Asahi-Kogaku Takumar (M37) Lenses.
Eight pre-set lenses were made for ASAHIFLEX cameras.
(All are attached to cameras using a 37mm diameter threaded mount.)
Ryohei Suzuki had created all 6 optical designs for these lenses by 1955
Standard lenses (Models I, II and III) of a 1:3.5/ 50mm and a 1:2.4 /58mm lens, were made. Approximately 60,000 copies were sold on the 5 ASAHIFLEX and 3 TOWER cameras from 1952 to 1957.
Long focal length lenses, 1:3.5/100, 1:3.5/135, 1:1.9/83 and 1:5/500 were made in the order listed. Approximately 10,000 copies were sold in the same period. No wide-angle lenses were made.
NOTES
Markets for Asahiflex I and IA cameras were founded domestically and in North America, specifically in the United States of America. Later camera models were available worldwide.
VARIATION
Changes were made to Asahiflex cameras and lenses during development. Here are some lesser known changes made to lenses during production and development.
Distance scale units
All lenses carry single distance scales on their focussing rings. Dual distance scales ( "Feet" and "Meter") arrived early in the M42 period in 1957.
Distance scales on all copies of these lenses were graduated in feet, at least initially. The first two models of the 50mm standard lense are graduated in feet, only.
Metric scales were tentatively introduced later as interest in the Asahiflex cameras grew, at home and elsewhere. Copies so marked in "Meter" (USA spelling) are uncommon. By far the majority of lenses conformed to the original design. Small numbers of metric graduated copies were produced within most large batches graduated in feet after serial numbers indicated below. (Subject to reporting of new data).
Research reveals metrication first arrived on accessory lenses; the earliest detected at approximately:
1:1.9/83mm (SN 54449)
1:3.5/100mm (SN 61327)
1:3.5/135mm (SN 74767)
Metrication of Standard lenses began with the introduction of model III.
1: 3.5/50mm III (SN 64617)
1:2.4/58mm (SN 71358)
1: 5/500mm (SN ?????)
Coarse and fine ring grips
Ring grips on the first Standard lenses made carry regular fine milling.
Focussing rings in the first two batches of the first accessory lens made ( 1:3.5/100mm ) were provided with 12 individual finger grips. Because it had a tele-photo construction the longer throw needed to turn the ring would be more certain. This makes design sense. However individual finger grips are absent from all further copies made. The later copies are adorned instead with regular fine milling, possibly for economical or logistical reasons.
In the 1957 with the advent of Asahi Pentax "Takumar" lenses, this early design principle was revived and focussing rings re-gained individual finger grips, permanently; the numbers provided varying according to the diameter of the lens.
Direction of rotation
On the first standard lens model focussing and aperture adjustments are made by turning the rings in an anti-clockwise direction (from a front view). All other lenses are adjusted by turning rings in the opposite direction. (Feet
Markets for Asahiflex I and IA cameras were founded domestically and in North America, specifically in the United States of America. Later camera models were available worldwide.
VARIATION
Changes were made to Asahiflex cameras and lenses during development. Here are some lesser known changes made to lenses during production and development.
Distance scale units
All lenses carry single distance scales on their focussing rings. Dual distance scales ( "Feet" and "Meter") arrived early in the M42 period in 1957.
Distance scales on all copies of these lenses were graduated in feet, at least initially. The first two models of the 50mm standard lense are graduated in feet, only.
Metric scales were tentatively introduced later as interest in the Asahiflex cameras grew, at home and elsewhere. Copies so marked in "Meter" (USA spelling) are uncommon. By far the majority of lenses conformed to the original design. Small numbers of metric graduated copies were produced within most large batches graduated in feet after serial numbers indicated below. (Subject to reporting of new data).
Research reveals metrication first arrived on accessory lenses; the earliest detected at approximately:
1:1.9/83mm (SN 54449)
1:3.5/100mm (SN 61327)
1:3.5/135mm (SN 74767)
Metrication of Standard lenses began with the introduction of model III.
1: 3.5/50mm III (SN 64617)
1:2.4/58mm (SN 71358)
1: 5/500mm (SN ?????)
Coarse and fine ring grips
Ring grips on the first Standard lenses made carry regular fine milling.
Focussing rings in the first two batches of the first accessory lens made ( 1:3.5/100mm ) were provided with 12 individual finger grips. Because it had a tele-photo construction the longer throw needed to turn the ring would be more certain. This makes design sense. However individual finger grips are absent from all further copies made. The later copies are adorned instead with regular fine milling, possibly for economical or logistical reasons.
In the 1957 with the advent of Asahi Pentax "Takumar" lenses, this early design principle was revived and focussing rings re-gained individual finger grips, permanently; the numbers provided varying according to the diameter of the lens.
Direction of rotation
On the first standard lens model focussing and aperture adjustments are made by turning the rings in an anti-clockwise direction (from a front view). All other lenses are adjusted by turning rings in the opposite direction. (Feet
