Speed is coveted by many. Speed means fast lenses, and fast lenses mean low f-numbers, and that means the ability to gather more light than slower lenses. All this put together means faster shutter speeds. One stop means a doubling, or halving, of the shutter speed, and therefore the lens allows capture of *faster* action.
No lens in the Pentax lineup delivers more speed than this one. F/1.2 is as fast as they go. Some new modern lenses, however, have gone below f/1.2, at the cost of size, weight, and price. Comparing, within the K-series, this lens and the next level down: the K50f1.4. The f/1.2 lens is only one-half stop faster, but is 45% heavier and 17% larger, or longer. Compared to the M-series 50f1.4, which I wrote about earlier, this f/1.2 lens is 64% heavier and 32% larger or longer, which is quite significant for only a half-stop.
The lens is 385g (0.85#) and, focused at infinity, 48.5mm long (1.9 inches) and has 8 aperture blades and 52mm filter threads. The fast aperture of f/1.2 is the fastest Pentax has made for this or any focal length. The lens bears the usual aperture ring and has a rubberized grip for easy manual focusing. Minimum focus distance is 45cm (18 inches) producing 1:6.7 reproduction ratio (0.15x).
Being a hopeless collector and semi-skilled photographer, I decided I needed this lens because of it's unique place in Pentax history more than the f/1.2. My other 50mm lenses are plenty fast enough, even the f/1.7, but at a very early stage along my path in photography, I found the beauty inherent in the equipment itself. Photographic lenses are things of beauty, an aesthetic that i can't describe both in physical appearance, quality construction, and engineering done before computing power made it easy. This lens was the crown jewel of the K-series, and so I needed to possess one.
The lens is significantly heavier than anything else I have in this focal length range which on the K-1 mII digital SLR makes it a little easier to use. Weight is definitely not prohibitive, but balances with the camera well. The lens has a slightly bulbous front element, and therefore can be prone to flare. I've written before about the utility of built-in lens hoods; this lens does not have one. However, a well-placed left hand can shield the lens from sidelight in such situations. Pentax made lens hoods specific for a lens (or a small number of similarly specked lenses), but any "standard" lens hood can be used if it can thread onto the 52mm filter threads.
The photos displayed here again are not unique to this lens. Any 50mm lens could have obtained similar images, and none were taken wide open due to the bright sunlight this day. I promise that in the future, I will do a short write-up showing all my 50mm lenses wide open so you can see what the differences are.
At any rate, the top photo is an in-camera HDR image of Newton County. The fall colors are showing up this year in fits and starts. Some trees are bare, others are still green, so unlike other years where autumn was "brown and down," the colors are not brilliant due to asynchronous color change. I typically do HDR images in Lightroom, from two or more exposures, but the K-1 mII camera (like many other modern DSLRs) will produce rich HDR images based on a similar series of exposures. I set the camera to HDR-advanced, and let 'er rip, and this is what I ended up with. A little overcooked, isn't it?
The bottom two photos were drive-by images along famous Boxley Valley, Newton County, Arkansas. I love old barns, and I especially love the round bales (aka, "cinnamon rolls") scattered all over the place, and of course, everyone loves a roving pack of bovids.
As usual, you can click on any image for embiggenation. Comment space is available on this page, and under each individual photo.