The character of the Sarapiquí forest changes completely after dark, as does the style of photography. At night, the subjects were suddenly at arm's length: frogs on leaves, a spider on a stem, and creatures whose colours and shapes would have been easy to miss during the day. Here I was able to use the remarkable macro and close-up properties of the 50–200 mm lens, which can focus as close as 78 cm even at its full 400 mm full-frame-equivalent focal length. Flash photography of nighttime wildlife is strongly discouraged in Costa Rica for obvious reasons, so I used a continuous LED light for illumination.

At Tirimbina, I went on a couple of nighttime tours of the forest with experienced guides who were extraordinary in their ability to spot well-camouflaged insects and lizards that I could never have seen without their help. There's no question, however, that I should have taken an evening to get familiar with nighttime macro photography before I started the tour, because the worst time to stop and adjust your settings is in the pitch black, surrounded by other tourists and being moved on every few minutes. A further problem with group tours like this is that everybody else has a torch, so your carefully composed shot with perfect lighting suddenly becomes orders of magnitude brighter as other guests train their torches on the insect or frog.

Centro Manú provided a much richer and more pleasant experience, despite some very challenging weather. This is an education and conference centre 6 km south of Guápiles, with tours led by the owners' son, Kenneth Matarrita, a passionate and experienced frog expert and guide. I went on a solo tour, which was reasonably priced and completely eliminated the problem of being surrounded by tourists who were not photographers.

It was still a difficult session because absolutely torrential rain fell throughout the frog tour, making visibility and the operation of the camera and lens extremely challenging. With a different camera system I would have had to stop because of the risk of water damage, but the incredible water resistance of the OM-1 camera and telephoto lens allowed me to photograph for a couple of hours in absolutely drenching rain without any impact on the system. The camera coped rather better than my waterproof clothing; I ended the evening completely soaked but with some good frog photographs.

The Tirimbina and Centro Manú photographs include a glass frog, tree frogs, a Smoky Jungle Frog, a tree snail and other small forest subjects.

The album also includes six photographs from Pierella Garden. They were taken in daylight but include some of the best shots from the entire trip of the Red-eyed Tree Frog, as well as a surprising shot of tiny but fully grown Honduran White Bats tucked beneath a leaf.

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