Pro video blog…Produced by Philip Johnston DoP/Editor

This is the latest picture of the Panasonic AG AF101 FilmLike camcorder. This looks the part and is how many of you will using the AF101…with Prime Lenses. The Prime lens marketplace must be buzzing with DPs ordering 35, 50,85mm lenses.

Alister Chapman says “PL mount lenses were developed by Arriflex for use with movie cameras, so PL mount lenses are an obvious choice. You used to be able to pick up older PL mount lenses quite cheaply, but when RED came along most of these got snapped up, so now PL mount lenses tend to be expensive. If you want top quality then Zeiss or Cooke lenses are the obvious choice. If your budget won’t stretch that far there are a number of 35mm SLR lenses that have been converted to PL mount.

PL  mount lenses often have witness marks for focus. This are factory engraved markings, individual to that lens for exact focus distances. They also often feature T stops instead of F stops for aperture. An F stop is the ratio of the iris opening to the focal length of the lens and gives the theoretical  amount of light that will pass through the lens if it was 100% efficient. A T stop on the other hand is the actual amount of light passing through the lens taking into account aperture size and transmission losses through the lens. A prime lens with an f1.4 aperture may only be a T2 lens after loss through the glass elements is taken into account. A multi element zoom lens will have higher losses, so a f2.8 lens may have a T stop of T4. However it is the iris size and thus the f stop that determines the Depth of Field.”

To read his fascinating story on Prime lenses…

Not all lenses are the same although Canon and Nikon produce at least 3 qualities of lens the best in Canon’s case being their “L” glass. You get better optics in “L” glass, optics to stop light loss, aberrations, vignetting and light versus optical quality. On a simple lens you will find that it will be slightly soft till you stop down to f5.6-f8 by that time your light is overtaken by grain if you are filming in a room with subdued lighting.

This is where the “L” glass comes in, I usually choose Canon “L” glass that is f2.8 all the way through which means that no matter where your zoom is 70mm or 200mm you can shoot at f2.8 and get sharp pictures. This is not true of lesser lenses in the Canon range where they start at possibly f3.5 and stop down to f6.3 loosing you a fair amount of light by the time you are at 200mm.

So in my opinion it’s prudent to always afford the best glass possible if you buy a DSLR like a Canon then as in this case you can use the same “L” glass on your AF101 using a Canon adaptor available Dec-Jan 2011.

Is there a major difference between Prime and “L” glass…in my books you always strive for the best but at around £8,000 per Prime lens it’s a bit prohibitive but remember you can always hire your Prime lenses and if I were a rental company I would be stocking up on PL glass as I think there is going to be an explosion of DPs renting PL glass.

Back to my question is there much difference, personally you have to to back in time to realise that for big 35mm productions you had one choice…PL glass after all it was made for the cinema in mind. OK so that was many years ago and if you wanted the best… PL was the answer. Today we have far superior optics both in PL glass and 35mm glass but for many of us the choice will be micro 4/3″ or 35mm glass due to constraints in budget and having the glass already.

As I said in the previous blog I do a lot of head and shoulder interviews so the shallow depth of field will be an absolute winner for me as demonstrated above.

Lenses are as important as the camera itself so aim high when choosing your glass for your AF101 wether you rent or buy, PL or 35mm, make sure you do not compromise your clients shoot with cheap glass.


Having been working in the video business since 1988 I have amassed a great amount of knowledge of both the kit and production values over the last 30 years.

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