"The best camera," goes the old saying, "is the one you have with you." It’s true, too—spend just a few minutes browsing places like /r/pics and you’ll find stunning image after stunning image taken on a wide variety of cameras, from DSLRs with telephoto lenses all the way down to smartphones. A modern smartphone is equipped with a hell of a lot of picture-taking power and can spit out pro-looking images without a whole lot of effort, and nearly everyone has one on them all the time. Does that mean, then, that the best camera today is a smartphone?

We explored this in our October 2014 "iPhone vs. DSLR" shootout—and we learned a lot. The first lesson was, at least according to a whole lot of people, that I suck at photography. And that’s all right—I do suck at photography. Most of the images I take are properly called "product photography," done inside in studio conditions with lots of lights and not necessarily a lot of variation in settings. Shooting in the real world is a lot more complicated.

More importantly, we proved conventional wisdom right. A smartphone does take awesome pictures, so you don’t need a DSLR, two bags of gear, and a tripod unless you really need an expensive DSLR, two bags of gear, and a tripod.

But—there’s always a but!—when used properly, especially under anything less than ideal outdoor lighting conditions, that expensive DSLR with its thousands of dollars’ worth of lenses and off-camera flashes can produce wondrous results. Do some post-processing in an application like Lightroom or DxO and you can get some stunning images that would be nearly impossible to pull out of a smartphone. Sometimes, at least.

Round two: Fight!

About 15 months have passed since the initial shootout, and I’ve tried to spend that time brushing up on my photography. I’ve dragged my Canon 5D Mark III around on every trip I’ve taken in the past year, shooting close to 20,000 pictures (some of which even came out well). I can’t guarantee I’ve gotten any better at photography in general, but I’ve certainly gotten a lot more experienced. My subjective evaluation of my picture-taking skill is still all over the map, but I like to think I’ve climbed a bit since last time.

Coupled with the release of a new iPhone—equipped with what by all accounts is a pretty darn good smartphone camera—we decided the time was right to revisit the smartphone vs. DSLR question at Ars. And this time around, we set out to use a much broader variety of locations.

For the smartphone side, I’m using my personal device, an iPhone 6S Plus. This is a current-generation iPhone with about as sophisticated a camera as you’re likely to find on a smartphone (though our Microsoft master Peter Bright preferred the camera on the Lumia 950 he recently reviewed). The iPhone has a 12-megapixel rear camera with an f/2.2 aperture (some sites quote it as f/2.0, but EXIF data from the phone's pictures says f/2.2), an 8.47mm sensor with tiny 1.2μm pixels specifically designed to cut down on crosstalk, and optical image stabilization. It’s also backed by sophisticated software that does its best to produce viewable, well-exposed images under any circumstances (without a third-party camera app, specific exposure settings like aperture and shutter speed are not modifiable, so with an iPhone you’re always shooting on auto).

On the DSLR side, we’re still shooting on the same Canon 5D Mark III body we used last year. It has a 22-megapixel sensor that measures 35mm diagonally, the same size as a frame of 35mm film (hence why the camera is referred to as a "full frame" DSLR). For lenses, we’ve upped our game a bit this year, relying on five different pieces of Canon glass—three zoom lenses and two primes:

Canon EF24-70mm f/2.8L II USM (rented)

Canon EF24-105mm f/4L IS USM (owned)

Canon EF70-200mm f/2.8L USM (owned)

Canon EF35 f/1.4L USM (rented)

Canon EF50 f/1.8 II (owned)

All told, that’s about $5,200 worth of lenses. The 24-70mm and the 35mm prime are both extremely high quality, which is why I rented them (though only a couple of images taken with the 24-70mm ended up in this shootout—I used it extensively for taking pictures of jets and moon rocks). The 24-105mm and the 70-200mm are solid workhorse lenses that you’d find in most Canon shooters’ kits, and the little "nifty fifty" 50mm f/1.8 is pretty crazily affordable for the image quality it yields (I use it mostly for product shots).

The DSLR body itself costs $2,500; add to that the cost of the 600EX-RT and 430EX II flashes I used for some of the images and the tripod I used for a few others (not to mention the bag to haul the whole mess around in), and you’ve got damn near $9,000 dollars' worth of equipment.

All this kind of makes that 64GB $849 iPhone 6S Plus look like a crazy bargain—and one that can do things the DSLR can’t, like shoot 4K video. At 10 times the cost, does a bag stuffed with lenses, flashes, and a DSLR really provide 10 times the image quality of a smartphone?

Maybe—or maybe not. As with all things, the devil is in the details.

How we tested

We took our iPhone and our DSLR bag to several different indoor and outdoor locations and shot hundreds of images with each. Rather than try to manually match settings on both devices like we did last time, this time around we relied on the iPhone’s built-in camera app to do its thing and produce whatever it thought was the best image of whatever we were pointing it at.

Conversely for the DSLR, we shot in a mixture of Manual and Program mode, capturing only full-size RAW files. The RAWs were then subjected to a full post-processing workflow in both Adobe Lightroom and DxO Optics Pro—this included exposure compensation, tone adjustment, color tweaking, white balance adjustment, and everything else one might normally do to a RAW frame (including DxO’s Prime noise removal, which, as near as I can tell, is basically witchcraft).

The only thing I didn’t adjust—much—was the framing of both images. Instead, I tried when shooting to make both the iPhone’s and the DSLR’s compositions match each other as closely as possible. In some instances, this meant digitally zooming the iPhone 6’s camera so that the frame contained what I wanted. As you’ll see, these digitally zoomed images, without exception, look like garbage. Anyone who has fiddled with photographs on a smartphone should already know this, but it bears repeating: don’t use your phone’s digital zoom. It’s terrible, and it will make your pictures look terrible.