I bought the above to try out budget Macro shooting. I realise the view finder is too dark when lens aperture is being set to F8 so I set to F2.8. However, depth of field is too shallow, any ideas what is the optimum set up?
Unless u used the depth of view preview button, your camera is unlikely to stop down the lens aperture to f8. It should remain at f1.8 ( regardless of what aperture setting u adjusted) , and close down when u take the shot. ( unless u used it reversed and the camera loses all coupling with the lens )
The dimming is probably due to some light loss from the extension. Especially when ur subject is also not the brightest. What extension tubes u using ?