Ibso
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| Ibso shutter on a Romain Talbot folding camera image by John de Grooth (Image rights) |
The Ibso shutter with a 3 blade diaphragm was made by Gauthier from 1908-1926. It was the first everset shutter (i.e. an 'automatic' shutter, not needing to be cocked) on the market.[1] It is found on many folding cameras of the period and has the usual limitation of everset shutters that it cannot offer very fast speeds; the original Ibso shutter gives speeds from 1 to 1/100 second, plus 'B' and 'T'. There are also IBSO shutters known that offer an extra speed of 1/150 sec.
The cylinder at the top of the shutter is a pneumatic air-brake which regulates the speed.
Gauthier replaced the IBSO shutter with the Ibsor.
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