what can i do with a 4+ close up filter?

well i picked up a 4+ close up filter from jessops today in the bargin bing for £5, but i am not exactly sure what it is used for or how to make best use of it? any suggestions?

Do you mean a 4X teleconverter instead of 4X filter?

If it's a teleconverter that mounts between the body and lens then it will effectively increase a lens's focal length by a factor of 4 - i.e. a 50 mm lens will give the same field of view as a standard 200 mm lens.

But the TANSTAAFL rule applies. The effective f-stop is also quadrupled and, unless perfectly made, the point of focus may not be exactly at the film plane/CCD plane resulting in some blurring of images.

If it's an add on that mounts to the front of the lens then it wiil give a 4X macro effect with possible fisheye effects. Generally the same tradeoffs as above exist particularly in regards to blurring if the add-ons focal point doesn't line up with original lens's.

The only other 4X I can think of is a star filter that will create four 'star rays' from bright sources in the photo. Sometimes they're called 4X, 6x etc to denote the number of star rays produced.

bfx

its just a filter that slaps on the end of the lens....

With that description your best bet is to take some pics and look at the results.

bfx

well here is the first pic i took with it, nothin impressive, but you get the idea....

That allows you to focus on objects closer than you normally would be able to focus with the same lens. Try to focus on an object without it, see how close you can get and take a shot. Then put on the close up filter and you should see that you are able to get much closer and still focus on the object.

The only downfall of a closeup filter is that you may get a slightly softer image than using without it. The more glass that you have infront of your lens the softer the image. As if you are a hard focus person use less filters.