Resolution and ISO Comparison tests, Konica Minolta A2

These are some 100% crops of an ISO speed comparison tests illustrating the noise as the ISO speed increases for the Konica Minolta A2 for various resolutions. All tests were taken tripod mounted, with a zoom of approximately 50mm and taken at f/8. Pictures were taken using the highest quality JPEG mode and hard sharpening. Exposures were fairly long, around 3.2 seconds for the ISO 64 pictures and correspondingly shorter as the ISO speed was increased.

A scaled-down version of the full image is shown below. The red rectangle shows the area that the 100% crops that follow are taken from.

Image quality with lower resolutions

Many people have observed that shooting at lower resolutions and using bicubic interpolation to generate higher resolution images yields images that are almost indistinguishable from the higher resolution images. Below are 100% crops of the same test subject with the same field of view, with the lower resolution images scaled up to 8 megapixels using bicubic interpolation. From the images below, all the images are extremely close, and, it is very difficult to notice any difference. Perhaps in other tests, where there are more fine details, the difference might be more notable.

Minolta A2, ISO 64, 8 Megapixels

Minolta A2, ISO 64, 5 Megapixels scaled up to 8 Megapixels

Minolta A2, ISO 64, 3 Megapixels scaled up to 8 Megapixels

Noise with lower resolution images

Noise is a major factor affecting the quality of high ISO images in the Konica Minolta A2, because of the small photosites on the image sensor. Some people have wondered if taking pictures at lower resolutions might have less noise. From the images shown below, this does not appear to be the case- there is no noticeable reduction in noise when taking lower resolution images.

Minolta A2, ISO 800, 8 Megapixels

Minolta A2, ISO 800, 5 Megapixels, Scaled up to 8 Megapixels

Minolta A2, ISO 800, 3 Megapixels, Scaled up to 8 Megapixels