I began to do just a few basic trials today with the new Pentax SMC DA 35mm ƒ/2.8 Macro Limited, to start to get a handle on how this new lens for reduced-size sensors behaves.
Physically the lens is quite small, about the size of a normal lens for a 35mm camera, although it is not a "pancake" lens like the other Pentax DA compacts (the 21mm, 40mm, and 70mm). It is all-metal and finely finished. Unlike many "normal" macro lenses it does not have a deeply recessed front element, but it has a built-in, pull-out lenshood that extends out a little less than an inch.
I'm not a macro photographer, and I have probably taken about as many macro shots in my 28 years as a photographer as I've taken pictures with on-camera flash—which is to say, almost none. My own interest in this lens would be as an all-purpose normal prime that effectively doesn't have a close-focusing limitation. Still, I presume that many potential purchasers would be interested in its macro capabilities. I gave it a brief trial by tossing my keys on the deck and taking a quick snap for a size reference, then switching the K20D to manual focus, setting the lens to its close-focusing point, and moving in on the subject until I had it in focus. The light was bright afternoon sunlight.
This was taken at a moderate aperture, hand-held, so I'm sure real macro photographers could do much better in terms of resolution and the proper depth of field. As a quick'n'dirty measure of "just how macro you can go," however, it should give you an idea—I could actually get so close that the lens hood, when extended, touched the keys.
Here's a detail of the shot above, which should be around 100% if you click on the image.
Next I did eight or ten quick trials to begin to see about flare performance, and I must say this lens, initially at least, is very impressive in this regard. In the shot below, the very bright sun (we enjoyed a very clear day here in Southeastern Wisconsin today—the best day of the year so far, in fact) was only partially obscured by the tree, so that this scene was uncomfortable to look at with the unaided eye. Despite this, the image remains admirably contrasty, with minimal flare artifacts. With my eyes, I couldn't see the wire passing closest to the sun, but the lens has rendered it very well, with almost no color anomalies and excellent contrast. You can't see this at web resolution, but in the original file there is both detail and color in the body of the bird. I'll continue to think of new ways to trick this lens into flaring out, but for the time being it has stood up to my nefarious mistreatment most impressively.
Next is a picture of yr. hmbl. correspondent, taken over the gunwales of two lunch boats at a local Japanese restaurant by my friend and fellow-photographer Nick Hartmann. (Our friend Josh Hawkins, an award-winning photojournalist from Chicago, was in town for a mental-health day—our mental health, he must have meant.)
By all means, don't waste time looking at my ugly mug—look at the important part of the picture: the bokeh. I must say that even in light of my affliction (no one should pay as much attention to bokeh as I do), my early impressions of this lens are quite favorable. The bokeh resembles nothing so much as that from an old Leica Summarit.
I won't show you any examples of corner resolution—I'm sure you don't want to see pictures of my lawn grass and my arbor vitae—but I'm not seeing any evidence of corner smearing so far. I need to be slightly more disciplined in my testing procedures before I make any pronouncements about that, however.
You probably think I throw everything up on T.O.P. but the kitchen sink, so here, without ado, is the kitchen sink. In the larger file the color shadings are admirably subtle, I can't detect pixel jaggies even at 100%, and it's easy to tell the plate is half covered with water. The image files from this camera and lens are generally just lovely. By the way, all the images in this post were shot in native DNG, opened in ACR, and resized for the web. A slight amount of unsharp mask (radius 1.2, amount 35) was applied to the pictures that open larger when you click on them (but not the two closeup details). I didn't adjust color at all. Everything was metered by the camera except the kitchen sink, where I aimed the camera off to the right a bit, hit AEL, and then reframed and shot. Again, no color correction.
It's far too early to get excited about a new lens when you've only done a few quick trials over a mere day and a half, but what I can say is—so far, so good. I shall keep you posted.
Featured Comment by Ctein: To address some questions in the comments: for close-up work, the focal length of the lens you use has no effect on your depth of field. That's entirely determined by your image magnification and your lens aperture. This is not true for distant photography, where the focal length of the lens can be very important, but if you're talking about anything at greater than 0.1X magnification focal length will never play a significant part.
Here's a useful equation that gives the depth of field on either side of the point at which are focused, as a function of image magnification (M):
DOF = C * f / (M^2)
C is the circle of confusion
f is the effective lens aperture: that is, the one that's been corrected for lens extension. If you're using the f# indicated on the lens ring, then replace f with f# * (M +1)
This is a very common misconception—that for a constant magnification, lens focal length affects depth of field in macro work but doesn't affect it in normal photography. In truth, it's just the opposite.