CONTAX SONNAR 2.8/90 T*(GtoM)

This is a record of using a Kyocera CONTAX G mount 90mm f/2.8 lens converted to Leica M mount by MS-Optics (Miyazaki Kogaku) with a Leica M digital.

Table of contents

Gallery
Impression
Lens specification
Reference links

Gallery
CONTAX G SONNAR 90mm F2.8 photo example (with Leica M-P /HASSELBLAD X2D)

Impression
The focus plane is well rendered from the maximum aperture, and both the front and rear blur can be enjoyed to the fullest.
Ms. Miyazaki, the representative of Ms-optics, who converted the lens, is also a great admirer of this lens. He happily talked about how often he used this lens when he commissioned the modification.

When I used this lens with the Contax G1/G2, the focal length of 90mm was adjusted with inaccurate autofocus (due to the camera’s structure, there is no way to check the focus after the lens is in focus), so I had bitter memories of blurred pictures when the aperture was stopped down, resulting in blurred shutter speed and out-of-focus pictures when the aperture was opened. I have a bitter memory of out-of-focus photos when the aperture was opened. Comparing the auto-focusing of the Contax G1 and G2, the G2 with improved autofocusing had a higher hit rate, but with 36 shots, half of the shots were usable. However, with 36 shots, the yield was only half of the total number of usable shots.

I have used Apo-Summicron-M 90mm, Summicron-M 90mm, Elmarit-M 90mm, Macro Elmar-M 90mm, etc. in the past, but I still have the M-mount lenses on hand. I feel that this lens is sufficient for M-mount lenses based on its descriptive characteristics.
However, I am curious about the Chinese-made 90mm/F1.25 lens, which has been very active recently.

When used with HASSELBLAD X2D, 11045 horizontal pixels (about 98%) remained in the 3:2 crop. This is a usable impression for most parts of the image.

Lens specification
AF lens for CONTAX G converted to Leica M mount (distance meter linked) at MS-Optics.
Mr. Miyazaki said that this converted lens is a new type barrel with double helicoid, which is easier to use than the previous one.
The hood is a genuine screw-on type, and the HOOD GG-3 can be used without modification.
The lack of a click stop on the aperture is a specification of MS-Optics lenses.
The aperture ring and the ring that you put your finger on when focusing have the same diameter and are located close together, so the aperture may move during focusing, which can be confusing.

Item	Value	note
focal length(mm)	90
Maximum aperture	2.8
Minimum aperture	22
Lens configuration	4groups 5elements	Sonnar-Type
Minimum distance(m)	1.0
Lens length(mm)	65
Lens max diameter(mm)	58
Filter diameter(mm)	46
Weight(g)	216(lens only)	259g(lens,hood and filter)