CONTAX Planar G T* 35mm(Ms-optics)

Review and photo examples of the Kyocera CONTAX G mount Planar 35mm

Gallery

CONTAX G1 +AGFA CT Precisa 100(Revesal film)

Leica M-P typ240

Review

The Kyocera/Contax Planar 35mm for the G series is a wide-angle lens released at the same time as the CONTAX G2. Since it is in planar format, the rear element of the lens and the mount surface are almost at the same position, which minimizes problems when using the lens with various cameras.
When using the CONTAX G1/G2 with AF, the focus position was sometimes questionable when the aperture was wide open, so the lens was often used slightly stopped down.

After switching from the CONTAX G1/G2 to an M-mount rangefinder camera as my primary camera, I had become estranged from CONTAX G lenses, but after acquiring an M-mount conversion of the Planar G 45mm, I began converting my G-mount lenses to M-mount using Ms-optics. The MS-35 helicoid of the lens I own is an older model, and the angle at the base of the lens is shallow, making it difficult to put my finger on the lens and making it very difficult to attach and detach the lens. It does not seem to have been designed for a lens barrel as large as that of this lens. The MS-45 used for the Planar 45mm F2, which will be introduced on a separate page, has a right angle at the base of the lens and is reasonably wide, making it easy to attach and detach the lens.
When I learned that the new MS-35 helicoid had an improved base, I asked Ms-optics to change the helicoid part, but the owner, Mr. Miyazaki, told me that it was impossible to replace the helicoid of a modified lens due to the structure of the lens, so I gave up the idea.
Since the lens has been converted to the Leica M mount, it can be used with various mirrorless cameras with the use of a mount adapter.
M-mount modification of this lens is widely practiced overseas, and some manufacturers sell not only the modified lens but also only the helicoid, allowing users to modify it themselves (for details, see the Web site at the reference link).

Specification

Name	HOLOGON	BIOGON	BIOGON	PLANAR	PLANAR	SONNAR	VARIO SONNAR
Focal length(mm)	16.5	21	28	35	45	90	35-70
Max aperture	8(fixed)	2.8	←	2	←	2.8	3.5-5.6
Min aperture	16(Attached filter)	22	←	16	←	22	←
Lens Construction	5elements in 3groups	9elements in 7groups	7elements in 5groups	←	6eleme0nts in 4group	5elements in 4groups	13elements in 8groups
Min distance(m)	0.3	0.5	0.5 0.8(*2)←	0.5	←	1.0	←
Lens length(mm)	11	35.5	30.5	31.5	38.5	63.0	54.0
Max diameter(mm)	57	59	56	56	56	56	60
Filter size(mm)	– Dedicated ND filters are available. Changes to f/8 > 16 to alleviate peripheral light attenuation.	55	46	46	46	46	46
Weight(g)	120	200	150	160	190	240	290
Weight(g) M-mount	124	151	194 (222)*1	115	161	219 (259)*1	–
Release date	1994	1996	1994	1996	1994	1994	1999

*1:Hoo +Filter
*2: Minimum focus distance of AVENON modified lens

Planar 35mm lens configuration for CONTAX G (scanned and traced from the lens manual)

Reference links

Zeiss Photography Historical Products(There is a data sheet for the CONTAX G lens in the middle of the linked page.)
FUNLEADER Web-site(Website of FUNLEADER, which sells modified lenses and helicoids for modification)
Zeiss PLANAR description page by Wikipedia