Magnification filter help needed please

I have just got two new filters for my Tamron 70-300 lens, [ on a Nikon D40 ], one is an AV filter which I tried out today but haven`t processed pics from yet so will see how they turned out later, but the other filter, a Macro +4 magnification, is refusing to play.
Whether on Macro or standard [ dual lens ], it could`nt focus on anything at all, just a blur no matter what distance I was pointing at.
With no filter, fine, with filter, complete blur, all angles, all distances, tried various manual and auto settings with the same result
I thought maybe it was due to being a long lens but surely on the Macro setting that should`nt be an issue ? It seems ok if I just hold the filter up and look through it but not when it`s on the lens.
Any ideas on what am I doing wrong

I'm not sure myself sorry Patch - hopefully Phil or Bob or one of the other more experienced Nikonites will be able to help!

I haven't ever used a close-up filter but I would guess that it would mean the end of the lens would have to be VERY close to the subject.

Try setting the lens to its longest setting (300mm) and the closest focusing point. Then without adjusting anything, other than the distance between the camera and the subject, move in very close, until the end of the lens is practically touching the front of the lens or the subject comes into focus.

Good luck

Steve

As Steve says - the close up filter (I'm asuming it's a domed glass lens attachment) needs to be used very close to something.

This is the set I have - is yours something along the same lines.

http://cgi.ebay.co.uk/Hoya-67mm-Clos...item19b6b1fe37

I was about to say the same as the above - perhaps a bit like extensions? You need to be ultra close. May be better on a longer lens.

xx

Doh, I am such a numpty, I assumed it meant it magnified to bring things at greater distance closer in ie things which were too far away for the lens so meant being able to increase lens range by using the filter, no wonder I could`nt get it to focus on anything

I tried as suggested and yep it can see things waaay closer up than the standard minimum Macro range of my lens, I just need to try it out in good light now as it was getting dark by the time I got to give it a go outside, it does seem to need a lot more light than without the filter on and even the flash did`nt help in the light outside as it was earlier on, [ though I was in a rush and did`nt have time to give it a fair go by trying various settings adjustments ], so will try it properly during the day time tomorrow, thanks guys, I knew I could rely on Yop for help

[ Now going off to write a hundred times ` I am sooo dim` ]