In general, manual lenses can be used for wedding photography, but it really depends on the situation. If you're shooting in low light, then a faster lens with a lower aperture is going to be more helpful. If you're shooting in good light, then a slower lens with a higher aperture should be able to do the job. It also depends on your skills; when shooting a wedding, you need to be quick and accurate. With a manual lens, you have to be very precise when focusing and you may not be able to get the shot you want as quickly as with an autofocus lens. Ultimately, it's up to you to decide what lens is best for your situation. If you feel confident in your abilities to use a manual lens and think it will be useful for the wedding shoots, then go ahead and buy it. On the other hand, if you're not confident in your manual focusing skills, then it may be a better idea to invest in an autofocus lens.