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How did they get the blurring to be so much in this photograph?
- Thread starter waloshin
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Looks like pretty standard shallow depth of field to me. The typical result of a photo taken with a long focal length and a wide aperture.
Edit: your cat photo wasn't showing when I first replied. If you want the kind of subject separation that you see in the photo of the XBox, you'll need a lens with a very wide maximum aperture, something like 100mm and f/2.
Edit: your cat photo wasn't showing when I first replied. If you want the kind of subject separation that you see in the photo of the XBox, you'll need a lens with a very wide maximum aperture, something like 100mm and f/2.
This effect is directly related to the aperture of your lens:
http://www.cambridgeincolour.com/tutorials/depth-of-field.htm
http://en.wikipedia.org/wiki/Depth_of_field
http://www.cambridgeincolour.com/tutorials/depth-of-field.htm
http://en.wikipedia.org/wiki/Depth_of_field
Subject distance from the background + your distance from the subject all team up to make the top pic as blurry as it is.
Your cat could have been taken at f/2.8, but because the other items are close to the cat, their details are more visible. The XBOX shot could have been taken at f/8, but because the BG is far away, it looks blurry.
Your cat could have been taken at f/2.8, but because the other items are close to the cat, their details are more visible. The XBOX shot could have been taken at f/8, but because the BG is far away, it looks blurry.
It's impossible to blur the background with a small point & shoot camera with a small sensor even with a large aperture.
Sony has a background defocus on their small sensor P&S cameras (takes two photos one in focus the other not and merges them in camera)
A micro 4/3 camera has some DoF control, an APC-S more and a full frame sensor it's no problem.
It's the main reason I switched to a Sony NEX camera over my Canon S90
Sony has a background defocus on their small sensor P&S cameras (takes two photos one in focus the other not and merges them in camera)
A micro 4/3 camera has some DoF control, an APC-S more and a full frame sensor it's no problem.
It's the main reason I switched to a Sony NEX camera over my Canon S90
For the same composition with the same f-stop selected? The way I understand it yes as you have to have a shorter focal length to get the same composition compared to full-frame. But the same focal length lens shot at the same focus distance with the same f-stop will have the same DoF field regardless of sensor size: the crop camera will simply have cropped the centre section of the full 35mm frame.
That's not completely true. You can get blurred backgrounds even with an iPhone 4S and its sensor is TINY compared to most point-and-shoot cameras. You can't get extreme results with the iPhone, but just look at these pictures from Apple's website:
http://www.apple.com/iphone/built-in-apps/camera.html#zoomerlay-gallery3
http://www.apple.com/iphone/built-in-apps/camera.html#zoomerlay-gallery6
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That's very true. In any case, apparent DoF is a somewhat subjective measure of defocus as in a practical sense it also depends upon the magnification (rescaling) of the final image. If you view an image at a very small scale it will look relatively sharp regardless of the DoF. However, if you make a large print (or view it at a large size) then any defocus will become more apparent.
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Here is a handy calculator for working out these sorts of questions:
http://www.dofmaster.com/dofjs.html
If I read your scenario correctly, then you'll see it's not quite right. A different sensor size will mean a different CoC (circle of confusion), and that will affect the depth of field.
The Cat picture was not taken with a small point and shoot. The camera was Nikon d40.
At what aperture? You need wide open to get those shallow DoF.
DoF Calculator for various cameras
I'm on the lookout for a 50mm f1.8 e-mount. That's a 75mm with the 1.5x crop factor.
It should make a nice portrait lens.
Indeed. And you need different apertures to get the same depth of field too. 25mm f/1.0 at 10 feet on m43 has the same DoF (but not CoC) as a 5D MkII with a 50mm f/1.0 lens at 10 feet. And should have pretty much the same view as well I think.
I'm not sure I totally agree. CoC values are to a certain degree arbitrary. Don't forget that CoC is also arguably more a function of the intended output, such as print size and viewing distance, than it is a function of the sampling resolution of the sensor. An appropriate CoC value for a billboard will be very different than for a high resolution fine art print, even if you shoot the picture with the same camera.
In this regard, I think the dofmaster calculator is incorrect in that it defines a specific CoC for each camera model, and that between camera models with similar pixel pitch, the listed CoC is different (see the D80 with CoC of 0.02mm and D3x of 0.03mm, but in reality the pixel pitch of each is very similar, the only real difference being that the D80 is DX and the D3x is FF).
It sounds as though your understanding of the physics greatly exceeds mine, so I'm prepared to believe that dofmaster's calculator could be incorrect. I think its amounts for total depth of field are at least reasonably accurate, but perhaps when you get down to matters of inches or less, it becomes very difficult to tell.
There are 3 (main) DoF controls... Two of which are linked, but not symmetrically....
1) Aperture - Basic control.... You should know this one....
However, these two (below) influence each other - but not equally....
2) Focal Length - Longer lenses (telephotos) have less DoF.
3) Distance - Getting closer also shortens DoF
Standing close to your subject and using a wide angle lense will not produce the same DoF as standing further away and using a telephone lense... even if the framing of the subject is the same the aperture used is the same.
I forget off the top of my head which combo produces the shallower DoF. IIRC the D40 doesn't have a DoF preview button, so you will need to actually take the photos to figure it out....
Luck.
Reminds me of this somehow, where similar portions of information have been thrown around: How do cinematographers focus on an object and blur the background?
It will always amaze me that thread starters get thumbed down for asking a legitimate question...
It is the same with some posts containing valid information. Since FacialBuuk does not offer "Not Like" buttons, they have to go somewhere, one of those places is MR.
And waloshin is sometimes just disliked for starting so many threads, though they have become more sane than they were two, three years ago.
And for those who want to know why you simply can't shrink down sensor...
Depth of field
The mind numbing diffraction & sensor article
PS Waloshin, your appear to be using the kit lens 18-55; which is a good all around lens but not a very fast lens f/3.5 at it's fastest and only at 18mm, at 50mm it's f/5.6. Do you have any other lenses? A 50mm f/1.8 is a nice fairly fast lens, a prime (usually sharper than a zoom) will give you more control over DoF.
http://www.kenrockwell.com/nikon/5018daf.htm
50mm is a popular lens, so much so there is a Toronto 50mm only photography meetup group.
Depth of field
The mind numbing diffraction & sensor article
PS Waloshin, your appear to be using the kit lens 18-55; which is a good all around lens but not a very fast lens f/3.5 at it's fastest and only at 18mm, at 50mm it's f/5.6. Do you have any other lenses? A 50mm f/1.8 is a nice fairly fast lens, a prime (usually sharper than a zoom) will give you more control over DoF.
http://www.kenrockwell.com/nikon/5018daf.htm
50mm is a popular lens, so much so there is a Toronto 50mm only photography meetup group.
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