Rating: 4/5Things I like:-Extremely bright full power output-Quiet zoom operation-Sturdy build quality-Straightforward operation-Includes high quality carrying case-Functional high speed sync-Sub 3 second recycle time with beep feedbackThings I don’t like:-Lack of i-TTL / e-TTL mode and automatic zoom-Light output doesn’t fill the frame evenly-No master wireless modeSummary: The KF-570ii is quite a good piece of kit with a decent build quality and bright output. This flash has a lot of power, but it tends to be focused on the center of the image. This means that the flash would be best used in a studio setting as a manual remote flash with a diffuser such as a softbox. You must understand what you are purchasing before you buy: this is a fully manual flash, meaning it will not automatically determine exposure. If you can find a use for a fully manual flash this is a good product to consider.-------Full Review::Build Quality & AppearanceThe KF-570 flash is well built, with a solid plastic frame, smooth head rotation and springy buttons. It doesn’t have much in the way of weatherproofing, but I see a fully manual flash as more of an indoors/studio kit anyways. The screen is easy to read with a bright backlight but only contains minimal information (power output level, zoom and mode). One thing that really stood out to me is how quiet the zoom motor is. I’ve got a few budget flashes lying around and the zoom motor on all of them are at least twice as loud. The quiet motor makes the flash feel a lot higher quality and inspires confidence in its longevity.::FeaturesThe KF-570 is about as basic as they come in terms of features – it is fully manual, meaning no TTL, no automatic zoom and no autofocus assist light. Because of its simplicity, the flash is very easy to operate and the buttons are minimal. It’s straightforward enough to just set up and go. On the plus side, this flash would make a good slave as its wireless mode works flawlessly and it puts out a nice loud indicator beep to let you know when it is recharged. Power can be adjusted in full steps or 1/3 incraments and the zoom ranges from 18mm – 180mm, though at wide angles the light does not fill the entire frame (see ‘power output’ for more information). The head can be tilted 90 degrees and rotated a full 180 for bounce. There’s no button to depress to rotate/tilt, it just goes with a little force.::Power OutputThe flash has bright output, brighter than both my mid-range Nikon and Neewer kits. Unfortunately this comes at a price, with a large hot-spot in the center of the frame. When the flash is zoomed in, the hot spot is far more noticeable, with the light being very focused in the center of the frame. Using the flash at its widest zoom setting with a 50mm lens would fill the frame, but with a 24mm lens and the flash set at 24mm there is a significant vignette effect. Zoomed in past 50mm and the effect goes away, though taking a wide angle photo with the flash zoomed in shows just how bad the effect is. The Nikon and Neewer flash still manage a smooth circle of light whereas the K&F flash has much more scattered hot spots (see attached photo). This flash would be best used in a studio setting with a soft box or other diffuser. Also, the bright output combined with high speed sync makes this a good flash to use in bright daylight situations. Note that the camera is set to the same settings on both the images compared below.::Other NotesThe included carrying case is excellent quality and the flash also comes with a plastic diffuser cover as a nice bonus.::ConclusionA fully manual flash is good for a beginner who would like to learn more about how cameras work or for professionals who are operating a wireless or studio setting where lights do not need to be adjusted often. It’s not as useful in situations where time is of the essence – for example, portrait or event photography. The K&F Concept KF-570ii is a well built flash with a strong output, but the lack TTL function is disappointing.Robert D.DrekiTechPlease note: I received a discount on this product in exchange for an honest review.