Who/Where do i focus on?? please help

jeniveeev

jeniveeev

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Hi - hope you can help. When im taking a group who do i focus on? say there are 5 people, all different heights standing in front of each other (smallest at front, tallest at the back) who do i set my focus on to get everyone in focus? i find that either the people at the back or front are out of focus and middle person is sharp? i know it has something to do with aperture so if i go from say f2 to f4 that will bring in more focus of the overall picture. or should i be looking at say f9/f11, but then i lose the light? i know its probably very simple but please put me out of my misery!?? Also should i be thinking of distance between myself and the group?
thanks kindly
jen
 
I'm not knowledgable enough to give you the right answer with specific settings but you are right in that the answer lies in a smaller aperture and is affected by the distance you are from the subject. F4 is still a fairly wide aperture so you'll get a narrow DOF. F8 could be sufficient to get everyone in focus but it depends on your focal length and the distance from camera to subject.
 
All of the above - it sounds like you've got the theory right in any case
The further you are from the group, the more apparent depth of field your lens will record, and a narrower aperture will also give you more DOF...

I'd also suggest re-arranging the group into an 'arrowhead formation' to reduce the distance front to back that you're trying to record...hope this helps...
 
Arkady said:
The further you are from the group, the more apparent depth of field your lens will record
Click to expand...
Rob, could you clarify this bit please just to make sure I understand as I'm certainly no expert.

If you shoot a group of people from a distance of 10ft from the subject at 17mm and f6.3 you'll appear to get a narrower DOF than if you shot the same group of people from 100ft away 70mm and f6.3.
 
Hi have a look here this will give you the depth of field for whatever lens length aperture you are using, as well as near and far focus and hyperfocal distance,for example if you where using a 50mm lens at f8 and distance to subject was 10 ft your dof would be 3.7 feet approx near focus at 8.4 feet and far 12.2 feet hope this helps
It will differ depending on crop factor of camera though
 
This one lets you input your camera as well.
http://www.dofmaster.com/dofjs.html

As has already been stated DoF is affected by aperture and distance from the subject, it is also affected by focal length.
A wide angle lens has a wider field of view (i.e. you see more from side to side ) it also has a greater DoF (i.e. more is in focus from near to far )

So changing to a wide angle gives you greater DoF, you then move closer which gives you a reduced DoF. Hence the need for charts etc unless you lens has an aperture ring and distance scale on it.
 
Arkady said:
All of the above - it sounds like you've got the theory right in any case
The further you are from the group, the more apparent depth of field your lens will record, and a narrower aperture will also give you more DOF...

I'd also suggest re-arranging the group into an 'arrowhead formation' to reduce the distance front to back that you're trying to record...hope this helps...
Click to expand...

thanks Arkady - the arrowhead formation is great idea, il definitely be trying it out.
 
thanks everyone, my head is now mince reading this and those calculation sheets. gosh i think il have to study this one to get my head round it! are you guys really accurate with your distances when you shoot or are you confident enough to guess-timate it? also, what lens would you use? i have an 85mm 1.8/50mm 1.8 and kit lens. i could also borrow a wide angle.....thanks for that SUVV. The group im shooting are 6 kids aged 7 to 23!

also - do i focus on the centre of the group aswell? :-)) . last question....i promise!
 
Rule of thumb - If you are shooting groups, and you want them all in focus, do not use anything larger (smaller Number) than an f8.0 aperture.

Focus on someone in the middle of the group, or a bit further forward. Remember it is the distance of the camera to subject that is important, so if the group is a long thin line, those at the end will be further away, better to have a shorter deeper group.

With these smaller apertures you need to keep an eye on the shutter speed and keep it up. With your 50mm lens on a D70, you need shutter speeds over 1/80 sec. You may have to increase the ISO to get into this safe zone.
 
jeniveeev said:
also - do i focus on the centre of the group aswell? :-)) . last question....i promise!
Click to expand...

Just to be awkward about 1/3 of the way from front to back ;)

Generally the 'field' that is in focus is generally about twice as deep beyond the subject as in front



Camera facing this way> ----------(---X------)----------

The X denotes where the camera is focusing and the brackets indicate what is in acceptable focus
 
will69 said:
Rule of thumb - If you are shooting groups, and you want them all in focus, do not use anything larger (smaller Number) than an f8.0 aperture.

Focus on someone in the middle of the group, or a bit further forward. Remember it is the distance of the camera to subject that is important, so if the group is a long thin line, those at the end will be further away, better to have a shorter deeper group.

With these smaller apertures you need to keep an eye on the shutter speed and keep it up. With your 50mm lens on a D70, you need shutter speeds over 1/80 sec. You may have to increase the ISO to get into this safe zone.
Click to expand...

Will - thank you for the advice. should i also use a tripod if my s/s is slower? il be using a D300 for the shoot so i can up the ISO without too much noise and hope its a bright day. also, if i up the ISO would i be better keeping the s/s low with a tripod or not? thanks
 
Uneducated_Rick said:
Just to be awkward about 1/3 of the way from front to back ;)

Generally the 'field' that is in focus is generally about twice as deep beyond the subject as in front



Camera facing this way> ----------(---X------)----------

The X denotes where the camera is focusing and the brackets indicate what is in acceptable focus
Click to expand...


thank you - this is really really helpfull. gosh im glad i asked this question!
 
jeniveeev said:
Will - thank you for the advice. should i also use a tripod if my s/s is slower? il be using a D300 for the shoot so i can up the ISO without too much noise and hope its a bright day. also, if i up the ISO would i be better keeping the s/s low with a tripod or not? thanks
Click to expand...

You can use a tripod, which has advantages in that you can use lower ISO and improve image quality. Biggest advantage of a tripod is that it makes you work slower, makes you think more, also affects attitude of subject which is reflected in the images. I am a big fan of tripods so I am biased.

Disadvantage is that it can be fiddly and is less flexible.
 
use your preview if you have one
press the shutter slowly focussing on the front person and see if the rear is ok
if not focus on the second etc

i usually focus round about 1/4 of the way and hope to be using f4 on a 38mm setting from about 3 metres away

thus the variables
lens focal distance
aperture
distance from the subject

take two or three and delete the ones which arent suitable...digital gives you allowances to make mistakes and correct them straight away

:)
 
I'd recommend using the tripod for this one, but still be aware of the shutter speed because the tripod won't stop motion blur.
I've had some pretty poor results at 1/60s yet seen some very good ones at 1/13s, so give yourself the best chance. Tripod and consider a little spray and pray :D
 
I would just " rule of thumb" it.
I would look to see how their feet were positioned front to back, and then focus on the person who seemed to be about 1/3 of the way in, but what ever part of the group he was in ( side or middle) I would then half press to lock focus, re-frame and shoot.
I would set F8 or F11 for deeper groups.

Some purists might disagree with this method but speed is essential when shooting groups, as is making a number of exposures.
 
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