I am looking at cheap options for macro photography. Currently I have a Nikon D200 with an 18-200mm lens and a 50mm f/1.8 lens. I am looking at Zeikos ZE-CU472 close up lens attachments to mount on my 18-200mm lens. OR Reverse mounting my 50mm lens with a BR-3 from Nikon. - Do either of these affect the aperture? - Would either cause a vignette on the image? - Which is better? - Are there any other methods or products which you can recommend?