FIELD GUIDESource-led reference
Port & Cable

P139 / Memory cards / Guide

Read a camera card-slot map correctly

Alternative families in one slot do not create extra slots.

The useful distinction

The worksheet does not guess which slot you use. Changing the camera clears the slot selection; an unspecified slot is not a pass.

Claim inspection dates: 2026-10-03, 2026-10-08 · Independent review pending

Guide note · not an individual product specification

The useful distinction

Understand the requirement.

A shared opening and two separate openings are different physical arrangements. [C139A]

Nikon Z 8 documents a CFexpress/XQD slot and a separate SD slot. [C139B]

The MRW-G2 instructions show CFexpress Type A and SD as alternatives in the reader’s shared slot and prohibit inserting two memory cards into that slot at the same time. Two supported families are not two independent openings. [C139C]

RDF8 documentation disagrees about simultaneous insertion: EN_RDF8_PS_1905 allows two cards on page 1 but says simultaneous two-card insertion is unsupported on page 2; Transcend-RDF8 describes three on page 1. This reference leaves concurrent operation unresolved. [C139D]

Bounded facts, visible unknowns

Specifications and limits

Read a camera card-slot map correctly facts and limitations
Scoped documentationSony ILCE-7M4 Slot 1 accepts CFexpress Type A or SD; Slot 2 accepts SD. [C139A]
Scoped documentationNikon Z 8 documents a CFexpress/XQD slot and a separate SD slot. [C139B]
Documented distinctionThe MRW-G2 instructions show CFexpress Type A and SD as alternatives in the reader’s shared slot and prohibit inserting two memory cards into that slot at the same time. Two supported families are not two independent openings. [C139C]
Documented distinctionRDF8 documentation disagrees about simultaneous insertion: EN_RDF8_PS_1905 allows two cards on page 1 but says simultaneous two-card insertion is unsupported on page 2; Transcend-RDF8 describes three on page 1. This reference leaves concurrent operation unresolved. [C139D]
Verified device listNot included. Check exact device and accessory documentation.
A boundary, not an omission to guess around.

The directory does not inspect, reserve or configure physical slots. A selected documentation path cannot prove which media is inserted in your own camera.

Before you connect

What to check

  1. Select the exact camera and the specific slot.
  2. Record whether supported families share one opening.
  3. Check recording-mode requirements separately from family support.
Trace a supported connection class →

Your next step

Move from the form to the requirement.

Compare this field note See the differences without assuming interchangeability.Work through a connection Choose your task before deciding on a cable.Explore this evidence trail Inspect the claims and their dependencies. (private workspace)

The source trail

Evidence for this page

AI-assisted inspection is not independent engineering review. Source scope and access limitations are disclosed below. Procedural checklists are editorial requirements, not hardware measurements.

C139ASource checked · pending review

Sony ILCE-7M4 Slot 1 accepts CFexpress Type A or SD; Slot 2 accepts SD.

Sony · ILCE-7M4 inserting and removing a memory card ↗

Locator: Slot 1 and Slot 2 instructions
Access: public page. Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

S117: full source recordInspect review dependencies → (private workspace)

Claim scope: Exact documented product and family scope; no physical test, exact-card certification or end-to-end approval.. Next review due 2027-01-01.

C139BSource checked · pending review

Nikon Z 8 documents a CFexpress/XQD slot and a separate SD slot.

Nikon · Z 8 inserting memory cards ↗

Locator: Inserting Memory Cards; removal warnings
Access: public page. Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

S118: full source recordNikon · Z 8 approved memory cards ↗

Locator: Approved Memory Cards
Access: public page. Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

S119: full source recordInspect review dependencies → (private workspace)

Claim scope: Exact documented product and family scope; no physical test, exact-card certification or end-to-end approval.. Next review due 2027-01-01.

C139CSource checked · pending review

The MRW-G2 instructions show CFexpress Type A and SD as alternatives in the reader’s shared slot and prohibit inserting two memory cards into that slot at the same time. Two supported families are not two independent openings.

Sony · MRW-G2 Operating Instructions — 5-019-283-B1 (1) ↗

Locator: PDF page 1, English compatible cards, precautions, specifications and illustrations A–C; printed identifier 5-019-283-B1 (1).
Access: public pdf text. All cards and computers are not guaranteed. Drawing interpreted for this reader only; no manufacturer artwork copied, no card geometry or current OS certification adopted.

S438: full source recordInspect review dependencies → (private workspace)

Claim scope: PDF page 1 English precautions and illustrations B/C; applies only to MRW-G2.. Next review due 2027-01-06.

C139DSource checked · pending review

RDF8 documentation disagrees about simultaneous insertion: EN_RDF8_PS_1905 allows two cards on page 1 but says simultaneous two-card insertion is unsupported on page 2; Transcend-RDF8 describes three on page 1. This reference leaves concurrent operation unresolved.

Transcend · RDF8 product sheet — Transcend-RDF8.pdf ↗

Locator: PDF pages 1–2 visually inspected; card slots, Compatibility, Performance, Ordering Information and three-card insertion wording. No printed revision identifier.
Access: public pdf text. Concurrent-operation wording is compared with S440 and remains unresolved. Document age or hardware revision is not inferred from a filename. No measured aggregate transfer, exact-card or OS certification.

S439: full source recordTranscend · RDF8 product sheet — EN_RDF8_PS_1905.pdf ↗

Locator: PDF pages 1–2 visually inspected: page 1 Additional Features, page 2 Operating Environment Note and Compatibility. Page 3 multi-product comparison not adopted.
Access: public pdf text. Page 1 allows two-card insertion while page 2 says it is unsupported. Kept as an unresolved documentation conflict, not a chosen device capability. Filename is not treated as a verified revision date.

S440: full source recordInspect review dependencies → (private workspace)

Claim scope: Explicit comparison of the two cited PDFs; no manufacturer clarification or hardware revision mapping is inferred.. Next review due 2027-01-06.

Suggest a correction to this field note →

Common questions

Questions this record can help resolve

Do two supported card families mean two usable slots?Distinguish alternative cards, physical slots, insertion and simultaneous access.

Put this checklist to work.

Choose the exact card family, reader and optional camera slot. Documentation stays separate from physical testing.

Open the card-reader worksheet →

Evidence behind this page

Scope first. Source second. Approval separate.

6 linked sources · 4 scoped claims · 0 sources with inspection/access flags.

Page scope: consumer_reference_expansion

Assessment 2026-10-22 · earliest scheduled source review 2027-01-01. This is a recorded-date assessment, not a live source check. Page-level independent review is not established by this panel.

Inspect 6 source scopes, access limits and dates

S117 · ILCE-7M4 inserting and removing a memory card

Sony · Manufacturer / product-owner domain · inspected 2026-10-03 · due 2027-01-01

Within inspection window

Scoped support: Slot 1 accepts CFexpress Type A or SD; Slot 2 accepts SD. Alternatives in Slot 1 refer to one physical slot, not two simultaneously occupied slots.

Not established / limitations: Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

Locator: Slot 1 and Slot 2 instructions

S118 · Z 8 inserting memory cards

Nikon · Manufacturer / product-owner domain · inspected 2026-10-03 · due 2027-01-01

Within inspection window

Scoped support: Z 8 has one CFexpress/XQD slot and one SD slot. Manufacturer instructions require attention to power, the access indicator and card temperature when handling media.

Not established / limitations: Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

Locator: Inserting Memory Cards; removal warnings

S119 · Z 8 approved memory cards

Nikon · Manufacturer / product-owner domain · inspected 2026-10-03 · due 2027-01-01

Within inspection window

Scoped support: Z 8 documentation identifies CFexpress Type B, XQD and SD-family media. Exact card qualification and recording requirements remain a separate manufacturer check.

Not established / limitations: Documentation-only family and port scope; no physical test, current stock or price check, measured performance, complete card list, or independent approval.

Locator: Approved Memory Cards

S438 · MRW-G2 Operating Instructions — 5-019-283-B1 (1)

Sony · Unclassified publisher domain · inspected 2026-10-08 · due 2027-01-06

Within inspection window

Scoped support: MRW-G2 shared-slot alternatives, Sony card-family wording, USB interface and supplied-cable limitations.

Not established / limitations: All cards and computers are not guaranteed. Drawing interpreted for this reader only; no manufacturer artwork copied, no card geometry or current OS certification adopted.

Locator: PDF page 1, English compatible cards, precautions, specifications and illustrations A–C; printed identifier 5-019-283-B1 (1).

S439 · RDF8 product sheet — Transcend-RDF8.pdf

Transcend · Manufacturer / product-owner domain · inspected 2026-10-08 · due 2027-01-06

Within inspection window

Scoped support: TS-RDF8K2 / TS-RDF8W2 selected media slots, CompactFlash UDMA7, SD/microSD UHS-I, USB 3.1 Gen 1 description.

Not established / limitations: Concurrent-operation wording is compared with S440 and remains unresolved. Document age or hardware revision is not inferred from a filename. No measured aggregate transfer, exact-card or OS certification.

Locator: PDF pages 1–2 visually inspected; card slots, Compatibility, Performance, Ordering Information and three-card insertion wording. No printed revision identifier.

S440 · RDF8 product sheet — EN_RDF8_PS_1905.pdf

Transcend · Manufacturer / product-owner domain · inspected 2026-10-08 · due 2027-01-06

Within inspection window

Scoped support: TS-RDF8K2 / TS-RDF8W2 UHS-II cards at UHS-I speeds and contradictory simultaneous-insertion wording.

Not established / limitations: Page 1 allows two-card insertion while page 2 says it is unsupported. Kept as an unresolved documentation conflict, not a chosen device capability. Filename is not treated as a verified revision date.

Locator: PDF pages 1–2 visually inspected: page 1 Additional Features, page 2 Operating Environment Note and Compatibility. Page 3 multi-product comparison not adopted.

Trace 4 claims to their source records

C139A · P139

Sony ILCE-7M4 Slot 1 accepts CFexpress Type A or SD; Slot 2 accepts SD.

Claim scope: Exact documented product and family scope; no physical test, exact-card certification or end-to-end approval.

Source links: S117 · Evidence trail → (private workspace)

C139B · P139

Nikon Z 8 documents a CFexpress/XQD slot and a separate SD slot.

Claim scope: Exact documented product and family scope; no physical test, exact-card certification or end-to-end approval.

Source links: S118 · S119 · Evidence trail → (private workspace)

C139C · P139

The MRW-G2 instructions show CFexpress Type A and SD as alternatives in the reader’s shared slot and prohibit inserting two memory cards into that slot at the same time. Two supported families are not two independent openings.

Claim scope: PDF page 1 English precautions and illustrations B/C; applies only to MRW-G2.

Source links: S438 · Evidence trail → (private workspace)

C139D · P139

RDF8 documentation disagrees about simultaneous insertion: EN_RDF8_PS_1905 allows two cards on page 1 but says simultaneous two-card insertion is unsupported on page 2; Transcend-RDF8 describes three on page 1. This reference leaves concurrent operation unresolved.

Claim scope: Explicit comparison of the two cited PDFs; no manufacturer clarification or hardware revision mapping is inferred.

Source links: S439 · S440 · Evidence trail → (private workspace)

Prepare this page for review → (private workspace)Read the evidence method →

Recorded evidence only. An inspection date, publisher label, source link or generated packet is not independent technical review, hardware testing, fabrication approval or a compatibility verdict.