Right, let’s talk about extreme photographyand an extreme ND filter. When you want to shoot the sun, you need a filter that’s ridiculously dark, and that’s where the K&F Concept ND1000000 Solar Filter comes in. I’ve just put this powerful 20-stop filter through its paces, and here is my take.

The Power of 20 Stops: Why You Need ND1000000

The '1,000,000' means this thing cuts light by a million times. It’s a 20-stop filter, which means that it halves the amount of light, 20 times! Perfect for solar photography.

It also has a fun side effect: extreme long exposures. A typical sunny-day exposure of 1/1,000th of a second magically becomes a full 1,000 seconds—about 15 minutes. It's a fantastic creative tool for making clouds vanish and water turn to glass.

An extremely dark ND1000000 solar filter by K&F Concept

The Gear: Pushing the Limits to 1,800mm

To truly test the filter's quality, I went maximum overkill:

The Lens: Sony 200-600mm ("Big Bertha")
The Reach: Sony 2x Teleconverter (takes us to 1,200mm)
The Rig: My old Sony A7 III, shooting in APS-C mode for a further 1.5x crop

That gives us an insane 1,800mm equivalent focal length. I tried to silhouette some moving leaves against the sun, but that test didn't quite work out.

Solar photography with the Sony 200-600mm lens and 2x teleconverter

Critical Safety Warning: Mirrorless Only

Perhaps the most important part…. when you point 1,800mm of glass at the sun, you are creating a fire hazard for your equipment. I asked K&F directly if this filter blocks UV and IR light, not just visible light, and they confirmed it definitely does, though they couldn't provide a certification spec sheet at the time.

My Rule of Thumb:

Mirrorless Cameras Only: Use this filter with a mirrorless camera and its electronic viewfinder. I limited my shooting to one-minute bursts to protect the sensor.
Do NOT Use on a DSLR: Never use this on a DSLR, in my opinion. The optical viewfinder is a direct path to your eye via mirrors, and you risk severe eye damage. Be safe.

Build and Performance Review

K&F is a great company that offers solid value with a "no-BS" approach.

Build: It's lightweight but not flimsy, featuring 28 nano coatings for anti-reflection, anti-ghosting, and anti-scratch protection.
Usability: It screws on perfectly with no cross-threading, and the ring is easy to grip and remove, even with my big heavy callused hands. It also comes with a nice, padded hard case.
Field Results: It performed flawlessly. I saw sunspots clearly, which was just bonkers. There was no weird vignetting and no focusing issues. The passing clouds also looked great too.

Solar flares and sunspots with the K&F concept ND1000000 solar filter

Final Verdict (and the Waiting Game)

This K&F filter is absolutely worth the money. It's a great piece of gear that performs exactly as advertised.

Now, I'm sticking it in the cupboard to wait for the next time I can use it. We've got a decent partial eclipse in the UK on August 12, 2026... but if I want to see the next total solar eclipse, I’ll need to wait until….. September 23… 2090!

I’ll set a reminder.