Radio Frequency Energy

[Pops]

I'm gobsmacked.
Reading through an instruction booklet (yes I do read them) I noticed this:
<quote>
If not installed and used in accordance with the instructions may cause harmful interference to radio communications. Even so there is no guarantee that interference will not occur in a particular installation. If this equipment does cause interference to radio and/or television the user is encouraged to correct the interference by:
1. Reorient or relocate the receiving antenna
2. Increase the seperation between equipment and receiver
</quote>
In simple terms 'move away from the telly when using but.....this quote is included in the instructions for using a camera lens.

On giving this thought I can only think that the USM is the possible culprit here. Can someone discuss this further and explain in simple terms how, using a camera lens, may interfere with tv or/and radio reception and...has anyone ever experienced this.

[Ian]

Re: Radio Frequency Energy

I think that's just a disclaimer to cover the manufacturer from even unlikely eventualities.

Do you have a USM-driven lens? Most 18-55 EF-S kit lenses are not USM types, though a small number of recent ones are fitted with USM.

USM is just an electrically powered motor (in this case using high frequency vibrations for mechanical action) - any autofocus lens will have an electric motor of some description, so I can't see that USM would be any more rf noisy in particular.

Ian

[devilgas]

Re: Radio Frequency Energy

iirc, RFi from motors is caused by the arcing of electricity between the brushes and the commutators, so, in theory, any device containing an electric motor can cause rfi. equipment shielding goes a long way to minimising this, but as ian says, it's the getout clause just-in-case.

bit like salted peanut manufacturers in the states allegedly putting "Caution, this product may contain nuts" on the packaging. kinda like the warning i had to put on this page: http://www.devilgas.com/diving/ys50ttl/ys50ttl.asp
as no doubt someone somewhere will give themselves a belt and try to blame me.

[Pops]

Re: Radio Frequency Energy

Thanks both...that's cleared that up