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Originally posted by dambu1 My Tamron Aspherical XR DiII SP 17-50mm has started producing images like the attached. I can't see any damage and it isn't making any strange noises. Any idea what could be causing this (or how to fix it)?
If you're referring to the vignetting (the black circle covering the corners of the image), it's because you are using a crop lens on your full frame camera. The lens doesn't make a large enough image circle to cover the whole sensor.
But your K1ii has a crop mode, or a 1:1 aspect mode (square image). Either of those will give you results that crop out that vignetting.
They will be lower resolution than the camera would be able to create with a full frame lens, but that is the best you can get with an APSC lens (DA lenses from Pentax, DC lenses from Sigma, or Di II lenses from Tamron (like yours)) on your FF camera. The lenses are designed this way assuming they will be used on an APSC camera (like a K3 or K70, or well, any Pentax that's not a K1 or a film camera), and it allows them to be smaller and lighter than FF lenses.
You'll probably want your K1ii in crop mode.
To switch between crop and FF mode without menu diving, you can use the wheels on the top of the camera.
Set the function dial (the one on the right side with writing on it) to crop. Then turn the setting dial (the one on the top that has no writing) while looking through the viewfinder and it will cycle between the three options. Thick black lines in the viewfinder will indicate whether you are in crop, square, or full frame mode (no lines in full frame mode; it's the whole viewfinder).
There are other ways to change this, including a setting to have the camera automatically detect when a crop lens is mounted on the camera and make the switch automatically.
That setting is in the second page of the menu as "Crop," and you probably would want it set to "Auto." I suspect it's set to "FF" right now, given the results you're getting.
Your final option is just to crop them out yourself on the computer before printing or uploading your pictures, and how you do this will depend on what software you use, but it's usually quite simple in any software I've seen. Be aware that some of the areas just inside the edges of the black circle will have an image, but not be super sharp.