Seacam Sea Flash 150 Digital Review


While TTL has a few challenges in shooting wide angle, TTL does come into its own with macro.  The Seaflash comes with a plastic rim to narrow the wide beam and there are accessories like snoots, etc in the Seacam product line.  For most of my dives, I used the diffuser to absorb a bit of light just in case there was too much power.

The metering with macro tends to be a lot more accurate than in wide angle, especially in Average mode.  As mentioned before, Average metering considers all lit objects and comes up with a balanced exposure it thinks is good for the scene.  This works well with macro, especially when there are areas (like fish with scene scales etc.) where exposing for the midtones would result in blown out highlights.  With macro, Average maintained a very nice balance at FEC 0, maintaining the mid-tones without blowing out the highlights.

Nudibranch. Note how balanced the lighting is with Average ETTL.  1/250 f22 ISO200 FEC 0 Average ETTL. 100mm f2.8L IS

With Evaluative metering, the tendency was to overexpose with FEC 0.  By ignoring the bright/shiny parts of the image, it would meter to mid tones and the results would be over exposure for the highlights.  This was especially true if there was quite a bit of bright spots and the subject is not as bright.  I found it will blowout highlights like sand if the subject was dark enough. However, the subject would be well exposed.  To prevent this, I used FEC -2/3 to control Evaluative metering for the strobes. 

There were a few instances where the metering was way off by 2 stops over.  My conjectured conclusion was that somehow, the metering was thrown off by something in the picture. Fortunately it only happened once or twice.


Overexposed Blenny. 1/125 f11 ISO100 FEC 0 Evaluative ETTL. 100mm f2.8L IS

I’m sure by now you are wondering why anyone would even bother about Evaluative for macro.  It works well for subjects that aren’t perfectly placed within the metering zone.  For instance, in the following image of the Saron Shrimp, the subject was in a hole.  Average would taken into account the metering of the dark background and expose a little dark. However, Evaluative meters to the Saron shrimp and overexposes the foreground, which is fine for me. FEC -2/3 brings back those blown highlights and one has a very nicely exposed picture, which can be further worked on in RAW processing.


Saron Shrimp. Note the sand foreground is blown but the shrimp stays well exposed. 1/160 f13 ISO100 FEC -1/3 Evaluative ETTL. 100 f2.8 Macro

The Seaflash has a few features that are very helpful with macro shooting.  The Auto AF Assist light feature on Canon strobes also work with the Seaflash, which assists with the very nice LED lights when the function is turned on in the camera and the camera is in Single Shot AF mode. It works very well so long as the LED light is pointed in the general direction of the subject since the beam is a spot focus beam and not very wide.  Seacam has a red filter for the LED light listed in the accessories list. I wish I had asked for those things for this test. My attempt at Mandarin fish and Dragonets was pretty poor since all my lights had no red filter.

The Flash Arms:


I was given the flash arms as part of the test kit.  I decided to test the buoyancy by dumping them in water individually. The shorter 150mm arms sank slowly in the pool while the 300 were just slightly positive.  With the test 60D housing and the


The Seacam Seaflash 150 is like every Seacam product out there, well-designed and built. It is the only strobe with built-in 2nd curtain sync and Auto focus light assist in the market for Canon. The beam is wide and it recycles quite quickly. Most importantly, the ETTL works well, especially for macro and in situations where fast reactions are necessary.

The 3W LED light is bright and lasts a long time. It also does double duty as a focus light as a momentary flash to achieve focus, activated by the AF start command from the camera.  This is a very useful feature which reduces the chances of scaring off light sensitive subjects from reacting to a focus torch.

Functionally, I couldn’t find too many things to gripe at except for minor things like 2nd curtain sync had to be in slave mode, thus running the risk of firing when others fire or the 1/2 steps in the power levels in manual being unclear in the manual or on the strobe.  2nd curtain sync requires the strobe to be in slave mode, which means it will fire when other strobes fire in the line of sight. It worked well in the test, was easy to setup and worked well over the 3 months I had it.  The silver finish is more susceptible to blemishes because it’s just more noticeable. There isn’t TTL in Slave mode, which is limiting if for example, one of the sync ports are dead. Or even shooting with the strobe off housing.  There’s not a lot to be negative about this strobe.  It seemed to be designed for certain types of users in mind, even though it’d work for most.

At nearly US$2806, it’s definitely the most expensive strobe for the125-160W class, which may make some balk. However, it is arguably the best strobe around for Canon cameras, in terms of features, quality and function, especially when it comes to ETTL and rear curtain.  Some strobes are more powerful, have more powerful LED lights, cheaper or lighter, but none of them are as complete as this strobe. If the ETTL and rear curtain are what you want, there’s no other strobe that can do this, especially for the 1D and 5D series cameras.

Price of equipment tested:

Seaflash 150D:  US$ 2.806,00
Diffusor US$  168,00
Flash Arm 150/300 US$  566,00


• Energy 150 Ws
• Underwater guide number 14 – ISO 100 / 1 m at full power
• Coverage light angle 130°
• 180 flashes at full power
• Recycle time 0,1 – 2 sec
• Manual light level selection in 7 + 5 different steps
• Color temperature 4400 °K
• 10° Power LED, 180 lm in 2 manual power steps and automatic mode,
continuous burn time 3 h
• Slave sensor, high intensive for all manual settings
• True S.O.S. safety signal for approx. 6 h
• Sync socket either S6 or N5
• Automatic charger, integrated in the accu pack, fully controlled by ΔU, temperature
and time, charging time 100 min
• High quality NiMH battery pack, NiMH 7.2 V / 1.85 Ah, selected, easy to change
akku pack with integrated charger
• Dimensions:  Flash L x Ø: 190 x 100 (90) mm, Akku/Battery pack L x Ø: 135 x 40 mm,
• Weight: 1350g(150D) - 50g negative underwater /1430g(150O) - 100g negative in fresh water (70g in seawater). Battery Pack: 300g
• Depth rating – 80 m(150D)/200m(150O)

Subjective Pros, Neutrals and Cons list:


-  Exquisite build quality and finish
-  2nd Curtain Flash Sync/ETTL capability
-  Excellent built-in LED light with Auto Focus lighting assist compatibility.
-  nice power band for macro, medium wide focus and closer wide focus illumination
-  Versatile beam : 130°, adjustable ring for macro and diffuser gives choices while underwater even.
-  Easy to set up for use
-  Quick charging battery


-  Documentation/Instructions aren’t very detailed
-  “In between” power levels not marked
-  No Fiber-Optic firing capability
-  Silver coating shows blemishes


-  Expensive
-  No TTL in Slave Mode
-  Rear curtain in Slave Mode, running the risk of firing when other strobes go off