I had great intentions of doing a video of this post and I even went out and got a new video camera, but actually getting it filmed has turned out to be a whole different story. So it's been a few weeks and I need to get this post done, and it's not going to be a video for at least a while yet.
I've been shooting at 1/1000th of a second and faster and syncing with flash using the Pocket Wizard Multimax's. It's not hard to do, but you do have to experiment a bit with settings.
The Theory behind it all
The basic premise of it is this: When you press the release the camera opens the shutter and sends a signal to the flash once it is fully open. The key part here is "once it is fully open" that means that at 1/250 the sync signal isn't sent the moment the shutter begins to open, but once it is fully open. This is important to us because with a full frame camera that signal is sent part way through the exposure. And if you set your shutter speed to 1/1000 then the flash will fire somewhere near halfway through your shot. So even if you have a long flash duration, you'll lose a significant part of the frame. What we need to do is to get the flash to fire the moment the shutter begins to open, and keep firing until it closes. The keep firing part is accomplished simply by using a flash (or flashes) with a long duration, longer than your shutter speed. The part about getting the flash to fire before it gets the signal is a little bit trickier. The Pocket Wizard Multimax offers a solution with its delay setting. Basically you set up the camera as a remote with one Multimax in receiver mode and no delay. You set up your flashes with Multimax receivers and set a delay on them so that they fire just before the shutter opens. Now I know some of you are probably thinking, "if you put a delay on the flashes and none on the camera then won't the flash fire after the camera?" and in a perfect world you'd be right. However the camera takes a lot longer to receive the signal and trip than the flash does. Cameras are mechanical and need to do a lot more than a flash does. And when I say a lot longer, I'm talking in 10,000's of a second here. Using another Multimax as a transmitter you fire the camera and the flashes, pretty simple really.
The new Pocket Wizard Flex TT5 with Hypersync should be able to eliminate having to use a separate Transmitter to fire the camera and the flashes. Just set the delay on the TT5 on the camera hotshoe and press the shutter release. The Transmitter knows when the camera is going to fire before it happens, and it can pretrigger the flashes. Same effect, different execution.
Setting it up
I'm going to assume at this point that if you're going to try this you know how to set your camera up as a remote so I won't tell you how to do this now. You can set the camera Multimax to whichever channel and zone you want, as long as it's above 16.
Next you need to set up your flash. Connect the sync cord to the flash from either of the Pocket Wizard ports, I frequently use both of them and put two flashes on the same receiver. Just make sure that when you set the delay you set it for both the ports. You do this by choosing menu:a:a:a that will set up Port 1 and Port 2. If you just want to use Port 2 (the flash port) you enter menu:a:a:b
The menu should now say "SET DELAY" and you should have some numbers at the bottom in the format 0.0000 To start with you want them to say something close to 0.0420sec, you adjust them using the ABCD buttons and the up/down arrows. This number will be different for every camera and flash combination but at least for the Nikon cameras I've found that this is a good starting point. Once you're done there hit menu again to return to the main screen, which should now say DELAY: 0.0420 above the zone letters. Don't forget this part.
Now all you need to do is set your flashes to full power and your camera to 1/1000 and do some tests.
Testing the setup
This is the most important and time consuming part of the whole deal. Once you have set a delay on the flashes and the camera is ready to go you need to confirm that the delay is correct. It probably won't be in the beginning, and you'll need to go back and adjust it. I find it easiest to put the camera on a tripod for this and point it at something reasonably close that fills the frame (5-10 feet is good) Then you need to point your flash at the same object and using the Multimax transmitter fire the camera and the flash. (doing this in a darkish place definitely helps) If everything is setup correctly you should hear the camera fire and see the flash fire. Then take a look at your image. Is there any flash in the shot at all? Is it lighting up all of the image or only part of it? If it's perfectly lit from top to bottom you're very lucky. Write down all the settings in your notebook. It probably won't be perfectly lit this first time and you'll have to play around a little. If there is no flash in the frame at all and you saw the flash fire then set your shutter speed down to around 1/250 and try again. If there is still nothing, go lower until you see the flash in the frame, if you get to 1 second and there is still nothing then you probably need to adjust your delay a fair bit until the flash shows up. Once you have the flash in the frame you can fine tune the delay. This is accomplished by trial and error, adjust your shutter speed to where you want it, then adjust the flash delay by one or two 10,000 in either direction and observe the results. Then go the other way and see how it changes. You should be able to move the flash in and out of the top and bottom of the frame. Remember that after adjusting the delay you need to press menu to exit to the main screen before shooting an image. Write down everything that you think works for you, including the Camera, shutter speed, flash type, flash power, and delay.
Problems
You may notice a whole bunch of different problems that come up with different cameras. Little things like sometimes you'll take 5 photos in a row and they'll all have slightly different amounts of shutter showing. Remember that if your shutter speed is 1/1000 then 1/10 of your frame is 1/10,000 of a second, and most camera shutters aren't that accurate so things like this happen. The only real solution is to play around a little more and use a flash with the longest duration possible.
If you end up doing this and have any other input please let me know!
Showing posts with label sync. Show all posts
Showing posts with label sync. Show all posts
Friday, March 13, 2009
Friday, February 20, 2009
High Speed Sync Part 1
In my last post I mentioned that with the new Pocket Wizards Hypersync mode they're saying that you can sync at up to 1/500th of a second and that I thought you could go faster. I'd like to clarify that a little. While Hypersync, or an early sync signal, is key to high speed sync and especially with a full frame camera, that alone won't do it. And 1/500th - 1/800th sync is pretty hard to get, 1/1000th is a little easier. The reason for that is that at 1/500th of a second shutter the opening is a slit, (see the photos in Camera Sync Speed and Flash from last July) and no matter how early you fire the flash you're not going to change that. What you need to rely on is the flash duration being slow enough to cover the entire frame as the shutter moves across it. That's kind of opposite of what we normally want for action, which is a really fast flash duration. And 1/500th shutter with 1/500 flash is often not as good at freezing as 1/250th shutter with 1/2000th flash duration.
As you've probably already guessed from reading this far there is a lot going on when you are syncing at high shutter speeds. I like to shoot at 1/1000 of a second and run my SB800's at full power. That gives me a flash duration of close to 1/1000 of a second, which is pretty close to the shutter speed, but it still doesn't quite always fill the entire frame. You will also notice that the light falls off a bit through the end of the frame as the flash duration measurement of T.5 (measured from when the flash hits full power until it drops to half power, thus the .5) includes a full one stop range in flash output. Ie at full power if the flash is at f8, when it drops to half power it'll be at f5.6, which is more than enough light to still be visible, and enough of a difference to be noticeable. Also when your flash duration is so close to the shutter speed you start to notice things like the 1/15,000 to 1/20,000 of a second irregularities in the shutter. Sometimes you see a little of the shutter curtain, sometimes you don't, there aren't many cameras that have shutters that are accurate to 1/15,000 of a second or faster.
So what I'm really saying is that to sync your flash at faster than 1/500th of a second you really need a slow duration flash, and slower is better to some extent. If you're shooting at 1/1000th and your flash duration is 1/500th, then the flash turns on, your shutter moves across the image, and then your flash turns off, with a bit of leeway on either side.
To do this you need to be able to fire the flash 1/10,000 of a second or so before the shutter opens, and you need to be able to adjust that sync point by 1/10,000's of a second to make up for variations in shutters and flashes.
David Hobby said in his review of the new Pocket Wizards on his Strobist blog that "It's only a matter of time before the message boards start lighting up with best settings for every camera and flash model combos to rack the full sync out as far as possible." Well I can tell you from experience that there is a different setting for every shutter speed and flash power combination with every different camera and flash model. So it's going to be a huge list. I started making one with exact sync offsets for my SB800's and my D2Xs and my D700 or D3 and realized that while you can get pretty close with a chart, I find I still need to finetune by 1/10,000's up and down every time I set up.
This is a lot of tech information and may be a little much for those of you that aren't total geeks, so I'll follow this up with a few more posts on the topic and eventually (hopefully soon) a video post about how to set up Pocket Wizard Multimax's to do all this.
As you've probably already guessed from reading this far there is a lot going on when you are syncing at high shutter speeds. I like to shoot at 1/1000 of a second and run my SB800's at full power. That gives me a flash duration of close to 1/1000 of a second, which is pretty close to the shutter speed, but it still doesn't quite always fill the entire frame. You will also notice that the light falls off a bit through the end of the frame as the flash duration measurement of T.5 (measured from when the flash hits full power until it drops to half power, thus the .5) includes a full one stop range in flash output. Ie at full power if the flash is at f8, when it drops to half power it'll be at f5.6, which is more than enough light to still be visible, and enough of a difference to be noticeable. Also when your flash duration is so close to the shutter speed you start to notice things like the 1/15,000 to 1/20,000 of a second irregularities in the shutter. Sometimes you see a little of the shutter curtain, sometimes you don't, there aren't many cameras that have shutters that are accurate to 1/15,000 of a second or faster.
So what I'm really saying is that to sync your flash at faster than 1/500th of a second you really need a slow duration flash, and slower is better to some extent. If you're shooting at 1/1000th and your flash duration is 1/500th, then the flash turns on, your shutter moves across the image, and then your flash turns off, with a bit of leeway on either side.
To do this you need to be able to fire the flash 1/10,000 of a second or so before the shutter opens, and you need to be able to adjust that sync point by 1/10,000's of a second to make up for variations in shutters and flashes.
David Hobby said in his review of the new Pocket Wizards on his Strobist blog that "It's only a matter of time before the message boards start lighting up with best settings for every camera and flash model combos to rack the full sync out as far as possible." Well I can tell you from experience that there is a different setting for every shutter speed and flash power combination with every different camera and flash model. So it's going to be a huge list. I started making one with exact sync offsets for my SB800's and my D2Xs and my D700 or D3 and realized that while you can get pretty close with a chart, I find I still need to finetune by 1/10,000's up and down every time I set up.
This is a lot of tech information and may be a little much for those of you that aren't total geeks, so I'll follow this up with a few more posts on the topic and eventually (hopefully soon) a video post about how to set up Pocket Wizard Multimax's to do all this.
Wednesday, February 18, 2009
Pocket Wizardry
Pocket Wizard has just announced the new Flex TT5, the successor to the MultiMax. While it's currently only available for Canon, a Nikon version will be available soon. You can read about it here
So why would a flash trigger be Nikon or Canon specific you ask? That's because it reads and uses the camera's TTL codes and each manufacturer uses slightly different pins on the hotshoe to transmit those codes. It also does something else that is way more important for me, it allows you to pretrigger the flash. They call this HyperSync, and this is their brief description of what it does
"With PocketWizard HyperSync™ Technology, the FlexTT5 can precisely advance the timing of your flash trigger so that increased flash sync speeds, up to 1/500th of a second is achievable with many strobes."
Now while they say 1/500th of a second sync speeds are possible, the reality of it should be far greater. I can currently sync at 1/1000 or even 1/2000 using the now old fashioned MultiMax's with just about any camera. Here are a couple of examples shot with my full frame D700.
You may notice that the image shot at 1/2000 only has light on the bike rider and not on the rest of the frame vs the image shot at 1/1000 that has light across almost the entire frame. This is not really a technical issue, I just used a couple of other flashes on the 1/1000 shot to light up the jump. It's a bit more work to figure out but not technically more difficult. Both images used SB800's to light the rider, and for the image shot at 1/1000 I used a couple of Quantum T2D's to light the jump.
I'll try to have a post up in the next day or so with details on how to sync at 1/500th and higher.
So why would a flash trigger be Nikon or Canon specific you ask? That's because it reads and uses the camera's TTL codes and each manufacturer uses slightly different pins on the hotshoe to transmit those codes. It also does something else that is way more important for me, it allows you to pretrigger the flash. They call this HyperSync, and this is their brief description of what it does
"With PocketWizard HyperSync™ Technology, the FlexTT5 can precisely advance the timing of your flash trigger so that increased flash sync speeds, up to 1/500th of a second is achievable with many strobes."
Now while they say 1/500th of a second sync speeds are possible, the reality of it should be far greater. I can currently sync at 1/1000 or even 1/2000 using the now old fashioned MultiMax's with just about any camera. Here are a couple of examples shot with my full frame D700.
You may notice that the image shot at 1/2000 only has light on the bike rider and not on the rest of the frame vs the image shot at 1/1000 that has light across almost the entire frame. This is not really a technical issue, I just used a couple of other flashes on the 1/1000 shot to light up the jump. It's a bit more work to figure out but not technically more difficult. Both images used SB800's to light the rider, and for the image shot at 1/1000 I used a couple of Quantum T2D's to light the jump.
I'll try to have a post up in the next day or so with details on how to sync at 1/500th and higher.
Sunday, December 7, 2008
Bike Mag Cover
Last month I got something really exciting in the mail, Bike Magazine, and for the second time in my life I had a photo on the cover of it. What set this cover apart for me was that it was shot at 1/500th of a second with flash. See my post on Camera Sync Speed and Flash for more details.The Details:
This was shot at 1/500 f5 with a Nikon D2Xs. I used 2 Nikon SB800's set to manual 1/2 power and mounted on a single stand. I can't remember exactly what the zoom was set at but I metered it out to match the sunlight coming from almost directly overhead. Flash's are on a stand at the bottom of the photo in the middle, behind the bush. Some people may wonder why I used 2 flashes at 1/2 power, isn't that the same as one flash at 1/1? Yes it is, the big difference is that the flash duration is way quicker, so you get a crisper image, and if I was going to take a second shot, they recycle way faster as well. I've started using 2 SB800's together now for a lot of different things, it just seems to work better for me.
Saturday, July 19, 2008
Camera Sync Speed and Flash
There seems to be a fair bit of confusion in the world about camera sync speeds, Pocket Wizards, and high speed sync so I thought I would try to explain and demonstrate how it all works.
Camera Sync Speed (SLR)
Your camera has a set sync speed which is the fastest shutter speed you can use with a flash for that particular camera. So say the camera companies. Knowing how it works can allow for some additional creative processes. I'm going to assume that you know what a shutter is, and the examples here were shot with a Nikon D2Xs, Canon's work the same way, they both have vertical focal plane shutters. Rather than rewrite what's already been written about shutters I'll refer you to a fairly good description with diagrams on wikipedia.
The sync speed of your camera is the maximum shutter speed at which the shutter is entirely open. After that point the shutter begins to close before it is fully open, creating a slit that moves across the focal plane as can be seen in these shots below.
"Wait a minute you're saying, how did you shoot faster than the sync speed of the camera, mine won't let me do that!"
Most SLR and DSLR cameras detect that a flash is attached and electronically limit the shutter speed to the maximum sync speed of the camera. By using a PC cord or a Pocket Wizard or other such remote you can bypass the detection of the flash. If the flash is not on the hot shoe, the camera doesn't know that it's there, and thus it doesn't limit the shutter speed. This can be a good thing if you understand how to use it. As you can see in the images above there is very little difference in the 1/250 shot and the 1/320 shot, if I'm shooting with pocket wizards I frequently shoot at 1/320. Even at 1/500 the flash still covers almost the bottom 2/3 of the frame, so if I position my flash lit subject in that bottom 2/3, and keep the top 1/3 lit by ambient light, everything will be fine. You can use the same trick for vertical shots as well, just keep the flash cropping in mind when you compose.
Pocket Wizard Multimax Fast Mode
The Pocket Wizard Multimax transceivers have a fast mode that according to the manual allows you to sync up to 1/1000 of a second. Of course that's dependent on your camera's sync speed, and the only camera I know of that can sync at 1/1000 is a Rollei with a PQS lens. It does affect your camera's sync however, as shown in the photos below. The photos with the HS are the ones shot in Fast Mode
As you can see from the images, with Fast mode on the Multimax there is no discernible flash cropping at 1/320, and at 1/400 you still have most of the frame available for flash. At 1/500 and 1/1000 there is a smaller difference, but still good to know about. Please note that every camera is slightly different so you should repeat this test with your own camera before you start using it this way.
Nikon Auto FP High Speed Sync
As I use Nikon Cameras I won't go into the Canon version of this feature, although i believe it is similar. Nikon pro cameras and the newer Nikon "prosumer" cameras allow you to use what they call "Auto FP High-Speed Sync" mode with the Nikon SB600 and SB800 flashes. It allows you to shoot up to 1/8000 with a flash. It accomplishes this by firing a bunch of vey fast flash pulses instead of one single flash, and these pulses blanket the shutter as it opens and closes so that the entire image is lit. There are several benefits as well as several drawbacks to this feature.
Benefits - As it allows you to shoot at a higher shutter speed you can adjust the ambient light level and keep a lower aperature even in bright daylight. Also you can shoot at a higher shutter speed to freeze action and still use fill flash.
Drawbacks - Because it fires a bunch of flashes the actual flash "duration" becomes much longer making it less than useful for freezing action between 1/250 and 1/1000. Also because it has to fire more than once the effective power level of the flash is greatly reduced, and the recycle time increases. The biggest drawback is the huge reduction in output. My Nikon SB800's at ISO100, 1/2 power, 70mm zoom at @7 feet give me @f8. With the same settings using Auto FP high speed sync I get less than f2.8 Even at full power I get less than f2.8 Not great if you need to have the flash more than a few feet from your subject.
Also this is a feature that is enabled on the camera, not the flash, so it won't work with Pocket Wizards, although the new Radio Popper wireless TTL system will probably work fairly well with it.
I'll follow up with review of this feature with the Radio Poppers once I get a set, hopefully fairly soon.
Camera Sync Speed (SLR)
Your camera has a set sync speed which is the fastest shutter speed you can use with a flash for that particular camera. So say the camera companies. Knowing how it works can allow for some additional creative processes. I'm going to assume that you know what a shutter is, and the examples here were shot with a Nikon D2Xs, Canon's work the same way, they both have vertical focal plane shutters. Rather than rewrite what's already been written about shutters I'll refer you to a fairly good description with diagrams on wikipedia.
The sync speed of your camera is the maximum shutter speed at which the shutter is entirely open. After that point the shutter begins to close before it is fully open, creating a slit that moves across the focal plane as can be seen in these shots below.
"Wait a minute you're saying, how did you shoot faster than the sync speed of the camera, mine won't let me do that!"
Most SLR and DSLR cameras detect that a flash is attached and electronically limit the shutter speed to the maximum sync speed of the camera. By using a PC cord or a Pocket Wizard or other such remote you can bypass the detection of the flash. If the flash is not on the hot shoe, the camera doesn't know that it's there, and thus it doesn't limit the shutter speed. This can be a good thing if you understand how to use it. As you can see in the images above there is very little difference in the 1/250 shot and the 1/320 shot, if I'm shooting with pocket wizards I frequently shoot at 1/320. Even at 1/500 the flash still covers almost the bottom 2/3 of the frame, so if I position my flash lit subject in that bottom 2/3, and keep the top 1/3 lit by ambient light, everything will be fine. You can use the same trick for vertical shots as well, just keep the flash cropping in mind when you compose.
Pocket Wizard Multimax Fast Mode
The Pocket Wizard Multimax transceivers have a fast mode that according to the manual allows you to sync up to 1/1000 of a second. Of course that's dependent on your camera's sync speed, and the only camera I know of that can sync at 1/1000 is a Rollei with a PQS lens. It does affect your camera's sync however, as shown in the photos below. The photos with the HS are the ones shot in Fast Mode
As you can see from the images, with Fast mode on the Multimax there is no discernible flash cropping at 1/320, and at 1/400 you still have most of the frame available for flash. At 1/500 and 1/1000 there is a smaller difference, but still good to know about. Please note that every camera is slightly different so you should repeat this test with your own camera before you start using it this way.
Nikon Auto FP High Speed Sync
As I use Nikon Cameras I won't go into the Canon version of this feature, although i believe it is similar. Nikon pro cameras and the newer Nikon "prosumer" cameras allow you to use what they call "Auto FP High-Speed Sync" mode with the Nikon SB600 and SB800 flashes. It allows you to shoot up to 1/8000 with a flash. It accomplishes this by firing a bunch of vey fast flash pulses instead of one single flash, and these pulses blanket the shutter as it opens and closes so that the entire image is lit. There are several benefits as well as several drawbacks to this feature.
Benefits - As it allows you to shoot at a higher shutter speed you can adjust the ambient light level and keep a lower aperature even in bright daylight. Also you can shoot at a higher shutter speed to freeze action and still use fill flash.
Drawbacks - Because it fires a bunch of flashes the actual flash "duration" becomes much longer making it less than useful for freezing action between 1/250 and 1/1000. Also because it has to fire more than once the effective power level of the flash is greatly reduced, and the recycle time increases. The biggest drawback is the huge reduction in output. My Nikon SB800's at ISO100, 1/2 power, 70mm zoom at @7 feet give me @f8. With the same settings using Auto FP high speed sync I get less than f2.8 Even at full power I get less than f2.8 Not great if you need to have the flash more than a few feet from your subject.
Also this is a feature that is enabled on the camera, not the flash, so it won't work with Pocket Wizards, although the new Radio Popper wireless TTL system will probably work fairly well with it.
I'll follow up with review of this feature with the Radio Poppers once I get a set, hopefully fairly soon.
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