deltoidjohn
Veteran
When it comes to rear-mounted ND filters, is there any exact science to it? Does the filter need to be at the correct distance from the rear of the lens & the sensor in order to maintain the optical qualilty of the image projected by the lens? Does the glass need to be designed in a particular way in order to prevent the distorion of the light rays passing through? Does it need to become an extension of the lens, whereby each piece of glass has a very particular shape for a particular reason, or can you literally just slap a piece of ND glass (high quality, of course) anywhere between the lens and the sensor and it will do it's job?
The reason I ask is because, if the latter is true, and the ND filter can be placed anywhere in the space between the lens and the sensor without affecting focus, convergance, magnification, etc, (and assuming the glass is of high optical quality) then would it be possible/practical to have lens mount adaptors with switchable ND filters - much like the rear mounted gel filters found on larger lenses like the Canon 500mm f/4?
Obviously it would only be practical on certain adaptors (ie those designed for mirrorless mounts such as the GH2 and the FS100), but could this not be the solution many people are begging for? One of the biggest criticism's of both the FS100 and AF100 is the lack of built in ND filters. Given that many people are already using adaptors on these cameras to use lenses such as Canon FD, Nikon, Ziess ZF/ZE, etc, could this be a viable solution for those people?
The reason I ask is because, if the latter is true, and the ND filter can be placed anywhere in the space between the lens and the sensor without affecting focus, convergance, magnification, etc, (and assuming the glass is of high optical quality) then would it be possible/practical to have lens mount adaptors with switchable ND filters - much like the rear mounted gel filters found on larger lenses like the Canon 500mm f/4?
Obviously it would only be practical on certain adaptors (ie those designed for mirrorless mounts such as the GH2 and the FS100), but could this not be the solution many people are begging for? One of the biggest criticism's of both the FS100 and AF100 is the lack of built in ND filters. Given that many people are already using adaptors on these cameras to use lenses such as Canon FD, Nikon, Ziess ZF/ZE, etc, could this be a viable solution for those people?
