I got the K&F Concept 100mm Handheld Diopter Filter to expand my creative toolkit, and it delivers compelling effects. This filter, often referred to as a "split diopter," allows for a portion of the image to be in focus while another part is intentionally blurred or refracted, creating unique foreground and background effects.

**Design and Material Feel:** The filter is well-made with what appears to be high-quality optical glass. The handheld design feels comfortable, allowing for easy manipulation during a shoot. The construction feels sturdy and durable, which is important for a filter that will be actively moved during use.

**Ease of Movement and Use:** The handheld aspect of this filter is what makes it stand out. It provides incredible flexibility to position the diopter exactly where you want the split focus or blur effect. While it takes some practice to master, the freedom it offers for artistic compositions is exceptional. I especially appreciate how it lets me experiment with different angles and placements to achieve varied visual results in-camera.

**Sturdiness:** The filter feels solid, and the handle is securely attached. I have confidence in its build quality, even with regular handling.

**Room for Improvement:**
* Achieving a precise and consistent effect can be challenging, requiring a fair amount of trial and error.
* Like any handheld filter, it requires a free hand, which can sometimes limit other camera adjustments.

### Tips & Uses:
* **Selective Focus and Blur:** Ideal for creating a distinct plane of focus while blurring foreground or background elements, adding depth and artistic flair.
* **Dreamy Effects:** When used creatively, it can introduce soft, dreamy refractions, particularly effective in portraits or landscapes.
* **Abstract Photography:** Play with the filter's placement and the scene's elements to generate intriguing abstract compositions with unique light refractions and distortions.

As an exclusive contributor to a prominent stock media agency with 25 years of experience in freelance photography and videography, I offer informed and professional opinions of camera and video equipment.

I will update this review if anything changes within 1 year. A 5-star rating indicates the product meets my expectations for its purpose.