How we compared them

The Bolt H50R and the ACE 2 H50R share the same basic recipe: a 640 × 512 sensor, a 50 mm lens and 3× base magnification (Nocpix figures). The Bolt was really meant to be a more budget-friendly, entry-level 640. The ACE 2 H50R is its big brother, with a new 12 millikelvin sensor, a faster lens and a more premium build. We put them side by side from 50 metres out to 300 metres, then went over the scopes themselves: how they feel, how they are set up and how long they run.

On the recordings: the two were filmed under different conditions. They are pretty close, but it was not the exact same night, so keep that in mind as you compare.

This is the head-to-head. If you are also weighing up the cheaper Bolt P25R and L35R, our full Nocpix Bolt review covers all three Bolts.

Image quality

In our ACE 2 review we pointed out how new the 12 millikelvin sensors are and how they still need some fine-tuning. We have already seen improvements over the last couple of firmware updates. My suspicion is that every time Nocpix releases a new sensor, it takes some time to get the algorithms right and the processing dialled in, and that is what we are seeing now. Even so, the further out you go, the more the ACE 2 stays on top.

At 50 m and 100 m

At 50 metres there is not much to separate them. The ACE 2 shows more heat, but both hold very good detail, and that carries through to the 100 metre mark.

Zoom levels are not like for like

The ACE 2’s digital zoom tops out at about 10×, because it also has ocular zoom and works a little differently. The Bolt is digital zoom only. Keep that in mind when you compare the same zoom number on the two screens.

At 200 m

This is where the gap starts to open. The ACE 2 holds the shape and the brightness of the dog a little better, and you can see the detail quite well. To be honest, though, the Bolt is surprisingly good here and still holds the shape very well.

White hot vs black hot

With the current algorithm on the 12 millikelvin ACE 2, black hot actually seemed to hold the shape better, and I found it quite good. Out at 200 and 300 metres the difference between white hot and black hot on the ACE 2 was easy to see.

At 300 m

At 300 metres the ACE 2 really takes the lead. The Bolt struggles to hold the shape of the dog, parts of the dog’s body start to disappear, and even the human looks dull and faded rather than bright. Black hot on the ACE 2 is quite good again here. I think you will really start struggling with the Bolt from around 250 to 300 metres on certain species, so if you are a long-distance shooter, you may be better off stepping up to the ACE.

In the hand

Shape, weight and mounting

Both are traditional tube-style scopes on a 30 mm tube, and the tubes are about the same length. The Bolt goes into any 30 mm rings or mount you already have, as long as they are high enough to clear the objective. On our scales with the battery in, the Bolt H50R weighs 948 grams and the ACE 2 H50R 990 grams, so the cheaper scope is actually a touch lighter. Both have a screw-on eye cup, which I like.

Focus

The differences you really notice start at the front. On the Bolt the focus is built into the objective lens, and it is a bit of an effort to turn. The ACE 2 moves it up to the turret, where it is much quicker to reach and, in my opinion, a lot more precise.

Zoom

The Bolt has no ocular zoom at all. It is digital zoom only. The hybrid zoom on the ACE 2 was one of its standout features for me, so that is probably what you will miss most when you step down to the Bolt.

Display and rangefinder

The Bolt’s display is smaller, and looking through it, it does not have quite the same premium feel as the ACE 2. Its rangefinder sits up on top and works fine, but again, the overall design is a little more basic.

Battery cap and startup

The Bolt’s removable battery sits under a screw cap, where the ACE 2 uses a quick-release system. It is not a massive issue, but if you are swapping batteries in the dark, the ACE 2 is quicker and easier. Startup is slower on the Bolt too: around 16 to 17 seconds for the H50R from pressing the button, against roughly 10 seconds for the ACE 2. That is noticeable when you want the scope up and running in a hurry.

Menus, zeroing and ballistics: almost a tie

Inside, the two are basically the same scope. The menu layout, the zeroing system and the rangefinder settings match, and the Bolt keeps most of the same bells and whistles: recoil-activated recording, picture-in-picture, a microphone, and the same app with the same profiles and custom reticle builder.

• Zeroing is handled from one screen. You create profiles as you need them instead of working around a set of presets, and every adjustment lives inside that profile.
• Reticles are fully adjustable for shape, colour and brightness, and you can build your own in the app with your own aiming points and spacing.
• Rangefinder display is under your control. You choose how long the LRF reticle and the ranging data stay on screen, so range data is not sitting over your shooting reticle at the wrong moment. The LRF reticle is adjustable too.
• Ballistics can go in on the scope or through the app, with a built-in bullet library, named custom loads for reloaders, and named profiles so you know which rifle and load you are on in the dark.
• The app gives you a live viewfinder, your photo and video album, and firmware updates.

For a scope that costs considerably less, getting almost the same level of control over the major features is not usually how it works when you step down a price bracket. We go through these menus in more detail in the ACE 2 review. If you have trouble connecting to the app, our thermal app and WiFi connection guide walks through the fix.

Battery: the Bolt’s clear win

Both use an internal battery alongside a removable 18650, but they manage them differently. The Bolt H50R runs the removable battery down first and only moves to the internal once it is empty. The ACE 2 H50R draws from both at once. I prefer the Bolt’s approach, because you can swap the removable battery before you ever eat into the internal backup.

There have been suggestions that Nocpix draws from both on the ACE 2 to look after the long-term health of the internal battery, since a lithium battery left unused for long periods can also lose lifespan. So there may be some logic behind it.

On outright runtime the Bolt is well ahead in our rundown testing: roughly 9 to 10 hours from the Bolt H50R, against around 6.5 to 7 hours from the ACE 2 H50R.

Side by side

Bolt H50R or ACE 2 H50R?

The difference that matters most is the one you cannot see on the outside: sensor sensitivity and the lens. The Bolt H50R is rated at 18 millikelvin with an F1.0 lens, and the ACE 2 H50R at 12 millikelvin with an F0.9 lens. Put those together and, particularly as the distance increases, the ACE 2 is still the clear winner for overall image quality and shape recognition.

So it comes down to your needs and your budget. If you are mainly shooting at closer to medium distances and you want a thermal scope that gets the job done without the ACE 2 price tag, the Bolt H50R absolutely earns its place, and it performs extremely well for the money. If you want the best shape recognition you can get at longer distances, along with the better controls, faster focus adjustment, quick-release battery, more premium display and the hybrid ocular zoom, the ACE 2 is where the extra money starts to make sense. The original ACE 1 is also worth a look while it is still available.

Still weighing up sensor and lens size? Our guide on how to choose a thermal scope walks through it, and the full Bolt review puts the H50R against the cheaper P25R and L35R.