Bellows extensions when using various lenses may require exposure compensation. There is a formula for figuring it out (forgot the formula) but when I started with LF, I sat down with a calculator and figured it out from F stops to length and marked a small retractable ruler that I keep with my light meter. I just measure the distance from the lensboard to the film plane and see what increase is needed. You should be able to see how the image will appear on the ground glass. Lens selection will be governed by the maximum length of your bellows. How small are the objects?