There seems to be an abundance of hype and confusion with respect to the new Panasonic AG-DVX100's progressive scan "25fps" mode and since other manufacturers are certain to follow Panasonic's lead I have written this brief article to help clarify matters:

Firstly, the AG-DVX100's VTR section is just a standard mini DV VTR - it does not record 25 frames per second - It actually records 50 fields per second just like every other PAL DV camcorder.

However, with the AG-DVX100 the difference is that both fields are sampled from an identical progressively scanned frame - Therefore if you want to output to film at 25fps both fields can be combined to form a complete and perfectly interlaced full resolution frame.

It is also very important to note that in progressive scan mode the AG-DVX100 is much less light sensitive because it is actually shooting 1 frame with a 1/50 sec shutter speed as opposed to 2 fields, each with a 1/50 sec shutter speed; ie: its CCD block is effectively exposed to 1/2 of the light when in progressive scan mode!

Because the Camcorder's CCD is only effectively exposed to light for 1/50 sec every 1/25th of a second it gives the shutter effect of a film camera with a 180° shutter angle. This is why you get the 'flicker' or 'strobing' effect associated with shooting film when shooting with the AG-DVX100.

So what does all this mean to the user?

Well, if your final output is 25 or 24 fps film then the progressive scan mode of the AG-DVX100 will be a great advantage, as it significantly improves the resolution of the final product. However, if you are not outputting to film then please be aware that whilst progressive scan does help create a more 'filmic' look which might well add extra atmosphere to a drama shoot, it also creates restrictions when you're moving, panning, tilting and zooming the camera if you want to avoid strobing issues.

These are issues that experienced film DOP's and cameramen are well versed with, however if you are intending to use 25fps for the first time then I strongly advise you to experiment extensively before you decide.

Its worth noting that film is generally shot and projected at 24 or 25 fps essentially for reasons of economy - I'm sure if film stock was free all films would be shot at 100fps or higher in order to deliver superior smoothness. The 24fps frame rate for feature films was actually chosen because it is the slowest watchable frame rate. Did you know that modern projectors also project each frame twice in order to reduce flicker by giving the impression of 48fps projection?

Smoother is almost always better - That's why the latest TVs are almost all equipped with 100Hz display capability. Therefore, to a certain extent the 25fps mode actually degrades the image quality when viewed on a TV set!

For clarification - Any DV editing system can edit material shot on the AG-DVX100 because it shoots DV even if you are in '25fps' mode!