If you're looking for how far the iPhone's camera has come, look no further than behind Pete Souza's lens.

On Tuesday, the Chief White House photographer posted candid Instagram shots that he took this year only using his iPhone on Medium.

In the post, Souza explains that his approach to taking shots for Instagram is to use a DSLR (Canon 5DMark3, but also camera models from Sony, Nikon and Leica) for full-frame horizontals and verticals and his iPhone for all square photos on Instagram.

"Many followers have inquired about whether a certain photograph is taken with an iPhone or DSLR (digital single lens reflex camera)," Souza explained in his post on Medium. "In choosing the photographs for my year on Instagram, I decided to select only iPhone photographs that were captured in the square format on an iPhone. For many purists, the square format was the original inspiration for Instagram. And I certainly admire those that continue to post only square photos taken with a smart phone."

The brilliant images range from outdoor shots of the White House to candids of President Obama's briefcase and cup of tea in the Oval Office. What's more personal than someone's cup of tea?

Souza's images earned the praise of Apple CEO Tim Cook, who tweeted, "Stunning iPhone photography by White House chief official photog," upon seeing the images.

Souza's iPhone-shot Instagram images can be seen here.