A blurred lens will result in poor image contrast particularly at which frequencies?

A blurred lens primarily causes a reduction in the sharpness of images, affecting the perception of detail within an image. High spatial frequencies correspond to fine details and rapid changes in contrast. When a lens is blurred, these high spatial frequencies become difficult to discern because the blurriness spreads the light from these details, effectively reducing the contrast and making them less distinguishable.

In contrast, low spatial frequencies represent broader, more general shapes and less detailed variations. A blurred lens does not affect these low frequencies as severely because they do not rely on the same level of precision as high frequencies. Moderate spatial frequencies fall between the two, but again, the impact of blurriness is more pronounced on high spatial frequencies.

Therefore, the most significant loss of image contrast occurs at high spatial frequencies due to the inability to resolve fine details, making them the most affected by lens blurriness. This is the reason why the correct answer identifies high spatial frequencies as the frequency range where poor image contrast is particularly noticeable with a blurred lens.