Q: I have a 35-millimeter Pentax K1000 SLR camera body and ZX-7 body with lenses. Which Pentax digital SLR should I get to use with my existing lenses? The lenses are a Tamron 28-80mm zoom, 70-300mm macro focusing zoom and a 135 mm f/2.5 telephoto. I'm comparing the Pentax K-30 and K-50 bodies.

A: I'll get to my recommendation shortly, but first I'd like to detail my experience using vintage lenses on a new digital SLR.

I have a beloved Tamron 80-210mm f/3.8-4 zoom lens with the Adaptall-2 changeable mount. I used this lens all through college and absolutely loved it. It was mid-1980s vintage and was one of the best zoom lenses of its day, equal or better than competing lenses from Nikon and Canon. I've held onto it not only because of sentimental attachment, but also figuring that someday I might have a use for it.

When I switched from a Canon to a Pentax digital SLR system, I realized I could use my old Tamron on a new Pentax digital SLR body by changing the Adaptall-2 mount. I found a Pentax KA mount with the electronic interface, slapped it on my lens, put it on the camera body and went out to take pictures.

I never used autofocus until I went with a digital SLR system. Now that I was used to it, focusing my Tamron became a chore and I realized how much harder it was to manually focus an old, heavy lens using the smaller viewfinder of a digital SLR. (The viewfinder of a 35mm SLR is much larger than a digital SLR, unless you have a full-frame camera.)

It wasn't as much fun using my old lens as I thought it would be.

This was enough to dissuade me from using my old lens, but then I saw the results. In a word: yuck.

The lens didn't hold up well compared with a modern, digitally optimized Pentax lens, even inexpensive ones such as the 18-55mm or 50-200mm models. The images from my Pentax lenses were clearer, crisper and had better color. It was also much easier to get these results because all of the camera functionality was retained with the new lenses. Many older lenses lack the electronic contacts and firmware to integrate fully with the new cameras.

Get the K-30 camera and use the savings over the K-50 toward new lenses.

You don't have to forgo the old lenses entirely. In fact, the 70-300mm and 135mm f/2.5 lenses could be useful in certain circumstances.

A K-30 kit with the Pentax 18-55mm lens sells for about $599 online. If you shop carefully, you can find the K-30 kit with both the 18-55 and 50-200 lens for less than $650. This would be an excellent long-term investment and not much more than the K-50 body, which usually sells in the low $600 range.

This isn't meant to be a swipe at Tamron or using vintage lenses. Lots of photographers get great results using vintage lenses on digital cameras, especially mirrorless bodies, where a plethora of adapters are available.

I don't recommend vintage as sole or primary lenses, though. The compromises in performance aren't worth it.

Send questions to Don Lindich at donlindich@gmail.com. Get more recommendations and read past columns at www.soundadviceblog.com.