Think the Reciprocal Rule is safe? It fails with high resolution cameras

Esther BeatonBird Images, Photography Techniques, Photography Workshops, Quick Tips, Wildlife Photography

Tawny Frogmouth (Podargus strigoides) on nest among casuarina trees, Lake Tuggerah, Central Coast, New South Wales
Tawny Frogmouth (Podargus strigoides) on nest among casuarina trees, Lake Tuggerah, Central Coast, New South Wales

Enlargements showing sharpness at 1/500 shutter speed, without and with flash. Tawny Frogmouth (Podargus strigoides) on nest among casuarina trees, Lake Tuggerah, Central Coast, New South Wales. 

The reciprocal rule is handy to know when you are hand-holding your camera, especially with a long lens attached. It states “always use a shutter speed whose reciprocal is faster than the focal length of the lens”. So if you’re hand-holding a 500 mm lens, you have to use a shutter speed of 1/500 or faster.

I still don’t fully trust hand-holding my long lenses so I’m always lumbering around with a big tripod. But after I bought the Nikon’s f5.6 200-500 mm, I thought I’d give myself a break, and make use of its light weight.

Tawny Frogmouth (Podargus strigoides) on nest among casuarina trees, Lake Tuggerah, Central Coast, New South Wales

Even using the reciprocal rule of 1/500 shutter speed, the image isn’t crisp enough. Compare the side by side enlargements above.

Tawny Frogmouth (Podargus strigoides) on nest among casuarina trees, Lake Tuggerah, Central Coast, New South Wales

Still at 1/500th shutter speed, but I’ve added flash. Now I’ve achieved the maximum sharpness that the camera’s resolution is capable of. (Normally I correct the redeye, but in this instance I liked the dramatic effect.)

But I was getting pathetic results. That reciprocal rule, which worked so well in film and early digital days, just wasn’t working anymore. I kept complaining about the camera — that the mirror vibration was causing camera shake, the very thing the reciprocal rule was meant to prevent. Even with my heaviest tripod I wasn’t getting acceptable results.

And yet I was getting blazingly crisp images with flash. Clearly both the lens and sensor were capable of producing optimum sharpness. Finally after almost two years of struggle I had a realisation. The “reciprocal rule” no longer works — at least not with high resolution sensors like my Nikon D810. Once I started shooting at 1/1250 and faster (about 3x faster than the reciprocal rule), the sharpness was back at last. 

I got into some bird photography during spring and summer (thanks to inspiration from local photographer Geoff White) and I’m happily hand-holding my long lenses like never before. So the tip is: nix the standard reciprocal rule and use much higher shutter speeds with hi res cameras.

Also, have a think about coming along to a workshop, bird photography or otherwise.