The royal family's photographer reveals his 5 favorite photos of Queen Elizabeth

"What you have to remember when you're photographing the Queen is that she's this incredible iconic figure, famous around the world, hugely respected," Chris Jackson told Insider. "When the light falls in the right way, or you get a slightly unexpected expression, you can take a photograph that lives on in the archives."

Jackson noticed the soft lighting and clean background as Queen Elizabeth visited with hospital staff during the opening of a maternity ward at the Lister Hospital in Stevenage, England, in June 2012.

"Nurses and doctors had come gathered around, and the Queen was looking up at them," he said. "And, for me, it's just a slightly unusual expression. It makes me smile."

When her horse Estimate crossed the finish line at the 2013 Royal Ascot, Queen Elizabeth became the first monarch in 202 years to win the Gold Cup at the prestigious racing event.

"It was obviously a big ambition of hers for this to happen," Jackson said. "She's an incredibly keen horse breeder. It's something that's been such an important part of her life since she was given a horse called Peggy at the age of 4. This was such a lovely moment, because you saw genuine pride and enjoyment as she was handed the trophy. She lit up, and it's almost reflecting the gold on her face."

At the "Blood Swept Lands and Seas of Red" poppy installation at the Tower of London, each ceramic flower represented a fallen soldier.

"Remembering and looking back at those who've made the ultimate sacrifice is such a key part of her duty, and Remembrance Sunday is absolutely one of the most important dates in the royal calendar," Jackson said. "But to capture something that visually represented how important that is to the Queen was really special."

"Prince George is clearly in the moment mixing that Christmas pudding," he said. "And everyone's obviously feeling quite relaxed. But, at the same time, this picture has historical connotations because you've got the heirs to the throne and the Queen. It was a rare moment to capture all four of them together, looking so relaxed."

"What I liked about this picture was employing a bit of creativity here: a slightly slower shutter speed to capture the soldiers parading past the queen, and a slightly tricky photo to capture," Jackson said. "For me, to get the opportunity to do something a little bit different and create something that is slightly more unusual is quite rare because you're often under a lot of pressure to capture a particular set of images. So I like this one — it's a little bit more creative, and I think it's got a bit of energy with the movement to it."