A couple of fly fishers have recently asked me why trout they take pictures of blow out ‘white’ losing all detail. The answer is that the scales on the side of a trout – or any fish for that matter – form a perfect mirror that reflects light straight back into the camera lens. So the answer is easy. Make sure the side of the fish is not pointing straight at the camera lens, but always at a slight angle away from it, or shoot the fish against the sun, if needs be, using a little fill in flash. 

(Click in images to enlarge them)

These two pictures I took of Mavungana (Dullstroom) fly fishing guide and instructor, Collen Tshabangu, illustrate the point. In the image above  the fish blows out as its side, and the side of his reel, are reflecting light from the sun straight into the lens of the camera. Notice the difference below when Collen slightly changes the angle he is holding both the fish and the reel, tilting them both away from the camera lens.

In the two images below of the same fish, all that has changed is the angle the fish is pointing at the lens of the camera.

In the image above the trout blows out. In the image below, the angle of the trout has changed favourably relative to the camera lens and the trout, and the picture as a whole, are better exposed.

Any bright article under water, such as a white shirt sleeve, or a watch, also risks reflecting light back at the camera and blowing out. Below, a polyurethane underwater housing blows out the picture.

You can check this yourself after you have taken a picture by quickly viewing it on the LCD screen. In the image below, the angle of this grayling is to the lens is near perfect, just the tail is blowing out a bit and as a result, some highlight detail is lost in this part of the fish.

This level of detail is not going to be as obvious when you review the image in your LCD screen.