I am not finding much information on these old lenses, which seem much less common that the Turner-Reich triple convertibles. My experience with several samples of the TR has not been very good, at least (or especially) when converted. Is anyone using the Perigraphic, which from a combined 12" convers to 20" and 28"? The design seems to be simpler than the Turner Reich. Thanks in advance.
According to the "Lens Collector's Vade Mecum", this was a lower cost (at least compared to the T-R) lens which may be a 3 + 3 design. They suggest it needs stopping down for best results.
The T-R was a 5 + 5 design which many optical workers consider to be very difficult to center correctly. A 3 + 3 wouldn't have provided as much opportunity for aberration correction of the individual cells, particularly with the selection of glasses then available. Quality control should have been much less of a problem, though.
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