Help with C-Mount Lense

[PKassab 0]

Hey guys I got a question for you, what is the bet way to focus the C-Mount lense when youw working alone? Usually I have a few workers with me when I m focusing the lense but tommorow I am doing the installation alone and was wondering what you guys do when your workin alone. any imput is greatly appreciated.

 

Peter K

[AVCONSULTING 0]

What camera are you going to be using? Also are you going to have a handheld monitor?

[PKassab 0]

I am using day and night color view c mount Camera cameras and no i do not have a handheld monitor

 

Peter

[AVCONSULTING 0]

Have a good pair of running shoes or go and get a handheld monitor. If you are going to use an auto iris lens then you will need to focus it either at night or use some type of light reducing glass over the lens such as neutral density filters. You'll have to find a way to attach them to the lens if you are doing it by yourself. Also make sure you have the "C" mount selected on the camera or are using a 5mm focus ring.

[PKassab 0]

Where is a good place to get a handheld monitor

 

Peter

[AVCONSULTING 0]

You can look for something like this which is fairly professional

 

http://www.vitekcctv.com/ProductDetails.asp?ProductID=121

 

or something like this, just make sure it has a video jack on it

 

http://www.bestbuy.com/site/olspage.jsp?id=1051806186155&skuId=4572359&productCategoryId=cat03009&type=product

 

http://www.bestbuy.com/site/olspage.jsp?id=1063670358354&skuId=5864004&productCategoryId=cat03009&type=product

[rory 0]

you can also use a small color TV, with a long extension cord, thats what I use most of the time right now, as my handheld monitor went dead.

[Cooperman 0]

Test / installation monitors are probably the most useful bit of equipment we'll ever need, so it's worth investing in a good model.

Having said that, I haven't!

 

Instead about two years ago, I bought (in a sale) an ex demonstration portable DVD player (Panasonic) with an A/V input.

 

Brilliant quality 5" LCD screen, 'clam shell' design, and a battery pack that works all day (impresses clients as well!).

 

One point to consider when focussing any fixed focal length lens.

If you know the distance from camera to target point, you can set the camera / lens up near to a monitor (or suitable A/V input TV), adjust the focus on a target at the correct distance, adjust the aperture, and then gently tape over the 'rings' to prevent movement. A limited number of lenses (some Pentax / Cosmicar for example), have locking thumbscrews on the focus ring to prevent accidental movement.

 

This technique is fine for wide or ultra wide lenses, but is not critical enough for standard or telephoto lenses, where the target area is close to the camera (depth of field is too short to maintain an accurate focus throughout).

[cctv_down_under 0]

Ganz sell an excellent one.. but it is abiot on the expensive side of things.. but it has a loop through so that you can turn on the 75Ohm or not, and this means you can focus and still have signal at the other end, in honesty you still often need to tweak it after using a monitor, one hint though when using cams, make sure to focus by placing your housing beside it and focussing it through the Glass, Ganz is good because most of thier cameras can be left wireed and then focussed through the secondary output they provide for the spot monitor which means you dont have to move the camera and if using the service monitor you can see it and your guy at the other ewnd can see it and you dont have to move it.

 

Another tip is to buy a 12V monitor that is small then you can cheat by using your 12V drill battery to pwer the monitor, meaning you never need batteries, this works well up a ladder and is easy to adapt with just somne electrical lugs.. Service monitors should allow for both B/W and Colour and should always have a brightness adjustment on the monitor, otherwise you will read the wrong lighting, Using a digital cam to measure light levels also helps and pre foccusing the camera on the ground means you have less running to do!!

[PKassab 0]

Thanks guys, What i ended up doing was focusing the cameras at the DVR then takin them to the roof and putting them in the housings this worked very good, I might pick up one of those 5" DVD players I can get one for arounf 150 so its not a bd investment.

 

Peter