Playing With Lenses: Back to the Roots (1): SMC Pentax-A F4 35-70mm

Monday 13 May 2019

Back to the Roots (1): SMC Pentax-A F4 35-70mm

Cost: 28$ (average market price $44.92)

Back to my roots for 2 reasons... First, we are looking at another Pentax lens, the core or the roots of my collection, and secondly as I was shooting in my birthplace, Turnhout, in Belgium (except the first sample picture).

This lens if the only Pentax 35-70mm zoom lens with a fixed aperture of F4 across the whole zoom range. It also has the reputation to be the best one of that era. And it shows... nice colors and sharp across all apertures. And no signs of any color aberration. Pretty decent image quality for a zoom lens of this era.

The look of the lens is nice. It's not all metal, but it does feel solid and shows good quality. Zoom is butter smooth, and the aperture ring has a nice "click".

I truly like this zoom range, now that I made the step to Full Frame. From a nice wide angle to just beyond the human angle of view. On APSC, this would almost be a 50mm lens, so missing the wide angle features. In short, nice lens to take with you on a walkabout, but on a known place or as a tourist.

This is a keeper and will have a good spot in my collection, and will even be used now and then.

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: 35-70mm
Maximum Aperture: F4
Minimum Aperture: F22
Image Format: 35mm
Lens Mount: PK
Optics: 7 elements, 7 groups
Blades: 6
Focussing: Manual
Minimum Focus: 25cm
Filter Size: 58mm
Weight: 330g
Length: 80mm
Production: 1984 to 1985
Serial Number: 5590739
Made in: Japan

More information on Pentax

Samples: