SMC PENTAX 1:3.5/15 (Aspherical lens type of first generation)


Left side is SMC PENTAX 1:3.5/15 Aspherical Lens Version.

The Specification of SMC PENTAX 1:3.5/15
Angle of view 111 degree
Minimum aperture F22
Elements / Groups 13 / 12
Minimum focus 0.3m
Filter size 4 built-in filters:UV,1B,Y2,O2
Dimension Max Dia.80mm x Length 81.5mm
Weight 600g
List Price 92000JPY
Used Market Price Greater than 90000JPY
frequency of occurrence Rarely

(Contents)
In informality information, SMC PENTAX 15mmF3.5 is also one of joint development lenses by the both companies Carl Zeiss and Asahi Optical Co.. Many lenses with this type of lens similar to a world exist. For example, it is as follows: Y/C DISTAGON 15mmF3.5, Rollei QBM DISTAGON 15mmF3.5, Lieca(R)Super Elmar 15mmF3.5. And also, Nikkor15mmF3.5 is copied design from D15mmF3.5. It can hear also from Nikon imitating about how the basic design of this lens was excellent.

Somebody said "PENTAX 1:3.5/15 Lens is not Takumar lens, thus this lens is not aspherical." But I read "SMC PENTAX manual number 7511" in those days, SMC PENTAX 1:3.5/15 lens was described with "aspherical lens". Therefore SMC PENTAX series must exist aspherical type lens about 15mmF3.5.

In recently I researched to find out how to differentiate aspherical lens of SMC PENTAX 15mmF3.5 lens and spherical lens as follows:

SMC PENTAX lens has two types of engraved mark about 15mmF3.5,
one is "SMC PENTAX 1:3.5/15", others is "smc PENTAX 1:3.5/15mm"
And also, feet disitance mark are two types, one is "7 4 2 1.5", other is "7 3 2 1.5".
It can be concluded that PENTAX 1:3.5/15 lens has four types as follows:
1)Aspherical type as first model is characterized that the engraved mark has "SMC PENTAX 1:3.5/15" and the feet distance indicated characters has "7 4 2 1.5".
2)Spherical type as second model is characterized that the engraved mark has "SMC PENTAX 1:3.5/15" and the feet distance indicated characters has "7 3 2 1.5".
3)Spherical type as third model is characterized that the engraved mark has "smc PENTAX 1:3.5 15mm" and the feet distance indicated characters has "7 3 2 1.5".
4)Spherical type as forth model is characterized that the engraved mark has "smc PENTAX-A 1:3.5 15mm" and the feet distance indicated characters has "7 3 2 1.5" and has "A" position.
Then I found out the patent of optical design about SMC PENTAX 1:3.5/15 lens, this patent was example 4 in US-PAT 3864026.

In those days, it was developed SLR system in conjunction with Carl Zeiss and Asahi Optical Co.. This lens was used hybrid aspherical element as 10 group, this element had supplied from Carl Zeiss, this hybrid aspherical lens was used at first in the world. Then Carl Zeiss and Asahi Optical were dissolved a partnership in 1975 so that Carl Zeiss was not supplied aspherical element to Asahi optial. Thus, Asahi Optical optical designer tried to modify optical design about 15mmF3.5 lens quickly.

(Impression)
My inpression about this lens as follows: Distortion is rectified very well and the excellent depiction. The first element in this lens has very large shape, since it is easy to come out of a ghost, I feel difficulty, when using it. But it is shown me the image of this lens was more excellent than other super wide angle lens.

Sample Photo