Pentax A 35-105 f3.5

The Pentax A 35-105 f3.5 lens was released in 1984, back in the old troglodyte era allegedly before camera companies knew how to make zoom lens. Nowadays, zoom lenses are made through computer designs, and the old zooms are scorned. As one professional photographer put it, they are complete “crap.” And to be sure, some of the older zooms leave something to be desired. I once performed a photo shoot on a video production set with an old manual focus Canon FD zoom lens. The shots were almost entirely ruined by serious flare issues. I took nearly the same shots with an old Pentax prime lens and ran into no problems at all. Zoom lenses contain more elements and are therefore more prone to flare problems. So old zooms with inferior coatings may in fact be “crap.” But since Pentax was a pioneer in the development of flare resistance via its SMC multi-coatings, how does an old, 15 element Pentax zoom lens perform on the current DSLRs? Is this old zoom little more than the optical equivalent of “crap”? Or is it capable of greater things?

The A 35-105 was well liked in its day. In an old internet discussion list of Pentax shooters, the lens finished second in a favorite lens poll (behind the legendary FA* 24/2). When it was released in 1984, it was the best Pentax zoom in its range, perhaps the best Pentax zoom that had been released up to that point. It quickly garnered a reputation for being a “stack of primes.”

The lens, although not particularly large, is heavy. It weighs 615 grams — about the same as the DA* 16-50, one of Pentax’s heavier DA zooms. It consists of a metal barrel stuffed with thick, heavy glass. It feels substantial when attached to a camera.

When I first received this lens and looked through the viewfinder, I could tell it was a different kind of lens, unlike any I had used before. This is a lens with character — unusual in a zoom lens, particularly when compared to today’s top zooms, which seem to all be excellent in a generic sort of way. This is not to imply that the character of the A 35-105 is all splendid. It has its quirks. It’s capable of disappointing on occasion. But it is also capable of producing stunning images.

First, in terms of sharpness: does the lens have the sharpness of a prime? Well, not quite. It’s close, however. There is some real sharpness in the lens. It’s not always easy to draw that sharpness out, but it’s there. Consider the following photograph, taken at the wide end of the lens:

And here’s a ~100% crop:

Not bad at all. In fact, pretty darn good, although a lens like the Pentax K 35/3.5 would produce even sharper results. But this is more than adequate.

What about in the middle of the zoom, around 50mm? It still produces more than decent resolution:

And the 100% crop:

And what about at the long end of the zoom? Well here, there might be a loss of resolution. In any case, I struggle to get as much sharpness at 105mm than I do at 60mm or 40mm. But you would hardly notice it in the following samples:

And the 100% crop:

So sharpness is really not an issue. Are the current zooms sharper? Yes, the expensive ones are sharper; but not sharper by much. What about sharpness wide open? At f3.5, it retains some sharpness in the center of the lens, but quickly loses resolution toward the corners. But for isolating a subject, this is hardly a fault, as can be seen in the following two images, both shot at f3.5. If there is any problem shooting wide open it has to do with the minimum aperture of f3.5:

What about color rendition? Well, that has quite a bit to do with the coatings, and in a 15 element lens from the eighties, one can’t expect miracles. This lens does not render colors quite as well as some of my other Pentax lenses (all of which are either older primes with fewer elements or newer lenses with the latest coatings). Still, it’s pretty good; just not quite up to the usual high Pentax standards. This is manifested in a slightly greater tendency toward flare than one usually finds in Pentax SMC lenses, though it’s still fairly well controlled:

I suspect as well that the lens has a very slight yellow-green cast. But with modern DSLRs, this can easily be fixed by adjusting the white balance controls in post. It does a fine job with reds and greens:

On the internet this lens has a bit of a reputation for its “3D effect.” This is not an issue of isolation via narrow DOF (after all, it’s an f3.5 lens), but something more obscure and difficult to verify or even illustrate. Nonetheless, at times, it does seem to render depth better than other lenses. Again, it’s very subtle, and many may not notice it, or even regard it as a myth; nonetheless, in the following photograph, taken near the long end of the lens, I can at least imagine I see this quality:

And in perhaps these photos as well (but it is subtle and nearly imperceptible):

Whether these photos really do have the vague 3D quality is difficult to say; but whatever defects they have can hardly be blamed on the lens. The Pentax A 35-105 f3.5 is a solid performer, despite it’s age. It is, of course, a manual focus lens; but it does have an “A” setting on the aperture ring which allows for automatic exposure functions, including p-TTL flash. The price of this lens on the used market has gone up in the last year and a half. In January of 2010, I rounded up a copy on ebay for $98.00, but more recently I’ve seen copies sell for over $200. The reputation of the lens has been growing in recent years as Pentax users have been buying copies and putting them on their DSLRs. While not a great lens, it is still capable of making excellent images.

More examples: