View Full Version : Focus shhh...mocus! Help please!

18-07-2012, 11:52pm
Hi all....

These questions may be as simple but I am stuck in the fetal position!!
Please take no notice to the background objects, this snap was just me getting to know my camera.......2nd week!


What I am interested in is the blurred background.....I like it and don't exactly know how it was created? Is this as simple as a close subject and a large aperture? f/5.3 1/500 sec. ISO 1600.
I was shooting in sports mode ISO auto and AF-area mode auto. The pole to the left is in focus which may mean I need to set focus to single-point AF?
Right? LOL


19-07-2012, 6:27am
Go to the AP Library, New to Photography, and read the articles on Aperture. (section 11) :D

But..don't stop there, work you way through the New To Photography library, cause Aperture is only one part of the equation (Shutter Speed and ISO are the others). Once you understand how those three work together, you will be able to control your camera and make it do what you want it to!

19-07-2012, 9:00am
The pole to the left is relatively in focus, but that is probably not because you used multipoint focus, but because it is approximately the same distance from you as the subject you focused on (the young girl). It MAY be because of multipoint focus (one reason I don't use it often, because it rarely picks the part of the scene that I want it to), but it's more likely the above.
As rick said, there's heaps of information on Depth of Field in the tutorials and library that will help you understand how to get the blurry background that everyone likes. You're on the right track with putting it down to aperture, but taking a bit of time to read some of the stuff there will help even more to put it all into perspective.
Then just start putting up some photos for people to give advice on, and you'll be amazed how fast it all starts to come together.

19-07-2012, 9:58am
Thanks you guys,

I have re-visited these pages and you are both right... It is coming together a bit more :-)

The pole is more a composition issue rather than a focus issue!

Do many people use Aperture mode for shots like this with kids? I imagine it would be difficult to keep up with them adjusting for different DoF.

19-07-2012, 11:14am
I agree it is difficult to keep up with children if you are using aperture priority mode in low light as camera will compensate for exposure by slow shutter speed and it will blur the subject. I usually use manual mode with f2.8 - f4 whenever available and shutter speed between 1/80 and 1/500 depending upon the situation. I use up to ISO1600 in 7D as it shoots useable photos for that range and gives me enough room in low light to adjust exposure to my liking.
I set shutter, aperture, ISO in that order for shooting kids.

19-07-2012, 1:11pm
I'm assuming that the f/5.3 is due to the fact that the lens in use is the kit 18-55mm kit lens.
f/2.8 - f/4 is therefore not going to be an option.

D5100 is quite a nice little camera and very capable, but focus is slowish which is due to both the camera and the lens itself doesn't help either.

DAF, for what it's worth, the slightly out of focus(OOF) background is due to two (ok, maybe three) elements.. which you will find in the NTP guides.

1. focus distance .... that is how far from the lens is the subject.
2. focal length ... in this instance 40mm
3. aperture ... in this instance f/5.3

1. get closer .. best way to blur out backgrounds!!
2. longer is better for blurred backgrounds
3. faster( = smaller number = larger physical aperture) is better.

there are some conditions to watch for too tho.

I've seen that even tho the 18-55 kit lens can do some blur, it's not always appealing to the viewer.
There is a specific blur quality rendering which is referred to as bokeh(bo-kay).
This is how we rate the quality of the blur, and most kit lenses do a bad job of it, where the blur quality is quite harsh.
There are some kit lenses that can produce acceptable bokeh.

If you have the twin kit lens setup with the D5100(which I advised my brother against getting!! :p), then try using the other lens, if it is the 55-200mm lens.
That lens is better for doing portraits with a kit lens .. than you will get with the 18-55 kit lens.

ideally, you want a constant f/2.8 lens for portraits tho.. blurring the background is easier to do, and 99.9% of the time is also rendered more pleasantly.
Other options are to get a nice fast prime lens, and for this camera the Nikon 35/1.8 is an ideal choice.

Finally(and on a different note).. the WhiteBalance (WB) of the shot is way off.
Did you shoot in the NEF format?
If not why not!
Raw format is better, and as you're only new to it, start to get used to it now.
If you did shoot in NEF format, open the raw file and adjust the WB manually on the PC.
It needs a massive tint adjustment into the green channel.. way too much magenta to begin with.

19-07-2012, 4:41pm
Thanks and thanks

For the great information passed on... It is much appreciated!

Arthurking....thats correct the 15-55mm kit lens was used and the twin lens I received with this package is a 55-300mm f/4.5-5.6. Guess that doesn't help too much though by the sounds of things!
I have many things to learn about my new little hobbie before I go to buy more equipment....

I did shoot this in JPEG as I wanted faster processing of images. I guess quality over quantity is a good arguement too.

Thanks again

Mr Bob
19-07-2012, 7:11pm
If you like the shallow depth of field, try a basic prime lens.
I grabbed a 50mm prime lens for my D60, with the f/1.8 aperture you can get quite a shallow DOF, and also get great shots in low light
Mine is the Nikon Nikkor AF-S 50mm f/1.8G

Of course, it has no zoom, which might mean some extra running around to get yourself in the right position for the shot.

There is also a cheap 35mm f/1.8G prime lens for the Nikon which is wider.
You can always crop the image afterwards :)

They're great for static/arty shots, but might not be as good for taking shots of the kids,
(the moment you want to capture will be missed while you find the right position to compose the shot)

Mark L
19-07-2012, 8:47pm
Do many people use Aperture mode for shots like this with kids? I imagine it would be difficult to keep up with them adjusting for different DoF.

Aperture or shutter priority mode is going to be better than sports mode. You can control the camera.:th3:
If you're after the blurred background then I'd be using aperture mode to learn. ie- you select the aperture and the camera looks after the rest. Though I would also select ISO and not leave it on auto ISO.
Experiment and learn. I'm still finding it a little hard, after paying for film for years, to be carefree with the exposures. It's free now.

20-07-2012, 4:07pm

Arthurking....thats correct the 15-55mm kit lens was used and the twin lens I received with this package is a 55-300mm f/4.5-5.6. .....

..... If you like the shallow depth of field, try a basic prime lens.......

Even better suggestion!(only because it's the much cheaper option and quicker to boot!)

The 55-300 lens will be fine, because all you want to try is the longer focal length, and an aperture as fast and wide open as you can muster up!!

Mount the 55-300, set the zoom length(focal length) to approximately 100 or 105, or whatever is marked at about that range.
Being an f/4.5 - f/5.6 aperture lens, my guess is that at 100mm you may see an aperture value of about f/5 to f/5.3 or so .. this is fine. Slow!! .. but fine.

If you can get the subject in the frame as you want, then go longer, but on a cropped sensor body and with limited room to move about you may struggle with composition.

So with the 55-300 lens mounted, and the lens set to 100mm, set the camera to Aperture priority as already said by others and then follow your subject around but where you have to maintain a distance .. approximately 5m or maybe more if you can. But not too far away either.
Remember that both focal length AND the distance to subject make a huge difference to the DOF, and the longer the lens and the closer the subject, the blurrier the blur too!

I suppose it also makes sense that you would keep practising with these concepts at longer focal lengths and working distances that suit the type of photography you're trying to achieve.
The issue you'll start to see with longer focal lengths is that you will capture less and less of the actual background, so not only is there less background distraction with the blur, but there is also simply less background!

With a more wide angle lens, you capture more of the background, to produce what's commonly referred to as an environmental portrait. That is you're placing the portrait subject against a complimentary background.. eg, kids playing at a playground .. etc.
To get a bit more blur in that situation .. there are fewer technical options ... format(that is sensor size format, and aperture and aperture. Faster aperture will give you more blur.

20-07-2012, 6:30pm
Thanks to everyone for their input..... Great stuff!! :-)