Introduction to Manual Focus on a Camera Lens

Manually focusing your camera lens can seem tricky. Compared to the ease of autofocus, you may wonder why you even still have manual focus as an option. It still has a number of important uses, however, and it’s a great skill to learn. In this introduction to manual focusing a lens, I’ll explain what sets manual focus apart, as well as how and when to set focus manually.

What Is Manual Focus?

Almost all camera lenses have the ability to adjust focus. Focusing is when the elements of the lens move back and forth within the lens – or the whole lens moves forward and backward – to change how it projects the light.

In practice, what this means is the lens renders a specific area “in-focus” and sharp, with the regions in front and behind becoming increasingly less sharp.

Manual focus is when you adjust the in-focus region to be closer or further from the camera. Usually, this is done by rotating the focusing ring on your lens while autofocus is disabled.

Manual vs Autofocus on a Camera Lens

Focusing the lens, whether by manual or automatic methods, is just choosing where the region of sharp focus is. Manual focus and autofocus both do the same thing at the end of the day, which is to move the region of sharp focus further away or closer toward the camera. At a mechanical level, here’s the difference:

• Manual focus is when you move the focusing ring yourself to change how far away the lens is focused.
• Autofocus is when the camera moves the lens elements in order to place focus on your chosen subject.

Autofocus can become complex when you consider the impact of autofocus modes like AF-S or AF-C, along with AF area modes like dynamic tracking, Eye AF, and more. But don’t let this complexity fool you. Both approaches move the same lens elements and – if done correctly – position your focus on the same spot.

While you can get the same results from either manual or autofocus, some images are significantly easier to get with one mode or the other, and that’s why both modes exist. Later in this guide, I’ll explain when to use manual focus. Before I get to these situations, however, first you need to understand how to switch over to manual focus.

How to Enable Manual Focus on Your Camera

The simplest lenses are exclusively manual focus. They have no focus motors, and no support for things like screw-driven autofocus. (Older Nikon AF-D lenses like the 50mm rely on the camera body turning a little screw to autofocus, for example, while newer lenses just need an electronic connection.) Exclusively manual focus lenses, like the TTArtisan 50mm f/1.4, can be significantly less expensive than autofocus capable versions, but they will always require you to manually focus. Manual focus doesn’t always mean cheap, though: Lenses like the $8,000 Noct are manual focus only, too!

On many lenses with autofocus support, you’ll see a switch with positions labeled A and M. Other lenses will have more complex options like M/A, A/M, or A-M. The differences depend on the lens in question, but they usually involve whether manual focus override is possible while the lens’s autofocus is on. Nevertheless, if you’ve set your lens simply to the “M” setting, it almost universally means that you’ve turned off autofocus and entered manual-focus-only mode.

To get to manual focus, regardless of your camera or lens maker, this switch-on-a-lens interface is the most common. Moving the switch lets you set focus manually, and if you want to get back to autofocus, it’s just one click back. With that in mind, it’s easy to give manual focus a try, while still having the backup option of autofocus.

Other times, there will be a manual focus switch or menu option on the camera itself. This usually functions the same way as the switch on the lens; it’s just a different way to do the same thing. If either the lens or camera – or both – are set to manual focus, the general behavior is that autofocus is disabled. (Test this on your camera to be sure, since a few cameras still focus automatically when AF-On is pressed, even if set to manual focus mode.)

When to Use Manual Focus in Photography

Now that you understand how to set manual focus, let’s take a look at some of the best times to use manual focus.

1. Low Light

Low light levels, like a candle lit reception or dark street, can present a particular challenge to the autofocus system. In these cases, switching over to manual focus may be easier than trying to fight the autofocus system. The performance difference between autofocus and manual focus will be most noticeable on older cameras, as some of the newer cameras can autofocus under really low light levels, levels that would even be challenging to manually focus in.

2. Astrophotography

Astrophotography presents one of the most difficult subjects for autofocus, combining both very low light and a need for very precise focus. In this case I almost always choose to manually focus on my astrophotography subjects, even using magnified live view (a technique I’ll discuss more later in this guide).

3. Pre-Focusing

Consider a scenario where you’re expecting action in a specific location: whether it’s someone sliding into home plate, or the bride stepping into the doorway of the church, you want your camera to already be focused at that point, ready to go. By setting focus manually on that point, you can just click the shutter when the action occurs, without worrying about finding focus.

4. Tricky Subjects

This next category is a bit more nebulous, but it’s basically “times where autofocus is just getting confused.” This might be a really low contrast subject, like a dark subject on a black background, or a transparent subject. Either way, it’s a subject that autofocus just isn’t working well on. In these cases, setting focus manually may be easier than fighting the system. Also, don’t think that focusing manually requires you to set focus perfectly – sometimes the system just needs a little nudge in the right direction, by setting focus roughly in the correct place. I find this works really well for transparent subjects and macros subjects, where the system may try to focus on the background instead of the foreground.

5. Shallow Depth of Field

Depth of field is the common term for that concept of “in focus” areas I discussed earlier – for more info, check out our beginner guide to depth of field. Some lenses, particularly at fast aperture like f/1.4 and telephoto focal lengths, have very narrow depth of field. This narrow zone of focus can challenge autofocus systems. In these cases, manually focusing may give better results. Many macro photographers manually focus by rocking forward and backward, then taking their photo at the opportune moment, rather than relying on autofocus.

6. Studio Settings

Manual focus can also be a great option when working in the studio with still subjects. With your camera typically on a tripod, manual focus is a lot easier, and gives you the ability to be very precise with your focus placement.

How to Get Sharp Results with Manual Focus

There are a number of ways to get better results with manual focus, but the first one, unfortunately, isn’t a trick. It’s just good ole’ practice. Manual focus is a skill, and requires developing a bit of dexterity, especially when working with moving subjects. With that said, it’s definitely a skill you can develop. Understanding intuitively which direction to move the focus ring, and even roughly how much, all comes down to muscle memory. Practicing your technique can help with building this “feeling” for it.

Fortunately, technology is always there to help us out. There are a few things to make sure you’re getting the most accurate impression of your focus area. The first is the diopter adjustment (usually a wheel on the side of your viewfinder). Depending on your eyesight, the viewfinder by default may not look very sharp to you, or it may require some straining before it looks clear. Your view through the viewfinder should be immediately and effortlessly crisp. If it isn’t, it’s going to be far more difficult to focus manually, so you should adjust the diopter control.

On the other hand, if you prefer using the camera’s rear screen to focus, you’ve got even more options to make your life easier. The first is the use of a loupe. While you’ll still be limited by the resolution of your screen, this tool both magnifies the screen and blocks glare, making it easier to gauge focus.

Another useful tool is the simple magnifying button to zoom in on your live view screen. Many mirrorless cameras support magnifying the image in the viewfinder via the same button, too. It takes a bit more time but offers a much easier view most of the time.

Also, you don’t have to go it alone. When in manual focus, many autofocus systems will still be working, and you’ll often have an indicator like the brackets and dot, to help guide you. The brackets >< indicate what direction the system thinks you should turn the ring, while the dot shows when you’ve achieved focus under the active focus point.

If you have a newer camera, chances are good that it supports focus peaking, too. Focus peaking is a graphical representation, overlaid on your screen, where objects that are in focus are outlined in bright colors. This is a great manual focus aid, particularly on fast lenses with a correspondingly narrow depth of field. Often, focus peaking even works when you’re using old, manual-focus-only glass! It’s a great way to revive old lenses if you have a newer camera.

Lastly, if you’re still having difficulty nailing focus, consider widening your depth of field. Stop your lens down to a smaller aperture value, take a step back, or use a wider angle lens. Any of these will give you more depth of field and therefore give you some slack when focusing.

Conclusion

Knowing how to set your camera up for manual focus, and how to manually focus once it’s set, is a great skill to have. There are plenty of scenarios where autofocus will have difficulties or fail completely, but that doesn’t mean you need to put away your camera. You just need to practice and understand how to shoot via manual focus. Plus, being comfortable with manual focus opens up a huge library of specialty, adapted, and manual focus only lenses that you can explore.

Just don’t start to think that manual focus is “better” or “more professional” than autofocus once you learn how to use it. Both are simply tools. I would rarely use autofocus for Milky Way photography, but I would rarely use manual focus for photographing sports! They have their own strengths and weaknesses. The key is to learn how to use both hand-in-hand so you don’t miss an important photo.

Let me know in the comments section below if you have any thoughts or questions about manual focus in photography!