I am shooting with a Canon XS with a 50mm in reverse. When I reverse the lens the F defaults to 00. I can not change the f when it is reversed at all. Obviously when I add a tube on it it make the area of focus that much smaller. I have tried changing the f stop prior to reversing the lens from 1.8 to 22 and when reversed the image is still the same. So, two questions.
1. Is is possible to change my f when this particular lens is reversed (Canon 50mm prime 1.8)?
2. What lens would you recommend for a very raw noob to begin to capture some good Macro.
Unfortunately, NO, it is not possible to change the f/stop with a Canon EF lens mounted in reverse--that is one of the areas where the Nikon F mount has an advantage: 43 million Nikon lenses with aperture rings, and perhaps 7 million AF-S G lenses with no aperture rings, out of the 50 million Nikkor lenses on the market.
If you want to use a Canon EF lens reverse-mounted, you need a costly, $539 Novoflex-made electronic aperture control adapter.
EOSRETRO Novoflex Eos Reversing Lens Mount - To Reverse Mount Eos Lenses On An Eos Body
A much,much less costly idea is to buy what Nikon users buy to do the same thing, and spend $39 for the Nikon BR2a lens reverse ring and $17 for a Nikon F to Canon EF lens mount adapter.
2657 Nikon BR-2A 52mm Lens Reversing Ring
and then buy almost ANY brand of 50mm f/2 to f/1.4 lens that has an on-lens aperture control ring, like a $60 Nikon 50mm 1.8 AF lens. All the lens needs is a 52mm front filter thread to work.
If you want to get an affordable macro lens, the Tokina 100mm f/2.8 ATX macro in Canon EF mount is a good, low-cost macro lens. "Budget macro" gear can be surprisingly good; reverse mounting even a fairly low-cost lens can produce some surprisingly good results. But the idea of paying $539 just to be able to get diaphragm control on something as simple as a reversed lens on Canon bodies is one of the "gotcha" areas the EF mount has had since its inception in 1987. So, it makes sense to look at non-EF mount lenses for use in reverse-mounting scenarios--Pentax K or M42, Nikon Ai,AiS or AF-D, or Olympus OM series lenses have some good options for reverse mounting.
One of the handiest solutions would be the Nikon 36-72mm f/3.5 Series E Zoom lens for reverse mounting with a BR2a and Nikon-to-Canon lens adapter.