IR Correction

Can i know whats benefits of IR corection also i know if IR led is open in Cameras all pictuers will be in white and black so there is any way to make it in color although IR is on

IR correction is a term used in lenses. It compensates for the slight shift in focus caused by IR light wavelengths, which are longer than visible light. This causes standard lenses to be slightly out of focus when the camera switches to night mode (turns IR cut filter off).

If you're using an integrated IR camera at night, IR is on, the image will be in black and white. If you switch the camera to color mode it will no longer "see" the IR illumination. If you need color at night, you need to look at either white light illuminators or super low light cameras, and keep the camera in day/color mode.

This image illustrates what I mean by focus shift:

Is the difference just a coating or is the lens ground differently/has a different shape? Are there any downsides besides price?

Are IR cut filters and IR lenses only found together? Those cheaper, integrated IR bullet cams, don't have either right? Is that why they seem out of focus in the daytime?

It's coatings, shapes, and glass. I haven't seen downsides, but I'm not the world's foremost expert in lenses, either.

Lots of people use cameras with IR cut filters without IR corrected lenses. Some people don't know better.

In cheap cameras without IR cut filters, I can't make a ruling on focus one way or the other. I've seen them be slightly out of focus day or night. It's not really consistent. Most reasonably cheap (I'm talking $150, not $30) IR bullets have movable cut filters. The lenses are not always IR, though.

Thanks alot for your reply now i understood that