Portrait Photography Question - Autofocus or Manual Focus?

[mrobely]

What looks sharp in the viewer looks fuzzy when I see it on the computer screen later, sometimes, so I am trying to figure out if that is because I am moving camera slightly when I squeeze shutter or it's my vision when I'm focusing.

Perhaps your viewfinder's diopter needs adjustment then. I was fiddling with mine just the other day to make sure it was still correct, and going from one end of the spectrum to the other is a small but noticeable difference.

Very good reminder, thank you. I do often overlook this simple step.

But I ALSO RARELY USE THE DIOPTER, the viewer screen gives a much better display.

 

[KmH]

I'm not a professional, but if your model is changing positions quickly, how can you focus manually and do it accurately?

We did it all the time before auto focus was readily available.
All it takes is learning how to do it and some practice.

Some DSLR cameras have manual focusing aids.

 

[PersistentNomad]

In general, the only time I find manual focus reliable and desirable is when shooting macro or still lives.

 

[fmw]

In general, the only time I find manual focus reliable and desirable is when shooting macro or still lives.

It is a matter of practice. The major issue is that viewfinders no longer have split image rangefinders so one has to depend on the digital focus aid in digital cameras. As long as you want to focus on the nearest part of the subject, auto focus works well and quickly. The issues occur when you don't want to do that. With portraiture you normally want to focus on an eye. If your AF will do that reliably, then that is the way to go.

 

[robbins.photo]

It is a matter of practice. The major issue is that viewfinders no longer have split image rangefinders so one has to depend on the digital focus aid in digital cameras. As long as you want to focus on the nearest part of the subject, auto focus works well and quickly. The issues occur when you don't want to do that. With portraiture you normally want to focus on an eye. If your AF will do that reliably, then that is the way to go.

Only if you don't understand how your camera's autofocus system works. If you do and set it up/use it correctly it absolutely will not always focus on the nearest part of the subject. That simply isn't true.

 

[john.margetts]

One serious problem with manual focus on modern lenses is that they are designed for fast auto-focus. This means that the distance between close and infinity on the focus ring is very short. The camera can produce very accurate, very small motions which the human hand struggles to repeat.

Back when we had to focus manually the distance between close and infinity was much larger - on my Prakticar on my BC1 the distance between close and infinity is about 320 degrees. This makes focusing very slow but easy to be accurate (especially when coupled with the split image centre in the focus screen).

 

[vintagesnaps]

Try doing what Lew suggested. If you're doing portraits you should know this - since you don't yet, then you should work on getting better at using your camera and figuring out what type focusing works best for you in a variety of situations before you do portraits.

And get out with the 50mm that you haven't even used yet. That seems to say you are not even close to being ready to do portraits. If you practice and learn you'd be more likely to set yourself up for later success.

 

[The_Traveler]

But I ALSO RARELY USE THE DIOPTER, the viewer screen gives a much better display.

From this I infer that you are either always using a tripod or that you are holding the camera away from your body so you can see the lcd screen.

Sources of problem with tripod:

• lousy unsteady tripod
• image stabilization turned on (a no no unless your camera has a special mode)
• shake from shutter pressure.

Sources of problem when holding the camera away from your body so you can see the lcd screen.: massively unsteady way to hold a camera.

I generally hold the camera with right hand supporting the r side of the body and finger on shutter button, left hand under the lens and body, both elbows tucked tight against my body.

 

[weepete]

Manual focus is fine provided you can get enough depth of field to make it work. But in situations where you need to be quick and use a wide aperture then AF is more reliable.

 

[chuasam]

Autofocus.
It's soooo difficult to manual focus on a modern DSLR because there isn't the split prism screen.

 

[astroNikon]

... if I can figure out how to set one AF point on my Canon, I believe there is a way. For those here with Canon Rebel T3i, is there a way to set only one focal point? I can dig into the users guide, if need be.

"is there a way to set only one focal point" =>

 

[Braineack]

But I ALSO RARELY USE THE DIOPTER, the viewer screen gives a much better display.

apparently not...

 

[smoke665]

Not to high jack the OP's post but why do they not have the split prism anymore??? My vision is continuing to decline which forces me to use the screen at 10x for really sharp manual focus. Auto focus is great most of the time unless you're in low light or low contrast, which causes it to do a lot of hunting, especially on any glass without focus limiting. I've also noticed that when set to single point, the tiniest movement can cause it to shift to a new focus point.

 

[astroNikon]

Not to high jack the OP's post but why do they not have the split prism anymore??? My vision is continuing to decline which forces me to use the screen at 10x for really sharp manual focus. Auto focus is great most of the time unless you're in low light or low contrast, which causes it to do a lot of hunting, especially on any glass without focus limiting. I've also noticed that when set to single point, the tiniest movement can cause it to shift to a new focus point.

How does your camera change focus points unless it's on some auto setting?
If you manually set the focus point your camera won't change focus points.

I've set my diopter so that the viewfinder is in focus. But in lower end cameras the viewfinder is much smaller and darker than the better camera bodies.

I don't know when the split prism finally disappeared but there were 3rd parties (and are some new ones) that make focus screens for cameras.
this company seemed to put the other ones out of business ==> Focusing Screen

The main issue is the lenses nowadays are super short focus throws which makes minute adjustments hard. My really old AF lenses have very long throws. As time went on to make AF faster the throws (turns on the focus ring) became much shorter. with AF-S they're even shorter so sometimes focusing on something is difficult. The newer lenses with MF override seem okay though focusing manually.

 

[smoke665]

How does your camera change focus points unless it's on some auto setting?
If you manually set the focus point your camera won't change focus points.

Probably wrong choice of words. Not sure how the OP's model works or the features it may have but on my K3 II, I have three focus tracking modes, one of which will lock focus, and two which will adjust for movement. Even if the focus tracking mode is set to lock focus, it will still "refocus" every time you half push the shutter to recompose (unless you use the AF lock button, which will hold it for a few seconds). Since the camera is going to focus on the point you place it on, any movement in between could set a new focus point (unless you've used the AF lock) while you're recomposing.

Both my Live View (Screen) and Viewfinder have the option of utilizing all or a combination of up to 27 focus points, from single point to multiple points, to selective points. Not sure of other brands, but when using the Live View Screen, mine uses CDAF (contrast detection), low light or those situations having little contrast can cause a lot of hunting even with a short throw lens. One feature that I like when using Live View is the "Focus Peaking" option, which outlines the edges of objects in focus with white.

The view finder on the other hand uses phase detection to focus. The main advantage is the ability to focus in low light situations. The disadvantage is it's really hard to get an accurate focus in manual, especially for those like me with vision problems, something the old split prism would help.

My answer to the OP's question on using AF or manual, would be to read your manual and understand how your camera operates, because frankly there isn't a one answer fits all. The modern digital cameras (even the lower end models) have a lot of options. Knowing how those work will allow you to utilize the best options for the shot.