We all know what long lenses are for. To "reach out" to distant subjects and "bring them closer." Except, this isn't really so. A lens that is long for a given format simply isolates a small detail of the view in front of the camera (called the "angle of view," in this case a narrow one), when compared to a lens of normal length. Of course this does mean that you can fill the frame with a relatively small subject from a relatively long distance. This is vital for photographers who want to make pictures of subjects that are difficult to approach closely, like wildlife or sports action. Since I don't tend to photograph those subjects, and since I like to work up close to the people and things I do photograph, I work almost exclusively with normal or moderate wide angle lenses.
However, there's another use for long lenses, which is to photograph a perfectly ordinary, approachable, subject from an unusually distant position. This does some really interesting things to the look of a subject, and to the way it relates visually with foreground and/or background elements.
While I seldom use moderately long lenses (sometimes called "portrait length"), I've always had a soft spot for a really long but hand-hold-able lens along the lines of a 300mm ƒ/2.8 for 35mm film format. So, some weeks ago when the Pentax elves from Golden, Colorado, asked if I'd like to try out their newly introduced 200mm ƒ/2.8 (for APS-C sensor size), I jumped at the chance.
The first thing I noticed out of the box was that the build quality and materials of this DA* (say "dee-ay-star") lens is first rate, seemingly in the same league as their "Limited" lens line. The next thing I noticed was how a lens of this type really makes the APS-C sensor format shine. This is a hefty amalgam of glass and mechanicals, but compared to the equivalent 300mm ƒ/2.8 lens I had years ago for my film Nikon cameras, this lens is diminutive. It fits easily into any tall compartment/section of a typical shoulder bag. Also, while they certainly aren't giving it away, the cost is a fraction of what an equivalent lens for "full frame" or FX format will set you back. I think that's important because it means that someone with tastes similar to mine just might be able to find room in the budget to acquire this lens while the expenditure for its "full-frame" avatar would simply not be justifiable for a lens you use only once in a while.
This is the first Pentax "SDM" lens I've had a chance to use. That's their term for high-tech motor-in-the-lens autofocus technology. So the second thing I noticed about this lens was that the focus mechanism is so fast it's startling. There's no way I could possibly spin the manual focus ring and move those big pieces of glass that fast, much less stop on a dime at the correct distance. Even so, another nice thing is that a lens this long and this fast is really easy to focus manually, even in an APS-C viewfinder. Believe it or not, there are plenty of situations where I really prefer to focus manually and the relative difficulty of doing this with short, slow, lenses is perhaps my biggest gripe with the APS-C format. As with all recent Pentax digital lenses, if the camera is set to single AF you can instantly go manual—for a single shot—simply by twisting the manual focus ring, without having to throw any AF-to-MF switches. The lens features IF (Internal Focusing) so in either auto or manual focus the lens shows no external change, neither in length nor rotation, as you focus through the range.
The third thing I noticed was a problem with this particular sample of the lens: a major front focus error. At a distance of ten yards or so the plane of focus is off by a couple of feet. It was obvious the moment I looked at my first test exposures on a monitor. Luckily, my K20D has the feature of user-accessible AF correction for individual lens types. Luckily again, the entire amount of available correction was just enough to set the camera/lens system perfectly. But to use AF on any Pentax prior to the K20D, this particular lens would have to go straight back for service.
With that, let's get to my only other negative comment on this lens, which is that it sometimes displays more flare than I'd like to see, despite its well-designed deep lens hood (which reverses for storage). This is a little tricky to analyze because the pictures we tend to make with a lens this long can pack a lot of air between the photographer and the subject. Spring and early summer in New England are not known for crystal-clear atmospheric conditions, and compressed haze can look a lot like flare. But it became clear to me that in very bright conditions, and especially if brilliantly lighted objects are in a deeply out of focus background, the overall image can be degraded by non-imaging flare density. Often this can be quickly remedied with a liberal application of the Contrast and Black sliders in ACR, but it's a problem that could once in a while ruin a potentially good picture. I doubt that this is a sample problem but more likely results from less than ideal suppression of internal reflections by the lens coatings.
Back to fun stuff:
These poppies at a friend's wildflower garden could have been photographed with any normal, or macro, or short-tele lens, but there's something really different about making such a narrow-angle view from a couple yards away with the 300mm-equivalent focal length. As with the other illustrations here, the shot was hand held. I set the controls for C(ontinuous)AF and Auto-Select and just watched as the system snapped the focus point around when I changed framing.
I was curious how auto-everything-AF would handle "action" and took the lens to a couple of parades. Obviously, the auto-select mechanism will sometimes choose the "wrong" focus point, meaning simply "not what I would have chosen." But for the most part it seemed quite clever, generally favoring closer objects in the scene but without obstinately grabbing for the nearest possible point. Given that the mechanism is faster and more decisive than I can be turning the focus ring myself, I suspect in terms of general average success rate the camera would beat me with moving subjects, despite sometimes picking the wrong focus point. I also tried using S(ingle)AF with S(elective) focus point. On the Pentax you can move the selected point around with the navigation buttons on the camera back. So, for example, as you spot a potential picture and realize the part you want to focus is left of, and below, center, you can thumb the West and South navigation buttons as you aim and the lens will snap-to on the selected spot as you half-squeeze the shutter release. With enough practice, I think I could learn to use this approach well enough to beat the auto-everything success rate. You can see some of these trials over at my Working Pictures blog archives [May 28, June 4].
This was a situation where I was glad that manual focus is so smooth and decisive with the D* 200mm ƒ/2.8. Auto-select AF would have been hopelessly confused by all the figures in the foreground, and the sergeant's face did not fall at any of the 11 AF points the way I wanted to frame the picture. On top of that, since she was not standing at attention, she wasn't holding perfectly still, while everyone else was moving around a lot. Manual focus was the simplest way to get the shot. It's worth noting that the file is extremely clean and flare-free despite the harsh overhead sunlight. It takes much worse conditions than this to bring on the flare mentioned earlier.
I haven't said anything to answer the perennial question "but how sharp is it?" Well, earlier this week I delivered two pictures graphically similar to the one at the top of this post, prints interpolated up to 16x24" image area. The response, from a client looking at them right up close, from reading distance, was, "look at the detail!" It's sharp enough.