In a fluorescent microscope setup, you have a relatively dim sample. You have two objectives available, a 100x NA 1.2 oil objective and a 60x NA 0.72 air objective. Which would be better for your dim sample?

A worm is 3 mm in size and occupies 60% of the FOV. What is the diameter of the FOV at this unknown magnification?

Impressionist painter Georges Seurat created paintings with an enormous number of dots of pure pigment, each of which was approximately 2.00 mm in diameter. The idea was to have colors such as red and green next to each other to form a scintillating canvas, such as in his masterpiece, A Sunday Afternoon on the Island of La Grande Jatte (figure below). Assume 1 = 420 nm and a pupil diameter of 4.90 mm. Beyond what distance would a viewer be unable to discern individual dots on the canvas? m SuperStock/SuperStock

What is the smallest thing we can see? O smallest object that we can process with our eyes is limited to the size of the photoreceptor cells in the retina. In order for us to to distinguish any detail in an object, its image cannot be smaller cannot be smaller than a single retinal cell. Although the size depends on the type of cell (cone or rod), a diameter of of a few microns (mm) is common near the center of the eye. We should model the eye as a sphere 2.50 cm in diameter with a single slender lens in front and the retina behind, with photoreceptor cells 5.0 mm in diameter. (a) What is the smallest object object that you can perceive at a point near 25 cm? What angle is subtended by this object in the eye? Express your answer in units of minutes (1° 60 min) and compare it with the typical experimental value of about 1.0 min. (Note: there are other limitations, but we will ignore them here).

Ordinary X-ray photographs cannot produce sharp images of internal organs whose densities are not varying significantly from their surroundings. What technique overcomes this problem?