Three images of mating Canada Darners.
Top Image: Taken with my 80-400 VR lens, set at the 1.5 internal crop-factor. The Darners seemed glued to the spot, so I decided to get my 105 mm macro lens from my car a short distance away. I managed only a few close shots with the macro lens before the Darners flew away, still hooked up in tandem.
The Darners landed in the grass a short distance from the first location. This shot was again taken with my 105 mm macro lens. Again, I managed only a few shots before they flew off, in tandem, again.
From the location in the grass, the Darners again flew to this location. This image was also taken with my macro lens, and again when I got too close, the Darners flew off, this time separating on take-off.
The second and third images taken with the 105 mm macro lens are considerably cropped, whereas the top image taken with the 80-400 mm lens at 1.5 crop-factor is only slightly cropped in PS. Conclusion: the 80-400 lens wins again.