A sleeper lens: SMC Pentax-F F4-5.6 35-80mm

Cost: 14.99$ (average market price $19.86)

Some describe it as the worst Pentax lens ever made, and recommend to go for the sharper SMC Pentax-F 35-70 instead. However, I actually liked this lens. The fact that this lens was made in Taiwan, instead of Japan as normal for Pentax lenses, might point to a lesser average quality, or at least more variation in quality. But either I got lucky, or I just liked the image quality of this lens.

I found it to be reasonable sharp for a base zoom lens of this era, and the colors are nicely saturated, with good contrast. I also liked it when shooting in black and white.

The negative is more on how to use this lens as a manual lens. I'm sure that when used on a Pentax camera with auto-focus, this is a non-issue, but when used manually on my Sony, the focus is ring is very narrow, and very stiff. Not what I would expect from Pentax. But heck, the pictures were good, but I would not try this on fast moving objects.

In a nutshell, it's not a bad lens, and at a cost of less then $15, I would call this a sleeper lens. Not very well known, with a bad reputation, but when you find a good copy, not that bad at all. A keeper...

To combat partial reflection, Pentax developed chemical coatings for the lens surfaces with minimum light loss. SMC is "a remarkable seven-layer lens coating process that cuts the reflection ratio down to just 0.2% per lens surface. The result is a dramatic improvement in both color fidelity and brightness and the elimination of flare and ghost images."
SMC was patented and first applied in 1971, when Pentax was still making screw mount equipment. The multi-coated lens lines changed from Takumar and Super-Takumar to Super-Multi-Coated Takumar and later on to SMC Takumar. SMC Pentax was used for the newly introduced K-mount lenses. Pentax's SMC is still today considered as one of the best lens coatings on the market.

Lens Specification:

Focal Length: 35-80mm
Maximum Aperture: F4-5.6
Minimum Aperture: F22-32
Image Format: 35mm
Lens Mount: PK
Optics: 7 elements, 6 groups
Blades: 6
Focussing: Auto (on Pentax)
Minimum Focus: 40cm
Filter Size: 49mm
Weight: 185g
Length: 56-72mm
Production: 1994 to 1990
Serial Number: 4466707
Made in: Taiwan

More information on Pentax

Samples:

1/60 sec - ISO800 - Handheld

1/60 sec - ISO200 - Handheld

1/60 sec - ISO800 - Handheld

1/60 sec - ISO1000 - Handheld

1/60 sec - ISO1600 - Handheld

1/60 sec - ISO5000 - Handheld

1/60 sec - ISO4000 - Handheld

1/50 sec - ISO6400 - Handheld

Sources:

Wikipedia - Pentax

Pentax Forums

flickr.com