The attached frame is during a controlled shoot inside with two soft boxes. I hope you notice the spots against the black background in the attachment. I had cleaned my UV filter before using. Is it dirt on the lens, inside the lens or some other abnormality?

It looks to me like dried water droplets on the lens, or on the uv filter you had cleaned. Sometimes I've had trouble cleaning those kind of droplets off, not only my cameras, but also my eyeglasses, scuba masks, etc. By trouble I mean thinking that I've gotten it all off, because the dried droplets can be hard for me to see. I doubt that it's inside the lens.

You weren't filming near the ocean were you? Sweat droplets are similar since they are both salt water.

Looks like something on the lens, Likely an outer surface, and it maybe very subtle.

The issue is that the depth of field is so large, and the outer most optical path surface so far from the the center of the lens, anything on the surface can leave a blurred artifact in the image, especially if brignt direct or reflected light hits the spot. The black background is perfect for bringing it out.

The problem is my Hoya UV Filter. Many people complain about difficulty in cleaning Hoya. If someone knows a way to clean the Hoya filter I would appreciate a solution. The only other alternative is no filter.

I've got Hoya's on both my XL1s and XH A1.

I just use a solvent spray from my optician, designed for cleaning spectacle lenses and the cloth that comes with every pair of glasses I've ever owned (which is quite a few).

Works for me, no spots, no smears, no scratched coating, nada.


CS

The reason I stopped using UV filters was this. Like a reflection on the lens. That's what it looks like to me.
Bill

I purchased a liquid that takes off most of the spots on my UV filter but I am going to go with Bill's advice. No filter.

Install a filter only when you need it for sure for lens protection, such as wild parties with spraying carbonated liquids or close shots of babies enjoying their meals