Summarit-S 35 f/2.5 ASPH. (CS)
The fast and universal wide-angle lens
The lens for every situation
The Summarit-S 35 f/2.5 ASPH. (CS) (28 mm in 35 mm format) is ideal for landscape and architectural photography as well as for studio work. Systematically designed with maximum contrast performance at maximum aperture from infinity to its closest focusing distance, this unusually fast lens is predestined for use as a universal lens.
Its sophisticated design and construction almost completely eliminate optical errors such as distortion and chromatic aberration. The Summarit-S 35 f/2.5 ASPH. (CS) is also available with a built-in central shutter.
The highlights
For studio and architecture photography
- Innovative central shutter for maximum design freedom when using additional light
- For studio and architectural photography
- Excellent imaging performance over the entire range and at all aperture settings
- Extremely fast
- Creative use of sharpness and blurring for the plastic extraction of motif details
- Best image quality up to the edges due to aspherical optics
- Weather- and dust-sealed lens
Technical Details
To reduce chromatic aberrations to an absolute minimum, five of the eleven lens elements are manufactured from glasses with anomalous partial dispersion of which three also display particularly low dispersion characteristics. Two elaborately manufactured aspherical surfaces ensure that effects like distortion are kept to an extraordinarily low level.
Rear-group focusing guarantees consistently outstanding imaging properties from infinity to the closest focusing distance.
Modulation Transfer Function
The MTF is indicated both at full aperture and at f/5.6 and f/8 at long taking distances (infinity).
Shown is the contrast in percentage for 5, 10, 20 and 40 lp/mm across the height of the 35mm film format, for tangential (dotted line) and sagittal (solid line) structures, in white light. The 5 and 10 lp/mm will give an indication regarding the contrast ratio for large object structures. The 20 and 40 lp/mm records the resolution of finer and finest object structures.
Distortion & vignetting
Distortion is the deviation of the real image height (in the picture) from the ideal image height. The relative distortion is the percentage deviation. The ideal image height results from the object height and the magnification. The image height of 27.04mm is the radial distance between the edge and the middle of the image field for the format 30mm×45mm.
The graph of the effective distortion illustrates the appearance of straight horizontal and vertical lines in the picture.
Vignetting is a continous decrease of the illumination to the edges of the image field. The graph shows the percentage loss of illumination over the image height. 100% means no vignetting.
Technical Data
Summarit-S 35 f/2.5 ASPH.
| Order no. | 11064 | CS: 11050 |
| Image angle (diagonal, horizontal, vertical) | approx. 74° / 64° / 45°, corresponds to approx. 28mm focal length in 35mm format |
| Optical design | |
| Number of lenses/groups | November 9, 2019 |
| Entrance pupil | infinity: 84.77mm (in front of bayonet in incident light direction) |
| close focus limit: 84.85mm (in front of bayonet in incident light direction) | |
| Focusing range | 0,55m to ∞ |
| Distance setting | |
| Scales | Combined meter/feet graduation |
| Smallest object field | 334mm× 502mm |
| Largest reproduction ratio | January 1, 1970 |
| Aperture | |
| Setting / Function | Electronically controlled diaphragm, set using setting/selection dial on camera, including half values |
| Lowest value | 22 |
| Bayonet | Leica S bayonet |
| Filter mount/ Lens hood | External bayonet for lens hood (included), internal thread for E72 filter, filter mount does not rotate |
| Dimensions and weight | |
| Length to bayonet mount | approx. 122/ 156mm (without/with lens hood) |
| Largest diameter | approx. 88 / 132mm (without/with lens hood) |
| Weight | approx. 930 / 1080 g (without/with central shutter) |