A fluorescent imaging device, comprising: an imaging unit, comprising: a fluorescent camera comprising an optical detector that is configured to acquire at least one fluorescent image of a fluorescing sample, wherein said at least one fluorescent image comprises multiple raw pixel values, and a user interface configured to display an image formed from multiple display image pixels, said multiple display image pixels derived from said multiple raw image pixels; a processing unit configured to provide said multiple display image pixels to said user interface; characterised by further comprising: a distance sensor configured to measure a distance to said fluorescing sample and provide said measured distance to said processing unit, wherein said processing unit is configured to: obtain a gain value, determine from said measured distance a distance between said optical detector and said fluorescing sample, match said determined distance to one of a plurality of distance values, each associated with a respective gain values range, obtain said respective gain values range stored in association with said matched distance value, impose limits of said respective gain values range onto said gain value, thereby determining a limited gain value, and apply said limited gain value to said multiple raw image pixels, thereby deriving said multiple display image pixels. an imaging unit, comprising: a fluorescent camera comprising an optical detector that is configured to acquire at least one fluorescent image of a fluorescing sample, wherein said at least one fluorescent image comprises multiple raw pixel values, and a user interface configured to display an image formed from multiple display image pixels, said multiple display image pixels derived from said multiple raw image pixels; a processing unit configured to provide said multiple display image pixels to a fluorescent camera comprising an optical detector that is configured to acquire at least one fluorescent image of a fluorescing sample, wherein said at least one fluorescent image comprises multiple raw pixel values, and a user interface configured to display an image formed from multiple display image pixels, said multiple display image pixels derived from said multiple raw image pixels; a processing unit configured to provide said multiple display image pixels to said user interface; characterised by further comprising: a distance sensor configured to measure a distance to said fluorescing sample and provide said measured distance to said processing unit, wherein said processing unit is configured to: obtain a gain value, determine from said measured distance a distance between said optical detector and said fluorescing sample, match said determined distance to one of a plurality of distance values, each associated with a respective gain values range, obtain said respective gain values range stored in association with said matched distance value, impose limits of said respective gain values range onto said gain value, thereby determining a limited gain value, and apply said limited gain value to said multiple raw image pixels, thereby deriving said multiple display image pixels. a distance sensor configured to measure a distance to said fluorescing sample and provide said measured distance to said processing unit, wherein said processing unit is configured to: obtain a gain value, determine from said measured distance a distance between said optical detector and said fluorescing sample, match said determined distance to one of a plurality of distance values, each associated with a respective gain values range, obtain said respective gain values range stored in association with said matched distance value, impose limits of said respective gain values range onto said gain value, thereby determining a limited gain value, and apply said limited gain value to said multiple raw image pixels, thereby deriving said multiple display image pixels. obtain a gain value, determine from said measured distance a distance between said optical detector and said fluorescing sample, match said determined distance to one of a plurality of distance values, each associated with a respective gain values range, obtain said respective gain values range stored in association with said matched distance value, impose limits of said respective gain values range onto said gain value, thereby determining a limited gain value, and apply said limited gain value to said multiple raw image pixels, thereby deriving said multiple display image pixels.