What the S5 Protection Lens Cap actually protects

The NiSi S5 Protection Lens Cap is designed to attach to a NiSi S5 150mm holder's adapter ring when the kit's filter holder is removed. In that position, it covers the built-in S5/S6 Circular Polariser (C-PL) that stays mounted on the adapter ring. The cap also works with or without the C-PL in place, and it is compatible with the S6 holder.

That means you can keep the adapter ring on your lens between shots instead of removing the whole assembly. The cap then acts as a barrier against scratches and dust while the C-PL remains installed.

How to fit the cap for everyday protection

Follow these steps when you want to leave your S5 or S6 adapter ring on the lens and protect the C-PL between shooting sessions.

  1. Remove the filter holder: Detach the S5 150mm filter holder from the adapter ring. The cap is designed to attach to the adapter ring once the holder is off.
  2. Leave the adapter ring on the lens: You do not need to remove the S5/S6 adaptor ring from the lens. The cap fits over the ring in this state.
  3. Leave the C-PL mounted if you wish: The cap works with the C-PL installed on the adapter ring, so you can avoid removing and refitting the polariser after each use.
  4. Attach the cap: Place the NiSi S5 Protection Lens Cap onto the adapter ring. It is compatible with both S5 and S6 holders.

When this cap earns its place in your bag

If you often switch between shooting and moving with your 150mm square filter system still assembled, the cap saves you from repeatedly removing the C-PL and adapter ring. That reduces handling of the polariser and keeps dust away from its surface. It is also useful when you store the holder kit between locations and want the adapter ring and C-PL protected without disassembly.

The cap is not a replacement for a filter pouch or a full case for the holder itself. It covers the adapter ring and C-PL area only. The supplied information does not state whether the cap seals against water or impacts, so treat it as dust and scratch protection rather than a rugged travel case.

Product facts for the NiSi S5 Protection Lens Cap

One limitation to keep in mind

The supplied product information does not include care instructions, safety warnings, or operating steps beyond attaching the cap to the adapter ring. If you need guidance on cleaning the C-PL or storing the full holder, check NiSi's documentation for those procedures rather than assuming the cap provides additional protection.