Why are iPhone X photos higher quality than iPhone 7?

My relative has an iPhone X, while I have both an iPhone 7, and a DSLR camera.

At a recent family event I compared his photos with mine and his iPhone X photos look almost as good as DSLR. I did a quick Google search but couldn't find an obvious answer.

Is the most significant improvement hardware-based, or software-based? If it's the latter, can older iPhones be configured to get these benefits (I noticed his images are in HEIC format which my iPhone 7 only seems to use in Burst mode)?

Assuming both the iPhones are running the same latest version of iOS.

Is the most significant improvement hardware-based, or software-based?

Certainly iPhone X, being a generation newer than iPhone 7 has better hardware. If you compare the camera specs for both the iPhones this is what you get:

Essentially, the specs appear quite comparable. However, photo quality isn't just about megapixels, optics and sensors. What isn't obvious is that iPhone also employs computation photography in addition to relying on bare camera hardware.

Additionally, with better chip in iPhone X (A11 Bionic) with an addition of Neural Engine, compared to iPhone 7 (A10 Fusion), iPhone X is better equipped, hardware-wise to perform better computations (software) to give you better looking end results.

It's really a culmination of hardware and software that dictates what a device can produce.

In addition to the answer offered by Nimesh, there's also the issue of how you compared the photos.

My assumption is that you were just checking them out on your iPhones, and this probably explains a lot of what you noticed because the display on an iPhone X is leaps and bounds above that used in an iPhone 7. More specifically:

• the iPhone 7 incorporates a Retina HD LED-backlit LCD display with a resolution of 1334 x 750 pixels
• the iPhone X uses a Super Retina HD OLED display with a resolution of 2436 x 1125 pixels

Not only is the iPhone X's resolution much higher, but it uses an OLED screen as opposed to an LCD one. Photos viewed on this will appear to look significantly better than those displayed on an LCD.

In other words, while the iPhone X is definitely taking better photos, how much better they're looking is exaggerated if you're viewing them on an OLED display, as opposed to viewing the photos on the same display.

So, for a valid comparison you'd need to view the photos from both devices on the same display (e.g. on the same computer) to get a better sense of how much difference there was in the quality.