[DavidTrap (David)]

Hi Charles,

I've got a QSI583 that I've used with various camera lenses.

I've had similar disappointing results with zoom lenses (Nikon 14-24 and 70-200). Had better results with an 85mm prime and some distortion in the corner with a 50mm prime.

My hunch is that while the physical back focus distance is correct for camera lenses, when you put a filter in the way the refractive index of the filter shortens the effective focal length sufficient to really disturb the optics of zoom lenses. The lenses came to focus a significant distance from the infinity marker on the lens. The prime lenses were less affected. I had some improvement using a 1mm spacer behind the QSI-Nikon adapter.

You've got a fairly tilted image - how are you supporting the weight of the camera / lens?

I also wonder if the image stabilization mechanism needs to be "powered up" to maintain the optics in perfect alignment? The prime lenses I used were 25 years old, so definitely manual.

Just my thoughts,

DT