Ultimaxx 420-800mm (840-1600) f/8.3-16 HD Telephoto Zoom Lens for Nikon D3300, D3400, D3500, D5000, D5200, D5300, D5600, D7200, D7500, D750, D850, D500, & More Digital SLR Cameras

FYI, there is no iris or f-stop ring on this lens, f-stops listed are only at the different zoom positions.Camera and assembly.1) Confirmed D5100 camera was working with Nikon lens before evaluating.2) Adapter mated to lens and camera without issue.3) D5100 complained "No Lens Present" but could monitor zoom and focus through eyepiece OK.D5100 would NOT raise the mirror to use the display screen as it could with the Nikon lens.a) Re-Installed Nikon lens to re-check and display screen worked without issues.b) Apparently, the lens being completely manual, or no Nikon compatable contacts, that is preventing the use of the display screen.Lens seemed to zoom and focus without any issues.Viewfinder image was a little dark but could be attributed to the f-stop being listed from 8.3 to 16, depending on zoom.When checking the lens stacked with the 2x adapter, I noticed vignetting in the corners of the viewfinder.a) Removed the 2x adapter to check the lens by itself to investigate the source.b) Lens alone, at the lowest zoom (420mm) viewfinder was fine but vignetting increased as zoom was increased to maximum (800mm).c) Re-installing the 2x adapter there was Vignetting at the lowest zoom, at the highest zoom it was worse (darker, more of the image) than the lens alone.

Vignette highly defined in edges of full frame camera. It is not full frame lens.2x multiplier low quality build. Received damaged but after seeing how it was made was not worth requesting replacement.Amazon shipping needs a class in how to ship camera gear. Third lens I have received in past couple weeks where it was put in paper or plastic bag without any padding, bubble wrap or protection. That is not reseller issue. It is serious warehouse issue but there is no longer way to contact on website to file complaint.

The color isn't quite as vibrant as you would get with a professional telephoto lens, the photos taken with this lens are very good quality. The lens itself is well built with precision parts and the 2X extender is decent quality as well. I found that shooting with a 1600mm lens requires a sturdy tripod and a remote shutter release. At that magnification even the slightest touch pressing the camera button will blur the image.You could also use the delayed shutter release option if your camera has that feature. I find an inexpensive remote easier to use. I've uploaded some photos for review. First one in a Nikon 300mm lens, the rest are with this 420-800mm lens at different zooms. Pretty good quality for such a reasonable price.

Spent 2 days trying to calibrate it. The focus area when it does happen is too small to be effective. ( i have a shorter lens that I can Blow up the photo and just just as good if not better resolution at the bottom of this lens(400-500mm).The lens is so subject to vibration that extened you need to shoot only in bright sunlight, very stable tripod or platform, use a remote, shutter up, and most importantly shutter speed around 1/1000 or higher.Not sure what I will do with it.

Unable to focus. Converter doesn't attach to my other lenses. I will be returning this purchase when I get the return information. Thank you