Glass Bodies a variant-level encyclopedia of vintage lenses and cameras by iwillpat

SMC Pentax-A / FA 645 45mm f/2.8

Pentax · Pentax 645 · 1984

Also known as: SMC Pentax-A 645 45mm f/2.8 · SMC Pentax-FA 645 45mm f/2.8 · smc PENTAX-A 645 45mm F2.8 · smc PENTAX-FA645 45mmF2.8 · Pentax 645 45mm f/2.8 · Pentax 645 45/2.8 · Pentax-A 645 45mm · Pentax FA 645 45mm · ペンタックス 645 45mm F2.8 · smc PENTAX-A 645 45mmF2.8

Variants & identification

Variant Mount Years Serial ranges Production
SMC Pentax-A 645 45mm f/2.8 (manual focus, 1984) Pentax 645 1984 — —
SMC Pentax-FA 645 45mm f/2.8 (autofocus, 1997) Pentax 645 1997 — —
  1. A-version figures are from the PentaxForums lens database and camera-wiki (citing Popular Photography, June 1984); FA-version figures from Ricoh Imaging's Japanese and US spec pages. Both are 9 elements in 8 groups; the 75 g difference is the autofocus barrel.
  2. No launch price in yen or dollars was found for either version. Ricoh Imaging USA's current $1,299.95 for the FA is not a launch figure and is not entered as one.
How to tell them apart (expand)
  • A or FA after PENTAX on the front ring: A is manual focus with a screw-in hood, FA has a screwdrive coupler, a push-pull AF/MF ring and a bayonet hood
  • Both versions: 67 mm filter, 66.5 mm long, f/2.8 to f/22, 0.45 m closest focus, 8 blades, A position on the aperture ring
  • 400 g is the A, 475 g the FA

SMC Pentax-A 645 45mm f/2.8 (manual focus, 1984):

  • Engraved smc PENTAX-A 645 1:2.8 45mm; metal barrel; no AF/MF switch and no screwdrive coupler in the mount
  • 67 mm filter thread with a screw-in RH-RA 70 mm hood and S80-120 case (PentaxForums)
  • 400 g and 74 × 66.5 mm (PentaxForums; camera-wiki, citing Popular Photography, June 1984)

SMC Pentax-FA 645 45mm f/2.8 (autofocus, 1997):

  • Engraved smc PENTAX-FA 645 1:2.8 45mm; screwdrive AF coupler in the mount and a push-pull AF/MF focusing ring; the focusing ring does not turn during autofocus (PentaxForums)
  • Bayonet PH-RBC67 hood and S90-100 case supplied; 76.5 × 66.5 mm and 475 g, heavier than the A (Ricoh Imaging)
  • Product code 26335 (Ricoh Imaging USA)

Specifications

Construction
9 elements / 8 groups
Aperture range
f/2.8–f/22
Diaphragm blades
8
Min. focus
0.45 m
Dimensions
74 × 66.5 mm
Weight
400 g
Filter
67 mm
Years manufactured
1984
Country
Japan
Coating
SMC (Super Multi Coating) on both versions

What reviewers say

History

The 45mm f/2.8 is the moderate wide angle of the Pentax 645 line, launched with the camera in 1984 and covering a field a little wider than a 28mm on 35mm film. The PentaxForums lens database and camera-wiki’s table (which cites Popular Photography, June 1984) agree on the figures: 9 elements in 8 groups, f/2.8 to f/22, 0.45 m closest focus at 0.15×, eight blades, a 67 mm filter thread, 74 × 66.5 mm and 400 g, with a screw-in RH-RA 70 mm hood. Japanese Wikipedia gives the same construction and notes the A 645 lenses’ mount contacts for the body’s program and shutter-priority modes.

The FA version of 1997 kept the glass. Ricoh Imaging’s spec page lists 8群9枚, F22, 8 blades, 0.45 m, 0.15× and 67 mm for the smc PENTAX-FA645 45mmF2.8, and Japanese Wikipedia lists the same construction for both; what changed is the barrel, which gained a screwdrive coupler, a push-pull AF/MF focusing ring that does not rotate during autofocus, a bayonet PH-RBC67 hood in place of the screw-in one, and 75 g, to 475 g at 76.5 × 66.5 mm. An A lens on the 645N or NII is manual focus; an FA on the 645 is the same. Ricoh USA still lists the FA at $1,299.95; the Japanese site marks it discontinued without a date.

This is the one 645 prime reviewers argue about. On PentaxForums the A averages 8.86 over eight reviews and the FA 8.33 over nine, the lowest of the 645 primes there; Pål Jensen calls the FA the most flare-prone Pentax lens he has used and no better than the zooms that cover 45mm, and a reviewer of the 35mm calls the 45 “not so great” in passing. The defenders answer in the same threads: the centre is good from f/4, the corners arrive by f/8, a hood is essential, close-range bokeh is unusually pleasant for a wide angle, and it is fast, light and cheap, which is why Skycreeper and pepperberry farm both say it is better than its reputation. Richard L. finds his A copy sharp corner to corner at f/9 and suspects the production varied. Todd Reed on Emulsive shot the A 45 for landscape and mission architecture and published the results without a verdict.

What to check: veiling flare and ghosting into the light, which every critic mentions, so test with the sun near the frame and insist on the hood; a loose aperture ring on the A (reported by one owner); AF accuracy on the FA, which one 645Z owner had to fine-tune; and the usual haze and fungus in a lens now thirty to forty years old. No launch price in yen or dollars was found for either version.

Expand Collapse

This history is AI-written, from the sources listed at the foot of the page. Where the record is silent it says so rather than filling the gap — but no human wrote these sentences.

Example photos

Sample photo taken with the SMC Pentax-A / FA 645 45mm f/2.8
SMC Pentax-A 645 45mm f/2.8 — Hiyotada, via Wikimedia Commons (CC0)
Sample photo taken with the SMC Pentax-A / FA 645 45mm f/2.8
Pentax 645NII with the SMC Pentax-FA 645 45mm f/2.8 — Nick4Penta, via Wikimedia Commons (Public domain)
Sample photo taken with the SMC Pentax-A / FA 645 45mm f/2.8
Pentax 645, SMC Pentax-A 645 45mm f/2.8, Fujifilm NPS 160 (Kurt Bauschardt) — Kurt Bauschardt, via Wikimedia Commons (CC BY-SA 2.0)

Sample photo wanted — shot with a SMC Pentax-A / FA 645 45mm f/2.8? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $250 across 29 fixed-price listings on 2026-09-19 (middle half $220–$320). First day tracked.

Asking prices from the listings scanned, not sales; junk-flagged rows and auction lots excluded; other currencies are not converted.

Show 35 more listings

Buying from Yahoo! Auctions outside Japan. It is a domestic marketplace: sellers ship within Japan, and most will not register an overseas buyer. A proxy service bids on your behalf, receives the item and forwards it, for a fee and a wait. Buyee, Jauce and ZenMarket each accept a Yahoo auction number directly. Listed alphabetically for information — none is recommended over another, and none of these is an affiliate link.

Listings updated 2026-09-19. Links go to the shop or marketplace that carries the item.

Related: SMC Pentax-A 645 150mm f/3.5 · SMC Pentax-A / FA 645 35mm f/3.5 · SMC Pentax-A / FA 645 75mm f/2.8

Sources (8)

Every page here is assembled from public sources, and the gaps are real ones. If you own this lens, know a serial number I'm missing, or can see where I have it wrong, tell me — corrections, serials and sample photos are all worth having.