Noise is one fundamental quality attribute in digital cameras. Traditionally, noise has been measured from solid patches of artificial test targets. In image quality research, it has been difficult to find connections between a test target and subjective test data. In addition, image quality algorithms computed from natural images are not well correlated. In this paper, we propose a novel approach for measuring color noise from natural images. With the proposed method, the suitable surfaces for noise calculations are located from the scene using a reference camera image. It is now possible to use the same image files for subjective and objective measurements and correlations are easier to find. The results show that the method is promising. Its performance was better for predicting subjective noise compared to the visual noise metric that is the state-of-the-art test target method for digital cameras.