Re-Using Zeiss T* Contax 645 Lenses with the ALPA: Some Tests, illustrations and facts...
January 13, 2016
Test ALPA Products
Sometimes people cannot believe that exceptional lenses on the right camera are still exceptional after 16 years and more. Today's test with our Carl Zeiss T* Distagon 3.5/35 for Contax 645 on our ALPA 12 FPS with the new ALPA lens module for Contax 645 lenses together with a Phase One IQ180 digital back. Our cameras are built to last and help good stuff to survive.
Please find here some sample shots as an overview and full-resolution images, plus illustrations of movements in the context of what is achievable with those lenses. We captured all the test images with a Phase One IQ180 digital back (80 MP resolution, pixel pitch 5.2 microns).
CAUTION: Due to gusty wind there might be some blurry trees and bushes.
SAMPLE A - Carl Zeiss T* Distagon 3.5/35 mm
Taken with the IQ180 and 5 mm of a rising front (upwards shift). The gusty wind and daytime made us capturing this at f8 and 1/4 sec @ ISO 35. This image shows a plain photograph and distance set to infinity. The 5 mm rise equals an image circle of 72 mm and, therefore, in the upper edges beyond the official image circle. BTW: Yes, the sky was somewhat purplish that evening ;)
SAMPLE B - Carl Zeiss T* Sonnar 2.8/140 mm
Taken with the IQ180 and 5 mm of a rising front (upwards shift). The gusty wind and daytime made us capturing this at f11 and 1/2 sec @ ISO 35. The full resolution portion shows the University of Zurich at a distance of approximately 1.5 kilometers. Again, the result proves the low vibration of the ALPA 12 FPS and a small pixel digital back. Also, the all-new IQ3 100 MP has similar-sized pixels of 4.6 microns. Therefore no big issue for the FPS when used correctly and with a sturdy tripod.
ILLUSTRATION - Image circle and movements
What do you see when using the entire movement of 12 mm (in this case, rise)? An illustration for understanding the real-life image circles of the Contax 645 lenses (70 mm) and what you can see. These are illustration graphs only..
The Carl Zeiss T* lenses for the Contax 645 are still an interesting focal length addition to the ALPA, even after many years. The Makro-Planar 4.0/120 mm remains an excellent lens for close-up work. For portraits, the Sonnar 2.8/140 mm offers the often sought-after reduced depth of field, and the 210 Sonnar and the 350mm Tele-Tessar offer Zeiss quality even for the digital medium format.
The image circles are at least 70 mm and completely cover 33x44 mm and 40x54 mm sensors. The longer focal lengths, in particular, allow considerable adjustment travel in some cases. The ALPA 12 FPS and Silex Mk II (together with ELA) control the electromechanical iris and the focus motor through the ALPA lens module Contax 645.