The three-element reducer FRA400C f/3.9 was developed as a dedicated accessory for the Askar FRA400C astrograph. This reducer reduces the focal length by a factor of 0.7x, which in the case of the Askar FRA400C astrograph gives a value of 280 mm at f/3.9. Such parameters allow not only to take breathtaking photos in a wide field of view, but above all to shorten the exposure time by up to half. This device allows for the mounting of 2" diameter filters, screwed into the M48x0.75 thread located on the camera side.
Key Features of the Askar FRA600 f/3.9 Reducer
• focal reducer dedicated to the Askar FRA400C astrograph • 0.7x multiplier giving an effective focal length of 280 mm at f/3.9 • can be used with 2" diameter filters • 55mm back focus
Technical parameters
• multiplicity: 0.7x • compatibility: Askar FRA400C • focal length without reducer: 400 mm • focal length with reducer: 280 mm • aperture without reducer: f/5.6 • aperture with reducer: f/3.9 • rear thread (camera side): M48x0.75 • front thread (from the extractor side): M72x1 • possibility of mounting a filter: yes, with M48x0.75 thread • backfocus: 55mm • length: 57.4 mm
Set components
• Askar FRA400C f/3.9 reducer
Guarantee
24 months
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