On my first shot of St Paul's Cathedral, both phones struggled to expose for the scene, resulting in blown out clouds and rather dark buildings.
With HDR mode enabled it was another story. While the One M8 still suffered from too bright clouds, the Mini kept everything under control, resulting in a great photo.
The same was true on my next test, where in normal shooting mode, the building was dark on the Mini and the sky had a blown-out corner on the M8.
HDR mode helped brighten up the Mini's picture -- although it looks a little surreal -- and it didn't do a lot to rescue the M8's shot.
Heading up the river, I found this old, knotted rope. Both phones captured it with good exposure, but I prefer the slightly warmer tones of the Mini. The Mini's 13 megapixels also provide considerably more detail, which is particularly noticeable at full screen.
Further along, this old metal thing was marginally darker on the Mini, but again, I found its warmer colour tones more pleasing.
This veg stall in Borough Market was captured well by both phones, with good exposure and rich colours. There's very little to choose between the two.
A different veg stall here, and both phones did a decent job, with just a little overexposing on the garlic and leek stalks. The One Mini's shot is slightly warmer, but in this scene it looks a bit over the top. The M8's photo looks the most natural.
Moving indoors to snap photos of my excellent colleague Luke Westaway, the M8 was the clear winner. Its photo was brighter and much sharper. By comparison, the Mini's attempt lacks a lot of detail and doesn't seem to have focused well in the low light.
With flash on, it's a little tough to call. On one hand, the M8's duo-flash has been rather overpowering, darkening the background and causing a lot of red-eye. Luke is sharper here than on the Mini's photo, however, which again, didn't do a great job with focus.
Speaking of focus, the Mini doesn't have the second depth sensor lens on the back of the phone. That means that photo tricks -- like refocusing after you've taken a photo or being able to selectively edit the background, but not your friend in the foreground -- aren't possible. Although I found those tricks quite fun on the One M8, they're hardly killer features and I doubt you'd feel like you're missing out. What I will miss, however, is the ability to take full 360-degree "photo-sphere" panoramas, although there are apps available on the Google Play store that will let you do this.
The camera interface itself is much the same as the M8's. Like the rest of Sense 6, it's stripped down and easy to navigate and you can save custom camera settings to quickly load up in a hurry.
The Mini comes with a 5-megapixel front-facing camera too, which will come in handy for video calling or, more likely, taking a mass of selfies. Front-facing photos are sharp and well exposed and I reckon among the best you'll find from a phone. It also has an HDR mode and you can apply real-time effects. On the downside, it's not a very wide angle lens, so you really have to stretch your arm out to get yourself in the shot. This could quickly become annoying if you like squashing all your friends in a scene.
The phone has a 2,100mAh battery stuffed inside it, that managed to keep going for 9 hours, 31 minutes in my video-looping drain test, which isn't too bad. By comparison, the One M8 achieved a little under 10 hours on the same test, while the Google Play edition of the Moto G achieved just over nine.
It's not a bad effort at all and you won't struggle to make it through a full day of use. Of course, that still depends on how demanding you are of your phone. If you spend your entire morning playing Asphalt 8, you can expect to give it a boost in the afternoon if you want any power left for photos on your night out. If you keep the screen brightness down and avoid anything too strenuous, you shouldn't need to worry too much. Keeping Bluetooth, GPS and Wi-Fi switched off will help eke out those last drops of power.
There's also the same extreme power-saving mode found on the M8. It restricts processing power, background data and anything else power-hungry in order to keep that list bit of juice for as long as possible. It won't last on 10 percent charge over a weekend, but if you're at a bar on a Friday evening and need enough battery to call a cab at the end of the night, it may come in handy. The sealed metal body of the phone means it's not removable, so you'll need to carry an external battery pack, rather than a backup internal battery, if you're going away from a plug for a while.
As with its previous mini flagship, HTC has taken the design of its top model but watered down the internal specs. It's a disappointing move, particularly if you've fallen in love with the slick design and brutal power of the M8 but just can't wrap your hands around its 5.1-inch screen. The Mini 2's metal body is extremely luxurious though and is unquestionably among the most attractive compact phones around, which goes some way to justifying the price.
If style and good looks are of the utmost importance, the Mini 2 may be worth shelling out for. Bear in mind though that the Motorola Moto G has similar internal specs and can be picked up for less than half the price. If you're after a top-end flagship but in a smaller body, the Sony Xperia Z1 Compact sports everything you'd expect from a premium phone, crams it into a 4.5-inch frame and costs roughly the same as the Mini 2.