync is 1/200th.

The 10D does not even have a shutter as fast as 1/16000... so how on on earth could your lights synch to it 1/16000 on a camera with a max shutter of 1/4000?

10D shutter maxes out at.. 1/4000

Tj you know more about this than I do though.. are you able to get the AB's to work with the FP/Hsync?

I did not think studio strobes could do that.
Anyways.. you obviously can't get to 1/16000 with a camera whos' shutter only goes to 1/4000?

[Todd]

Thanks for replies...I only put the -10D on only for a test, the -1D was the camera I'm using for the high shutter speeds. It will be another day or two before I'll be set-up again for more tests. It just seems odd that it can sync consistant at 1/3200 and not at 1/4000 when it should sync much faster. The 1/500th sync limit is using speed lights (such as 550EX) in any mode other than fill flash, for in fill or FP flash it will sync at all shutter speeds. I've not tried using the ST-E2 in FP or a 550EX in FP; the IR signal from the ST-E2 or the flash from the speed light may trip the system in time, may not, that is my next test. I just thought someone may have already found the limits (if any) on the Alien Bees and sync speeds.

Thanks

Todd Asher

[CyberDyneSystems]

Check back in a few days.. we do have a few members with Bee's.. they'll drop in soon enough.

[DocFrankenstein]

Well... on full power the alien bees burst of light is 1/500 sec long if I remember correctly.

So it's possible that you'll be able to sync at 1/600, but you'll lose most of the light

[Todd]

Again, thanks for the replies.
I just tested my last options:

ST-E2....Tripped the flash as expected, sync was off at all shutter speeds!

550EX...Only when in manual mode (not ETTL) and FP, it tripped and was in sync at all shutter speeds including the 1/16000 I was looking for! Might have to play around with hard wired or wireless solutions in the future...but this will suffice for now

This is great news and possibly one day someone may do a search on sycn speeds and find an answer!

Todd Asher

[froman98]

If you're able to get a flash that will sync with your camera at 1/16000 wouldn't that give the model an instant suntan/burn?!?!

[snibbetsj]

Buff recommends a shutter speed of 1/160 with the AB's. Why do you want such a fast shutter in the studio?

[snibbetsj]

I'm wanting to get to 1/16000 shutter sync, and I know many people live on this shutter speed using studio flashes,

Where did you hear this? The max shutter speed of a 1DII & 1DsII is 1/8000.

[RichardtheSane]

Where did you hear this? The max shutter speed of a 1DII & 1DsII is 1/8000.
He is probably referring to his 1D and not a mark II version

[snibbetsj]

He is probably referring to his 1D and not a mark II version

I didn't know the 1D was that fast. Actually, I was wondering where in the world he heard that most people "live" on 1/16000 with studio flashes. I've never heard anyone that used that, all the strobes I've ever heard of have a flash duration longer than that.

I would believe 1/160 but not 1/16000.

[RichardtheSane]

1d sure does go that far :)

But i agree with you... I couldn't see why anyone in a studio would need 1/16000 either. It is not as if the models are moving that much!

[SkipD]

I just checked the Alien Bees website to find out the flash duration of the three models. There's a lot more information on their site, but at full power the B400 is 1/6400th second, the B800 is 1/3200th second, and the B1600 is 1/1600th second.

There is absolutely no reason that I can think of to use a shutter speed faster than the normal maximum rated sync speed for the camera (1/250 sec. for my 20D).

[Reminisce]

I am so confused.
Im sure everyone here is trying their hardest to assist you and im not sure if they are giving you the answers you want. But specifically agreeing with the above poster, why would you need a monolight to sync at such a shutter speed at all? I honestly cant think of any instance where that speed/light would be needed. Just trying to get some insight here.

[chtgrubbs]

Sorry Todd, but cameras just don't sync at those high speeds. A focal plane shutter has to be completely open , by which I mean the first shutter curtain goes completely across the film plane before the second curtain starts its trip across the film plane. This speed is usuall somewhere between 1/125 and 1/250 second. Any faster and the second shutter curtain will have started moving and will block the light from sensor. I believe the figures you have seen relate to to flash duration, which is the actual time the flash is "on" and is independent of shutter synch speed, or possibly refers to the synch reaction time of a radio slave, which how long it takes to react to the shutter release and trip the flash.

There is no reason to synch at such high speeds. You can stop motion with a strobe because the short flash duration is what makes the exposure, unless the ambient light level is too high, and if you have enough ambient light for 1/16,000 of a second you for sure don't need a flash!

[mbze430]

those speed that is on their website has NOTHING to do with shutter speed. Those # are the duration of a full power pop.

Normally most studio strobe will sync with the shutter speed at 1/125. Higher end stuff might go a bit faster. But in a controlled enviroment, why would anyone need to go this high is still beyond me.

[Longwatcher]

I can see needing sync to 1/500, sometimes my models are moving about, although I found 1/180 seems to work good for model and flash sync with 10D, I can get 1/250 out of 1DsMkII and Alien Bees and not sure why it works slightly better then 10D. I found that if I shoot at 1/125 I sometimes get blurred hands. I can see some occasions to go higher then 1/500 like for scientific or artistic purposes, although nothing I am normally likely to need.

What I can't figure out is, except for using external on-camera flash (AKA 550/580EX), how you can get the lights to sync higher then 1/250? I can't get mine to go faster then that before the shutter starts closing. I like playing with my camera, but I can't get it to do that (either 10D or 1DsMkII).

Am I not knowing how to do something?
???

[CyberDyneSystems]

those speed that is on their website has NOTHING to do with shutter speed. Those # are the duration of a full power pop.

It may have little do with synching with the shutter,. but the numbers are pertinant.

What seems to be missing in this thread is a grasp of the concept that the camera's shutter does not need to be synching with the flash beyond the cameras max of say 1/250 for you to get the effect of a shutter of 1/6000

If your strobe duration is 1/6000.. then that pop of flash IS your shutter.

[mbze430]

if the flash was pointed directly at the camera, than it might sync at 1/6000. It also depends what the distance between the light and camera. There is no standard way for manufacture to come with these #s.

[RDKirk]

if the flash was pointed directly at the camera, than it might sync at 1/6000. It also depends what the distance between the light and camera. There is no standard way for manufacture to come with these #s.

I think you still fail to understand what's happening. It doesn't make any difference which way the flash is pointed.

The focal plane blades take a finite, rather slow amount of time to pass across the sensor--that speed generally ranges from 1/125 to 1/250. It doesn't make any difference what the shutter is set on--it still takes that long for each curtain to get over the sensor. That is the "maximum flash sync" speed. Up to that speed, the first curtain opens fully and the full sensor is totally exposed before the second curtain starts across. At settings faster than that, the second shutter starts across BEFORE the first shutter has gone completely across, and the film is exposed by a slit formed by the two curtains--which gives a shorter exposure of any given part of the sensor. The higher the shutter speed, the narrower the slit. But it still takes 1/125 to 1/250 for that slit to travel across the sensor.

The electronic flash, OTOH, is extremely fast in comparison. The flash duration is the length of time it takes the capacitor to dump their charge. The slowest flash units--the huge 5000 watt second units--take the longest. They may take up to 1/125 to dump their huge charge (which is why Canon advises using 1/125 for studio flash units--they figure all their customers are flush enough to own the big flash units). Smaller flash units take from 1/500 to as little as 1/3200. These are very brief blips of time.

Now, remember it still takes the slit of the focal plane shutter a whole 1/125 to 1/250 to travel across the sensor. So if the flash is only 1/1600 long, at the higher shutter speeds, the shutter will have barely started across the sensor before the flash has come and gone. The higher the shutter speed, the less of the sensor gets exposed before the flash has come and gone. That's why the shutter has to be set at a speed at which it's completely open when the flash goes off.

Presuming the ambient light level is comparatively low, the only thing exposing the subject is the flash. Because the flash is so quick, it is the "effective" shutter. You've seen those high-speed photos of bullets ripping through apples---that's done with extremely brief electronic flash while a relatively very slow shutter is hanging wide open (as far as the flash is concerned).

[Todd]

Greetings All-
The reason I'm running my shutter at 1/16000 is for high speed motion/impact shots. I've not been able to get enough light to run that shutter speed until I got the four Alien Bee B1600 lights. The flash duration was not important as long as I could fire the flash prior to the shutter opening. Using the 550EX in manual and in FP mode everything is now working great.
I really do not understand why I could not get the flash to fire in time when it was plugged into the camera. It seemed that 1/4000 should have worked or not, instead of some of the time! Oh, well.
I really want to thank everyone for replying to my question.

Thanks-
Todd Asher

[Jon]

To get the flash to illuminate the whole frame, it would have to have a pulse at least as long as the time the shutter takes to move across the entire frame (which is not the same as the shutter speed you set on a camera). To get that at faster than X-sync speed, you'd need to fire the flash before the first shutter curtain opens and the flash would have to continue to be on until the first shutter curtain has travelled all the way across the sensor. That's what the 550EX' HS flash mode does (actually, it fires a whole series of small bursts during the time the shutter's open), and what old M- and FP-sync flash bulbs did (with a steady burning of the Mg or Al filament). Regardless of the shutter speed you set, the first and second shutter curtains always travel across the sensor at the same speed. You get different exposures by altering the delay between them. SO, if X-sync is 1/250 sec, that's about how long it takes the curtains to travel across the sensor. If the curtains moved any faster, you'd be able to get X-sync at that faster speed.

So, if you're trying to stop motion with a high shutter speed, you're not actually getting that instantaneous 1/16000 sec. from your shutter that you might want. Different parts of the frame are getting that 1/16000 sec. exposure at different times over the course of the 1/250 sec. it takes the shutter to expose the whole sensor. If you look at early press photographs, taken in the Speed Graphic era (with a quite slow focal plane shutter), you'll see examples of this. There's at least one fairly well-known picture (Lartigue (http://www.masters-of-photography.com/L/lartigue/lartigue_car_trip.html)) showing a period auto speeding along the road. The wheels are decidedly oval due to their having moved during the course of the exposure. You can also see this in photographs of fan or propellor blades, which may take on a curved appearance due to the shutter's non-instantaneous exposures.

True instantaneous action-stopping pictures rely on a fairly long shutter speed in very low ambient light, and a very short exposure from the flash. That's what Harold Edgerton was famous for.

[Todd]

Jon-
I can't advise on the other digital EOS cameras, however, the -1D only uses the mechanical shutter while in bulb mode and in all other modes simply turns the CCD on and off. This may or may not work on CMOS sensors, but that is how I'm getting these "shutter" speeds!

Thanks again for the replies,

Todd Asher

[Moments]

Greetings All-
The reason I'm running my shutter at 1/16000 is for high speed motion/impact shots. I've not been able to get enough light to run that shutter speed until I got the four Alien Bee B1600 lights. The flash duration was not important as long as I could fire the flash prior to the shutter opening. Using the 550EX in manual and in FP mode everything is now working great.
I really do not understand why I could not get the flash to fire in time when it was plugged into the camera. It seemed that 1/4000 should have worked or not, instead of some of the time! Oh, well.
I really want to thank everyone for replying to my question.

Thanks-
Todd Asher

Todd,
Don't know how to fire the flash before the shutter opens would work, or what your sync problems were but, I think that the reason for the 550 doing a better job is as to it's not being as powerful as the monolights. If you are looking to freeze motion, you need to look at the flash duration of the stobes. The strobes should have a listing of the range of the duration. The fastest flash duration will be when the strobe is set to it's least amount of power and as the power goes up, the flash duration goes down. The flash duration is how long it takes to complete the flash and the more power thats in a flash (burst of light) the longer it takes to complete. So to freeze action power down your lights and you will see it sharpen the action.

When I had to shoot a drop on water hitting the surface of more water, we rented a Broncolor pack that was able to adjust the flash duration regardless of the power. (don't know how it works, but the pack cost over $5000.00 so it should do anything you want it to do) We shot it at 1/6000 of a second for the flash duration and the cameras shutter speed was at 1/60. It was perfectly sharp.

[chtgrubbs]

Apparently I was wrong when I described how shutter synch works in my previous post. It was correct for film, but some digital cameras shut the sensor off before the shutter actually closes. See this post for a discussion about how it works:

http://forums.dpreview.com/forums/read.asp?forum=1025&message=13475079

[chris clements]

My brain hurts! I've read this thread through several times, but still don't understand why the shutter/synch speed should be of any relevance in these circumstances.
Surely the two key points are -
(a)for this sort of shot the flash duration is effectively the shutter speed.
(b)a lower-powered flash will (generally) have a shorter duration.

... what's passing over my (pointed) head ? ?

[rz22g]

One thing to keep in mind is that a strobes flash duration rating is not the true duration. Alien Bees explains that manufacturers obtain this rating by caculating how long the light is above 1/10 of its peak intensity. A light rated at 1/6400 will actually emit light longer than this. The flash emits and dims off at the end. The tail of the flash might not contribute much to the exposure but it can cause blur.

I have tested with my AB 400 at lowest setting (1/6400 duration), in a completely dark room with a 1 sec exposure. I wave my hand, the shutter is activation and the stobes are tripped manually. The action is not frozen.

[Cwaller]

i have two AB 800s with the 40D, would i sync them at 1/160? I'm new.

[SkipD]

i have two AB 800s with the 40D, would i sync them at 1/160? I'm new.Do you realize this thread is over four years old? For a new question, it's probably better to start a new thread rather than to dig up ancient threads that are not 100% related to your question.

I can sync my AB lights to my 20D at 1/250 second, even using the Elinchrom Skyport Universal radio slaves. Try it and find out what your limit is.

[RDKirk]

My brain hurts! I've read this thread through several times, but still don't understand why the shutter/synch speed should be of any relevance in these circumstances.
Surely the two key points are -
(a)for this sort of shot the flash duration is effectively the shutter speed.
(b)a lower-powered flash will (generally) have a shorter duration.

... what's passing over my (pointed) head ? ?

Your (a) is true, as long as the flash exposure is three stops or more than the ambient light exposure.

A lower powered studio flash may not have a shorter duration. Portable (hotshoe) flashes always energize their power capacitors to full charge, then emit reduced power by cutting off the flow of electricity from the power capacitors, like turning off the spigot of a water tank. The remaining power is still in the capacitors. Because the power is quenched, reduced power results in reduced duration as well.

Most, especially older design (3 or 4 years old) studio flash units reduce power by reducing the charge of the capacitor, then dumping that entire reduced charge. The speed at which the power capacitor can dump its charge is at least as long at reduced charge levels as it is when fully charged, and often even longer.

In cases where the full power of a flash unit is attained by using multiple power capacitors, setting a lower power level merely means that each capacitor is filled to a lesser level; the result will be the same. Some multi-capacitor units, though, do actually switch out capacitors at discreet lower levels--that's what happens with the 1/4 power switch on White Lightning X1600 flash units.

So reducing the power of a studio unit might not give you a shorter duration, and it could even be longer.

[SkipD]

Your (a) is true, as long as the flash exposure is three stops or more than the ambient light exposure.

A lower powered studio flash may not have a shorter duration. Portable (hotshoe) flashes always energize their power capacitors to full charge, then emit reduced power by cutting off the flow of electricity from the power capacitors, like turning off the spigot of a water tank. The remaining power is still in the capacitors. Because the power is quenched, reduced power results in reduced duration as well.

Most, especially older design (3 or 4 years old) studio flash units reduce power by reducing the charge of the capacitor, then dumping that entire reduced charge. The speed at which the power capacitor can dump its charge is at least as long at reduced charge levels as it is when fully charged, and often even longer.

In cases where the full power of a flash unit is attained by using multiple power capacitors, setting a lower power level merely means that each capacitor is filled to a lesser level; the result will be the same. Some multi-capacitor units, though, do actually switch out capacitors at discreet lower levels--that's what happens with the 1/4 power switch on White Lightning X1600 flash units.

So reducing the power of a studio unit might not give you a shorter duration, and it could even be longer.Do you realize how old this thread is? It's nearly five years old except for the new post by Cwaller today.

Chris Clements - the person you quoted from - hasn't posted here since September of 2007.

We need to be alert to ancient threads being resurrected. It seems to be happening a lot lately.

[RDKirk]

Do you realize how old this thread is? It's nearly five years old except for the new post by Cwaller today.

But isn't that why threads are allowed to persist so long? Apparently someone uses the "search" function (or searched manually)...which is what we always tell people to do.

[SkipD]

But isn't that why threads are allowed to persist so long? Apparently someone uses the "search" function (or searched manually)...which is what we always tell people to do.Yeah, but you were talking to the equivalent of a blank wall in answering the post you did. The fella you replied to hasn't posted on any of the forums in this group for over two years. :rolleyes: