Pulsar Helion 2 XP50

Pulsar followed up their first series of Helion thermal spotters with the pocket-sized Axion line. The Axions are very capable units, but their compact dimensions place limits on lens diameter, sensor size and endurance that don’t affect the Helion, leaving the top slot in Pulsar’s range to be occupied by the brand new Helion 2 XP50.

I’ve owned an original Helion since soon after they launched. Barring the inconsequential loss of some paint from the heat-sink, and the flange from the eyecup, it’s as good as it ever was. Better, actually, since regular firmware updates, and upgrading from the old IPS5 battery to the current IPS7 standard, have provided significant performance and functionality gains. In that sense, the Helion 2 picks up where a fully-updated Helion leaves off. We’ll see shortly what it adds, but first a recap of features and strengths of the Helion platform.

Get a grip

First off, the size is just right for wrapping your hand around and navigating the four rubberised buttons on top. For the convenience of right-handed users, these are placed to the left of the centreline, but a left-hand hold is almost as comfortable.

The nearest button selects your recording mode and captures stills (JPG) or video (AVI) for storage in the on-board memory: increased from 8GB to 16GB. The next scrolls through the stepped magnification of the digital zoom and holding it down toggles the picture-in-picture function, permitting close scrutiny of a selected object without losing wider awareness of the scene.

Next comes the menu button. Quick presses let you scroll through the brightness, contrast, zoom and rangefinder functions. Stop at any of these and push the buttons either side of the Menu button to increase or decrease the setting. The menu gives finer 0.1x increments than the main zoom button, which simply doubles the magnification with each press. A long push of the menu button takes you into the main menu itself, which has two screens with a total of 12 major functions on each. Key, is the WiFi link for updating firmware, downloading stored image files, or maybe streaming the image for a buddy to watch on a tablet or smartphone.

More functions

Other useful functions are the palette selector (especially on the Helion 2, which offers a suite of colour palettes in addition to the classic hot-white/hot-black options); the recently-added "Image Boost" function, which enhances edge detail to produce a deeper, more-contrasty image and the icon brightness control, which lets you dial down the menu brightness to conserve your natural night vision on nocturnal sorties.

After exiting the menu with a long press, you can then press and hold the furthest button to toggle between hot-white and a second user-selected palette or blip it to scroll between four pre-set combinations of contrast and brightness (Identification, Forest, Mountains and User), enabling quick optimisation for the conditions.

Finally, there’s the power button. Formerly black, but given a blue accent colour on the Helion 2, a short press will recalibrate the sensor, eliminating the artefacts that inevitably build up as it registers the changing scene 50 times each second.

Closing the lens cover and then recalibrating a couple of times gives the best results. A longer press of the button puts the display into screensaver mode, conserving power and reducing the glow from the eyepiece, whilst a further push instantly reactivates it. Alternatively, hold the button down as a counter runs down to zero and power off the unit completely. Restarting it takes just 8 seconds, so it’s worth doing if you need to eke out the charge in your battery for any reason.

Power source

The battery is another of the Helion’s strengths. Called the B-Pack, it has a Li-Ion core and now comes in a standard 6.4 A-h, size (IPS7) with a run-time of 10 hours. A 21-26-hour (IPS14) pack is available separately, as is a BPS battery holder that takes 3 x AA-cells. All are backwardscompatible, as earlier models have the same footprint: locking securely into the R/H side of any Helion, Accolade or Trail unit via a top-mounted cam lever. The battery is a snug fit in its opening, too, but only the logo on the side and a low ridge underneath indicate its orientation, so installation requires a couple of seconds of extra concentration.

Additionally, power can be supplied using an external power bank, such as Pulsar’s 5 A-h PB8i, connected via the MicroUSB port on the R/H side. This port also serves to hook the Helion up to your smartphone or PC for rapid image transfers or charging.

User-switchable

Up at the front is the large 50mm objective lens. It has a native magnification of 2.5x and is manually focussed via a tactile ribbed ring. On my minimalist XQ19F model, replacing the lens is a workshop job, but on all Helion XP models, lenses are user switchable. The optional 28mm and 38mm alternatives reduce detection range (1,000m and 1,350m) and magnification (1.4x and 1.9x) but boost the field of view (22° and 16.3°). All come with a folding lens cover that clicks shut and lies tidily along the side of the unit when open.

At the eyepiece end, a soft rubber pad adds comfort and protects the dioptrefocusing ring. Setting this correctly is essential to bring the display into sharp focus. On my Helion, this control moves too freely. Fortunately, this is not an issue on the Helion 2.

We’ve moved into differences now, so let’s focus on these. The most significant from the user’s perspective is the addition of a new higher-definition, full-colour AMOLED display. Those who like to view the thermal world in red, violet, rainbow, etc. will appreciate how this intensifies the 8 colour palettes. Myself, I prefer the ‘hot-red’ option that highlights only the hottest part of the image. This really comes into its own in woodland where heat retained by timber can make animals hard to detect in standard monochrome views.

New tech

The hot-red function works even better on the Helion 2 because of new sensor technology that reveals temperature differences over a third more precisely than before. Just as the move to a finer 17 μm sensor pitch improved lens performance, new sensitivity refinements are now enhancing image detail. Previous sensors were rated at <60 millikelvins (mK). This denotes a seriously tiny temperature difference… but the Helion 2’s sensor can detect differences of <40 mK. Think of it like sharpening your pencil before drawing a picture!

In practice, what this means is that the Helion 2 is better able to cope with the ‘flattening’ effect produced by rain and fog, and to see low-temperature features such as a buck’s antlers or a fox’s brush. The resulting images are strikingly natural, requiring much less active interpretation. The AMOLED display responds more quickly to movement too, so image quality is also retained better when scanning, making the most of the fast 50Hz refresh rate. In short, the increase in image quality is so significant that the new sensor is the true nextgeneration feature in the Helion 2.

Conclusion

It seems odd, then, that Pulsar has matched Helion’s superb new sensor and sumptuous 50mm germanium lens with a modest 640x480 display; and that it still outputs video at 640x480 in AVI. This leaves it hard-pressed by the new XQ38S, which offers 1024x768 definition in the newer and more versatile MP4 format, and also incorporates the new <40 MK technology. The price contrast is striking too, as an Axiom XQ38S will save you a cool £1.5K.

Ultimately, therefore, choosing a Helion 2 XP50 isn’t the only way to cross the new 40 mK threshold in image quality, but rather about the endurance of the uprated B-Pack system, the reach of its lens – capable of detecting a 1.8m high target at 1,800m - and the size of its sensor. These all add real value. So, if you don’t want to be tempted, don’t pick up a Helion 2: because once you have, anything else just feels cheap!