Plugged In: Find modern life in old-style camera lenses

By Joe Kashi, for the Redoubt Reporter

One of the more sensible “retro” tactics is to adapt high-quality, older-model lenses, purchased used, to modern digital cameras. Often, used lenses in good condition are far less expensive and sometimes better than current models.

Many camera manufacturers make a point of ensuring good backward compatibility with their older manual lenses. This usually works best with cameras that use in-body image-stabilization hardware, such as Pentax, Sony and Olympus. That’s because IBIS-based cameras stabilize any lens that can be physically mounted on that camera. Hardware-based image-stabilization is one of the most practical and useful photographic advances of the past 25 years, and being able to stabilize older lenses is key to using them to best advantage.

The Pentax K-series, bayonet-mount lenses provide a good example. Any K-mount lens made since the mid-1970s will mount, focus on infinity and work with even the most modern Pentax dSLR cameras. In my experience, some of these lenses, mostly single-magnification “prime” lenses, are optically preferable to affordable current offerings. Here’s why.

Most current lenses are zoom lenses in which optical designers try to get acceptable performance over a wide range of magnifications. Achieving that level of performance is difficult and uncommon among even modern zoom lenses, although a very few excellent zoom lenses are available for a wide variety of camera models.

Among the best, no-apology-needed zooms are Canon’s 15- to 85-mm zoom, Sigma’s new 18- to 35-mm wide-angle-to-normal zoom for Canon, Nikon, Sony and Pentax dSLR cameras ($800), Tamron’s 17- to 50-mm (non-VC) lens for Sony and Pentax IBIS-based dSLR cameras ($500), and the prograde Micro Four-Thirds zooms available from Olympus (12- to 40-mm, $998) and Panasonic (12- to 35-mm and 35- to 100-mm, $1,200) lenses.

Generally, current zoom lenses use a great deal of plastic in their construction, while older “prime” lenses, even consumer-grade models, are constructed of very solid metal. That kind of durable construction is rare and costly among current optics, even those claiming to be prograde lenses. A few diehards, notably current Pentax Limited Series lenses, continue to be made of high-quality metal and I’m more comfortable with their durability.

When considering the purchase of a used lens, first research that lens very carefully. It’s a bit more difficult to get information about older lenses compared to current production reviewed all over the web. However, many brand-specific forums, such as some of the forums and, frequently contain a wealth of information about the usability and optical quality of older lenses.

Be aware that lens mounts have evolved over the past few decades. Even if an older lens fits your camera, it might lack either autofocus or auto-exposure capability. If you’re not comfortable doing one or both of these tasks by manual adjustments, be sure that you get newer optics that include these features.

Consider the reliability of the used-equipment seller. I have purchased most of my used lenses from well-established vendors, mostly, and These vendors rate the condition of their used lenses carefully and somewhat conservatively. I purchase only lightly used equipment in top condition.

Over the past year or two, I have used zoom lenses less often, preferring the often-better optical quality of single-magnification prime lenses. Prime lenses are usually smaller, lighter and brighter, as well. In some instances, very useful magnifications are available longer as prime lenses.

My dSLR cameras are made by Pentax, whose basic, K-series lens mount is mechanically unchanged for the past 35 or so years, even though electrical contacts, autofocus and auto-exposure capabilities have been added to the basic K-mount during the intervening years. Although my experiences might be illustrative, it’s likely that your situation might differ somewhat, depending on your camera make and model.

As an example, I like how a 135-mm lens works on a dSLR camera, yet hardly anyone currently makes new prime lenses in that magnification. The first used 135-mm prime lens that I bought for my Pentax cameras was a f/3.5, costing under $100, and really small and light. I had difficulty focusing it with current cameras, perhaps due to my eyesight. More on that shortly.

I then purchased locally a faster, Pentax, 135-mm f/2.5 lens made in the 1970s. This used lens is much brighter and easier to focus manually, but still very small and light relative to any comparable zoom lens. Oh, and despite its light weight, it’s made entirely of high-quality metal. They really “don’t make them like that anymore,” which is a shame.

Although the image quality of this 1970s lens is surprisingly good on a modern Pentax dSLR, I wanted something a bit sharper and, ideally, with autofocus and auto-exposure for those times when I needed to shoot quickly. The solution was a late 1990s Pentax FA series 135-mm lens, a little more plastic than before, but with modern optical glass and computer-designed optics, along with autofocus and auto-exposure that work with current Pentax dSLR cameras. I still have, and use, both of these 135-mm lenses in preference to my much heavier and expensive zoom. They’re not only easier and lighter to handle, but sharper, as well.

I also like the higher magnification of a 200-mm lens, particularly for wildlife and other outdoor photographs, but have been wary of the lower sharpness found in zoom lenses at this magnification range. I didn’t want to spend the $1,100 or so to buy Pentax’s current 200-mm, f/2.8 prime lens. The solution? I bought an older, manual-focus Pentax 200-mm f/4 “M” series telephoto prime lens. It’s not perfect, but more than good enough with a bit of post-processing sharpening and reduction of chromatic aberration. It cost $109 used. Again, small, light and made entirely of high-grade metal.

What’s the catch? Possibly several, but none insuperable. Many older lenses must be manually focused. Accurate focus, always critical, is easy with traditional focusing screens that included split-image rangefinder and micro-prism ring features. Accurate focus is often difficult, though, using the featureless “matte” focusing screens found in modern dSLR cameras.

The solution? Replace that bland matte focusing screen with one that includes the traditional split-image rangefinder and micro-prism ring. Anyone can manually focus with accuracy using these features. You can do this camera “surgery” at home if you’re very careful, first read the installation instructions and have a very steady hand. Being an experienced surgeon would help here.

The cheap replacement focus screens found on Amazon and other sites are useless junk. I tried and discarded one. Instead, get a really high-quality focusing screen from Each screen is made specifically to order for your camera and desired features. The basic Katzeye, split-image screen costs $105, but I recommend also purchasing their $55 optional brightening feature, which avoids any problem with your camera’s autofocus and auto-exposure features. Although not inexpensive, using one of these replacement focusing screens allows you to accurately focus inexpensive manual focus lenses, so it’s economically sensible and makes the use of older manual focus lenses quite practical.

Manual exposure is also not difficult. Most better dSLR cameras have a procedure for using manual-exposure lenses, although you may need to read your camera manual carefully. Using my Pentax cameras, I set the mode dial to manual exposure, turn the aperture ring on the older lens to a sharp intermediate setting, such as f/8, and then press the green button. The camera then sets the correct shutter speed and exposure.

Because manual exposure seems to be occasionally inaccurate, I always bracket my exposures when using manual lenses. That’s a small price in wasted electrons for the ability to use inexpensively purchased used lenses that are small, light, frequently unavailable new, yet often very sharp.

Local attorney Joe Kashi received his bachelor’s and master’s degrees from MIT and his law degree from Georgetown University. Many of his technology and photography articles can be accessed through his website,

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