Certified Professional Photographer (CPP) Practice Exam

Using a teleconverter does indeed typically lead to a decrease in sharpness. This happens because teleconverters work by magnifying the image that is coming through the lens, which can exacerbate any optical imperfections present in the lens. The added optics in a teleconverter can introduce additional aberrations and can generally cause a softening of the image. As a result, the overall resolution and clarity may be compromised.

Additionally, the reduction in the amount of light reaching the sensor means that not only will the camera's autofocus system potentially struggle in low-light situations, but the depth of field may also be impacted, further influencing image quality. While other factors do exist that can affect image quality as well, the fundamental consequence of a teleconverter is that it often trades off some sharpness for additional reach.