How to focus properly in the studio

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Corbus

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Hi, first time poster here.

I have a D60 and have been given free access to try out a studio for a few hours. I've encountered a bit of a problem, lighting and everything is fine as already set up, but I can't seem to get the focus right. I'm using a 50mm AF-S, the problem I have is when doing full portraits of toddlers. If I focus on the eyes, this is fine if doing a close up, but how should I focus when doing a full body shot? If I focus on the eyes this cuts out the legs, so I need to be able to have everything in focus without specifically focusing on the eyes. Does this make sense? At the moment, the full body shots tend to ive the face a fairly soft focus.

I'm new to all this and am wondering if the three focus points is the problem? As far as settings go on the D60, the AF options are closest subject, single point or dynamic area. Looking at the camera it seems I've had it on closest subject, which I guess is the more likely problem?

This is just a one off in the studio but I'd like to take some good pictures of the kids while I have the chance.
 
what are your camera settings (apeture, shutter speed and iso)? sounds like you're using f1.8 in a studio which is a bit odd

f8 @ 60/125/250th or something depending on your lights and output would be something to experiment with :)

are you using a lightmeter?
 
What aperture are you using? If you use a smaller aperture then you'll get a greater depth of field and allow more of the body to be in focus.

You also have to consider the lighting though. The level of lighting used will affect the aperture you need to use. In the studio I generally use about f8 which should be fine to get a full body shot in focus from head to toe.
 
^^ smaller as in smaller hole (i.e higher number) rather than f2.8 which is a large aperture

:)
 
Single point is what I generally use. Two ways of doing it. Either focus on the eyes, keep the button half depressed (whick locks to focus) and recompose. Downside with toddlers is that the little blighters move quickly so this is not foolproof (good for static subjects though)

Other way is single focus point but moved in camera so it is over the eye area. I know how to do this on a Canon but you will have to ask a Nikonite how to do it or go delving in the manual.
 
Sorry if this sounds stupid but when you say it cuts off the legs do you mean they are out of focus or not in the picture? It sounds like you mean they are not in the picture in which case after focussing on the eyes recompose your shot to include the legs.
 
AliB said:
Single point is what I generally use. Two ways of doing it. Either focus on the eyes, keep the button half depressed (whick locks to focus) and recompose. Downside with toddlers is that the little blighters move quickly so this is not foolproof (good for static subjects though)

Other way is single focus point but moved in camera so it is over the eye area. I know how to do this on a Canon but you will have to ask a Nikonite how to do it or go delving in the manual.
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a1ex2001 said:
Sorry if this sounds stupid but when you say it cuts off the legs do you mean they are out of focus or not in the picture? It sounds like you mean they are not in the picture in which case after focussing on the eyes recompose your shot to include the legs.
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The space in the studio isn't great, so when I keep the focus point on the eyes when composing, the bottom half is completely cut off.

Ah, right. As I said, fairly new to this, I assumed that locking focus on the eyes and then recomposing would only lock focus within that particular focus point, thus throwing the eyes out of focus. I'll have to give this a go using single point.

Thanks
 
Knock a wall down, move backwards.

Or get a wider lens, or plan your shots for head and shoulders?
 
Corbus, I was going to type a reply but it was going to end up being a bit lengthy and might have missed the point that is relevant to your difficulties. It might help if you post an example or two to show exactly the setup you have, the shooting distances and angles involved and how you have your subjects posed. Once we see what you are trying to achieve, and how you are going about it, it might be easier to provide more specific advice.

In the meantime, try reading this - http://visual-vacations.com/Photography/focus-recompose_sucks.htm
 
Sounds to me like you are only using the centre focus point, All you need to do is select a different focus point and all should be well.
 
BOM said:
Sounds to me like you are only using the centre focus point, All you need to do is select a different focus point and all should be well.
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I only have three though, if I choose the left or the right this will throw evertyhing out of focus won't it?

Unfortunately I won't get a chance to upload any pictures before I go back in there, I only have use for a couple of hours later today and will be taking the kids there, will see how it goes though.
 
Corbus, fundamentally the camera will only be focused truly sharply on a (flat) plane that is parallel to the sensor. the depth of field that a given aperture provides is just an area that should be acceptable sharp on either side of that truly sharp plane. As to which focus point to use, consider this....

You point the camera directly at a flat wall, 3m away, so that the wall is exactly parallel to the sensor (or perpendicular to the lens if you prefer). You use the centre focus point to focus on the wall. The camera focuses at 3m and the whole wall is in focus, top to bottom, left to right.

If you were then to select a different focus point and focus again, what would happen? Well, nothing. The camera would still be focused on the wall and everything would still be in focus top to bottom, left to right.

Now, draw a life size person on the wall. Would it matter whether you used a focus point at the top to focus on the "eyes" of your drawing, the centre point to focus on the belly, or the bottom focus point to focus on the knees? The answer is "No". Everything is on the same plane and everything will be in focus.

Of course, real people are a little bit bumpy, so you will get small differences in the exact focus distance, depending upon whether you focus on the eyes, belly or knees, and with some people that variation might be quite large :) but you would choose an aperture that gave you sufficient DOF to include the whole person and, in truth, I doubt you would notice much difference in results if you were stopped down a bit, say to f/8 for example.

The problems only really start to appear when your subject has a lot of depth, like someone sitting with their legs outstretched in front of them. Then you need a very large DOF and, if you focus on the eyes, which are at the far part of the subject the feet may well end up out of focus. Alternatively, if you are shooting at an odd angle, like from way above the subject, again you create a much larger depth to your subject, because the top of the head and face is much closer to the camera than the feet. So once again you need a very large DOF to cover the whole subject. If you focus on the eyes then the feet will probably be out of focus.

So, what can you do? Well, there are a few things....

- Stop down so that your DOF is sufficient to cover the whole subject;
- Adjust your own shooting position so that the "depth" of your subject becomes less;
- Adjust the pose/position of the subject so that the subject presents a less deep target;
- Focus somewhere roughly in the middle of the field rather than at one end or the other.

Certainly, focus/recompose will add to the complication of working out where your focus will end up, unless you have good spacial skills and can imagine an arc that is traversed by the camera as you recompose. The best thing to do is to figure out whereabouts you want the focus to be targeted, and then choose a focus point that is closest to that point, in order to minimise the degree of recomposition required. One sure thing - if your subject has a lot of depth, and you want your whole subject in focus, the eyes may not be the optimum focus point to aim for.

If you want to figure out where you should be aiming and what aperture you need then it's time for the old DOF calculator - http://www.dofmaster.com/dofjs.html.
 
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