Tompot blenny among the reef

A characterful tompot blenny rendered with sharp eye detail and rich, believable colour — the strongest asset here. The animal peers out from a nest of algae and anemone, and the tentacles at lower left add welcome environmental context. What most holds the frame back is the foreground clutter directly across the fish's mouth and chin: those hydroid fronds crossing the face soften the read of the subject and steal attention from the eye. Slightly more separation between fish and foreground, or a shooting angle that clears the muzzle, would let this portrait breathe. Fine work overall for a demanding underwater subject.

The blenny is placed left of centre with its gaze leading into open frame — a sound choice that gives the animal room to look. The purple anemone tentacles anchor the lower left and add colour and context. The main weakness is the tangle of algae crossing the mouth and chin, which competes with the face and muddies the subject's outline. The busy background reads as habitat rather than distraction, but a cleaner line of sight to the muzzle would sharpen the whole composition considerably.

Strobe lighting is handled with restraint — the fish's face and eye receive warm, even illumination without the harsh hotspots or backscatter that plague underwater work. Highlights on the cheek and jaw carry gentle modelling, and the falloff into the darker reef behind gives the subject some separation. The light direction flatters the textured skin and mottled fin. A touch more edge or fill light on the shadowed right flank would round the form further, but this is well-judged, controlled artificial light.

Exposure is well balanced for the conditions. The eye and lit face hold detail without clipping, and the orange throat retains gradation rather than blowing out. Shadow areas in the background stay dark but never crush into total black, preserving a sense of the surrounding reef. The brightest algae highlights sit just under clipping. Overall a deliberate, disciplined exposure that keeps the key subject readable while letting the surroundings recede — appropriate for isolating this small subject in a cluttered scene.

Colour is the standout here. The warm ochres and oranges of the blenny play against the cool purples and greens of the reef, a natural complementary palette that gives the frame real vibrancy. White balance looks accurate — no excessive blue cast, and the whites in the mottled skin read clean. Saturation is rich without tipping into artificial. Mid-tone contrast in the face gives the skin texture depth, and the tonal range from the shadowed reef to the lit cheek is handled smoothly.

The EF 100mm f/2.8L Macro is the right tool for this subject, and at f/5.6 the depth of field is well judged — the eye and near face are tack sharp while the background falls softly out of focus, isolating the animal. Focus lands precisely on the eye, which is exactly where it belongs for a wildlife portrait, and the catchlight and iris detail are crisp. 1/250s at ISO 640 freezes the fish cleanly with no motion blur, and noise is well controlled on the full-frame sensor. The one limitation is that f/5.6 leaves the crossing algae in front of the mouth softly rendered yet still prominent enough to distract; stopping down a little would have brought more of the head into focus, though at the cost of pulling the background sharper. Given the trade-offs of macro depth of field underwater, the settings are a sensible compromise and the execution is clean and confident throughout.