Soft Focus on Right Side of Video Frame -Vivotek IP8332

[jmolli 0]

I've had an IP8332 for a couple of years that monitors my cars in the parking lot of our complex. Its always had a slightly soft focus on the right side of the frame, but it seem to have gotten a little worse lately. The center and left side of the image is nice and sharp but the right side is soft, its particularly noticeable at night when it flips to night mode (B&W).

 

Can anyone advise if it would be worth the trouble of replacing the board lens (3.6mm fixed, IR, MP). I'm thinking its either the lens or the orientation of the lens relative to the image sensor. If its the orientation, I think I'm out of luck since the lens screws into a small plastic rectangular box shaped module.

 

If anyone has any experience with this type of thing on a board lens camera, I would appreciate your advice.

 

Thanks,

 

John

[MaxIcon 0]

It's not a bad idea to check the glass and lens elements for smudges or fingerprints. I had an analog cam that had haze on the back lens element that caused soft focus. This'll require taking the lens out, of course. I've posted a link to an IP8332 focus procedure below - it's a bit of a pain.

 

If your Vivotek has a screw that locks the lens into place, these can also cause trouble, both by shifting the focus slightly as you tighten the screw, and by tilting the lens slightly when tightened. I don't see one in the procedure below, but Vivotek changed the design in that area a few times over the years, and most of mine have a screw.

 

Whenever I take out a screw-locked lens, I leave out the screw and use a few wraps of Teflon tape on the threads to hold it in place. This holds it securely, makes it much easier to adjust (like not having to remove the IR board on the Vivotek), and there's no shift when you're done. Make sure the tape doesn't have any bits sticking out the back when screwed in.

 

Best bet might be to re-focus so that it's the same at both edges. I like to use a Siemens star for this, as it makes it super obvious when your focus is the best it can be. Print it out and compare focus between the edges and the middle.

http://upload.wikimedia.org/wikipedia/commons/thumb/5/50/Siemens_star.svg/2000px-Siemens_star.svg.png

http://en.wikipedia.org/wiki/Siemens_star

 

Here's a post linking to the Vivotek re-focus procedure:

http://www.forum.use-ip.co.uk/threads/how-to-adjust-the-lens-focus-of-the-vivotek-ip8332-bullet-camera.164/

 

So, if you want to replace the lens, that'll be trial and error. There are few specs for M12 lenses except the thread spec, so one 3.6mm lens will focus at a different number of turns than another, and that will affect the field of view. Some lenses need to be turned in far enough that they hit the IR filter assembly. You just never know until you try.

 

These guys have had decent reviews from board users, and may have a better image overall than the original Vivotek lens, which is prone to purple fringing.

http://www.m12lenses.com/M12-Mount-Mega-Pixel-Lenses-s/21.htm

 

ETA: Sorry, I just remembered that the Vivotek has a 1/4" sensor, and the lenses at the link above are all for 1/3" sensors. They'll work, but the FOV will be different, since the image circle from the lens will extend well past the sensor edges, making the captured image a smaller FOV than the original lens. On the plus side, quality is always better in the center of the lens, so you'll get better image quality.

 

You can use a 1/3" lens on a 1/4" sensor using the crop factor, which gives an approximate idea of the scale change. Using this setup, your crop factor would be 1.33, and you'd divide your current lens size by this to get the right size to use in 1/3". To match your 3.6mm 1/4" lens, you'd need a 2.7mm 1/3" lens.

 

This doc has a good overview of some of the issues M12 lenses have, as well as a crop factor table:

http://www.ptgrey.com/support/downloads/documents/TAN2010002_Selecting_Lens.pdf

[jmolli 0]

MaxIcon,

 

Thanks for the comprehensive reply. I did find the lens cover to be dirty on the inside of the glass and dismounted the camera yesterday to unscrew the front lens cover and clean the glass. Wish I had that focusing procedure while I had it apart.

 

The cleaning did improve the image quality a little, but the softness on the right side remains. I will give the focusing procedure a try next weekend. Is it really necessary to remove the IR board to turn the lens for focus adjustment?

 

John

[MaxIcon 0]

I believe there are 2 versions - one with a lock ring, and one with a setscrew - but I haven't had mine apart for a while, and the differences between cameras gets fuzzy over time. Either way, you have to remove the IR board to get at the lock. If yours doesn't have one, you might not need to.

 

One you've got the lock removed and Teflon tape on the threads, you can grab the lens and rotate it, either with fingers if they're not too stubby or gently with needle nose pliers.