Ron wrote:
So if I wanted to use an extension tube with the 28-90 zoom which tube would i choose? Can I get 1:1 with that?
Ron, there's more to it than simply using a tube with any lens there is. As I said, 1:1 magnification is generally considered to be obtained by add an equal amount of extension, as the millimeter of the lens being used. This said, if the tube mounts to your 28-70mm zoom without problem, the a 25mm tube will almost give you life size reproduction when it's zoomed into 28mm. However, this isn't saying the quality of photo you get is going to be usable.
There's other problems which can occur. Vignetting, and especially distortion can ruin what might be a nice shot with a different lens. If you want life size, there's really not a perfect solution, other than a dedicated macro lens if you wish to keep the quality as high as possible. I can't tell you how well your combination will work, since I haven't tried it. And I'm assuming the reason you're trying to find an inexpensive alternative is due to cost. Could you specify an amount you're trying to stay with? You might prefer going with diopters as a start, and add more expensive items with time.