I'm using this with my iPhone 16 Pro and Peak Design case. It works well overall. The press fit is ok but it will fall off if bumped or not fully pressed on. Over the course of a four day trip, it fell off or was knocked off twice but luckily landed on the edge and the glass didn't touch anything, so it didn't get scratched. It's a bit nerve wracking to be honest, but I've yet to find a better option that doesn't involve dedicated cases/cages to hold the filters. Luckily, it's inexpensive enough to justify using it even knowing it will eventually get scratched falling off.

As far as performance, it functions as advertised. I wish they made a stronger version of it since ND32 isn'tstrong enough for the bright midday sunlight in which I was often using it. Even ND64 would be questionable, so something like ND8-128 would be great. It also comes with a compact and easy to use case for when it's not on your phone.

In the end, it's not perfect, but I would buy another one if they made a stronger version like I mentioned above and in a similar price range. If I were using it daily, I'd probably opt for a more secure option that requires a dedicated case, but this one is fine for casual use.

Excellent filter for mobile videography! The snap-on design is secure and easy to install, and the ultra-lightweight build but cannot use it with any of my phone cases. Which makes it so I don't use it that often. The variable ND adjustment works smoothly, helping achieve more professional-looking video in bright conditions. Image quality remains sharp, and the coatings do a great job reducing glare and reflections. A must-have accessory! But I do not enjoy carrying it around wondering if I will need it.

This is the first variable ND I've used for iPhone that hasn't been terrible or required a special case to use. It fits relatively tight but isn't hard to remove. There's no light leaks which is very important. The colour shift is slightly warm, you can obviously correct your video but the image is nice enough even if you don't. There's hard stops at the beginning and end (though not the middle stops) so you won't over rotate and accidentally get an X on your video. Price is reasonable compared to competitors. It should fit with most cases that don't have huge camera lips. It works, and it works well.

The main reason it gets four stars is that the case is really large and thick for no reason. It's too big to be pocketable and is excess protection for something that should come with a nice soft microfiber case (useful for cleaning too). This is something you would want to always carry around with you, but it's not suited to be permanently attached to your phone and the case basically requires you to carry a bag.

Also ND2-32 won't cut it for the brightest of days and I find myself rarely using ND2, something like ND4-64 would probably be a better range for phone video.

Overall I'm happy to have an ND filter option for my phone that I actually like to use and can always keep in my camera bag, just not my pocket.

Works really well. And fits perfectly!!! Simple design. Very easy to use, you just stick it to the lens of the camera. Great product.!!

Great concept from K&F at a very reasonable price. Just make sure your phone case is compatible, It works with my smallrig case but its a tight fit (not a bad thing).

Great product for my use, I keep it in my pocket, ready to take a picture at anytime. Portable and convenient.

In their product description it says "(Custom-fit for 17 Pro/Max; also compatible with 16/15/14 Pro". I have an iphone 16, this is not compatible with the iphone 16. It didn't fit.

I added this K&F CONCEPT FNA01 snap-on ND2-32 filter to my iPhone 17 Pro setup and it has genuinely transformed how I capture photos and videos outdoors. The variable neutral density range (ND2-32) gives me excellent control over light, allowing me to shoot longer exposures or reduce glare in bright sunlight without overexposing highlights or losing detail in shadows. The snap-on design is incredibly convenient — it attaches securely and removes quickly without any bulky cases or adapters getting in the way. The optical quality is impressive, with minimal color shift and sharp results even when paired with the phone’s high-resolution camera. I’ve used it on everything from waterfall shots during hikes to golden-hour portraits and timelapses at the beach, and the difference in dynamic range and creative possibilities is noticeable. As someone who loves documenting family adventures and creative moments but doesn’t always want to carry a full camera kit, this filter makes professional-looking results accessible right from my phone. The build feels premium and durable, and it stores easily in my bag. For iPhone photographers who want better control over bright conditions and creative exposure effects, this K&F filter is a smart, high-quality accessory that delivers beautiful results.

Easy to install. Fits snug.

I’m a professional photographer and videographer, I sometimes use my iPhone 17 pro as a second camera, but I need to get the shutter speed down to 50th or 100th, this device helps me do this, better than I was hoping, five stars from me !!