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Sony p41 focus

Looking for the software to focus Sony p41 I build IR trail cams for scouting whitetail deer so that the white flash does not spook them.

The problem is that some cams are not in focus when I change the glass I have two different size pieces of glass. I know that they can focus cams by plugging in to the USB port. Was hoping that you could help me out.

Thank you for your time

Nathan Ysker
Wed, 04 Jul 2007 16:18:11 -0700

I don't quite understand what you are saying. The DSC-P41 is a fixed-focus camera. You can't adjust focus on it. See this thread: SONY DSC-P41 / 43 SUCKS ! BLURRY ! I SWITCHED TO 2003 MODELS

Chieh Cheng
Wed, 04 Jul 2007 16:21:14 -0700

OK let me back, On my P41 cameras, I have removed the cut filter on the camera and replaced it with a coated material that is of the same size. This material allows my camera to se near IR light from the range of 700nm to 1200nm or the cameras limit. The only problem is some cameras have really poor focus even when left in auto. In the past I have
bought new cameras and I have had them refocused at a repair shop because the camera was way out of focus. I guess my question is how to do they refocus these cameras at the repair shops or factories. Then is it possible to use that same method to refocus my camera with the IR cut filters removed. Next if there is some type of software, is it possible to get this software.

Nathan Ysker
Wed, 04 Jul 2007 17:29:59 -0700

First of all, there are too many variables in your set-up to determine what is causing the out-of-focus condition.

First question: Is your replacement "coated material" the same thickness as the original IR-cut filter"? Is it glass? It must be the same thickness for the focus to be the same.

Cross Reference
Last paragraph on page 330 of the "Hacking Digital Cameras" book explains.

Second question: Does the camera focus correctly when the IR-cut filter? Put it back in and try it.

If the answer to the second question is "yes", then your IR-cut filter is the wrong spec. If the IR-cut filter doesn't focus correctly, then the camera is out of calibration.

Chieh Cheng
Thu, 05 Jul 2007 10:26:57 -0700

Hello, Nate asked me to explain this a little more. My name is George dean and I have been working on this project with Nate for a while now. I guess we would like to know how to they calibrate the cameras. With the IR cut filter removed, if the camera is placed in auto mode it will focus OK, but if placed in Program mode all settings are out of focus. IF the cut filter is in place it will focus on both program and auto settings. The replacement material is the same thickness, but from our testing in order to get the camera focused on all settings the CCD must be shimmed away from the lens. What we have noticed is this shim is not the same for all cameras. Sometimes it is .00025" others it is .00030".

Also how tight you tighten the screws can play a factor on the focus on the programmed settings. But in all reality you should not even have to replace it with anything, as all the cut filter does is filter out IR light it does not focus it. We also noticed if the CCD and lens assemble were attached to another main camera board it will also be out of focus, But when place back on the original it will be fine. So we started thinking there must be a program to use to calibrate the camera.

Since the shim method is trial by error. We thought if we could adjust the calibration of each camera we might be able to save some time. So do you think you could help us find this program or method?

George
Fri, 06 Jul 2007 12:57:21 -0700

"But in all reality you should not even have to replace it with anything, as all the cut filter does is filter out IR light it does not focus it."

That is absolute not true. It's probably the cause of your problem, because you are basing your troubleshooting on false assumptions. Pick up a copy of "Hacking Digital Cameras". Try focusing with and without the IR-cut filter. You will find that without the filter, the camera becomes extremely short-sighted, like a camera with a strong macro lens.

After you straighten out your assumptions, re-troubleshoot, and let me know if you have any questions.

Chieh Cheng
Fri, 06 Jul 2007 13:00:02 -0700

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Title: Chapter 16: Eliminating the IR Blocking Filter from Your Digital Camera
Weblog: Camera Hacker
Tracked: Fri, 06 Jul 2007 13:00:57 -0700

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