Smartphone cameras are always improving, but there are serious technical reasons why they'll never approach the picture quality that a proper DSLR can offer. DSLR -- Digital Single Lens Reflex -- cameras remain the single best choice for total creative control over your photography.
Sensor Size: The Biggest Difference To Your Photos
One of the key reasons for that is the use of larger sensors within DLSR bodies. As such, while a given DSLR like the Nikon D3S and a given smartphone like the LG G3 may report roughly the same megapixel rating, there's a massive difference between the size of sensors on both devices. Unless our smartphones grow substantially in size, that'll always be the case, because in order to accommodate a larger sensor, you also need a larger lens body to attach to it.
So why does the sensor size make such a difference, and not the megapixel count? As with any other camera, capturing a photograph is essentially a matter of capturing light, and in that respect all digital cameras are the same, because they're focused on the same task. Light is captured in each pixel which sits on the sensor, but the larger you can make each pixel, the more light it can capture. On a typical smartphone you're looking at a sensor which measures 4.54x3.42mm.
Comparatively, a full frame DSLR sensor like the Canon 6D's measures in at 36x24mm, giving a huge size advantage over a smartphone sensor. Even smaller size DSLR sensors dwarf those of smartphone sensors. What's happening here is that smartphone makers are shoving as many pixels into their sensors, but in a substantially smaller area, which means that each individual pixel is itself much smaller and less sensitive to light -- which is what you need to capture any picture -- than the larger pixel sizes on a full DSLR sensor.
That equates to significantly less image sensitivity, more noise and a great deal less flexibility in photographic possibilities. It's true that DLSR bodies are larger than those of the competing small format cameras or smartphones, but that does have an upside, giving a more solid frame to hold or prop up, reducing camera shudder and providing crisper pictures as a result.
Ergonomics: More Comfortable Photography, More Powerful Controls
They're also significantly more ergonomic to hold for lengthier periods of time, whereas holding and framing a smartphone involves largely holding up a rectangle. One of these shapes is built for human handgrips -- and it isn't the smartphone. Then there's the issue of creative control, and that's where a DSLR really starts to shine. DSLRs can appear to be complex creatures, and in truth they are, but that's because they put the creative controls directly in front of the photographer at all times.
It's like the difference between driving a fully manual car and being on a rollercoaster. Both move forwards and have that as an identical characteristic, but the range of controls open to you on the manual vehicle give you far more scope for travel once you get used to modes of operation. The same is true for a DSLR, where it's just the matter of a button press to change a single setting, and with it the framing, scope or emotion of a single photo. Given that each photo represents a moment in time, being able to quickly change settings to capture exactly the shot you want while you can is quite vital, and that's where DSLRs can shine.
Lenses: Your DSLR Becomes A Photographic Platform
The other aspect of creative DSLR photography comes from the lenses themselves. DSLRs grew out of SLRs (no prizes for guessing that's Single Lens Reflex cameras, in this case using film), and that means that while digital photography is itself somewhat in its infancy, there's more than half a century of development in lens glass. It's no exaggeration to say that there's a lens for every type of photography, but equally while the absolute top-notch lenses do cost serious money, you can get started with simple lenses that can deliver quite stunning results with just a little bit of trial and error.
Because DSLR lenses are in a constant state of development, lens quality just keeps getting better, but standard lens mounts mean that yesterday's camera can easily accommodate today's lenses. You also gain the advantage of different lenses for different types of photography and outlook. While most smartphone cameras have fixed, usually wide angle lenses to capture large scenes, with just a change of lens you can shift field and type of vision markedly for all sorts of creative results.
Even the most skilled photographers are endlessly experimenting with lens, camera and lighting combinations, because the photographic journey is one of continual learning, and a DSLR gives you the flexibility to start your proper photography education.