What exactly do you focus on when shooting a subject?

paigew · Apr 30, 2014

yes I use "Only cross-type AF points"

I use the joystick for vertical and the dial for horizontal toggling.

KelSS90 · Apr 30, 2014

I use single point focus and single-servo mode on my D3200. It seems to work out for me, but my issue comes when I am shooting more than one subject. Should I switch into auto area focus... Single point focus somewhere in between to two faces...? I open my aperture up but I still have issues getting everyone's eyes nice and sharp.

*I considered starting a new thread but feel like this goes along with the discussion here and this particular thread led to my question -- Mods feel free to remove this post if need be!

JacaRanda · Apr 30, 2014

KelSS90 said:
I use single point focus and single-servo mode on my D3200. It seems to work out for me, but my issue comes when I am shooting more than one subject. Should I switch into auto area focus... Single point focus somewhere in between to two faces...? I open my aperture up but I still have issues getting everyone's eyes nice and sharp.

*I considered starting a new thread but feel like this goes along with the discussion here and this particular thread led to my question -- Mods feel free to remove this post if need be!

Probably not a good idea since that mode will likely focus on the closest object. See section 3.3 DSLR Autofocus Modes Explained

ronlane · Apr 30, 2014

KelSS90 said:
I use single point focus and single-servo mode on my D3200. It seems to work out for me, but my issue comes when I am shooting more than one subject. Should I switch into auto area focus... Single point focus somewhere in between to two faces...? I open my aperture up but I still have issues getting everyone's eyes nice and sharp.

*I considered starting a new thread but feel like this goes along with the discussion here and this particular thread led to my question -- Mods feel free to remove this post if need be!

You should pose them on (or close to) the same focal plane. Then focus on one subjects eye and you should be good, if using apertures of 4.5-8.

KelSS90 · Apr 30, 2014

JacaRanda said:
Probably not a good idea since that mode will likely focus on the closest object. See section 3.3 DSLR Autofocus Modes Explained

Thanks for that link -- the chart especially made all of the mode combinations nice and clear.

I've done some reading on this before and still have trouble when the subjects are on different planes (like a 7 year old standing and a 9month old standing - his head just about waist high on the older child). Everything I see says to open the aperture if you are trying to get multiple planes in focus... But doesn't say where to set your focus point.

Braineack · Apr 30, 2014

KelSS90 said:
Everything I see says to open the aperture if you are trying to get multiple planes in focus... But doesn't say where to set your focus point.

if anything you want to close the aperture, something like f/5.6-8 to ensure all subjects fall within the DOF. I'd focus first on 7yo, take a picture, then the 6mo old and take another. Both SHOULD turn out if you chose the aperture correctly so they fall within the DOF, but it depends on the F:R focus ratio, so focusing on both doesn't hurt to help ensure you get a good capture.

runnah · Apr 30, 2014

There is way more to it but if you think of it as the lower the aperture number the shallower DOF will be.

KmH · Apr 30, 2014

You are using an entry-level, consumer grade DSLR that has a phase-detection auto focus module having limited performance. It's not nearly as sophisticated as the AF systems in Canon's more expensive cameras. The AF module is actually from an older model and expert reviews give that AF module low marks.

Though your T3i (US), Kiss X5 (Japan), 600D (everywhere else) has 9 AF points, only the center AF point is a cross-type focus point.
If a person's eyes are in shadow cast by their brows (dark eye sockets/raccoon eyes) there may not be enough light for AF to work well, but the center cross-type point will out-perform the other 8 regular AF points. You may want to use the camera's AF assist light or a reflector get sufficient light into the subjects eye sockets to help AF.
Subjects shot outside often have dark eye sockets.

In Live View, because the main mirror up the 600D can't use the phase-detection AF module and has to rely on the less accurate, and in the 600D slow, contrast-detection AF system.

You apparently have only a partial understanding of what DoF is, how DoF relates to image focus, and how to control DoF to your advantage.
You're not alone. DoF is the most complex technical aspect of doing photography and the way it works is not as immediately intuitive as the exposure triad is.

The more you understand about how your DSLR camera's various subsystems work, the better you are able to get the camera to do what you want done.
Autofocus - Wikipedia, the free encyclopedia
Understanding Camera Autofocus
Tutorials - Sharpness
Understanding Depth of Field in Photography

Derrel · Apr 30, 2014

If you are regularly missing focus on portraits, it's time to re-evluate everything you are doing. First off, strat shooting at f/6.3.

KelSS90 · Apr 30, 2014

Thanks guys! That helps with the multiple subject shots. It's not every time, but I'm definitely not consistent enough with it. Time to get out and practice more.

NedM · Apr 30, 2014

Braineack said:
Show us an example of a photo you took where the focus isn't quite what you expected.

Focus really shouldn't be hard to achieve, but it would be hard for me to achieve while hand-holding the camera, in manual mode, with a live subject. I could imagine plenty of misses. Are you at least using your camera's focus notifier?

Here is a shot where I had my single point focus on her eyes, and somehow it focused on her heels instead.
I don't understand how that could be when I clearly had the focusing point on her eyes. (This always happens to me)

I recomposed once I saw the single point notifier blink inside my viewfinder alerting me that the lens has focused.
I shot without a tripod like I usually do, because my subjects are for the most part very still.

If you were me, where would put the focusing point in this image to achieve sharpness?
I know people say you should always find contrast.
Well, what if there is no contrast or not enough to focus?

ronlane · Apr 30, 2014

Are you using the shutter button as the focus button? Did you hold it down to recompose? If you are using the shutter button and not holding it down when you recompose, you are focusing again after you move the camera (I'm sure you know this.)

NedM · Apr 30, 2014

tirediron said:
Just everything. The larger the aperture, the longer the focal length of the lens, and/or the less the camera-to-subject the shallower the the depth of field, and the greater the need to be spot-on with your focus. If your DoF is from 10' to infinity and your subject is at 40', you don't so much have to worry about nailing that near eye, whereas if your DoF is only 12" and the subject is 20' away, you have almost zero margin for error. Read this tutorial here, and study this calculator here to learn more.

Thanks tirediron, I'll be sure to look into the calculator and try my best to understand what's happening.

SDreams said:
You mentioned that youre usually outdoors. Do you use a tripod or remote shudder release? Maybe these as well as turning off your lens' VS control would help as well.

No, I handheld my shots as I find carrying a tripod and using it a hassle when shooting my subjects.(I usually shoot at very fast shutter speeds) Also, I don't use VS/IS/VC when shooting as well.

Derrel said:
If you are regularly missing focus on portraits, it's time to re-evluate everything you are doing. First off, strat shooting at f/6.3.

You're right, I probably need to reevaulate what I'm doing. I'll shoot at a higher apeture next time around and start from there!

KmH said:
You are using an entry-level, consumer grade DSLR that has a phase-detection auto focus module having limited performance. It's not nearly as sophisticated as the AF systems in Canon's more expensive cameras. The AF module is actually from an older model and expert reviews give that AF module low marks.

Though your T3i (US), Kiss X5 (Japan), 600D (everywhere else) has 9 AF points, only the center AF point is a cross-type focus point.
If a person's eyes are in shadow cast by their brows (dark eye sockets/raccoon eyes) there may not be enough light for AF to work well, but the center cross-type point will out-perform the other 8 regular AF points. You may want to use the camera's AF assist light or a reflector get sufficient light into the subjects eye sockets to help AF.
Subjects shot outside often have dark eye sockets.

In Live View, because the main mirror up the 600D can't use the phase-detection AF module and has to rely on the less accurate, and in the 600D slow, contrast-detection AF system.

You apparently have only a partial understanding of what DoF is, how DoF relates to image focus, and how to control DoF to your advantage.
You're not alone. DoF is the most complex technical aspect of doing photography and the way it works is not as immediately intuitive as the exposure triad is.

The more you understand about how your DSLR camera's various subsystems work, the better you are able to get the camera to do what you want done.
Autofocus - Wikipedia, the free encyclopedia
Understanding Camera Autofocus
Tutorials - Sharpness
Understanding Depth of Field in Photography

I've been using only the center AF point whenever I went out and shot portraits, so at least I've been doing something right.

What's the difference between cross-type points and regular points?

Thanks Keith, I'll be sure to do some heavy reading on the articles you referenced here.
DoF is such a complex topic but I'm hoping to have sharp focusing down at least.

Braineack · Apr 30, 2014

what are the camera settings of that shot? looks like you nailed the focus...on her feet. You into that sort of thing?

What lens as well? I know if I would shoot with my 85mm on my D3100 and D5100 with both cross and non-cross focusing points, while using a larger aperture, I would often miss the focus.

NedM · Apr 30, 2014

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ronlane said:
Are you using the shutter button as the focus button? Did you hold it down to recompose? If you are using the shutter button and not holding it down when you recompose, you are focusing again after you move the camera (I'm sure you know this.)

Yes, I depress the shutter halfway and when the AF point indicator/notifier blinks, I then recompose and press the shutter all the way.

That could be possible, I could be depressing the shutter whilst recomposing resulting in a missed focused on the subject.