Image At Night Blurry With Dome On, Fine With Dome Off, What Is Wrong?

A member is asking about a Digital Watchdog varifocal dome IR camera - the DW-D3563DIR.

He says, "Camera operates fine with lights on and then the IR cuts in and the image gets blurry. I was going to change the settings on the camera and as I took the cover of the camera the image cleaned up nice and sharp as I put the cover back on the image got blurry again."

It's a cover issue and a night only issue. Any sugggestions?


Dirty / scratched dome or IR bleed (if it's an IR camera). Clean the dome very well and if there's a foam/rubber ring make sure it's seated firmly against the dome when it's put back on.

John, I am a DW rep. Please pass my info onto the member, if he'd like some assistance. This account is under my personal email, I will send you my work email to your IPVM mail account.

Also, with some domes and turrets, if it is tilted up all the way, some IR LEDs may be behind the internal case, not thru the bubble, causing the IR to reflect back into the bubble and imager.

Something on the dome that scatters IR wavelengths but not colors in the visible spectrum?

It is an IR problem with reflection. You verified this by testing during the day with artificial light and at night by taking the cover off.

The problems I have had is with the gasket slipping out of position and with the lens being at a far extereme of it's axis, as mentioned before by Ahmed. If that does not do it, I would look at how the camera was assembled and installed. My techs can do things I would not think possible. lol

It might be that the frequency response of the camera is different at night, and the dome itself is no longer transperent from the point of view of the camera. It could also be that the camera is focusing on the bubble or something it "sees" in the bubble in the near field. Can you change the light level of the view to skew it from night to day as a test?

Here is DW's response:

"What it sounds like to me is that you’re getting IR reflection in your dome. TO fix this, you need to make sure the rubber gasket around the camera lens is flush against the dome. This will prevent the IRs from reflecting back into the lens can giving you the blurry effect. If this does not resolve your issue, please let me know and we can evaluate it further from there."

Btw, DW says they emailed us the same day of our request but we did not receive that (could have been filtered by spam folder, etc.).

So a number of you guessed it! Nice job!

Btw, end user says this is a new camera. Will update when he checks this.

Update from member:

"I have just come from the site and I did try the camera again, this time I straightened the camera gimbals so it was pointing straight out against the dome and not angled like it was. Although there was a marginal improvement, the picture was still cloudy and blurry."