Joseph Petzval's 1840 design for the portrait objective lens consisted of a cemented doublet lens in front, a doublet lens with an air gap in the rear, and a diaphragm between the two lens groups. At f/3.6 this lens was considerably faster than the f/15 Chevalier lens that was in wide use on Daguerreotype cameras at the time, and shortened the exposure time from about 10 minutes down to only 30 seconds. This was a considerable benefit for portrait photographers and the lens became immediately popular.
|One of the early Kickstarter Lomography Petzval lenses in its packaging. Scattered about are the waterhouse stops that serve as diaphragm openings.|
This lens is difficult to focus. First of all, the lens has an appropriate rack-and-pinion focus system with considerable play -- part of the nature of the design. This is the original way this lens was focused and adds to the mystique of using it. Nonetheless, on a lens that has an extremely shallow depth of field, the point of focus needs to be dead on, and this is hard to do. Second, it is not easy to see the focus on a modern SLR finder screen. On my Nikon cameras I found myself gently racking the focus knob in and out with the camera motor blazing away in an effort to bracket the focus point. This is where something like focus peaking would come in handy, and that is why I decided to mount the lens on a Leica instead.
|The Petzval lens mounted on a Nikon D800 -- a great combo, but, as I found out, very difficult to focus.|
The focal length of the lens is 85mm -- a perfect size for a full frame portrait lens. Aperture is set using waterhouse stops that slip into the lens from a slit on the top. Stops range from f/2.2 down to f/16. To maintain the soft edge qualities for which this lens is noted, you are probably going to want to stay with the more wide open stops. I found myself settling in on the f/2.8 for almost everything. An additional set of design stops is available as an accessory.
Because the waterhouse stops just slip into their slot there is nothing to hold them in place, and they will fall out if you hold the camera sideways or tilt it upside down -- just another aspect of this lens that adds to its charm, I suppose.
While the center of the lens produces a sharp image relative to the edges, it is not the same type of sharpness coming from modern, high quality digital lens. The characteristics of the Petzval lens are unique. Getting used to them will take a bit of experimenting. There is a soft halo around even the sharpest areas of the image, especially at more open f/stops. Yet another part of its charm.
|The out-of-focus areas in this image are a typical example of the of swirling bokeh characteristic of a Petzval lens. Shot at f/2.8.|
The lens itself is only 2 3/4" long. A brass lens hood is integrated nicely into the design, and, when attached, the overall length comes to 4 1/4". The hood screws off to gain access to the front of the lens, which accepts 58mm filters. I found that a +1 close-up filter came in handy.
|Swirling bokeh is only visible over the the trees in the upper right of the frame because of its mottled contrast -- something to keep in mind if this is the effect you want to achieve.|
I found myself settling on the f/2.8 waterhouse stop as my ideal aperture setting. It provided the swirling bokeh the lens is known for and seemed to produce a center sharpeness better than the f/2.2. On portraits the f/2.2 had a soft halo around the sharp areas a lot like you get by using a close-up filter on a f/1.4 lens. This is not necessarily bad, but the sharp areas in this case were a little too soft for my taste.
|The swirling, while apparent on the left, is downplayed here because the background is fairly close to the subject. Even so the softness characteristics of the lens have their own unique feel.|
|This was taken at the minimum 1 meter focus distance of this lens. I was surprised that the bird allowed me to get that close.|
|The star effect is a result of photographing a glittery surface in a strong light with the star-shaped waterhouse stop inserted in the lens, as shown below|
|The most obvious display of the Petzval swirling focus is apparent when shooting with lights in the background.|
|It is tempting to apply older monochrome photographic techniques to the Petzval images. The look and feel just seems to suit.|
|I couldn't resist applying a wet plate technique to this Petzval portrait. The application was done in Photoshop using Alien Skin Exposure 5 software vintage looks.|
Let's face it, if you're acquiring this lens it's probably more for the fun of using it than anything else. Much of the enjoyment we derive from the New Petzval lens is in the link it provides to a past era of photography. The simple fact that we can participate in the mystique of that lineage is part of the unseen value that comes in the package.