12 September 2011

Minolta MC Rokkor-PF f/1.4 58mm Lens on Four Thirds Cameras

I recently added the 58mm f/1.4 Rokkor lens to my growing collection (somewhat to my surprise) of Minolta lenses intended for use on E-system cameras. I was curious to see how the lens performed with respect to the quality of out of focus areas, as well as whether the lens would require exposure compensation, how its sharpness compared to other lenses, etc. so I shot this series of test photographs. I hoped some of the quality of the legendary 58mm f/1.2 might have been incorporated by the designers into this "slower" lens.

All images were shot with the E-510 mounted to a tripod, illuminated by one incandescent lamp and ambient light from two CFL bulbs in the room. The lighting was approximately 7EV. The images were HQ out of camera JPEGs reduced to 640 x 480 using Irfanview using the highest quality resampling. The camera was set to a 2 second self-timer, mirror lockup was not used. IS disabled. Lens mounted to the E-510 using a 4/3 to MD adapter from RJ camera.

Exposure compensation set to -0.3 EV. No attempt was made to compensate for any variations in exposure at different apertures. The pictures show that wide open a brighter picture is obtained, gradually darkening through the middle apertures and then lightening again when stopped down. I chose only to go from wide open (f/1.4) to f/8 due to the possibility of diffraction effects at f/11 and higher.

The focus point was on the "S. Cargo" label. Manual focus was determined using 10x Live View.

The lens: Minolta MC Rokkor-PF f/1.4 58mm Serial No. 5070045, the glass clear, clean and aperture working.

References: The Ultimate Normal Lens Challenge: Minolta's most common lenses compared Minolta 58mm f/1.4 MC Rokkor-PF Lens Sample Photos

By the way, here is an example of modifying the 58mm Rokkor for a 7D showing various parts of the lens. There is a drawing of the 50mm's.

I thought the transitions to out of focus areas were pleasingly soft, but the strong highlights produced sharp edged discs. You can make what you will of it, try comparing to the Rokkorfiles images from the other lenses.