It sounds like you're looking for a free way to add lens blur in After Effects, possibly because the native "Lens Blur" effect (which is only available in After Effects CC and later, as part of the CC effects suite) is missing or not working in your version.
The legacy "Lens Blur" effect was replaced by "Camera Lens Blur" in Adobe After Effects CC 2015, causing potential missing effect warnings in older projects. Users should switch to the native Camera Lens Blur or use free alternatives like Fast Bokeh by Rowbyte and Boris FX BCC Lite. For detailed troubleshooting, see the discussion on Adobe Community After Effects 14.2 upgrade removed Lens Blur plugin lens blur after effects missing free
Here’s a breakdown of solutions:
Ctrl+K / Cmd+K).Here are the three best ways to replace Lens Blur for free. It sounds like you're looking for a free