Originally posted by Barnster The difference between a FA and a DA is THE PRICE!!!But seriously,the FA series were made for film cameras,like the MZ cameras etc around the 1990's to early 2000's.If you put say for example a FA 50mm on your digital camera,it would be a 75mm because of the 1.5x crop factor.The DA series are completely designed and used for digital cameras only.If you need to look at the different type of FA or DA's,have a look at Lens Reviews in this forum.
Please, no more crop factor, you will just confuse the hell out of someone.
There is no difference
AT ALL between how an image will look with a 50mm FA lens vs a 50mm DA lens.
focal length is focal lenght.
The real differences between DA and FA lenses will be
- the application of an anti glare coating on the rear element to stop glare and contrast reduction caused by reflections off the sensor, as it is more reflective than film was,
- light hitting the film / sensor plane. Digital sensors are sensitive not only to the level of light but the angle light hits them. This causes vignetting if the angle is too far from perpendicular, hence DA lenses are designed to have th elight hitting the sensor at closer to perpendicular
- the image circle FA lenses are designed to cover a 24mm x 36 mm frame, DA lenses are designed to cover a 16mm x 24 mm frame, and may not cover a film frame, although this varies on a lens by lens basis
- FA lenses have an aperture coupling, and can be used on any MF film body all the way back to the K1000, DA don't and need to work on cameras after the pentax Program Plus (I.e. KA mount bodies). Note there is a varient of the FA lens, FA-J which don't have aperture couplings.