The Pentax SMCP-FA 80-320mm f/4.5-5.6
Been looking for an inexpensive telephoto zoom lens to get you buy until you can afford the excellent Pentax D FA 70-200mm f/2.8? I was too, and that's what brings us here. Currently there are a few good options for a budget telephoto lens in the Pentax K-mount. There are a few other Pentax options from the film era, like the well regarded manual focus Pentax 70-210 f/4 lens. Tamron makes a 70-200mm f/2.8 option that seems to offer great image quality, but has a used price that is typically around $500. There's also the older 70-300mm options from Sigma and Tamron, all of which are inexpensive but give up a bit in the image quality department.
I wanted a lens with autofocus and the ability to adjust my aperture settings in camera if need be. This narrowed the search a little. I wanted to lose the least amount of image quality, and of course I wanted to spend the least amount of money. After much research and shopping, I found a used Pentax SMCP-FA 80-320mm lens for sale at $80. I decided to give it a shot.
Pentax SCMP-FA 80-320mm Specs and Handling
The Pentax SMCP-FA 80-320mm lens was introduced in 1997 and remained in production until 2002. This lens features an 8-bladed aperture that can be controlled on the lens body or set in the "A" setting to allow modern camera bodies control of the aperture. The aperture is variable, from f/4.5 to f/5.6, which isn't terribly slow when compared to a lot of other budget telephotos that reach into the 300mm range. In fact, the lens remains at f/4.5 through a good portion of its zoom range, nearly reaching 200mm before it begins to stop down. The lens construction is 13 elements in 10 groups. The 80-320mm is also a screw-driven autofocus lens.
The lens construction does feature a lot of plastic, it was introduced in the late 1990's after all. My copy was purchased in "bargain" condition, and does have some wear and tear on it. The extending portion of the lens does have some play in it. The zoom ring on my copy is slightly stiff, but it also has yet to exhibit zoom creep. Focusing this lens manually is similar to most modern lenses, which is to say it works fine but isn't noteworthy. The 80-320mm does feature a metal lens mount. The rubber grip rings on the focus and zoom ring actually do feel quite nice, and mine have aged well over the years. Overall, I would call the build quality good for a budget lens, but not extraordinary.
For more specs on this lens, check out the incredibly detailed chart over at the Pentax Forums.
Full Frame Performance
The performance of this lens on the full frame Pentax K1 is actually quite acceptable. Sharpness is good from 80mm to about 230mm before it starts to slip progressively softer as you reach the full range at 320mm. The lens is surprisingly decent when shot wide open in those same focal lengths. Sharpness does improve noticeably as you near f/11 which seems to be the sweet spot for my copy of this lens.
Autofocus performance on the K1 is also quite acceptable. For a budget lens, I'd say it's likely one of the better performers. It delivers relatively quick focus in single point AF. In continuous, it seems to be mostly accurate and maintains an okay level of quickness. In terms of AF noise the story is much the same. It's a 1997 lens, and it sounds like one. It's not terribly annoying to me in single AF, but sounds as if the drive motor is trying to destroy the lens in continuous focus. Having said all of that, it works well enough for my purposes, but can't be compared to the modern Pentax D FA 70-200 lens.
As far as overall image quality is concerned, I've been quite happy with its performance keeping in consideration what the lens is. It exhibits some CA when shooting into bright light without a hood, but is manageable in post production in most cases. Flaring is surprisingly well controlled, even more so with a lens hood. I haven't noticed an significant ghosting, but shooting directly into bright sunlight can wash out the contrast noticeably without the lens hood. Bokeh, being subjective as it is, can be hard to quantify. In my opinion it does a great job of rendering out of focus areas.
The Pentax K70 is where my SMCP-FA 80-320mm lens spends most of its time. I originally purchased this lens to leave on the K70 while on landscape outings with the K1. This enables me to shoot from 28mm to 480mm full frame equivalent without having to switch lenses. Using the 80-320mm on the K70 has been a joy.
Autofocus performance on the K70 is much the same as it is on the K1. Single AF is relatively speedy for a budget lens and continuous is a little slower. The noise when paired with the K70 is again much the same. It's tolerable in single AF and a little cringe-worthy in continuous. Accuracy seems good in both modes after calibration, however. I did have to calibrate the 80-320mm lens to my K70, but it seemed happy at default settings on the K1.
My experience in the past using Micro-Four Thirds cameras taught me that lenses don't always perform the same across sensor sizes in the image quality department. I'm quite happy to acknowledge that this doesn't seem to be the case with the Pentax. Sharpness is nearly identical to the K1 when accounting for resolution differences. The lens is sharpest from 80mm-200mm here again, still good until about 230mm, and then progressively softens as you reach 320mm. As with the K1, the lens is acceptably sharp wide open, but it improves noticeably as you near f/11.
The Overall Experience of the Pentax SMCP-FA 80-320mm
Using older lenses has been something I've enjoyed since I owned my first mirrorless camera a few years back. Modern Pentax DSLR's are some of the best suited cameras to shooting across the ages. Between the K-mount going back all the way to the 1970s and features like pixelshift, the Pentax DSLR is incredibly capable of milking every ounce of performance from these old film lenses.
With the SMCP-FA 80-320mm lens having all of the electrical contacts that were around in the late 90's, it's a dream for compatibility with the modern Pentax camera. The cameras can shoot in any mode with this lens attached. The Shake Reduction system knows what lens it is and works wonders with it. I have been able to pull off carefully done and acceptably sharp shots at 400mm equivalent focal length with a 1/13 second exposure on the K70 with this lens. It's a truly pleasurable experience.
Overall, this lens has been a great addition to my kit. For the roughly $80 I paid to get it here, I'm thrilled with the performance. Will it hold up to the new Pentax D FA 70-200 f/2.8 lens? Of course not. Compared to most other lenses in the under $100 dollar price range, though, this lens is a performer. It boasts good to great sharpness, bokeh that I thoroughly enjoy, an excellent zoom range, and a good enough build quality. Once you learn this lens and what its sweet spots are, it's certainly worth the price tag.
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Please check out my video review of this lens over on YouTube for more!