Panasonic Pancake Primes

14mm on the left, 20mm on the right

 

14mm f2.5 (H-H014)  and 20mm f1.7 (H-H020AK)

Single focal length lenses in the age of zooms   For many years in the second half of the 20th Century I used nothing but fixed focal length lenses. There was no such thing as a consumer grade zoom. These days the quality of zooms is such that I use them almost exclusively.

Why use fixed focal length lenses ?  It seems to me that these need to bring something desirable to the user experience.  It might be smaller size, wider maximum aperture, better optical performance, some special feature not available in a zoom or lower price.

Why pancakes ?  Clearly these are designed to be as small as possible thereby making for a very compact kit. There is ongoing  marketing and consumer interest in the possibility of the M43 system delivering high image quality in a very small package. Witness the recent arrival of the Lumix GM1, for instance.

Both the 20mm f1.7 and the 14mm f2.5 have been available since the early days of the M43 system.

I had the opportunity to purchase both lenses at an attractive price. I bought the Mk2 version of the 20mm. This is said by Panasonic to have the same optical construction as the original but with improved coatings for decreased flare and better contrast.

20mm

 

Initial impressions  Both lenses are very small, the 14mm remarkably so. They take up very little space in a camera bag and add  little to the effective dimensions of any camera body onto which they may be mounted.

Physical  The two lenses share styling cues. Both have a smooth turning manual focus ring which actuates a focussing motor. The 20mm focusses by moving the entire inner barrel including filter, back and forth. I was unable to determine whether the rear element is fixed or whether it moves with focussing. These lenses park themselves at infinity focus when powered down and there is no way to operate  manual focus with the lens off camera.

The 14mm focusses internally, there being no movement of the front element or filter with focus.

As a consequence the 14mm focusses very fast,  providing AF speed equal to the 12-35mm zoom.  The 20mm is noticeably slower to focus. In use with general photography this is not an issue.  However if you wanted to photograph, say, small children playing, the 20mm might not quite keep up.

There are no other controls on the lenses. Neither has OIS.  Each uses a 46mm screw on filter.

20mm

Optical   I tested both lenses alongside the Lumix 12-35mm f2.8 zoom for comparison. I photographed a test chart and also made many general photographic pictures.

14mm f2.5  This lens was not quite up to the standard of the 12-35mm at 14mm. It was not as sharp at the edges or corners, exhibited noticeable barrel distortion, obvious corner shading and chromatic aberration.  Stopping down improved edge/corner performance a bit but it never cleaned up completely. There was slight decentering on my copy, evident as slightly greater softness on one side than the other. Resistance to flare was quite good.

20mm f1.7  This lens turned in a better optical performance. Even at f1.7 sharpness was very good with mild softness evident in the corners. By f4 the lens was very sharp right into the corners. There was mild barrel distortion and clearly evident corner shading at f1.7.  Flare resistance was good.  I rated this lens as equal to the 12-35mm (at 20mm ) at f2.8 and smaller apertures. The advantage of the 20mm is that it is 1.5 stops faster  wide open and the lens is entirely usable at f1.7.

14mm

Usefulness  Many photographers find that a  diagonal angle of view of about 55-65 degrees suits their requirements for general walk around photography. With a DAV of 57 degrees the 20mm is more or less in the middle of that range. If I had to use just one single focal length lens for every shot, I would select the 20mm.

The 14mm focal length is a bit more problematic. As  a wide angle complement to the 20mm I would prefer a 12mm. The problem for the 14mm f2.5 is that it is not really wide enough for some  purposes and the aperture is not much greater than most kit zooms at 14mm.

14mm

Summary  The 20mm f1.7 is one of the most popular single focal length Panasonic lenses and deservedly so. It has a convincingly wide maximum aperture, good optical performance from wide open and  a  useful focal length. One downside of this lens is that banding in pictures can occur with high ISO settings on some cameras. Unfortunately the banding problem persists with the Mk2 version. I have no idea why banding might occur but the problem has been reported often on user forums.

The 14mm is less popular,  also deservedly so. It's optical performance is no better than the wide end of a kit zoom and it's maximum aperture is not greatly larger than one of those zooms. It is also in many situations not really wide enough to complement the 20mm as part of a compact 2 lens kit.

If one were wanting to build a kit based on fixed focal length lenses I would think the 20mm would be an easy first choice for the standard, general purpose lens.  For a wide angle complement I would look at the Olympus 12mm f2. The only problem for this lens is it's price, which is much higher than the Lumix 14mm f2.5 and not much less than the Panasonic 12-35mm f2.8 or Olympus 12-40mm f2.8 zooms.