Manual
Focus like the good old days
Manual focus lenses do not have the capability to adjust the focus automatically, you have to lend a hand
Static scenes
If you are taking a picture of something where the point you are focusing does not change, you actually will benefit from manual focus. So much so that, some people actually use back button autofocus to only focus when they need it. This does not mean that your subjects should be static, if you are taking pictures of cars taking a corner, you may want to keep the focus on the apex and catch the car as it moves there, rather than trying to track the car as it enters the scene.
Similarly macro shots usually need you to focus a selected area in peace. You end up using a tripod and carefully compose the picture and the light. There is not much benefit from an autofocus there.
Landscapes are another example. You focus at infinity (and if you have hard stop at infinity this is super easy, see more below).
Better control
If you want fast autofocus, basically an electric motor has to rotate some gears in your camera. Physically a smaller range of movement will allow the electronics to come quickly to the desired location. This is why good and fast autofocus lenses have actually short movement on the focus ring. If you want to use an autofocus camera with manual control, you will see that the movement is certainly possible, but the precision is maybe not that great..
Well until of course you try a proper manual focus lens. These lenses are mechanically made to offer great control on the focus ring. They move very precisely, and when you let go they stay there (at least better lenses). For better precision, manual focus lenses (usually) have longer movement on the focus ring, this is especially true for macro lenses where a fine control of the depth of field is very important
Hard stop at infinity
This is a very nice feature to have in a manual focus lens. It basically means that, if you turn the focus ring all the way, the lens will focus properly on distant objects. This is great for landscape shots, and you can actually be faster than an autofocus lens, because even before you raise your camera, you can make sure that the camera is already in focus. One particularly annoying example are with shooting night sky. My Nikon 20 is an autofocus lens, and it is not easy to set the focus to infinity when it is really dark. Autofocus has a difficult time trying to focus, and even if you end up focussing properly at some point, the focus ring easily moves things a tiny bit when you are handling it (i.e. trying to position your camera in complete dark).
Unfortunately not all lenses have this feature. I have yet to see a lens with autofocus to have hard stop at infinity, maybe half of the manual lenses I tried have it. Longer lenses (100mm or longer) also have an additional issue that infinity for them is a bit further away than for lenses with medium or short focal lengths.
Fast moving subjects
Do you want to take pictures of your kids running around, or do you have an overexcited pet that runs circles around you. Autofocus is what you want. Especially newer cameras have sophisticated tracking algorithms, that will latch onto your subject and will keep tracking it.
Hand held shots
Manual focus, especially with large aperture at closer distances is tricky, any movement that you or your subject have (even a few millimeters) can get your subject out of focus. Autofocus can track these changes (i.e. leaves moving in a breeze) properly without you worrying about it.
See where the focus is
Most modern cameras will highlight the point in focus in your viewfinder/screen so you can actually make sure that the camera is actually focussing on the point where you wanted (or thought) it was focussing. Especially crowded scenes where you have objects both close and far (i.e. a road in a forest) can be confusing and mistakes are easily made when you manually try to focus to a point.
Final words
- There are many cases where manual focus lenses will work brilliantly
- They are better with subjects that do not move as much, it requires a bit more patience to get things right
- Still the ability to autofocus quickly will come in handy more often than not
These pages are for Amateur Photographers and not really for seasoned photographers and professionals. I have no affiliation or commercial interest with any brand/make. I write from my own experience. I ended up using mainly Nikon, so I am more familiar with this brand than others. See price for notes on pricing as well as photography related links.