The equine photographer, who specializes in dressage shoots, said she's had to train herself over the years to rely on her intuition and knowledge of horses to get that special moment, rather than on her Canon 40D.
"Dressage is like dancing on horseback, and I love when we can get those shots for riders," she said.
Ehmen is one of about a dozen photographers with HoofClix, led by owner Mark Lehner, who specializes in equine event photography.
Ehmen and Lehner have been hard at work for the past few months capturing contests leading into this month's big events in dressage, jumping and cross country trail riding.
The balance of art and athletics came from an early age for Ehmen. She began riding at age 5, but can't ever remember a time she wasn't around horses.
While pursuing a degree in pharmacy at Purdue University, an internship changed Ehmen's mind about a career in science.
"I had a 4.0 and everything and I decided I didn't want to work the rest of my life in that field," she said.
Instead, she combined childhood loves of photography and dance to create a career that suited her passions.
A senior photography project in 2007 prompted Ehmen to focus on the equine industry. While attending a show in Thomson, she met Lehner and passed along her portfolio with her final semester's work.
In a week she had a call to start freelance work.
"He told me I had to come to Aiken, Georgia and Florida if I wanted to pursue this as a specialty," she said.
Since then, she has spent afternoons running her dance studio and weekends covering large horse trials with 300 to 600 horses and riders.
"We're assigned to rings or work in teams for cross country events, and we stick to our area," she said. "There isn't a lot of interacting or 'participating' in the event."
Each rider requires a photo of his or her number and sets of daily photos, and can come by Ehmen's trailer that night to go through shots.
"We don't do a lot of editing, but you still have to understand timing and lighting so well because we don't have the luxury to go back and edit all evening," she said.
An assignment also means Ehmen's artistic inclinations sometimes get put on the back burner. In between changing angles and keeping an event fresh for herself, she's obligated to capture specific shots for riders looking to show off their form.
"Everyone's looking for the photograph, so you do have to shoot the same shots and positions for each rider," she said.
The grueling routine sometimes leads to 10-to-12-hour days in the same position.
"For the rider, they come out, do their event and go back to the barn. We're out there the entire day, rain or shine," she said. "We've shot events in 100- degree weather, or it might be rainy and freezing cold. It wears me out more than anything."
The gift of understanding a horse's timing and canter sets Ehmen apart from photographers who didn't grow up around events.
"I have a real sense for the rhythm of the horse," she said. "I don't have to watch them. I can hear it in their stride as they're coming toward me and know when I'll capture that photo with their legs at the fullest extension or in the point of their jump."