Lens · prime
SMC Pentax-A 50mm f/1.4
Pentax · 1984-1989
Vintage35mm
Pentax's fast 50mm with program mode compatibility. The 'A' aperture setting enables automatic exposure control while retaining full manual capability. SMC Pentax-A 50mm f/1.4: 7 elements in 6 groups, 8 aperture blades, 0.45m minimum focus, 49mm filter thread, 235g.
- Focal length
- 50mm
- Max aperture
- f/1.4
- Mount
- Pentax K
- Format
- 35mm
- Elements / groups
- 7 / 6
Known for
- Low light photography
- Portraits
- Program mode use
- Available light
Considerations
- Some vignetting wide open
Optical characteristics
Silverlog's editorial rating: our own judgement, not measured data.
Sharpness (wide)4, level 4 of 5
Sharpness (stopped)5, level 5 of 5
Contrast5, level 5 of 5
Flare resistance5, level 5 of 5
CA control4, level 4 of 5
Vignetting control3, level 3 of 5
Distortion control5, level 5 of 5
Bokeh: Smooth 8-blade rendering
Rendering: Classic fast 50 character
Colour: Neutral, accurate
Silverlog's editorial rating, 1 to 5; five is best. Not lab-measured.
Common issues
- Focus ring stiffness
- Aperture blade oil
Buying guide
Common A-series fast 50. Check aperture operation.
Specifications
| Mount | Pentax K |
| Focal Length | 50mm |
| Max Aperture | f/1.4 |
| Min Aperture | f/22 |
| Aperture Blades | 8 |
| Min Focus | 0.45m |
| Filter Size | 49mm |
| Weight | 235g |
Optical design
| Formula | Double Gauss |
| Elements | 7 |
| Groups | 6 |
| Coating | SMC (Pentax) |
Pricing
- Typical used price
- £60 - £120
- Mint
- ~£160
Indicative, no dated source.