Nikon Coolpix P900

 


In this section:

Variation of Widest Available Aperture with Focal Length of the P900

Testing the Resolution of the P900

P900 at and near Maximum Zoom

Telemacro with the P900

Reducing the Focus Distance of the P900 with a +0.4D Closeup Lens

Testing of Three Achromat Closeup Lenses with the P900

P900 with the Raynox DCR-250 Macro Lens as a Microscope




Variation of Widest Available Aperture with Focal Length on the P900


By setting the P900 to Aperture Priority (A Mode) and to the widest aperture of f/2.8 at full WA (24mm equivalent) then slowly zooming in, the focal length increases in steps, with the widest available aperture at each step.  I took shots at different zoom settings and read off the focal length (35mm equivalent) at each zoom setting from the image EXIF data.  I used the results to plot the graph shown below.  (Click on the image for a larger view.)



As can be seen from the graph, the range of focal lengths at which the widest aperture remains constant increases as the focal length increases.  At 150-250mm EFL the widest aperture remains at f/4.5, while at 300-600mm it remains at f/5.0, at  650-1100mm it remains at f/5.6, and at 1200-1800mm it remains at f/6.3.  The widest aperture only reaches f/6.5 at the final step from 1800-2000mm EFL.


When zooming on the P900, the LCD/EVF display shows only a zoom bar to indicate the approximate  focal length.  However, when set to A mode, with the zoom set at full WA of 24mm EFL and widest aperture of f/2.8, as the lens is zoomed in, the changes in f number as displayed on the LCD/EVF can be used as a guide to the actual focal length at that setting, based on the above graph.  For example, the change from f/5.6 to f/6.3 occurs at the step between 1100 and 1200mm EFL.




Continue to P900 Resolution Testing


Continue to P900 at and near Maximum Zoom


Continue to P900 with a +0.4D Closeup Lens


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