9/28/2012

Nailing Focus: Part 2 - Focus Techniques

Yes, believe it or not there are techniques for getting good focus and I'm going to look at these here today!   This should be read alongside Nailing Focus: Part 1 - Focus Modes to help you get a full understanding of what I am talking about in them both! OK, so here are the different ways you will be able to focus with your DSLR......

FULL AUTO FOCUS 
In this mode, the camera will pick the focus point for you. It will pick focus for the closest subject, or closest part of a subject, which may very likely not be the one you want. Once you get a bit more proficient with your camera I suggest you don't use this mode anymore - again, we are striving to control the camera ourselves and not let it choose for us as it doesn't always know best (you do!) Basically, this is a bit of a click and hope method, which means sometimes it will get it spot on (those times everything is on the same focal plane) and others horribly wrong, so I only use this when I'm passing my camera to my husband.



MANUALLY SELECT AUTO FOCUS POINTS
With this method, you can choose the focus point rather than letting your camera choose it for you. In my model I have nine focus points (see first image below) - you may have more or less. To select a focus point on my Canon Rebel I have to press the button on the front of my camera (circled in red below in the second picture) and then move my front wheel around to pick one of these points. (You will have to check your camera manual to see where it is on your make and model)  You can manually toggle to any of  these focus points to get one that suits your composition.  In the case of a portrait shot, you should use one that falls over their leading eye. Sometimes it can be difficult to keep toggling these points with a fast moving toddler, in which case you can use the central one and use focus-recompose.....





FOCUS-RECOMPOSE
This is where you depress the shutter halfway to activate focus (using the central focus point) then, keeping your finger on the shutter, move the camera to the composition that you want.  Once you are happy, you depress the shutter fully.This is probably the simplest method after AUTO MODE, and I use it all the time, but it does have a couple of drawbacks.  The first is that if your subject moves between the time you half depressed the shutter and then took the shot, you are likely to have an out of focus or "soft" image (depending on how much they moved) The second is if you are using a very narrow depth of field (small F stop) the slight movement of you moving the camera to change your composition can be enough to throw off focus. (In this situation it might be better to manually toggle your focal points)

BACK BUTTON FOCUS 
This is one you may or may not have heard of before.  Simply put, all this means is that you assign another button on your camera to activate focus (this is usually the * on the back of the Canons, again check your particular model) rather than the shutter button. So, instead of pushing the shutter halfway down to focus, you push the * button, and it locks focus. Now, you may be wondering why you would do such a thing. The first reason would be if you are shooting a stationary subject (when the distance between the camera and the subject is constant), you can simply lock in the focus by pushing the back button, and shoot away with different compositions without having to re-focus each time. BBF also works very well when used with Al Servo on moving subject - you can just hold the back button down and use the shutter to take your shots. As long as the back button is held down, it will keep tracking the subject and focusing on it.  Some people hate BBF and others love it, so it is definitely a personal preference thing - I've only just recently started using so I'm still getting used to it but I'm definitely in the "love" camp!



FULLY MANUAL FOCUS 
I nearly never included this one as I am not entirely sure if you would ever want to use this in child photography - but you also have the option to manually focus on your subject by moving your dial on the front of your lens (after you have changed it from AF to MF) The only time I can ever imagine wanting to use this would be if I deliberately wanted to unfocus the whole of the scene slightly (perhaps to give it an "out of this world" feel) but that's it. And I've never felt the need to do that yet either.

Using these focusing techniques with the different modes mentioned in the previous post, should start to help you get sharper pictures more consistently.  Hopefully everyone will find something new here regardless of the stage they are at - if you are currently using Full Auto Focus, then don't move straight onto back button focusing - maybe just start off by manually changing your focal point (the center one to begin with) and take it from there!  There is actually a LOT of information here and if I'm honest, the first few times I  read about this subject (particularly BBF) there was definitely a lot of head scratching going on! (still is sometimes) So, if anyone would like clarification on any of these then ask away and hopefully I'll be able to help.

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18 comments:

Anonymous said...

Thank you so much for your blog, it is a joy to read & so helpful! A qu about bbf if you can help pls? Canon 50d has 'AF-on' button as bbf but has 4 options to choose in activating it. Do you know which option to choose for photographing toddlers? Thank you from a SAHM & photography newbie.

Audrey said...

Hi there, I would go with either Option 2 (Metering start / Meter + AF start) or Option 3 (AE Lock / Metering + AF start) In both these options the shutter will no longer activate focus, but still fires the shutter. Focus will be activated by pressing the “AF-ON” button. The difference between the two is whether you also lock in the exposure. With Option 2, there’s no locking of exposure, unless you separately press the “AE Lock” button. With Option 3, your exposure will be locked and won’t change until you pull your finger off the button entirely. (If you use Manual mode you don't need exposure lock so go with Option 2) I hope that helps - let me know how you get on!

Anonymous said...

Thank you so much! I read your last article on bbf & will take your advice & learn about focus modes focus points metering & ae lock first! Also sleep deprived mum above post should have referred to canon 60d & 10 options not 4 in case others read it & get confused. Wrote long post before but lost it just wanted to say thanks again and don't know how you manage to keep up blog while raising gorgeous boy!

Audrey said...

You lucky thing having a 60d! Thanks for your comments, especially about my boy being gorgeous!!!

Ava said...

Hi Audrey!

Thank you so much for all the tips you're giving! This is me go to blog for answers.
Question..
What is the best focus technique for photographing large groups that are still. I get confused on where the focal point should be.

Audrey said...

Hi Ava - photographing large groups could be a post in itself (and maybe one I'll do!) but in short, use Single Point AF, and focus on one person in the middle of the group. The most important bit is to use a large aperture to make sure that you get everyone in focus - you will need quite a large depth of field (i.e area of focus) so I would use at least F8 to be on the safe side. Hope this helps a little bit!

Ava said...

Thank you Audrey! And yes please do a post on large groups. I did a group of 8 the other day and totatly botched the pics... my aperture was low ;/

Audrey said...

Ava, I feel your pain - done exactly the same thing myself!

Sandra R. Vigil said...

Thank you thank you thank you! I've spent a few hours now reading your blog. It's by far the easiest to understand and it helps that we have the exact same camera. Question for you- so am I understanding correctly that you either toggle your focus points or do bbf using the center point- not both? I guess I always thought you did both. Also when activating your bbf in the menu, which option do you choose. I've read 1or 3 are best but not sure what the differences are. Thanks again!!!

Sandra R. Vigil said...

Thank you thank you thank you! I've spent a few hours now reading your blog. It's by far the easiest to understand and it helps that we have the exact same camera. Question for you- so am I understanding correctly that you either toggle your focus points or do bbf using the center point- not both? I guess I always thought you did both. Also when activating your bbf in the menu, which option do you choose. I've read 1or 3 are best but not sure what the differences are. Thanks again!!!

Audrey said...

Hi Sandra! You can use back button focus with any of the focal points - it's really just assigning the back button to do the job of half-depressing the shutter. As for focus points, the central focal point is more accurate, so there may be times when it is better to use that rather than toggle the focus points. Using Al Servo is one of those times! When activating BBF, the different options relate to whether you also want Exposure Lock. I use option 1 if that helps!

Anonymous said...

I have a question that may be a really dumb question,,,what is the difference between the focus square on the LCD that you can move around to any place you want and the auto focus points that you can manually select? I guess I am just wondering why you would have to pick a point if I though the focus square could be moved around to whatever point you wanted and it would focus wherever the square was? (hope this makes sense) Also are you able to pick more than one focus point? I'm assuming not?

Audrey said...

I think (though not sure - you may have confused me slightly here!) that what you are talking about is one and the same. The square is your focus point - your camera will automatically select a focus point for you if you are on Auto, or you can manually select one of the squares yourself. Obviously, having more control is better as your camera can get it wrong. With regards to picking more than one point, with more entry / mid level cameras you will only be able to pick one point, with pro models, you can usually also pick "zones" - so 6 squares clustered together. I'm going to assume though that you have nine squares or so, in which case, you can only pick one. Not sure if this the answer you were looking for!

Anonymous said...

Ok sorry, maybe i am just confusing myself! Let's see if I can explain this better...on Live view (on the LCD screen) I can move that little focus square to any place I want it seems (not just those 9 points) by simply moving the arrows up/down left/right,,,If I can manually move that square anywhere I want MF) what is the difference between that and manually selecting the focus points, are these only enabled if you are using the view finder vs the LCD??? sorry if this is even more confusing...

Audrey said...

Sorry, I have no idea - I don't have this feature on my camera. Are you sure that the squares on Live View control focus? Personally, I would do a test and if they do accurately focus on areas other than the nine squares you have (and you control them) I can't see any reason not to use them. Sorry I can't help - never heard of that before!

Anonymous said...

I have a Canon Rebel T3i, when I use the LCD (vs the viewfinder) there is the focus square that can be moved anywhere...Is the 9 focus points something that can only be used when shooting with the view finder? I am really sorry, I am probably just confusing my self (and you)...

Audrey said...

I think I've got what you are talking about! (my little brain got there in the end) I never used this feature as it's apparently a lot slower to focus in this way. So, I'm going to say, depends on what you are shooting - stationary subjects and you are happy with Live View, go for it, but running subjects, switch to manually selecting the focal points and use your viewfinder. Personally, I would get used to looking through your viewfinder and manually selecting a point but if you are happy with the Live View, by all means do it :)

Anonymous said...

Thanks so much. Maybe this is why my pics have not been as sharp as I want them! Definitely going to switch to view finder!

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