Tsai Ing-wen, who is running for president in Taiwan, is on the cover of this week’s edition of TIME Asia. Freelance photographer Adam Ferguson, who authored the cover portrait, takes us behind the scenes:

“The shoot followed a morning interview by TIME’s Emily Rauhala and Zoher Abdoolcarim in Taipei,” Ferguson tells TIME. “I was setting up a studio on location and I was nervous I wouldn’t get [a lot of] time, but Tsai was very relaxed and happy to work with me.”

Ferguson was allocated 20 minutes with Tsai, which he felt would be enough.

“It was my initial idea to light Tsai with a traditional butterfly beauty lighting set up,” he says, referring to the lighting style that creates a butterfly-shaped shadow under the subject’s nose. “I thought [this style] was simple enough to allow her personality to speak rather than the lighting being too dominant.” But, as the shoot started, Ferguson thought it wasn’t working. “I really wasn’t happy with the results I was getting,” he says. “The portraits I made were two-dimensional and didn’t capture the political aspirations inherent to Tsai and her party, so after about 15 minutes I asked Tsai [for] a break.”

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Ferguson had followed Tsai the previous day. “She had seen me dripping with sweat jostling with Taiwanese photographers trying to make a candid image of her traveling, so I think she recognized that I was serious about making an image that I was happy with and agreed to the extra time,” he says.

Ferguson chose a lighting technique that was more dramatic with harsher shadows. “It gave her face more shape, accentuated her features and in my opinion promoted a more complex reading of her,” he says. “I enjoy political portraiture because there is space to capture personalities in a way that is rawer than the visual tools used in the fashion or commercial world of imagery. I have deliberately not pandered to a visual language that accentuates youth. Our daily lives are already saturated with imagery like this, through advertising, and my intent was for this to be a strong character-driven portrait that speaks about aspiration more than beauty.”

The resulting portrait, which appeared on the cover of TIME’s Asia edition, has been the subject of intense debate in Taiwan, with some accusing the photographer of making Tsai look older than she is.

Ferguson is unfazed by the controversy. “With Tsai I was hoping to capture an expression that was serious, contemplative and strong—all emotions that I believed epitomized her current political aspirations,” he says. “I suspect people are surprised by a lighting style with high contrast because it is not the way subjects are lit in more conventional context.”

And, he adds, giving her face extra depth gives viewers more to look at — and, in this case, more to talk about.

Read TIME’s interview with Tsai Ing-wen.

Adam Ferguson is a freelance photographer based in Bangkok, Thailand.

Olivier Laurent is the editor of TIME LightBox. Follow him on Twitter and Instagram @olivierclaurent

Contact us at letters@time.com.