No, a telephoto lens is probably not the right one for aerial photography.
Yesterday, my husband and I took the helicopter out to get some aerial photos in the Alamo Lake area. I’ve been writing for Aircraft Owner Online magazine and have a bunch of stories that don’t have photos to go with them. This flight was a chance for me to do some fun flying while getting the pictures I needed.
I set up the helicopter’s “nosecam” to capture an overall view of the area. The camera has a wide angle lens which does add some distortion to the photos, but not enough to render the photos unusable. In fact, during my recent Southwest Circle Helicopter Adventure excursion last week, I captured hundreds of very usable shots, some of which you can find here. The camera has no controls; it’s set up to take a shot every 5 seconds.
My husband also brought along his Nikon D90. I didn’t pay much attention to the lens he’d bought along. He usually uses my old favorite, an 18-85 (I think) zoom, and that would be perfect for this mission. We took both front doors off and put in the dual controls so either of us could fly while the other took photos.
I took off and we headed west. Once I’d established us in level fight, I offered him the controls. He took them. I reached for the camera.
And that’s when I saw that he’d put on a 70-210 zoom lens.
I felt my heart sink as I looked through the lens. At our 500-foot cruising altitude, it was simply too zoomed in to be useful. Sure, I could take photos of the occasional grazing cow we flew past, but there was no way I’d be able to capture the “big picture” views I needed for my articles. For that, we’d have to gain another 2,000 feet in elevation.
Sorely disappointed, I put the camera down and just watched the desert scenery go by.
Bringing the wrong lens along on an aerial photo flight is something I see first-time aerial photographers do all the time. For some reason, they get the idea in their head that things will be far away and they need telephoto power to frame them properly. In a helicopter, this can’t be further from the truth. I routinely cruise at 500 feet AGL and am willing to go as low as 100 feet (depending on the circumstances) for a photographer to get the shot he needs. Some of the best photos taken from my helicopter have been taken with focal lengths less than 50mm.
A telephoto lens is a bad choice for another reason: the longer the lens, the faster the shutter speed required to prevent blur caused by a too-low shutter speed. The rule of thumb formula is generally 1/focal length for minimum speed. So a 70mm lens would require a 1/70 second minimum shutter speed. But since our digital cameras have a 1.5 focal conversion (meaning that a 70mm lens is equivalent to a 105mm lens), that ups the speed to 1/105 second minimum shutter speed. Not a big deal on a bright Arizona day, but remember: that’s a minimum rule of thumb and I don’t think it takes into account the increased vibrations of a helicopter. (I wouldn’t shoot anything from a helicopter at less than 1/500 second without gyro stabilization.)
When I took back the controls a while later, Mike took the camera. I think he immediately saw what I meant. He was surprised. He did take some photos — among them, some bulls locking horns out in the desert — but not many. The camera simply wasn’t properly equipped for our mission.
Fortunately, the nosecam had us covered.