|Transparency Media Adapters (TMA)
Flatbed scanners have a light source that is reflected off of the printed media. This reflected light registers on the scanners CCD (imager) and creates a digitized image. However, this technology does not work with transparent media such as film. To overcome this limitation, some flatbed scanners feature the option of a TMA.
The TMA places a light source on the other side of the media (typically, in the lid of the scanner) and passes light through the media and onto the CCD.
Depending on the scanner, the TMA usually does not replace the need for a dedicated film scanner, especially when scanning small format negatives (35mm). For larger film such as medium format (6cm x 4.5cm, 6cm x 6cm, 6cm x 9cm, etc.) and large format (4" x 5", 8" x 10", etc.), the resolution of flatbed scanners with a TMA may be acceptable, however, dynamic range may still be objectionable. This depends primarily upon the quality requirements and/or expectations of the operator.
Good quality flatbed scanners with a TMA can be obtained for 1/10 to 1/2 the cost of dedicated purpose medium and large format film scanners.