Head to head · specs cited · drawn to scale

Mamiya M645 1000S vs Pentax K1000

Every spec below is quoted from the makers' official pages — where a figure isn't published we say so rather than guess. Sizes are drawn at true relative scale from published dimensions, and the bag-fit row is computed against our measured bag catalog.

The 3 biggest published differences

Weight (body): the K1000 leads at 620 g vs the M645 1000S's 1570 g.
Type: M645 1000S has Medium-format SLR; K1000 has 35mm SLR.
Format: M645 1000S has 120 (6×4.5); K1000 has 35mm.

	M645 1000S Mamiya 645 mount	K1000 Pentax K
Overview
Type	Medium-format SLR	35mm SLR
Format	120 (6×4.5)	35mm
Lens mount	Mamiya M645 bayonet mount	Pentax K
Released	1976–c.1985 (M645 1000S variant)	1976-1997
Film camera
Film format	120 (6×4.5)	35mm
Metering	none in base body (meterless Waist-Level Finder S configuration; metering only via optional PD/CdS Prism Finders)	CdS TTL average metering (open-aperture, match-needle)
Shutter	Moving Coil Electronic Focal-Plane Shutter	Horizontal-travel, rubberized silk cloth focal-plane shutter, mechanical
Shutter speeds	B, 8 – 1/1000 sec	B, 1 sec to 1/1000 sec; flash X-sync 1/60 sec
Battery	One 6V silver-oxide battery (4SR44) or 6V alkaline (4LR44) — powers the electronic shutter, not required for metering in this configuration	1x LR44/SR44 1.5V (meter only; camera fires all speeds without battery)
Body & Handling
Dimensions (W×H×D)	99.3 × 100 × 166.5 mm	143 × 91.4 × 48 mm
Weight (body)	1570 g	620 g
Weather sealing	—, not published	—, not published
Shutter durability	—, not published	—, not published
Price
Launch price	—, not published	—, not published
Size, to scale
Front view, drawn at the same scale from each maker's published W×H (mm).
Smallest bag that fits
Body	Think Tank Retrospective 4 V2.0 Fits body only · View at B&H Photo Video	Think Tank Mirrorless Mover 20 V2 Fits body only · View at B&H Photo Video

Sources

official · M645 1000S specifications: Mamiya M645 1000S original instruction manual (scan, Scribd-hosted; same manual as butkus.org/focale22.com scans) · accessed 2026-07-10

“Dimensions and Weight: (width, height, depth, w/80mm f/1.9 lens) (w/Waist-Level Finder S) (w/1.9 lens) 3-29/32" x 3-15/16" x 6-9/16" 55.4 oz (99.3 x 100 x 166.5mm) (1570 g) ... Standard Lenses: Mamiya-Sekor C (multi-coated) 80mm f/1.9, automatic diaphragm, with meter coupler, 67mm filter size”

official · K1000 specifications: Wikipedia (figures consistent with widely-cited manual dimensions; original manual PDFs at butkus.org/cameramanuals.org/ManualsLib are scanned images with no extractable text, and no official Pentax/Ricoh museum spec page could be located) · accessed 2026-07-10

“It is 91.4 millimetres (3.6 inches) tall, 143 mm (5.6 in) wide, and 48 mm (1.9 in) deep, and weighs 620 grams (21.9 ounces).”

K1000 dimensions carry medium confidence (archived-source caveat on its fit page).

Open in the comparator (add a 3rd/4th body) Bags for the M645 1000S Bags for the K1000 Fit checker

Spec values are the manufacturers' published figures, compared factually — we don't rank cameras. Fit verdicts are planning estimates from published interior dimensions, not guarantees. See methodology.

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