Promaster Auto Teleconverter Canon FD Manual Film Cameras

The Promaster Spectrum 7 Auto Teleconverter for Canon is designed to double the effective focal length of Canon FD Manual Focus Film Camera lenses while maintaining automatic functions. Here is a detailed overview of its features, performance considerations, and usage tips:

Key Features:

1. Compatibility: Ensure your lens is compatible, as not all lenses perform optimally with teleconverters.
2. Magnification: Provides 2x magnification, effectively doubling the focal length of the attached lens. For instance, a 100mm lens will function as a 200mm lens. Performance Considerations:

1. Image Quality: Using a teleconverter typically results in some reduction in image quality. This includes potential losses in sharpness and contrast, as well as increased chromatic aberrations. The impact varies with the quality of the teleconverter and the primary lens.
2. Aperture Reduction: The teleconverter reduces the maximum aperture of the lens by two stops. For example, a lens with a maximum aperture of f/2.8 will have an effective maximum aperture of f/5.6 when used with this teleconverter. This reduction in light can affect exposure settings and autofocus performance.