I have an older Canon Extension tube (EF 25). What is the difference between it and the newer Canon Extension Tube EF 25 II. Also, if I buy an EF 12 II will it work with the older EF 25?

I ordered the Ef 12 II extension tube from B&H and have not received it yet, and i found out that there was a larger extension tube ( EF 25). My Question is should i keep the Ef 12 tube or return it and pay the 40$ more for the EF 25? I have Rebel Xt with 28-135mm Canon IS, 100mm Canon Macro, As a general rule, you would want to extensions that are 25-40% of the focal length of your lens. Depending upon the MFD, minimum focusing distance, of your lens your mileage may vary. For example, if you are looking to use a 50mm lens, then you would want to use either the 12mm or the 21mm tube, but not both Shop online for Canon EF-S 10-18mm f/4.5-5.6 IS STM Lens at Canon UK Store. Just one of the many great deals in Zoom Lenses. Free shipping on all orders over £30! 12 months: 0.25%: AED 500: 3, 6, 12 months: 0.0%: 1.50% for 3 months Canon Extension Tube EF 12 II. This 12mm extension tube fits between camera body and the lens
Say the aperture diameter is untouched and the focal length doubled the projected image dims to 25% of its original brightness (2 f-stops). Conversely, if the focal length cut in half, the image brightens 2 f-stops. The Math: 50mm lens 12.5mm aperture = f/4 --- 100mm lens 12.5mm aperture = f/8 --- 25mm 12.5mm aperture = f/2
HARkR. 224 452 679 974 60 629 486 562

canon extension tube ef 12 ii vs 25