When all theory has been expounded, do the friggin' experiment! Here's a set of comparisons between a linear and circular polarising filter, on all the DSLRs I could lay my hands on: 1. An old Mk1 Canon 5D fitted with 50mm f/1.8 Canon 'plastic fantastic' lens - 2. Almost equally old Nikon D700 fitted with 50mm f/1.8 AF-D Nikkor - 3. Nikon D800 with same 50mm AF-D Nikkor - 4. Nikon 'DX' D7200 with 35mm f/1.8 AF-S lens - 5. Sony A7Riv with 50mm f/1.8 AF-D Nikkor lens via adapter (manual focus) - All the above are SOOC JPEGs with no post work done apart from resizing and adding title text. All shot at f/4, ISO 100, Aperture priority, and AWB. Except the D7200, which was shot at f/2.8 to equalise the D-o-F and the D700 that was set to its base ISO of 200. Surprisingly, there is no discernable difference between the linear and CPL filter shots taken with the same camera, despite there being a slight visual tint and density difference when looking directly through the filters. I guess AWB and auto-exposure really do work to level out any difference! I was also surprised to find that the CPL filter was visually denser and gave an average 1/2 stop slower shutter speed, but as you can see the end results are difficult to tell apart. WRT AF: None of the cameras struggled to find focus, or missed focus enough to worry about. Although focus speed seemed a bit slower with either polariser fitted. I put this down to having a dimmer, and maybe less contrasty image to focus on. I deliberately threw the lens well OOF before each shot, and let the camera AF do its thing - except for the adapted lens on the Sony, which was manually focused. Here are 100% crops of the AF focus area from each camera: And to round things out the cropped focused area from the Sony MILC. Conclusion: The older DSLRs with AA filters did show quite a dramatic colour shift when fitted with a polariser. However the type of polariser appears to make little to no difference. Also, with the cameras tested, there were no severe side effects from using a linear polariser. In fact the extra half stop of light from the linear filter might be advantageous. So based on the above results, it's my opinion that reports of the death of the linear polariser are grossly exaggerated. Further, the spread of fear and panic over using linear polariser on DSLRs and AF/AE film cameras was IMHO largely unfounded, and a cry of wolf to stimulate sales of 'upgraded' filters. Maybe the above experiment should have been done years ago? Oh, P.S. The filters used were an old Nikon Linear polariser and a slightly newer Hoya CPL.