They seemed to have a negative impact on AF.
Hi - What were you getting?
Soft images. I was getting soft images from the EF 100-400 f/4.5-5.6L IS II USM lens. I was shooting birds-in-flight, BIF, photos with brightly lit, partially cloudy skies. I wanted to capture some of the detail in the clouds. It is not that the shots were OOF, because in a way they were. The sharpest part of the images were where the locked and active AF point was located.
The images were just simply not razor sharp. I tried a couple of different bodies with pretty similar results. I had tried a 6D, 1D4, and a 7D2. Of course, I captured different shots with each camera, but the results were consistent.y soft, with the sharpest area being the acting AF point.
That is when I noticed the protective CP filter and removed it. Problem solved. Now, the only filters I use on my lenses are Clear filters. With the exception of an ND filter, you can reproduce the effects of most filters in post. ND filters can dramatically alter your exposure, not your image. You cannot alter the exposure in post, just the resulting image.
Thanks for the in-depth detail. Always good!
OK, I submitted my samples on the SX50/60/70 Forum to demonstrate to users just what one can get using a Pola - ie, reflected glare on that background leaf could be "tamed". It was solely an indicative comparison which would hopefully and helpfully offer a solution to reflected glare. I was not expected for the sample to be removed and placed here in the "Share...." forum. Glare can be a problem, but a quick twist of the Pola and its gone - mostly. I'm not aware if any PostEdit package that can do this.Glare is glare, and as it does its thing it removes much wanted detail and can ruin a photo. The other value of a Pola are reflections, created on the surface of water or glass. And yes, making blue skies "pop". But now you've mentioned your Cloud Blur issue I'll test for this too.
I wonder if the second shot was taken with the same settings - it looks either like it is out of focus or has insufficient DoF...