Easily the most interesting of the bunch, the flagship Zenfone 4 Pro is built around a 5.5-inch AMOLED display - Pro often goes with AMOLED in Asus' lineup.
There are generous bezels on the top and bottom - Asus hasn't bothered to keep up with the recent trends. On the plus side though, that makes room for a nice large fingerprint sensor below the display and an earpiece that doubles as a second speaker.
The Zenfone 4 Pro is a glass sandwich like so many others these days. It's Gorilla Glass on both sides, and Asus doesn't make a big deal out of the version - we had to go to Corning's website to find out that it's GG5. Nice. Less so is the smudgy mess that the back immediately turns into, but such is life - the Zenfone is no different from the next phone with a glass back in this respect.
The dual camera sits in a common bump in the upper left corner of the phone, with a '2x zoom' inscription so you don't forget its top feature. It's a similar setup to the iPhone 8 Plus and Galaxy Note8, with a regular 25mm-equiv. main cam and a second 50mm-equiv. moderate telephoto one.
The camera is a lot like the Note8's - the primary shooter uses a 12MP 1/2.55" dual pixel Sony IMX362 sensor like the one you'd find in an HTC U11, and similar in principle to the imager used in recent Galaxy flagships, Note8 included. The f/1.7 aperture lens is stabilized too and Asus promises 4 stops of stabilization - on a 25mm lens that means you should be able to get photos free of hand shake induced blur with shutter speeds down to 2/3s.
The second rear cam is a 16MP Sony IMX351 affair - it's the same 1/3.06" sensor LG used on the V30's main cam. Here, however, it's paired with a 50mm-equiv. lens, giving the Zenfone 4 Pro 2x zoom capability. That's proper optical zoom which Asus extends digitally to 10x total, but we all know that digital zoom is something you'd rarely want to use.
By the way, that's not just a flash next to the camera - there's also an RGB sensor for determining the temperature of the ambient light and assisting with white balance. And if the dual pixel autofocus isn't enough, there's also laser autofocus, and Asus promises a 0.03s time to lock focus.
Sony everything - the front camera is an 8MP unit with an IMX319 sensor and large pixels too - 1.4µm like on the IMX362. The 22mm-equiv. focal length is plenty wide for group shots, and the f/1.9 aperture lets a lot of light in. Overall, it's a truly impressive specsheet in the camera department, though we obviously couldn't properly test it out at the event.
It's not just the camera department that impresses, actually - the Zenfone 4 Pro is powered by the current top-of-the-line chipset from Qualcomm, the Snapdragon 835. There are 6 gigs of RAM on board and storage options start at 64GB. Battery capacity is a respectable 3,600mAh, and there's fast charging support and a myriad of charging technologies to extend battery life in the long run.
With a (speculated) price tag of 600€ for such a complete package, the Zenfone 4 Pro seems to make a lot of sense in today's flagship market where the big-name offerings cost upwards of 800€. That said, we're yet to properly test one to make sure it's as good in practice as the specs suggest.
The Zenfone 4 Pro is the flagship, but the non-Pro might be better for you in more than one way. There's the price difference, obviously, but the vanilla model replaces the telephoto cam for an ultra wide-angle one - if you wanted one of these you only had LG to go to, but not anymore. The ultra wide-angle cam covers a 120-degree field of view, just like LG's latest implementation on the V30. Meanwhile, the main camera is the same as on the Pro - 12MP, dual pixels, and all. The RGB sensor is is present too.
The body of the Zenfone 4 is a glass sandwich similar to the Pro, only this one is covered with Gorilla Glass 3, as opposed to GG5. Another notable difference is that the camera modules sit flush with the back on the 4, while the Pro has a bump.
It may not be Pro, but the Zenfone 4 does keep the stereo speakers and the fingerprint sensor - no corner-cutting here.
The list of changes on the Zenfone 4 proper, when compared to the Pro, includes an IPS LCD in place of the AMOLED display, still 5.5 inches in diagonal, and still FullHD. Our initial impressions are that it's a good LCD with high peak brightness and contrast and good color stability at an angle.
The Zenfone 4 comes in two versions in terms of chipset - it's either the Snapdragon 630, or the 660 - the S835 is reserved for the Pro. RAM is 4GB on the S630 version and 6GB on the one with the more powerful chip. Battery capacity is 3,300mAh on either one, complete with fast charging.
We also have a review unit of the Zenfone 4 here at the office, all set to enter the review pipeline. You can expect a detailed review in the coming weeks. In the meantime - there are Zenfone 4 Selfies and Maxes on the following page.