Pixalo Photography Community

Go Back   Pixalo Photography Community > Photography Forums > General photography questions and answers

General photography questions and answers: Discuss How Do You Get The Focus/Un-Focused Effect?...I`ve noticed a lot of photos on the forum where the main subject is highly in focus but the background ...
Welcome to the Pixalo Photography Community. As a Guest you are free to browse the site, but see what extras you get as a Member here.


Reply
 
LinkBack Thread Tools Display Modes
Old 23-02-2005, 21:49   #1 (permalink)
New here
 
Join Date: Feb 2005
Location: Fife, Scotland
Posts: 19
markyg is an unknown quantity at this point
User's Gallery
How Do You Get The Focus/Un-Focused Effect?

I`ve noticed a lot of photos on the forum where the main subject is highly in focus but the background is out of focus. I tried to do this this morning but I suspect my camera (Fuji FinePix A101) isn`t up to the job. Is it a camera effect or is there someway to pull this off?

Cheers as per!!

Case in point!

markyg is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 23-02-2005, 21:53   #2 (permalink)
Member
 
Join Date: Jan 2005
Location: kings hill
Posts: 4,636
Matty is an unknown quantity at this point

Image editing O.K.
User's Gallery
Welcome to the world of Depth of field!!!

i will let someone who can articulate the answer into a concise reply, rather than the really long ramble i will probably come out with!
Matty is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 23-02-2005, 22:09   #3 (permalink)
Getting Comfy
 
Pook's Avatar
 
Join Date: Jan 2005
Location: Blackpool UK
Posts: 156
Pook is an unknown quantity at this point
User's Gallery
Re: How Do You Get The Focus/Un-Focused Effect?

Quote:
Originally Posted by markyg
I`ve noticed a lot of photos on the forum where the main subject is highly in focus but the background is out of focus. I tried to do this this morning but I suspect my camera (Fuji FinePix A101) isn`t up to the job. Is it a camera effect or is there someway to pull this off?

Cheers as per!!

WHat you need to read up on is "depth of field". Basically, the area of aceptably sharp focus behind and in-front of the object you have actually focused upon. This changes with focal length and aperture. If you're using an automatic camera, you may have little control over this.

Basically assuming a standard 50mm lens is used on a 35mm camera, to obtain the effect you describe, you need to shoot at a wide aperture.. say F2.8. If you closed the aperture down to say f22, then the blurred background will be much sharper. On a manual camera, you would also have to adjust the shutter speed to compensate.

To fully learn how to use depth of field, you need to learn about reciprocity law. Ok.. don;t panic.. this is easy... a diagram will help.



Now... look at that table.. you will see apertures down the left, and shutter speeds down the right. Notice something? As the aperture gets wider (lower f number) the shutter speed gets faster! This is the reciprocity, or relationship between aperture and shutter speed. 1/1000th of a second at f2.8 is the same as 1/8th of a second at f22. The same amount of light reaches the film, or chip... the exposure is the same!! So why have the ability to control these two things independantly? For control over things like depth of field, that's why.

As stated earlier, a wide aperture (low number) gives shallow depth of field... your background will be blurred, and a small aperture (high f number) will give a deep depth of field.. sharp background. Howerver, you cant just choose a f number at random, as your exposure has to be correct. If you knew that your correct exposure should be 1/30th at f16, then if you want to shoot at f2.8, you just work it out....

1/30th at f16
1/60th at f11
1/125th at f8
1/250th at f5.6
1/500th at f4
1/1000th at f2.8

You need to increase your shutter speed by 5 stops, and you open up the lens by 5 stops... one balances the other.... The Reciprocity law. The exposure will be identical for all those combinations, but your depth of field will change dramatically.

Other things effect depth of field too. Focal length primarily. Long lenses have inherently shallow depth of field, even when stopped down to max, whereas wide lenses, such as a 18mm on a 35mm camera, has depth of field so deep when opened up, that you hardly even need to focus... so to get the effect you describe, a long lens, with a wide aperture would have been used.

Having a manual camera, or at least manual control over your camera is pretty essential for this. Cameras that allow you to adjust the aperture and then the camera adjust the shutter to match are called aperture priority auto cameras, and lots of auto cameras allow this too.. you need at least this latter option to have full control over depth of field.

Hope I haven't confused you too much.
__________________
WWW.DAVID-GREGORY.CO.UK
--------------------------------
Horseman DigiflexII with Phase One H10 and Various Nikkors for studio,
and Canon 350D and various EF lenses for location.

--------------------------------
Pook is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 23-02-2005, 22:17   #4 (permalink)
Forum Regular
 
Join Date: Jan 2005
Location: Gloucester UK
Posts: 741
MyPix is an unknown quantity at this point

Image editing O.K.
User's Gallery
in laymans terms,

the point you focus at is split into thirds,
two thirds are in focus behind the shot, and one third in front
so if you focus at 10 meters away, and at the right depth of field ( blured/unblured) , it could be 2 meters behind and 1 meter in front in focus, and the rest is blurred,

now,, the higher the Fstop also known as aperature the smaller the distance between the focusing points, the larger the fstop,the greater the distance and more is in focus, another way of saying it would be that the depth of field is bigger.

this can be set on ' simple ' cameras by choosing the shooting options , for example, you will have a portrait mode, closeup mode, and mountain( landscape ) mode,
the closeup and portrait will give the blurred effect on anything around 3-7 meters away, the landscape mode will have everything in focus ( pritty much )

hope this helps

MyPix
__________________
Its not the camera that takes a good pic ;o)

But i use a Nikon
MyPix is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 23-02-2005, 22:20   #5 (permalink)
Member
 
Join Date: Jan 2005
Location: kings hill
Posts: 4,636
Matty is an unknown quantity at this point

Image editing O.K.
User's Gallery
thanks for that Pook, very nicely explained!
Matty is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 23-02-2005, 22:42   #6 (permalink)
Pixalo Crew
 
Join Date: Jan 2005
Posts: 19,250
Steve is just really nice
Steve is just really niceSteve is just really niceSteve is just really niceSteve is just really niceSteve is just really niceSteve is just really niceSteve is just really niceSteve is just really niceSteve is just really niceSteve is just really nice

Image edit - ASK
User's Gallery
Users Camera Equipment List
The simplest way I can think of wording this very tricky subject is to tell you that a lower number of F stop (usually referred to as aperture) will also reduce the distance from front to back of your subject that will be in focus(usually referred to a Depth Of Field) D.O.F.

So basically you need a camera with an aperture priority mode, select a low F stop, ensure that you have the focus spot on your subject and shoot.

There is a lot more to it that this as Pook has touched on, but that’s the basics.

The good news is that if your Fuji doesn’t have aperture priority mode, your new Canon A95 definitely does.
Steve is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 23-02-2005, 22:47   #7 (permalink)
New here
 
Join Date: Feb 2005
Location: Fife, Scotland
Posts: 19
markyg is an unknown quantity at this point
User's Gallery
Okaeydoke I got most of the above explanations.....the benefits of an engineering degree. So it seems I definately need a better camera if I am to improve my picture quality. Now the question is how much to spend........got £1k coming soon.......ho hum

Thanks again guys, quick explanation and concise!!! Very impressed!
markyg is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 23-02-2005, 23:46   #8 (permalink)
Loves the place
 
silkstone's Avatar
 
Join Date: Jan 2005
Location: Silkstone Common, Yorkshire, UK
Posts: 5,719
silkstone is a glorious beacon of lightsilkstone is a glorious beacon of light
silkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of lightsilkstone is a glorious beacon of light

Image editing O.K.
User's Gallery
Users Camera Equipment List
This may just cause some (circle of) confusion :wink: but I produced a spreadsheet which you can get here that will give you the depth of field at different focal lengths and apertures.

There are a few assumptions in it, and I would take it with a few grains of salt, but it's fun to play around with different values and see the results.

P.S. If you have £1000 to spend, the 350D was made for you.
silkstone is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 24-02-2005, 00:11   #9 (permalink)
Quite Chatty
 
Kimmett's Avatar
 
Join Date: Feb 2005
Location: Nottingham Uni/ Southampton
Posts: 51
Kimmett is an unknown quantity at this point

Image editing O.K.
User's Gallery
To acheive a shallow DOF in the picture you posted, your camera should have a close up, or macro mode. Try that

Kimmett
Kimmett is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 24-02-2005, 10:23   #10 (permalink)
Marcel
Guest
 
Posts: n/a
User's Gallery
Quote:
Originally Posted by silkstone
P.S. If you have £1000 to spend, the 350D was made for you.
Nope if you have a grand, then a second hand 300d (body only for you), the change you can give to me to put to a 350d for me

Ta
 
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 24-02-2005, 18:04   #11 (permalink)
Forum Regular
 
Join Date: Jan 2005
Location: Gloucester UK
Posts: 741
MyPix is an unknown quantity at this point

Image editing O.K.
User's Gallery
Quote:
Originally Posted by Bod
Quote:
Originally Posted by silkstone
P.S. If you have £1000 to spend, the 350D was made for you.
Nope if you have a grand, then a second hand 300d (body only for you), the change you can give to me to put to a 350d for me

Ta

PAHH!!!.......spend it on a real camera like a Nikon D70 , lol

MyPix :wink:
MyPix is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 14-03-2005, 13:27   #12 (permalink)
Oz
Getting Comfy
 
Oz's Avatar
 
Join Date: Feb 2005
Location: Southampton, UK
Posts: 177
Oz is an unknown quantity at this point
User's Gallery
Quote:
Originally Posted by Steve
The simplest way I can think of wording this very tricky subject is to tell you that a lower number of F stop (usually referred to as aperture) will also reduce the distance from front to back of your subject that will be in focus(usually referred to a Depth Of Field) D.O.F.

So basically you need a camera with an aperture priority mode, select a low F stop, ensure that you have the focus spot on your subject and shoot.

There is a lot more to it that this as Pook has touched on, but that’s the basics.

The good news is that if your Fuji doesn’t have aperture priority mode, your new Canon A95 definitely does.
Quality - was curious about trying out DOF and this thread has been most useful - I now know how to (in theory at least) and that I can on my camera!
Oz is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 14-03-2005, 14:14   #13 (permalink)
CT
Feet under the table
 
CT's Avatar
 
Join Date: Mar 2005
Location: West Mids UK
Posts: 3,368
CT is an unknown quantity at this point

Image editing O.K.
User's Gallery
Good explanation there by Pook. Grasping the reciprocity relationship between shutter speed and aperture and their halving and doubling relationship to each other is the basic key to a good understanding of photography. As you progress you'll find photography is a contant battle and compromise between what you want to do and what the prevailing light will allow you to do. One of the biggest problems is that as the size of the aperture decreases and the shutter speed lengthens, camera shake starts to enter the equation. In other words as we select that small aperture to get everyting in focus from the foreground to the horizon, camera shake becomes more of a potential problem as the shutter speed lengthens. Us human beans are pretty crap camera supports when it comes to long exposures. :wink:


Hand holding the camera.

Grab hold of the thing. don't be afraid to cup your left hand under and around the lens. Pull the camera firmly into you face so that is firmly pressed against your cheekbone and brow. If you wear a neck strap, try winding the slack around your right hand so that it actually tightens the camera into your face Your elbows should stabilise the whole thing by being pulled down onto your chest. Your feet should be spaced for balance, and when you take the shot breath out gently like a marksman as you press the shutter. Practice the technique till it's second nature.

The minimum safe shutter speed for handholding with a 50mm lens is 1/60 sec. That's to eliminate just your movement, and takes no account of any movement in the subject. If you can go faster then you should, but 1/60 is the minimum. That's not to say you should miss a great shot for the sake of trying 1/30 or even 1/15 but it takes practice to achieve those speeds hand held and it's always a bit of a gamble.

The good news is there's a simple way to always know what the safe hand holdable speed is with any lens. ...

The safe speed is equal to the focal length of the lens in use - or the nearest marked equivalent. The longer the focal length of the lens, the more each tiny bit of camera movement will show up in your shots.

28mm 1/30

50mm 1/60 Nearest marked equivalent

80mm 1/125 Nearest marked equivalent

200mm 1/250

500mm 1/500

1000mm 1/1000

Remember these are minimum safe speeds- if you can go faster you should.

Bear in mind that as you vary the focal length on a zoom lens, the minimum safe shutter speed changes. - easily forgotten.

You can see why a good solid tripod (and remote release) is an essential piece of kit if you want to work in all conditions.

Wonder of wonders! we now have image stabilisition lenses (IS) which is something to consider when you're shoppig for glass. These actually give you 2 or 3 stops slower hand-holdable shutter speeds than none IS lenses. Very useful for available light work!
CT is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 14-03-2005, 14:28   #14 (permalink)
dod
Feet under the table
 
dod's Avatar
 
Join Date: Feb 2005
Location: Nairn
Posts: 1,907
dod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura about

Image editing O.K.
User's Gallery
You can always cheat :wink: With a bit of care it could be done fairly well instead of this hash up. But you get the idea.

dod is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 14-03-2005, 14:32   #15 (permalink)
dod
Feet under the table
 
dod's Avatar
 
Join Date: Feb 2005
Location: Nairn
Posts: 1,907
dod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura aboutdod has a spectacular aura about

Image editing O.K.
User's Gallery
Quote:
Originally Posted by CT
The good news is there's a simple way to always know what the safe hand holdable speed is with any lens. ...
I've always used that as well but when I went for the 10D because of the 1.6 crop factor giving the impression that say a 50mm is an 80mm, I've also changed the "safe" speeds. Is that a fair assumption or just daft?
dod is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 14-03-2005, 15:05   #16 (permalink)
CT
Feet under the table
 
CT's Avatar
 
Join Date: Mar 2005
Location: West Mids UK
Posts: 3,368
CT is an unknown quantity at this point

Image editing O.K.
User's Gallery
Quote:
Originally Posted by dod
Quote:
Originally Posted by CT
The good news is there's a simple way to always know what the safe hand holdable speed is with any lens. ...
I've always used that as well but when I went for the 10D because of the 1.6 crop factor giving the impression that say a 50mm is an 80mm, I've also changed the "safe" speeds. Is that a fair assumption or just daft?
Great question! It actually makes my head hurt thinking about this, and I'm still not sure. :lol:

A 50mm lens only becomes an 80mm lens because we're thinking of it in 35mm film terms. It's actually still a 50mm lens as far the chip in our digital camera is concerned, so I think the old safe rule still applies, but I'm quite happy to be put right on that. If the focal length 'actually' changed then the max aperture would become smaller (effectively) too wouldn't it?
CT is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 14-03-2005, 18:45   #17 (permalink)
Forum Regular
 
KenCo1964's Avatar
 
Join Date: Mar 2005
Location: Co. Durham England
Posts: 1,068
KenCo1964 is an unknown quantity at this point

Image editing O.K.
User's Gallery
I’d have to agree with that?????
KenCo1964 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 24-04-2005, 15:57   #18 (permalink)
Been here a while
 
AquilaEagle's Avatar
 
Join Date: Apr 2005
Location: Herts, UK
Posts: 311
AquilaEagle is an unknown quantity at this point

Image editing O.K.
User's Gallery
A most useful thread! thanks
AquilaEagle is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 24-04-2005, 20:10   #19 (permalink)
Been here a while
 
ppuga's Avatar
 
Join Date: Mar 2005
Location: México City, México.
Posts: 290
ppuga is an unknown quantity at this point

Image editing O.K.
User's Gallery
Excelent question, and excelent answers here!

Here are the best DOF explanations I've read, I think.
ppuga is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Focus sawdust Photos for fun 2 06-07-2007 19:16
Tutorial: Depth of Field Effect with PS danpen Tutorials and Guides 4 08-06-2007 07:51
slave flashes have no effect with D80 Doug Flash and Studio Lighting Equipment, Techniques and Setup 9 17-05-2007 20:43
Orten Effect Done in Photoshop CS Boofers Photos for fun 2 03-05-2007 01:44
Tips and Hints for a focus or soft focus problem. daveyuk Tutorials and Guides 13 16-03-2006 19:34


All times are GMT +1. The time now is 14:16.


vBulletin Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
ReviewPost & PhotoPost vB3 Enhanced, Copyright 2003-2014 All Enthusiast, Inc.
SEO by vBSEO 3.3.0
Copyright © 2006 - 2017 Pixalo.com

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196