URGENT - Webcam focuser adapters - a problem

[coxellis]

I received a webcam for repair last week and have identified a problem with some focuser adapters supplied for use with webcams.

This problem particularly effects webcams that have been rechipped with the ICX098BL or ICX618ALA sensors as the sensor is slightly higher inside the lens mount than the original sensor, but it also effects unmodified webcams.

On the left is the focuser adapter supplied by myself and other dealers such as Modern Astronomy, on the right is a delrin focuser adapter which was returned with a webcam for repair. You can see from the picture that the adapter on the right goes another 2 or 3 mm further in to the lens mount. This means that it pushes against the sensor surface. In the case of ICX618ALA and ICX098BL rechipped cameras, this can force the sensor contacts to break. In the case of the original factory fitted sensor, it touches the surface of the sensor away from the sensitive area which means that although it doesn't damage the sensor surface where the image is captured it's likely that it will damage the sensor surface away from this and later, with cleaning, it's possible that this damage could spread.

You should never tighten a focuser adapter past the point where resistance to tightening is felt, even if the main body of the focuser adapter is not flush with the front of the camera.

Always purchase a focuser adapter from a reputable dealer.

If the distance from the body of the focuser adapter to the end of the thread is greater than 14mm then this problem may arise.

My apologies for using a backdoor method for posting this info, but I don't seem to be able to start new threads if I log on under 'astronomiser'.

From my own point of view, I've had a few modded webcams back in the last year with this exact problem, but if I can avoid this inconvenience and expense in future, both for myself and my customers, then it has to be worth a post....

[spaceboy]

But is the thread size not the same in depth ?

[coxellis]

very similar, yes, but that doesn't effect how far it will travel in to the camera body; that being a function of the length from the adapter body to the end of the threaded section. The fact is, the one on the right will screw in til it scrapes and pushes against the sensor surface.

[Photosbykev]

This problem may only affect webcams with modified sensors? The original webcam has a threaded socket around it which the right hand adaptor has been designed for and works correctly, or at least it does in my webcam. The squared off shoulder at the end of the threaded section contacts the face of the threaded socket before the bottom of the thread reaches the sensor.

[brantuk]

Thanks for the heads up Andy - I'm sure many folks will benefit from knowing this.

[coxellis]

This problem may only affect webcams with modified sensors?

As stated in my original post, the problem effects webcams with the original sensor in a far less serious fashion in that the adapter hits the sensor face but away from the sensitive area though this could lead to problems as defects tend to 'grow' with cleaning.

I would suggest that it's better never to have anything contact the sensor face other than the correct cleaning materials used correctly.

The original webcam has a threaded socket around it which the right hand adaptor has been designed for and works correctly, or at least it does in my webcam. The squared off shoulder at the end of the threaded section contacts the face of the threaded socket before the bottom of the thread reaches the sensor.

The threaded socket remains in place with cameras with the sensors swapped (at least, that's the way I do it). The socket is a straight through threaded tube though so there is nothing to stop the adapter from screwing straight through and on to the sensor face...

as they say, a picture paints 1000 words...

...as you can see, the threaded section has screwed straight through the lens mount until it is less than 1 or 2mm of being flush with the face of the lens mount that connects to the circuit board - this is considerably less than the thickness of an ICX098BQ sensor assuming it's mounted entirely flush to the circuit board which may not necessarily be the case in all cameras.

Basically, this is intended as advice and as with all advice it is your choice as to whether or not you decide to follow or ignore it - I have posted this reply simply as clarification - yes, it could do serious damage to a re-chipped camera, but there is also a chance that it could damage an unmodified camera therefore my advice and the advice of my company astronomiser is to not use a focuser adapter with a distance greater than 14mm from the body of the adapter to the end of the thread. As a business, I wouldn't post this information unless I was absolutely certain of the facts.

Andy

[Photosbykev]

it was a query Andy, as I checked my adaptor and webcam with a depth gauge before I posted my comment. There may have been a change in the adaptor after I purchased mine but I don't know. Your findings warrant people checking their adaptors before using them

[coxellis]

Absolutely Kev - basically, if someone's adapter is over 14mm and made of delrin, it's a simply job to sand 2mm off and clean it up with a craft knife - I made the post to save both me and my customers hassle and expense. I have no idea who makes these adapters (or interest in knowing tbh) but if they read this, reducing the thread length by 2mm will solve the problem.

[FLO]

URGENT - Webcam focuser adapters - a problem

Thank-you for bringing our attention to a potential problem with one of your competitors products, and for mentioning your own....

We contacted Wayne (who manufactures the adaptor) who is bemused by your comments. Over 4000 of his adaptors have been sold so far without a single complaint or return. The adapter gives 1.5mm clearance when screwed tight into the webcam, it would require another three whole turns to make it touch touch the sensor. It is unlikely anyone would do that as the force required would buckle the camera's casing.

Nevertheless, he has agreed to modify the design making it even less likely to happen.

Hope that helps,

Steve