Why It Might Be Time To Upgrade Your Strobes

Why It Might Be Time to Upgrade Your Underwater Strobes

Hands on with the Retra Flash, ONEUW 160X, Inon Z-330 & D-200 and Announcing the Sea & Sea YS-D3

 By Kevin Palmer

Those who have been taking underwater photos for a long while may have noticed how rarely new strobes are introduced to the underwater imaging arena. As a whole, we (underwater photographers) are a relatively small market and the cost of developing a new strobe model is significant. It is therefore no wonder models tend to be around for many years with small upgrades at best.

So it has been particularly exciting to witness the introduction of new strobes with big performance to our market in 2019 and 2020. These new strobes are at the top of their categories and deserve consideration by anyone who feels their existing strobes fall a bit short of their current needs. We have had some time to evaluate these new contenders to see how they perform beyond the specs, so let’s look at what sets the newcomers apart.

Retra Flash – A Modern Take on a Traditional Concept

This might have been the biggest surprise of 2018 as Retra is relatively small company traditionally known only as an accessory manufacture for the underwater imaging market and is perhaps best known for their excellent Light Shaping Device which is a sophisticated type of macro snoot. All new for 2020 is the The Retra Flash Pro and Retra Flash PrimeThis evolutionary design is clean and simple with a number of clever details, and it is very much focused on ease of use. The machined aluminum housing for the strobe sets it apart at this price point and helps to dissipate heat generated by this powerful strobe. The original Retra Flash was discontinued almost as soon as it started becoming popular, but the design carries over with numerous features and some notable changes to the new Retra models.

The Specs:

  • 100 Ws New Retra Flash Prime / 150Ws New Retra Flash Pro
  • 2.0 second recycle time (Prime) / 3-4.0 second recycle time (Pro)
  • 300 lumen pilot light
  • 4900K color temperature
  • 110º + beam angle
  • 13 manual exposure levels
  • Slave mode with smart pre-flash cancellation
  • 4 level smart battery indicator
  • Inon, Sea&Sea dual optical connector
  • 100m depth rating

The first thing you notice on the new Retra (aside from the brushed aluminum finish) is that the flash tube cover is domed to help distribute the light as wide and evenly as possible. Likewise the diffusers are similarly domed. Most of the controls are clearly marked and easy to use. The size is certainly within the travel friendly category and those who have used Inon’s larger strobes will find the size and shape to be very familiar.

Specifications on any strobe are generally provided by the manufacturer and rarely independently verified. More important is how they perform in the real world. So here is our take:


Power is great: Noticeably better (given the angle of coverage) than all previous AA powered strobes with the prime most closely matched (and slightly surpassed) by the Inon Z-330.  The Retra Pro is equal or better to the output of some earlier and existing proprietary battery powered UW strobes. This is great for wide angle and small aperture applications - like shooting sun-balls.



Coverage is extremely smooth and even with and without a diffuser. 110 degrees without a diffuser might be the new normal for strobes going forward which the Retra provides.

Recycle Time

When a strobe gets more powerful while using the same batteries, something has to compensate, capacitors have to get larger and more efficient and recycle time gets longer. At full power, recycle time on the Pro is going to be a fairly long wait compared to any other contemporary strobe. But in the real world, most people will rarely use this strobe at full power. At lower power settings, they will be snappy enough for general shooting. For those that demand faster performance, Retra's unique Retra Flash Additional Battery Compartment would be recommended.  This accessory allows the use of 8 AA batteries as opposed to just 4 and provides improved recycle speed for fast action, though at some expense of size and weight.

A special note here: with higher performance comes a need for better batteries to keep up. The Retra seems particularly sensitive to the quality of batteries. Original Eneloop or Powerex batteries that worked fine in your old strobe, might produce recycle times 2-4 times longer than factory spec. So plan on getting the newest Powerex 2600ma Low Discharge batteries or Panasonic Eneloop Pro batteries. Also, always use freshly charged batteries as the Retra flash performance declines noticeably with battery discharge. We would recommend changing batteries at least every two dives if you are shooting a lot of images - or even more often.

TTL Performance

The New Retras TTL performance appears to be very good with cameras that utilize a pop-up flash. LED optical TTL converters do not appear to work very well at this time from the models currently available. UW Technics is said to release compatible TTL Converters soon. Electrical TTL via sync cables is not available and manual electrical will require an electrical/optical converter made by Retra. Manual LED optical flash triggers do appear to work fine with the strobe set to Manual.


Controls are excellent and clearly marked. Cold water gloves should not be a problem. The one operation that is not as friendly as it could be is the battery compartment knob. The battery compartment seal is better than the original Retra, but it takes some work with the small knob to close everything up. This may get easier over time.

Color (how strobe lit subjects appear)

The original Retras had a pleasing, slightly warm temperature light that is usually a plus for underwater models and reef scenic wide angle shooting. The New Retras are even warmer than the previous generation – about the same as Ikelite DS-160s.



Inon Z-330 – More of a Good Thing

Inon is one of the oldest and most popular strobe manufacturers in the world with a reputation for reliability and performance in a small size. Underwater shooters have anxiously awaited the upgrade to the venerable Z-240 – one of the bestselling strobes of all time. The wait is finally over and though it took nearly 18 months to catch up with demand, the new Z-330 is now sitting in stock. Users have not been dissapointed.


  • Guide Number 33
  • 110 Degrees of Coverage Underwater
  • 5500K Color Temperature
  • 13 steps of Manual power control in ½ EV increments
  • 1.6 Sec. Recycle time at full power
  • Includes a rotatable light shade to help prevent backscatter
  • 220 lumen aiming light with auto shut-off
  • Enhanced controls with large knobs

At first glance, the Z-330 appears physically similar to its predecessor the Z-240, but it is easy to start picking up the differences. Like the Retra, there is an obvious dome over the Inon’s twin flash tubes affecting a similar 110 degree angle of coverage. Equally noticeable is the “eyebrow” shade on the front of the strobe. In use we found this to be much more than a gimmick – though it is easy to remove if desired. When shooting macro or close focus wide angle, the shades are perfect to control backscatter and flare from the strobes. This is a tool that requires some experimenting to really get the most out of it.


Power is excellent. On paper the Z-330 is over twice as powerful as a Z-240 while providing 10 degrees more coverage without a diffuser – pretty remarkable. In practice, the difference is really useable – particularly shooting wide angle in bright conditions. You can use camera settings that were impossible with the Z-240 which will put a grin on many shooters’ faces.

The Z-330 and the Retra Prime fill a similar niche in the underwater strobe category, though the price points makes it a particularly nice value.


The dome front makes a huge difference and Inon’s new style of included diffuser means maximum coverage with minimal loss of intensity. The Retra has a bit more even coverage, while the Inon has a bit wider overall coverage. You can see this on a wall chart, but in the ocean, in use on a reef, you won’t notice the difference. You will just love being able to get light everywhere you need it. We would probably recommend using the diffuser all the time on the Z-330 as it does smooth the light pattern considerably.

Recycle Time

In our experience, out of the box, with the same batteries, the Inon Z-330 will generally recycle faster than both of the Retras at a similar output, though the difference is not huge. The Inon is also a bit more forgiving with the level of charge on the batteries. We did as many as four dives without changing the batteries on the Z-330s and never noticed a decline in performance. Of course, when using the 8 battery configuration on the Retras, you will get faster performance and longer run time also.

When choosing batteries, the same rules apply as for the Retra for the most part – though not quite as critical. Inon goes so far as to give you the recycle times for different types of batteries. But you wouldn’t put cheap gas in your Ferrari, so get the good stuff mentioned previously.

TTL Performance

TTL accuracy has always been a hallmark of the Inon brand and the Z-330 is no exception. The TTL is excellent with the camera’s flash as the trigger, but also with virtually all of the LED optical flash Trigger/TTL converters. Electrical TTL with the appropriate TTL converter is also fully compatible. Inon also has a super sensitive 360 degree optical pick up for slave fill flash or backlighting purposes. The Z-330 can be triggered by both electrical and fiber optic on the same dive by different devices for specialty applications.


Current Inon owners will rejoice when they first try the controls on the new Z-330. The new controls are extremely comfortable and easy – even with gloves. The settings, labels and logic of the display will look familiar to Z-240 owners, but actually has been made much more friendly and logical and now includes glow-in-the-dark control labeling and indicators that seem to last for a full night dive.


Color (how strobe lit subjects appear)

The Inons are a very slightly cooler color temperature than the Retras and are closer to daylight. This is generally excellent for macro and very close focus work providing what most would call a “natural” look. Inon offers warming diffusers for wide angle work where a little warmer light can compensate for spectrum loss passing through water.

Inon D-200

Another new strobe on the market that is often overlooked is the economy oriented Inon D-200. This strobe appears almost identical to the hugely popular Z-330 – except the color. So what is the difference between these two Inon strobes?

In truth, the D200 shares most of the features found on the Z-330 including the same controls, same angle of coverage, same STTL and the same Inon reliability. What it loses is the electrical sync option (it is an optically triggered strobe only) and some of the Z-330’s potent power output. But for the person who shoots macro, fish portraits, close focus wide angle and other photography not requiring maximum power, the D-200 represents a good value and a viable alternative. All the other comments about the Inon Z-330 will fully apply here.



ONEUW One160X – The New King of the Hill?

A brand new design has arrived from Europe and it brings some exciting design and performance options to the underwater strobe market. It has long been known that there is a physical limit to the amount of energy 4 AA batteries can store and the speed at which they can transfer that energy to the strobe capacitors. While both Retra and Inon have made remarkable strides with efficiency and what is possible to achieve using the AA battery design, there is only so far it can go. This becomes apparent with the Retra 150W Flash that takes at least 3 seconds (often longer) to recycle after full discharge.

So what is a strobe designer to do when in pursuit of ultimate performance? Proprietary battery designs can solve this problem and have an enormous performance envelope that allows great design flexibility and potential evolution as requirements increase. For the serious shooter, this means more power and faster recycle times.


·        Max energy

·        157 Ws

·        Manual mode power control range – steps

·        Full -6 f-stop - 1/2

·        TTL mode EV control range – steps

·        ± 2 f-stop - 1/3

·        GN Guide number ISO100-1mt

·        20

·        GN Guide number ISO100-1mt - detection angle

·        20-90° | 18-110° | 16-130°

·        Beam angle

·        130° (circular)

·        Number of full power flashes

·        over 250

·        Recycle time

·        0,2-1,8 sec

·        Color temperature

·        4.600 °K

·        Pilot light

·        Led 200 lm 10° 2 steps

·        Power supply

·        interchangeable battery pack

·        Battery type and capacity

·        NiMH 4,8V 3050mAh

·        Battery charging time

·        90 min

·        Flash arm connection

·        M6 threaded hole

·        Dimension Diameter x Length (controls included)

·        99x200 mm

·        Weight in air battery included

·        1480 g

·        Weight UW battery included (with neoprene cover)

·        ≈-190 g (≈ -70 g)

·        Max operating depth

·        200 m


Yep, that is a lot of information and in part it shows how seriously this manufacturer takes its strobe design. This strobe looks like nothing else on the market and the craftsmanship is really obvious. The 160x feels like it is hewn from a solid block and in fact it is just that. Nicely machined from aircraft grade aluminum and finished in a sophisticated matt anodizing, the 160x seems built for serious performance with a really large display and set of controls. The strobe is roughly the size of an Ikelite DS-160, but the battery packs are smaller and lighter than the Ikelite’s. Nice to look at, but let’s get into the details.



There really is nothing on the existing market that can touch the 160X for power at its angle of coverage. It is confusing because ONEUW only claims a guide number of 20. This seems much less than what Inon and Retra are claiming – Right? Most manufacturers throw GN around as gospel, but these are extremely subjective numbers, measured differently by each manufacturer and rarely measured independently. So take them with a big helping of salt. OneUW is very conservative in its rating and has designed the 160x for maximum coverage while offering more power than any other strobe in its class. This includes the brand new Retra 150 Flash, the venerable Ikelite 160 and the discontinued Sea & Sea YS-250.

When shooting pelagics that don’t come close, lighting the interior of a wreck or trying to make things pop in shallow bright conditions – this extra power can make a big difference.


The 160x uses a large circular flash tube that produces an extremely soft even coverage over a full 130 degrees without a diffuser and even greater with a diffuser. This is more than most strobes produce with a diffuser. No other form of lighting is as evenly distributed as circular flash tube coverage.

Recycle Time

This is one of the areas the 160x really shines. When the action gets hot and heavy (think shark feed, sail fish, bait balls with tuna), nothing is more frustrating than waiting for your strobe to recycle. This is where extra power and superior battery technology come into play. While a conservative recycle time of 1.8 seconds at full power is suggested, most often you will be shooting at much less than full power and recycling in fractions of a second. You may not always need it, but knowing your strobe can keep up with your shutter finger is huge for certain types of shooters.

TTL Performance

The 160x is again fairly unique in that it offers true internal electronic TTL processing for Nikon and Canon. So what that means is one only need hook up an electrical sync cord to the appropriate bulkhead on the camera housing and you can enjoy full ETTL or ITTL communication and perfect exposures with your Canon or Nikon camera. No need for an additional TTL converter. Since the TTL processor is internal to the strobes, the photographer must choose a strobe made for Canon or a strobe to work with Nikon. The processors in the strobe are able to be firmware updated so as the camera TTL algorithm is updated in the future, the strobe can remain compatible. The strobe includes an electrical sync cord for added value.

For cameras with a pop-up flash, there is also Slave TTL through Fiber Optic available and of course manual operation can be available through electrical or fiber optic connections.


Controls on the ONEUW are like no other and very easy to use even with bulky gloves (the water is chilly in Europe right?). The functions are clearly displayed on the bright digital display on the back of the strobe. Large lit indicators means no squinting or readers required – even at night – or bright sunlight. Special mention is also deserved for the battery cap design. Anyone who has ever struggled to seal their battery compartment, or watched o-rings squeeze out while tightening a cap, or had a strobe flood through the battery area will marvel at the elegant simplicity and effortless function of this locking battery cap.

Color (how strobe lit subjects appear)

4600K is a generally pleasing color temperature for models and colorful reefs that will give a nice bump to the appearance of the subject. Those familiar with Ikelite’s look will find the color produced by the 160x similar.


ONEUW is a solid strobe that will be slightly more negative than a Z-330 and more similar to an Ikelite DS-160 or Retra 150W. So among the many available accessories is a Neoprene Body Cover that offers snug finish protection and some buoyancy compensation that would be a wise addition. This insures the 160x is only 2.4oz negative.


Sea & Sea YS-D3 "Lightning"

The YS-D3 is the newest of the new strobes and clearly Sea & Sea realized it needed to up its game to stay competitive. The strobe is due for release in early summer of 2020.

It is obvious from reviewing the specifications, that the YS-D3 is hoping to match the performance of the Inon Z-330. The strobe follows largely in the design of the YS-D2 and sticks with a single flash tube that throws a fairly narrow oval beam with no diffuser.  It includes two additional diffusers to widen the coverage, though the diffusers are translucent plastic and will likely cause a loss of output when in place. A hands on performance review will have to wait until the release of the strobe.

Angle of Coverage 105°
110° (with Wide-Angle Adapter)
Color Temperature 5800K
Guide Number 33' / 10.06 m at ISO 100 (on Land) No Diffuser
Recycle Time 1.7 Seconds (NiMH)
3.5 Seconds (Alkaline)


What to Choose?

These strobes are currently the best available in their categories. They each demonstrate a remarkably progressive approach to strobe design compared to the traditional expectations of uw strobe development. You could easily say “you can’t go wrong with any of them” and you would likely be right. But there are differences unique to each and every photographer has their specific priorities. It also should be noted that demand (as of the start of 2019) has far outpaced the production capabilities of Inon Z-330 (though wait times are improving). Retra is estimating May/June 2019, but warns this is only an estimate. ONEUW is just getting product delivered to the US now and is available on a first come, first serve basis. So for those with a timeline or trip in the near future, plan sooner than later – it will be worth it!

For current availability and further details, please contact a Reef Photo & Video Pro for assistance.