Tele-Takumar 300mm f6.3
Of the old 300mm lenses that you still get for under $100, one of the more interesting is the Tele-Takumar 300mm f6.3. First introduced in the early sixties by the Asahi Optical Company (later known as Pentax), this is an M42 screwmount lens which looks rather like a telescope: it is a long, narrow lens. In those days, Asahi Pentax sold more SLRs than nearly all the other camera companies combined. While the Tele-Takumar does not appear to have been a big seller, enough were sold that it’s not a rare lens. At any given time, there’s usually one or two available on ebay, sometimes at outrageous prices. I snagged one in January of 2010 for about $75, more out of curiosity than economic necessity. It seemed kind of intriguing to try out an old lens on a DSLR and see how it measured up to the newer, computer designed optics of the twenty-first century.
The Tele-Takumar 300 remains, at just under 26 ounces, the lightest 300mm prime lens Pentax ever produced. The build quality, like all the old Pentax screwmount Takumars, is superb: constructed entirely of metal and glass, sporting the tightest, most thoroughly dampened focus ring I have ever experienced. This is a preset lens, meaning it has two aperture rings: one to set the aperture, and another to open up the aperture for focusing. The first ring clicks to the desired setting like any other aperture ring; the second moves freely from wide open to wherever the first ring has been set. This "feature" is necessary because the Tele-Takumar lacks the automatic diaphragm feature common to all modern lenses. When the lens is stopped down, the viewfinder darkens, which makes it difficult to frame the shot and achieve focus. Having a second aperture ring makes it easy to open the lens back up for framing the shot, and then closing it back down to take the picture. This means that using this lens presents challenges beyond issues involved with manual focus.
So what of the quality of the lens itself? Does it take good pictures? Is it worth purchasing on ebay? Admirers of the old screwmount Takumars sometimes talk of the 3D rendering that these lenses allegedly manifest. I can’t say I really saw strong evidence such quality in the Tele-Takumar, although image quality, under ideal conditions, was superior to what one finds in most kit and consumer grade zoom lens. Under less than ideal conditions, however, things quickly became more complicated. The Tele-Takumar lacks multi-coatings and hence is, theoretically at least, prone to lens flare issues. I can’t say I noticed any strong evidence of flaring problems. My version of the Tele-Takumar came with a rather long and narrow metal hood which screws on to the end of the lens. Undoubtedly this hood helps keep flaring in check. Nonetheless, the Tele-Takumar can’t quite produce the contrast and rich colors of Pentax’s later multi-coated glass. I noticed as well that the lens struggled to render detail in highlights, such as sunlit whites, irregardless of whether they were blown out or not.
Lacking any sort of multi-coating, back or front, the Tele-Takumar is very susceptible to sensor flare. In practical terms, this means images lacking both contrast and saturation. Moreover, this flare problem is not merely an issue caused by direct sunlight striking the lens element. The Tele-Takumar originally came with a long, narrow metal lens hood that screws on at the front of the lens. This hood helps reduce the problems related to lens and sensor flare, but it doesn't get rid of them altogether. Any strong light, including back light, can produce symptoms of sensor flare. To draw the best qualities of the lens, you have to shoot with sun to your back.
Another issue with older glass, particularly in the telephoto focal range, is the penchant for chromatic aberation problems. Although the Tele-Takumar is no exception to this tendency, it is not as prone to it as some of the other telephoto Takumars, such as Takumar 300m f4. Indeed, it's probably no more prone to CA than many consumer grade zoom lens lacking ED glass. The Tamron 75-300 isn't a jot better in this respect.
Getting good results from any long lens, even of the best quality, can be a challenge; yet the Tele-Takumar presents more challengs than most such lenses. The first challenge is the slowness of the lens: f6.3 is as wide as it gets, and this makes the lens difficult to hand hold even in good light without first ramping up the ISO. The second issue is the aforementioned lens flare: you don’t want to be pointing this lens at strong light sources or particularly bright objects. A third issue, related to the slowness of the lens, is the darkness of the viewfinder, which makes focusing more difficult. A fourth issue has to do with the optimal f-stop, which is not f6.3 or even f8, but probably closer to f16. Of course, you can't shoot anything at f16 because the lens is too dark at that aperture. You really have to focus with the lens wide open and then dial back down to the set aperture for the shot.
Consider the photo below, shot on a tripod at f16. In terms of sharpness, it may not seem all that impressive, until you realize that it's a 100% crop of a 10mpx image:
The lens obviously performs better if you don't have to crop in post. The following photo was taken at f6.3 with the animal about 30 feet away:
The Pentax DA* 300 f4 would produce a sharper image with a creamier bokeh and better contrast; but for a lens that can be purchased for under $100, the Tele-Takumar 300 actually doesn’t do so bad. While you'll be hard-pressed to sell any images made with this lens, it's perfectly adequate as an introduction to the world of super-telephoto. On an APS-C camera, the 35mm equivalent focal range of this lens is 460mm.
The lens requires a M42 screwmount adapter for use on Pentax, Canon, Sony, or micro 4/3rds cameras. The lack of an automatic diaphragm means that the lens can be used with AV mode to attain correct exposure. It should also be noted that metering don’t always work well with these older lenses. On my Pentax K200D, multi-segmeted metering does not work with any lens that lacks an “A” setting on its aperture ring. Canon users have also reported difficulties using evaluative metering with screwmount lenses.
If you do decide purchase this lens, two things to be aware of : first, make sure it comes with the original metal hood -- in a lens without multi-coatings, the hood becomes an absolute necessity; and second, make sure it comes with tripod mount -- to get the best out of this lens, you need to get it on a tripod. With those two caveats in mind, this lens gets a mild recommendation. It's not a great lens and can't compete with the newer, faster, autofocus 300mm prime lenses; yet if you find a copy for under $100, it's may be worth adding to your collection. In any case, it will give you better images than those sub $200 telephoto zooms.
Below are two more photos taken with the lens at f6.3: