Wednesday, August 10, 2011

Dance Like a Speedlight, Sting Like an Alien Bee: an Introduction to Quantum Flashes



You like the TTL convenience of your speedlight and you like the power of your monolight.  Wouldn't it be great if you could have the best features of both in a TTL-capable strobe with the power of a monolight?   Fortunately, there is just such a strobe.  Hit the jump to learn about the Quantum Qflash.
 Quantum flashes combine some of the best features of both speedlights and studio strobes.  However, they are not well understood except by hardcore lighting enthusiasts, and to an average observer, it may seem that understanding their system requires an engineering degree.  In this post, I'd like to discuss their advantages, disadvantages, as well as how their powerful, versatile but somewhat complex system works.

WHAT ARE QUANTUM QFLASHES?
You know about speedlights, and you may know about monolights and pack-and-head studio strobes as well.  Quantum flashes (Qflashes) belong to a sub-category of strobes called battery-powered strobes.  However, even compared to other battery-powered strobes, Qflashes have unique characteristics such as TTL capability and indeed, wireless TTL capability - so it could belong to its own category.

Like speedlights, Qflashes have a flash head that includes the "brains" and "muscles" of the flash.  But unlike speedlights they are not fully self-contained because need an external "heart" (the power pack).  The power pack supplies only the energy to the flash -- it does not control the power per se of the flash (unlike pack-and-head systems).  To get TTL capability, they also need a second brain - the TTL adapter.  (Not too long ago, Quantum created a flash that has built-in TTL capabilities, the Trio.)

Why go through the trouble?  Qflashes have several advantages over speedlights:
- Bare bulb design.  Like studio strobes, qflashes have bare bulbs that are more versatile and provide better quality light when used with modifiers such as softboxes.  It also includes a parabolic reflector, which provides more natural-looking light than the square reflector of a speedlight or potato masher.
- Extremely resistant to overheating.  Qflashes can be fired successively without overheating.  By comparison, speedlights can go into standby or even melt if used at high power and rapid-fired several times.
- More powerful than speedlights.  High-end speedlights have about 60-75ws of power.  By comparison, T-series qflashes have about 150ws and X-series qflashes have as much as 400ws of power, enough to compete with some monolights.
- Power pack can also be used to power speedlights, providing exceptionally fast recycling times (fast enough to melt the plastic lens of the flash)
And Qflashes have advantages over studio strobes:
- TTL capability.  If the subject is moving, TTL will allow you to get close to, if not the correct, flash exposure.
- More portable than monolights.  The Qflash head is smaller than a monolight and relatively light (partly because it has no batteries).
Relative sizes of a speedlight (Nikon SB-26), a Quantum flash (X2 shown) and a monolight (AlienBee B1600)
 - Battery pack is more portable than power pack of pack-and-head systems.  Qflashes have fairly compact power packs that can be clipped to a belt or even attached to bottom of the camera.  You can't do that with the battery pack of most monolights or pack-and-head systems.
In addition, Quantum is also well known for responsive tech support.  I've had the occasion to contact them and they were friendly, very knowledgeable and straightforward.
On the other hand, they have some disadvantages:
- Costly compared to speedlights and Paul Buff monolights.
- Less portable than speedlights.
- Fewer flash modifiers than strobes or even speedlights (these days).
- Relatively long flash duration (1/250 to 1/300), though that can be an advantage under some circumstances (such as simulated HSS).
- Not as powerful as some studio strobes.
- Flash recycling is quicker than a speedlight, but when a speedlight is connected to an external pack, the recycling times are comparable.
 
COMPONENTS
Quantum's system is a bit more complex than Canon or Nikon's system because they use a modular mix-and-match approach for maximum compatibility.  If you keep that philosophy in mind, it will help you not get frustrated with their byzantine system. :)
A Qflash system needs at least three components in order to function:
  • a flash head -
  • a power pack
  • a sync adapter.
The power pack of the X-series Qflashes: the QPAQ

TTL adapter
1. Flash heads
Flash heads come in two series: the T series (150ws) and the more powerful X series (up to 400ws).  The T-series flash heads have T in their model name, beginning with the model T until the current model T5d-R.  The X-series flash heads have X in their model name, beginning with the X until the current model X5d-R.

Each generation of Qflash (regardless of whether it is T or X) has similar features.  A "D" in the name signifies that it can be used with digital cameras.  An "R" in the name means that the unit can be used to provide different output relative to other flashes when used in a multiple flash setup.  
 
Unlike speedlights, the Qflashes don't have hotshoes. Instead, it is connected via the TTL adapter to  the camera.  It has a 1/4-20 socket on the bottom (for connection to a stand or a bracket) and is mounted on a bracket or tripod.

The Trio is a little different from the other Qflashes because it has a hotshoe and already has the TTL adapter built in.

2. Power Packs.
Power Packs have two series as well to match the two series of flash heads (the T and X series). 
 
The T-series heads require a Turbo power pack.  The Turbo packs come in several varieties:
  • Turbo
  • Turbo 2x2 - higher capacity than the Turbo.
  • Turbo 3 - the highest capacity Turbo.
  • Turbo Z (more compact version of the Turbo, with less capacity)
  • Turbo SC (slim and compact - even more compact model)
  • Turbo Blade (the smallest and most compact Turbo battery, attaches to the bottom of the camera).
The X-series heads require the QPAQ-X power pack. The QPAQ-X has 200ws of capacity, and can be used to power either one or two heads.  If two heads are used, then each head's capacity is effectively 100ws.  However, you can add additional 200ws modules (called PXC) to increase the capacity of a QPAQ-X to 400ws, 600ws or 800ws (though each X-series head can only use up to 400ws).  With the correct type of cable, X-series heads can also be used with Norman 200B, 200C, or 400B packs, as well as Lumedyne packs up to 400ws.
PXC 200ws module

 Other notes:
  • Quantum also produces battery packs for other flashes, none of which packs are compatible with QFlashes.  QB1 powers flashes with 4 or 5 AAs. QB1C is the more compact version of QB1. Quantum Bantam is likewise a compact, lower power version of the QB1.  QB2 is for flashes that require 6 AAs.
  • A power pack needs a charger/AC adapter.   If you're buying used, check if the pack you're buying comes with it.  For the T-series, you may also need a cable to connect the flash head to the power pack (the cable is built into the X-series head).
  • If your Quantum battery is no longer holding a charge, there are recell services to fix your battery (such as http://dasaga.com/quantum_battery.htm ).
3. Correct adapters:
Qflashes can be used in TTL mode with many film cameras as long as you have the right cable.  For Canon and Nikon digital cameras, TTL is available with a 3d-R, 4d-R, or 5d-R Qflash (you also need the right digital TTL adapter).
 
Quantum's new model, the Trio, is also compatible with Canon or Nikon.  The Trio is like a T-series Qflash but with built-in TTL capabilities and FreeXwire radio TTL (there is also a Trio basic that has only the built-in TTL but not built-in FreeXwire).
 
Compared to the simplicity of Canon or Nikon's flash systems, or even Paul Buff's monolights, Quantum's products can be a little confusing.  Now you know why this guide is necessary! :)
 
FEATURES
INTEGRATION
One of the strengths of Quantum is that it plays well with Canon or Nikon's native flash systems.  With the right accessories, it is possible to mix a Qflash with your Canon or Nikon speedlight(s).  In fact, the QNEXUS accessory for the 5D-R flashes enables you to control the Qflash with your Canon or Nikon wireless commander.
LIGHT MODIFIERS
The Qflashes have a bare bulb design which may provide better quality light than a speedlight with rectangle reflector.  However, light modifiers made specifically for the Qflash are quite expensive.  Instead, I use a Cowboy Studio bracket to allow me to use my Qflash with any modifier made for Bowens.
Qflash mounted on a Cowboy Studio bracket

MODELING LIGHT
Some Qflashes have a small modeling light, (35 ws) allowing you to see the pattern of highlights and shadows in realtime, as long as the ambient is not bright. 
 
CONVERSION OPTIONS
The 2 and 2d Qflashes can be converted to 3d-R Qflashes, which have some of the capabilities of the 5d-R.  The 4d and 5d qflashes can also be converted to a 5D-R.
 
REMOTE TRIGGERING OPTIONS
Quantum has its own remote triggering system, the FreeXwire, which is actually the first wireless radio TTL.
Quantum also produces the RadioSlave triggers which is a separate triggering system with no remote adjustment capability, and is incompatible with FreeXwire.
 
In addition to the FreeXwire, it is also possible to remotely adjust a Quantum in manual mode using a QF12 or QF13 adapter, a Radiopopper JrX Studio, and a matching Canon or Nikon RPCube.
 
OTHER NIFTY FEATURES
  • Bounce and swivel - The head can swivel "only" 180 degrees (90 degrees each to the left and right).  But, the bounce angle is 180 degrees (speedlights can only point 90 degrees up), so the head can effectively cover 360 degrees.  Clever design!
  • Earphone jack - Do you find the ready beep useful yet a little indiscreet?  There's an earphone jack.
 
BOTTOM LINE
Quantum is powerful and versatile, combining some of the best features of a speedlight and a studio strobe.  Yet because of its price and complexity, it has a select (mostly professional) clientele.  Occasionally though it is possible to get a good deal on a qflash if you patiently shop at eBay.  Meanwhile, check out some sample shots from the Quantum Flash group on Flickr.