By now it’s no big surprise that whenever the Strobist community at www.flickr.com discovers (or even gets a whiff of) any emerging products that have something to do with the subject of off-camera lighting, they jump all over it like nothing else I or anyone else has ever seen. The phenomenon of the strobist pile-on is really something to behold. The latest product to grab everyone’s short attention span is the Pixel TR-331 for Nikon iTTL flash units and TR-332 for Canon eTTL flash units. Trying to discuss Nikon and Canon flashes at the same time tends to make my head spin so I am going to restrict my comments to the Nikon flash version. I am a Nikon guy and the Nikon triggers are what I will be working with. The Canon version of this trigger is rumored to be coming in December 2009 or January 2010. You’ve got to love rumors…
I will begin by saying that I have no affiliation with Pixel Corporation who manufactures these units and that I have no plans of becoming a North American distributor, spokesman or product model for their company. In fact, the first time I heard of Pixel was the discussion about their new TR-331 wireless flash triggers in the Strobist group on flickr.
In the early part of that thread the rumor was that these triggers where being sold only to distributors in lots of 100 and that the retail cost of a transmitter and receiver set might be somewhere around $200. I contacted Pixel to inquire about getting a set (or sets) to test; I was told in very clear terms (that lost absolutely nothing in translation) that Pixel does not send, lend or loan hardware for testing and that anyone interested in testing them would have to buy a set at whatever they determined the retail price was going to be. As I mentioned over on the strobist discussion, I wasn’t particularly thrilled with the idea of being a wireless trigger test monkey or in putting up hard cash for unseen and untested hardware and that’s based on my previous experiences with “value priced” remote triggers. Here is a link to the Pixel product page:
In the rapidly moving world of off-camera lighting a person tends to get bored quickly, which often leads to rash decisions that usually involve throwing caution to the wind and doing the exact same thing that you had just sworn only moments before that you would never do. Just be aware that whatever follows is strictly my personal opinion and not intended to sway you one-way or the other. You have to decide for yourself if these particular wireless triggers will serve your particular needs or not.
I now have one set of the TR-331 triggers in my hands. I have been asked by Pixel not to discuss direct pricing or what I paid for these triggers, which seems reasonable since Pixel currently appears to be in the process of working out the pricing and distribution details with distributors in various countries. I don’t know if they are planning to sell directly to consumers or not, so I’m not going to speculate about it and will just move on to the review or what I like to call…
The Tao of Wireless Flash Triggers
Enter emptiness; it is the space where there is nothing that the usefulness depends.
Unfortunately I can’t begin talking about “The Way” without first talking a little about the how Nikon flash works in general (or at least my understanding of how it works). So be patient.
The Pixel TR-301 (Nikon mount) is a remote flash trigger that essentially uses radio signals in place of a hard-wired hot shoe sync cord such as a Nikon SC-28 TTL.
In case you didn’t know, TTL means “Through The Lens.” The lower case “i” in iTTL stands for intelligent. When any iTTL compatible Nikon flash like an SB400, SB600, SB800 or SB900 is used in the on-camera hot shoe, the output of the flash is measured by the camera metering system and the exposure is adjusted on the fly. At least that’s the simplified version of the story we use to explain it to small children. It’s not so much that using flash (even automated flash) is too far above our understanding, it’s just that there are so many things to talk about and people tend to get lost halfway through the discussion, which usually breaks down into a back and forth debate that leaves people wondering why they should even care. Oh, we care… and we care until it hurts.
First let’s look at what happens when we fire a Nikon flash directly from the hot shoe of a Nikon camera that supports TTL.
- The on camera flash fires a pre-exposure sequence
- The camera metering system measures the reflected light in the center of the frame based on the pre-flash sequence and calculates the power for the flash
- The power level for the flash is adjusted based on any flash compensation that is set on the camera and on the flash, This adjustment also includes any exposure value (EV) compensation set on the camera
- The shutter opens and the flash fires
As you can see there are at least three things you can adjust to affect the exposure. And when I say affect, what I really mean is screw up. Now that we have a basic idea about how TTL flash exposure works with a flash sitting on the camera hot shoe, it seems simple enough to extend the electrical connections between the camera and flash unit by using some sort of compatibly wired cable. I am using a Nikon D300; if you go online you can look at the D300 manual and read about optional flash units (Speedlights) beginning on page 357.
On page 362 you will find this interesting bit of information:
“When an SC-series 17, 28, or 29 sync cable is used for off-camera flash photography, correct exposure may not be achieved in i-TTL mode. We recommend that you choose spot metering to select standard i-TTL flash control. Take a test shot and view the results in the monitor.”
Hmmm… It’s suddenly clear to me how I came up with that “Test Monkey” concept. Even though I am using intelligent TTL flash photography it appears I am still going to be “chimping” my exposures as I go. For those of you who may not be familiar with that term, it is defined here:
In my mind a wireless remote system that is designed to replace a dedicated TTL hot shoe cord is not going to perform any better or in theory behave any differently than the cord with the exception that it essentially gives us a longer, cordless cord. What I want you to remember is Nikon’s advice about trying spot metering because it makes a difference depending on where and what you are photographing.
Off-camera flash photography or “Strobism” is commonly done using a camera in manual exposure mode in order to allow control over the balance between existing or “ambient” light and the artificial light produced by compact battery-operated strobes. Because of the relatively short duration of the light from a strobe unit the ratio of the two lighting types can be controlled by adjusting the camera’s shutter speed and aperture. Another thing that controls flash exposure in manual mode is the power level of the flash being used (and the flash to subject distance). Simple dumb wireless triggers are fine for firing flashes but don’t have any way of adjusting the power level settings remotely. You have to walk over (or climb up to) the flash unit and set the power level manually. On Nikon DSLR cameras with built-in (pop up) flash units you can set the power level of remote off-camera flash units using the built-in flash to send command signals to the off camera units (slaves) using the Nikon CLS (Creative Lighting System). That system uses pulses of light or pre-flash sequences of light to send information to the remote slaves. The CLS system works very well with two minor exceptions; the range is somewhat limited and the remote flash units need to have a direct line of sight to the on-camera commander flash, in order to receive the exposure instruction signals. You might be able to cheat slightly on the direct line of sight limitation indoors where there are walls or ceilings for the pre-flash signals to bounce off of.
You are probably thinking or maybe hoping that the TR-331 units will extend that CLS function by transmitting these signals to the remote flash units in the same way as the built-in flash on the camera does but of course you cannot use the pop-up flash when the TR-331 transmitter is in the hot shoe of the camera because the pop-up has to be up to work. No pop-up flash means there are no in-camera controls to adjust the power level of the remote flash units in CLS mode. You might also think, or hope that you can still use the pop-up flash by simply plugging the TR-331 into the camera’s pc sync port. You can forget that plan because the sync port is disabled whenever the on-camera flash is raised.
When you have an SB800 or SB900 flash unit in the hot shoe of the camera they can behave as commanders for remote slaves just like the built-in flash with the added ability to control a third group of remote flash units. Since the TR-331 does not have a hot shoe on top of the transmitter, you cannot directly attach a flash to it to act as a commander for other off-camera flash units. So you have this long wireless wire but if you wanted to adjust the power level on the master or slave units you will need to walk over to the master flash on the TR-331 receiver and adjust it from there. While an SB800 flash operating in Nikon CLS allows you to set your remote units to several groups and adjust those groups to different power levels independent of each other, the TR-331 only appears to support one group consisting of one flash on a receiver set to MASTER and one or more flashes on receivers set to SLAVE. You can set the exposure compensation of the remote MASTER from the flash menu on the camera since I currently have only one RX unit so I was not able to test what affect adjusting the flash compensation (on the camera menu) has on the RX units set to SLAVE. There are no power level settings or adjustments on the TX or RX units and the flash adjustments on the camera menu are limited to those that would normally be available if the flash were on the hot shoe of the camera. Basically that means red-eye reduction, slow sync, rear curtain sync (I’m not 100% sure about this one) and flash compensation settings. There are no CLS group settings available on the camera when the built-in flash is not deployed.
Nikon CLS is not just about TTL metering but also about the ability to adjust the output or power ratios of separate groups of flash units. Because the TR-331 only has one available group you cannot use it to adjust ratios between groups remotely. Because the normal pre-flash does not appear to be used for TTL calculations with the TR-331 trigger, the flash appears to be dumping full power or close to it each time it is fired by the wireless trigger.
In general practice I have a lighting ratio in mind when I set up my off camera lights but my first best guess is often wrong and I have to lower the light stands, adjust the power and then reposition the lights. If you are shooting a live subject who is doing you a favor by posing for a photograph they usually get impatient very quickly and all this required fiddling with power levels is no help. I can understand why a lot of photographers are looking for a way to remotely control their lighting from the camera because more convenience generally translates into more productivity. I think they may be slightly disappointed by what I have to say next…
When I access the [remote, master, master (rpt), remote, su-4] menu on the Nikon SB800 flash I notice that as soon as I put the flash in the hot shoe of the TR-331 (turned on or off) that the master and master (rpt) menus went away and also that the A/AA menu option went away. To me this shows that the CLS functions are not supported when used with the TR-331.
I also tested to see if I could determine if the transmitter fires a pre-flash for exposure calculation in TTL mode. To do this I set the flash to rear sync mode on the camera menu and chose a shutter speed of around 1-1/2 seconds. The idea is that if there is an exposure metering flash (pre-flash), it will fire at the beginning of the exposure and then the flash will fire a second time (rear sync) at the end of the exposure. Flash, open shutter, flash, and then close shutter. Sounds good but it does not seem to work. I only get one flash. The TR-331 manual states the following:
[i-TTL] capabilities support various parameters through the camera flash setting, including exposure compensation, FV lock, anti red-eye reduction flash mode / anti-red-eye reduction slow sync, rear-curtain flash sync, site the ISO sensitivity, power zoom functions and so on.
The red-eye reduction flashes do seem to work though a lot of people are not wild about using that feature because it seems to make people blink before the actual exposure. The power zoom feature also works but it seems this would only be useful for those times when the remote flash unit was the same distance from the subject as the camera. I don’t think this would normally be the case except perhaps in a studio situation. For situations where the camera is much farther from the subject than the flash you will probably want to set zooming flash heads to manual and then adjust them according to your creative desires. I tested this and when auto zoom is on it makes the flash nuke the subject because it naturally assumes you need more power the more the flash head is zoomed to match the focal length of the lens being used. This distance information seems to work well on the TR-331. How useful it is will depend on what type of photographs you are trying to create.
The transmitter (TX) and receiver (RX) units have slow flashing red LED lights to show when they are powered on. This is very handy because the RX display is hard to read when a flash is mounted on it and there is no test button on the RX. Any time the two units are communicating the LED lights change from blinking red to rapidly pulsing blue. This blue flashing can go on for a relative long period of time. For instance, when I power up the camera it takes approximately six to eight seconds before the blue pulses stop. If that is the actual amount of time needed to alert the remote flash to exposure or mode changes then I would be concerned when shooting fast moving subjects. You might find yourself waiting on the flash a lot or taking time to take numerous test shots to see if the adjustments really updated on the remote flash. Both the SB600 and SB800 flash units seem to wake-up right away when you lightly press the shutter button on the camera.
The TX and RX units have battery level indicators on them, which is a nice feature. It may also alert you the fact that the battery is not seated fully in the TX or RX, even though other functions seem to be working. In fact the digital displays are very nice in general and a big improvement over tiny DIP-switches that are often difficult to change with just your fingers. Hold the power button down for two seconds and the TR-331 units spring into action with a little animation Pixel logo. The previous channel settings are retained from when the unit is turned off, which means you are not forced to constantly set it back to what you want. There is also a backlight on the display that is activated when you briefly press the function button. That’s neat. The function settings work just like a digital watch. Hold the button (or buttons) down for a couple of seconds to access the modes and channel settings. It’s simple and it works well.
When using the TR-331 for multiple flash setups, the first flash is designated the master and all other flashes are slaves. This means that you set the first RX to MASTER and then set all the other receivers to SLAVE. Because I only have one RX unit at this time, I have not been able to determine exactly how this affects the function of the units and speculating about how they might work seems pointless. The RX in SLAVE mode did seem to wake-up when the camera with the transmitter was turned on but it would not fire. After way too many test shots in different metering modes, I can say that the Auto FP (high speed sync) seems to work (I only tested it up to 1/2000th of a second so far).
The MANUAL mode is primarily for studio flash units or other flashes that are not Nikon TTL compatible. The TR-331 set ships with a couple of decent looking cables for using them with studio flashes. I got fairly reliable results when I used the triggers in manual mode but I have had numerous issues with the TTL mode because the flash appears to fire before the shutter is fully open (I can see the flash fire in the viewfinder).
I have replaced the batteries in the TX and RX with new ones and I am still having issues with flash sync. At this moment I can detect 20 individual wireless networks in my building. During the day when I am near a window I have detected as many as 40 at one time. I’m going to try testing the TTL mode again tomorrow from a different location. Switching channels did not seem to increase the reliability. It is possible that I have the units too close together and this is causing some sort of feedback or interference as well.
When I have managed to get the flash and shutter to sync using TTL mode it works pretty well and I can adjust the flash output by using the exposure compensation available on the camera. I tried testing sync with my trusty old D70 and had the same issues. I just wanted to rule out that I had somehow fried the hot shoe on the camera by possibly frying another camera.
In short, I like these units a lot though they may fall short of wish list of features that many photographers are currently hoping for at a price they feel they can afford to pay. At the moment they don’t seem to be working as reliably as I would like them to but I’m willing to give them the benefit of doubt until I can at least determine the source of the problem. There are a lot of things I like about the TR-331. It’s going to ultimately come down to features versus cost factored with reliability and performance. Even after establishing any sort of benchmark for reliability it is going to be prudent to have back-ups when something breaks.
The main point to remember with any sort of light metering system is that you are not going to be able to randomly set up lights, blast away at full power and then have some sort of automation solve every lighting problem for you. Automation only works up to a certain point and TTL metering cannot fix huge errors in lighting exposure.
I’m not done yet; I’ll have more thoughts on the Tao of Wireless Flash Triggers very soon.