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Poverty Wizards

Cheap radio triggers for flash

by Gisle Hannemyr
Published: 2005-06-17.

Table of Contents

  1. Introduction
  2. Radio Frequencies
  3. Compatibility
  4. Technical Specifications
  5. The Product
  6. Connections
  7. Tests
  8. Conclusion
  9. Link farm

1. Introduction

When it comes to battery operated wireless slave flash systems, PocketWizard is the top brand. With 500 meters (1600 feet) reach, two-way communication, and the ability to reprogram a hairlight located on a high boom from camera position, they provide very powerful capabilities. The downside of PocketWizard is cost, the top of the line MultiMax costs around $ 295, and the budget model, Plus is $ 165. There now exists low cost alternatives with a more limited range and without the bells and whistles. These are sometimes jokely known as Poverty Wizards or FleeBay Triggers.

The first of these to become available was a simple 4-channel radio slave made in China by Shanghai Jinbei Photographic Equipment Co., Ltd., sold on eBay under the name GT301B. I first noticed it on eBay in the spring of 2005. You will find similar units in stores outside of eBay.

Price vary widely between vendors. At eBay, you usually pay less than $30 for a transmitter/receiver pair (the actual amount vary from auction to auction), while other vendors may charge as much as $130 for a very similar item.

As far as I am able to tell, all the vendors sell a similar unit, from the same Chinese manufacturer. However, several versions exists. The initial receivers sold by Joe's Photo Auction did not have a pc-connector, the version I bought has. There also has been some changes to the trigger circuits, which means that older units may not necessarily be compatible with newer units.

The items reviewed in this article (one trigger and five receivers) is a 433 MHz, 4-channel model designated GT301B, and was purchased from Joe's Photo Auction in April 2005.

November 2009 update: The GT301B that is the the subject of this review is no longer available. Possible replacements are the Cactus V4 (433 MHz, 16 channels) from Gadget Infinity; and the YongNuo RF-602 (2.4 GHz. 16 channels) from YongNuoPhotoEquipment.

Several radio bands are made available for more or less unregulated use in different geographical areas this includes the 315 Mhz band used for RKE (Remote Keyless entry) in North America, and the ISM (Industrial/Scientific/Medical) bands.

Equipment designed to operate in these bands is designed to be tolerant for interference by other equipment operating at the same frequency.

I am currently aware of the following frequencies used by flash radio triggers:

Note that because of the different frequency allocations, use of the 315 Mhz devices is illegal in Europe, and use of the 433 Mhz devices is illegal in the USA.

3. Compatibility

Do not expect different versions of the same unit from the same manufacturer to be compatible with each other, even if they bear the same model designation.

For instance, there exists both a 315 Mhz version and a 433 Mhz version of the GT301B. These are not compatible with each other. Similarly, the V2 and V4 versions of the PT-04 trigger are not compatible with each other.

The simplest way to ensure compatibility is to order all the units you need with from the same vendor at the same time. Otherwise, you will need to communicate with the vendor to make sure that the units you buy are compatible.

There are additional user comments about compatibility in my blog.

4. Technical Specifications

The trigger voltage of the GT301B transmitter is less than 6 V (my unit measured 4.96 V), which makes it safe for all modern digital cameras. According to the vendor, the receiver is capable of handling old strobes with high trigger voltage up to at least 200 V. It worked fine with my old Vivitar 283 that has a 107 V trigger voltage, as well as my Nikon SB-800 and my Canon 550EX (both has a trigger voltage close to 6 V.

5. The Product

GT301B boxed

Most of the text on the outside of the box is in chinese, and reads (thanks to peter for the translation):

Product Features: Microprocessor encode/decode; very good interference rejection ability; microprocessor controlled; long distance remote controlled; low trigger voltage and current; trigger current only 0.01 mA; will not hurt camera; standby sleep mode; super low power consumption; long lasting battery; can standby for 1 year or trigger 20,000 times.

There is no manual included - just an one page “TroubleShooting”-guide. I had no trouble setting it up. After I'd loaded fresh batteries and connected the units, I was ready to shoot.

The units seem, however, to be sensitive to battery voltage. There is no “low battery” indicator. Even freshly charged rechargable NiMH batteries, and slightly run-down alakalines, give poor reliability and reduced firing range. If one experience problems in these two areas, replacing the batteries should be the first thing to try.

Operation is simple and intuitive. There is no on/off switch. The transmitter has a “test” button on top (which does what you expect), and the only other controls are two microswitches which selects one of four channels.

While being made from plastic, the unit appear to be of good quality and well constructed for the price. When I accidently dropped one of the receivers from a height of about one meter on to a hard, wooden floor, it broke open at its joins. However, there was no breakage and after I've reassembled it, it was as good as new.

Some users has reported that dry soldering has stopped units from working. Opening the unit up and resoldering dry connections has fixed the problem.

Below is a picture of the four items that comes with the basic kit:

DCS 460

The item on the left is the transmitter. It normally mounts in the camera's hot-shoe, but also have an 1/8" jack-plug socket for cameras without a hot-shoe. Included is also a 30 cm (12") cord with 1/8" jack-plug at one end and male pc-plug at the other. The item on the right is the receiver - it does not have a hot-shoe, but has a cable with a 1/4" jack-plug for studio strobes, and an 1/8" pc-socket for standard portable flash guns. The final item in the basic kit is a 1/4" to 1/8" jack-plug adapter.

The transmitter uses a 23A/LRV08 alkaline 12V battery (included) rated at 20 000 flashes. The receiver uses two standard AA/R6 1.5V batteries (not included) rated at 30 000 flashes.

6. Connections

The GT301B can only be used to trigger the flash remotely. There is no way to remotely control flash power, as with the more expensive radio systems and Canon's E-TTL and and Nikon's i-TTL systems. This is an obvious limitation. If you use manual or vari-power flashes, you have to work out the exposure manually or by using a flash meter. If you want a complex lightning layout, you also have to walk around to adjust each flash by hand. If you take advantage of the flash' auto mode, the flash should in principle take care of the exposure for you, but my tests show that this not always the case.

The receiver is obviously constructed with monolights with 1/4" jack-plug socket connector in mind, as is evident from the non-detachable cord with a 1/4" jack-plug at the end. For standard portable flash guns, newer versions of the receiver sports an 1/8" female pc-socket at the back.

All exposed plugs are “live”, so with my Vivitar 283 hooked up to the receiver via the pc-connector, all its 107 volts appear at the exposed 1/4" jack-plug. This will give you a nasty shock if you touch it. For safety, you should put insulating tape on exposed plugs.

The images below show how to connect the receiver to a standard flash gun (as opposed to a monolight):

GT301b receiver vith Vivitar 283 GT301b receiver pc-connector


All my GT301B receivers came with a standard 1/8" female pc-socket (depicted close up in the photo on the right above). If the flash has a cord with a male pc-connector, plug this into the receiver's pc-socket. The image to the left shows a Vivitar 283 connected to the receiver using this connection.

The pc-socket is not featured on the YHDC-B model.

GT301B receiver and flash with 1/8" jack to hot-shoe adapter Hama pc to hot-shoe adapter
If the flash does not have a pc-connector nor a 1/4" or 1/8" jack-socket, you need a simple two-contact shoe hot-shoe adapter with an 1/8" jack-socket. The image on the left above shows a set-up using such a hot-shoe adapter. You plug the receiver's jack-plug into the hot-shoe adapter by means of the 1/4" to 1/8" jack-plug adapter. Joe's Photo Auction sells the hot-shoe adapter shown for $8 a piece. They work, but they do not appear to be very well constructed, and may not last very long. You may be better off making your own or - provided your radio trigger features a pc-socket - getting a male pc to hot-shoe adapter as shown in the image to the right above.

For monolights that uses a HH-prong, Paramount Cords sells various adapters.

Note 1: The Sigma 500/530 DG Super must be set to C0 SL mode (that is the normal slave mode) to be fired from a simple two-contact hot-shoe that is featured on most radio triggers. It will not fire at all in manual mode without a full E-TTL connection to the camera body. It can't be set to FP (high speed sync) or second curtain sync in C0 SL mode. The Sigma EF-500/530 DG ST does not have a slave mode, and can not be used as a slave flash

Note 2: Some newer Canon Speedlites, in particular 430EX and 580EX, fire at random with some versions of the Gadget Infinity radio triggers. The problem is fixed in a later model. Check out compatibility with your Speedlite before buying if you use one of these. There is some discussion about this in this thread on Flickr. It is long, but look for entries from RAitch between 201 and 300 (on page 3). Older Speedlites, like the 550EX and 420EX, do not have this problem.

7. Tests

All tests uses as its subject an ordinary indoor scene (my living room, which a nice white ceiling for bounce). The tests were conducted after dark, so that the flash was the sole source of light. I use the histogram in Photoshop CS to judge exposure.

Timing tests

For my first, simple test, I used a vintage Vivitar 283 and a Canon Powershot G5 with a central shutter. The G5 was set up in manual mode, f=7.2mm (35mm FOV equiv.), ISO 100, shutter speed set to 1/250 second (the maximum x-sync or flash synchronization shutter speed according to the G5 manual), and aperture f/2.8. The Vivitar was set to bounce against the ceiling in auto mode with an aperture f/2.8.

The GT301B radio slave kit performed as advertised. The exposure was spot on. Lowering the shutter time resulted in identical histograms, which means that the unit is fast enough to keep up with at least a shutter speed of 1/250 second. Increasing the shutter speed beyond 1/250 second resulted in more and more underexposure.

I then tested the kit with a Nikon D80 with a focal plane shutter. This camera has an x-sync speed of 1/200 second. Firing a Nikon SB-800 Speedlight with the camera's shutter speed set to 1/200 second worked fine. However, firing a Nissin Di866 with the camera's shutter speed set to 1/200 second resulted in an image where part of the flash was blocked by the shutter blade. I had to lower the shutter speed to 1/160 second to to be able to use the GT301B kit to synchronize with the Nissin Di866. This is because the Nissin Di866 is slower to respond than the Nikon SB-800, and with the extra delay introduced by the GT301B, this makes a difference.

Here are some other timing tests: Dan Jeter, using a Nikon D2x with a focal plane shutter wich has a x-sync speed of 1/250 sec., has posted test images (now gone) that shows that setting shutter speed to 1/250 sec. results in a noticable shutter blade shadow, and that 1/200 sec. is the top speed that produces reliable results on a Nikon D2x. J.R. Sprawl, using a Nikon D70 with an electronic shutter writes: “With the radio slave, usable sync speed is limited to 1/640 sec. - at 1/800 sec. there is about a 1-stop exposure loss.”

Exposure tests

Again, I used the Vivitar 283 and Canon Powershot G5. The G5 was set up in manual mode, f=7.2mm, ISO 100, shutter speed set to 1/250 second and aperture f/2.8. The Vivitar was set to bounce against the ceiling, auto mode, and aperture f/2.8. As in the previous test, the exposure appeared to be correct.

I then changed the head position of the Vivitar to provide direct flash. This, however, resulted in a 1/2 stop overexposure with noticable burnt out highlights.

Conclusion: Auto does not always result in the right exposure. If you have the time, make a test shot and check the histogram. If necessary, adjust the exposure.

Range test

The units are not reliable if placed to close together. You need at least two feet between two receives, or a transmitter and transceiver, to stop them from interfering with each other.

My range tests for long distance was conducted outside by setting the flash with the reciver attached on a tripod and then moving away from it. Distance was measured by counting paces (not a very accurate method, I admit). I found the unit to work reliable up to about 100 meters (300 feet). Beyond that, it became more erratic and stopped working altogether at around 200 meters (600 feet).

Indoors, I found it capable of working through at least three wooden walls, which is the maximum size of my apartment.

While its range is clearly more limited than PocketWizard (500 meters) it is also much better than its rated range (25 meters). I find the range it offers adequate for my needs.

For a more accurate range test, see this user report by FotoFlip posted in the DPreview Lighting Technique Forum. He uses GPS to measure distance accurately.

8. Conclusion

The GT301B slave transmitter and receiver appear to be reasonably well constructed (for its price) and it works as advertised. The top synchronization speed is less than advertised, but adequate for most users. You may need to work with the histogram or flash meter to get correct exposure in some situations.

With fresh batteries, the units are fairly reliable, misfiring in about one or two instances out of around one hundered. With run-down batteries, reliability is significantly reduced.

In the connections department, the receiver is a bit of a kludge if you intend use it with something that does not have a 1/4" jack socket or a standard pc-connector. The 1/8" jack-plug to hot-shoe adapter works, but is not well constructed. You may want to look for alternatives, or even construct your own.

The main utility of this item is to let users of modern digital cameras use old, cheap and powerful auto flashes such as Vivitar 283 without having to worry about high trigger voltages damaging the camera. It also lets you move the flash unit away from the hot-shoe for more flexible lighting technique.

For complex lighting arrangements using multiple triggers it has obvious limitations, in particular when compared to more sophisticated and expensive flash systems. If you are a professional photographer requiring absolute reliability in all situations, this is not the solution. However, the price is nice (at least if you buy it off eBay). If you are on a tight budget, the low price may more than make up for its lack of bells and whistles.

User reports and ideas:
User reports in my blog, by several users
Ebay radio Slaves, Strobist.com group @ Flickr
Next, They'll be Using Nitro, by Strobist
Wireless trigger distance tests, by FotoFlip
Cactus PT-04 V2 wireless radio-based flash trigger, by N.K. Guy
Gadget Infinity PT-04 V2 Wireless Flash Trigger, by L7 Foto
YongNuo RF-602 Wireless Remote Review, by Dennis Dixon
Other radio triggers:
Alien Bees
Bowens Pulsar
Calumet
Elinchrom EL-Skyport
Gadget Infinity
Hensel Studiotechnik
MicroSync
MiniMagic
Pixel Enterprise Ltd.
PocketWizard
RadioPopper
Quantum
Secu-Line
YongNuo
Zap-Shot

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