Varifocal 3.5mm-8mm adjustment problems

[Grimgrak 0]

I can only get a very tiny adjustment window where the w-t adjustment and the zoom +/- adjustment meet to give me a clear picture. Idealy i'd like an additional 10 ft of zoom yet I can't get the camera to focus clearly when I zoom that far.

 

Do I need to get high up the number scale maybe a 12mm? Or am I missing something in my adjustment? Also if i need to swap to a 12mm or higher are all lenses mounted the same way and interchangable?

[crirvine 0]

1.What brand Camera?

2.What brand lenese?

3.Have you adjusted the backfocus?

4.What does the lense calculator say you need?

[zmxtech 0]

you might need a c mount spacer -my 25mm and 10-60mm zoom need em

[Scruit 0]

you might need a c mount spacer -my 25mm and 10-60mm zoom need em

 

Same thing with on mof my 60mm zoom lenses. Any combination of zoom / focus that was actually clear wound up with the same field of view. I added the spacer and adjsuted the backfocus and was able to get it set up right.

[RickA 0]

I think we need to know what type of camera and lens, it might be a dome camera or a bullet and then it's a different type of mount completely, but it does sound like a backfocus issue.

[survtech 0]

3.5-8mm is a CS mount. You shouldn't need a spacer. Try a 2.8-12 or a 5-50 if you want to zoom in closer.

 

Many varifocal lenses are a little "touchy", especially with focus. One trick is to get the focus as close as possible to ideal and lock it there, then use the zoom to tweak the focus. Also be aware that on some varifocal lenses the settings don't work the expected way - focus works like zoom and vice versa.

 

Make certain you have the iris fully open when focusing as this will provide the most ideal setting. Close the iris as needed for best picture after focusing. On auto-iris lenses, use a neutral density filter or a #5 welding glass to force the iris fully open before focusing. You can also use either one on manual iris lenses if the scene is too bright to focus properly with the iris fully open.

 

I know that many of you don't have the manpower for this, but we always use a 2-person team when aiming and focusing cameras. One watches a large monitor, 17"-23", and talks the other through the setup. Unless you can carry a 14" or larger monitor with you in the field, that is the only way to get the focus "perfect". Smaller monitors are OK for aiming but almost useless for focus since they don't have the capability to resolve fine focus.

[atropine 0]

On auto-iris lenses, use a neutral density filter or a #5 welding glass to force the iris fully open before focusing. You can also use either one on manual iris lenses if the scene is too bright to focus properly with the iris fully open.

 

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The easiest way to open the aperture fully, is to go to the manual shutter speeds, and keep increasing the speed until you begin to see the noise of AGC start to show it'self. At this point you know you've fully opened the aperture to full, you can then decrease the shutter speed by 1 step so as to ensure you're focusing a crystal clear sharp picture rather than a not so clear AGC UP picture.

[Deluxecctv.com 0]

Welcome to the world of vari-focal lenses. There are a lot of different factors to consider here. Again, like the other guys had mentioned, what type of camera and lens are you using. Thanks

[survtech 0]

The easiest way to open the aperture fully, is to go to the manual shutter speeds, and keep increasing the speed until you begin to see the noise of AGC start to show it'self. At this point you know you've fully opened the aperture to full, you can then decrease the shutter speed by 1 step so as to ensure you're focusing a crystal clear sharp picture rather than a not so clear AGC UP picture.

That assumes he has manual control over the shutter speed. Many cameras don't.

[cctothetv 0]

Sounds like you need a higher focal length. 12 or 15mm