Camera to take pics of active children / blurred background

Mel_P

Mel_P

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My daughter has 2 young (2.5 / 5 years) children who do not sit still for photos - so she needs a "fast" response camera BUT she wants a RELATIVELY compact camera - i.e. not an SLR. She also wants the ability to blur the background in shots - i.e to remove distracting backgrounds - i.e. large aperture and Aperture priority setting.

From other comments on this site and others the Canon S95 seems a good bet - UNLESS anybody else has a better suggestion (please).

I use a canon 7D / 17-55mm F2.8 IS USM to "snap" the children and she likes the results - but with 2 children etc this is an unrealistic option.

An suggestions please?
 
Have a search on eBay for the mirrorless camera family, they are like DSLR's but smaller, here's a few cheap and excellent models to look for;

Sony NEX-3

Olympus EP-1

Samsung NX100
 
What was that damned annoying TV advert recently for a camera that had "background Defocus"
Still say a small DSLR with a decent lens would be better.
 
Surely anything with a large aperture will allow you to isolate the subject, S95 with f/2 should be ok.
 
Fast moving kids really demand fast and reliable af and high fps, which makes me say a 7D or 1D is really needed here, with a longish lens like 70-200mm.

I am sorry I can't think of any compact - including Leica - that would get really good action shots.
 
I don't see it myself, they aren't race horses. 5mph tops.

I have a G12 which is very similar to the S95 although a slightly slower lens. I've never tried action type shots with it but I'll try a few tomorrow with my 'kids' (cocker spaniels) who move slightly faster but I doubt they'll be in the same league as a dslr/f2.8 combo however I'm now interested enough to try it.
 
now I am not spamming as i have 6 wk old one for sale ( only selling as i need 2 nikon bodies) but take a look at the Samsung EX1 high end compact as it has f1.8 wide aperture and its sensor is the same size as LX5, G12, S95, its an awesome camera for when you cannot/ dont want to lug loads about.
 
One problem with cameras like the S90 is that they have relatively wide angle lenses so you'll probably need to get in really close to get the background out of focus. I know that it can be done with some subjects (I have an LX5) but I doubt that anything other than a carefully staged shot has much chance of success and it's difficult to stage a shot like that with kids.

It'll be a lot easier with a micro four thirds or similar and the longer the lens and the wider the aperture the more chance of success but regardless of the possibility I wonder if with micro four thirds and the like and wide apertures we're straying into an area that'll take more expertise and more expense than the lady will want to bother with?
 
As already said, a compact is not ideal.

Any DSLR will do this, with fast AF and aperture priority. Look for a used entry level dslr with reasonable kit lens.
 
DSLR is out - far too big / unweildy for her to use / control 2 boys!
 
Mel_P said:
DSLR is out - far too big / unweildy for her to use / control 2 boys!
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Come on, an entry level dslr is no bigger than a bridge camera!

If she wants something that small is has to be a compact. But you won't get one that is good at what she wants it to do. Cake and eat it springs to mind!

If she wants the same results as your 7d and 17-55 f/2.8 she'll have to use something similar, and she won't get that from a compact.
 
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odd jim said:
If she wants the same results as your 7d and 17-55 f/2.8 she'll have to use something similar, and she won't get that from a compact.
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:agree:

To put that in numbers... and assuming an S95 (which is a 1/1.7" sensor). It has a crop factor of 4.55. The 7D is a crop factor of 1.6. To get the same field of view (i.e. the same "picture") as 50mm on the 7D, you will need to use an 18mm focal length on the S95. Using an online DoF calculator (e.g. http://www.dofmaster.com/dofjs.html) and assuming a 2m distance to subject, the 7D/17-55 IS will have a depth of field of 8cm either side of 2m. Using the S95 at 18mm and f2, the DoF is 15cm either side of 2m. Basically, to counteract the smaller sensor size of the compact, you will need to drop to an f1 lens to get the same out of focusness. As far as I'm aware, these don't exist.

Your compromise will either have to be in depth of field or sensor size (and hence bulkiness of camera). Ye cannae change the laws of physics you know ;)
 
Davie said:
Surely anything with a large aperture will allow you to isolate the subject, S95 with f/2 should be ok.
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Nope, as already said the small sensor size means you don't get much DoF, even at f/2.

I have an S90 and really you have to be shooting in macro to get any sort of background blur. It is a great camera, just not for these kind of things (or at least not compared to an SLR).
 
Another thought: the F2 lens on the S95 will give the same depth of field as an f5-f5.6 lens would on a APS-C DSLR and f8 would on a full frame camera (once you have the equivalent focal lenths on to give the same field of view).

The implication is that it's really, really difficult to get great depth of field separation on small sensors.
 
Nawty said:
Nope, as already said the small sensor size means you don't get much DoF, even at f/2.

I have an S90 and really you have to be shooting in macro to get any sort of background blur. It is a great camera, just not for these kind of things (or at least not compared to an SLR).
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Ah. I was going to try all this out for myself but seem to have lost the charger for the G12 :bang: It's probably still on holiday on the west coast. :(
 
Don't get me wrong, it'll capture great pictures of the kids, just not with a blurry background...
 
Hobby Horse time.

The size of the sensor doesn't affect DoF. DoF doesn't care about the size of the film or sensor. If you had one lens and you could use it on everything from a compact through to large format you'd get the same DoF on every format. The problem is that you can't use that lovely 85mm f1.4 that gives lovely shallow DoF on your full frame DSLR on a compact. On a compact you're stuck with something like a 6-20mm f2-4.9 and that will only give you shallow DoF in specific circumstances.
 
The other issue with the s95 is the shutter lag compared to a dslr it is very slow.
 
Mel_P said:
My daughter has 2 young (2.5 / 5 years) children who do not sit still for photos - so she needs a "fast" response camera BUT she wants a RELATIVELY compact camera - i.e. not an SLR. She also wants the ability to blur the background in shots - i.e to remove distracting backgrounds - i.e. large aperture and Aperture priority setting.

From other comments on this site and others the Canon S95 seems a good bet - UNLESS anybody else has a better suggestion (please).

I use a canon 7D / 17-55mm F2.8 IS USM to "snap" the children and she likes the results - but with 2 children etc this is an unrealistic option.

An suggestions please?
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Instead of trying to blur the background into oblivion why doesn't she just try to think more creatively about the background, try to photograph the kids in front of some nicely textured backgrounds like a fence, the beach, a hedge. Without top quality equipment and an understanding of how to use it, it's unlikely that she will get in-focus images with a shallow depth of field.

I would look into a older DSLR 400d, 450d (both great), and a 50mm 1.8 to go with it. The kit lens should be ok for her too if she thinks about the background rather than just trying to make it disappear :D




arad85 said:
I so knew you were going to post.

Yes it does. Physics say it does, respected books say it does, even the websites that you post to support your argument say it does.

http://en.wikipedia.org/wiki/Depth_of_field#DOF_vs._format_size

as an example of some literature that explains it.
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as I understand it, even the link you posted says that in the 'same picture' comparison- the depth of field changes as a result of changing the focal length. I read this (and my own knowledge suggests) as saying that a 50mm lens gives a particular depth of field at a particular distance to subject irrespective of sensor size. I.e. on a d700 in fx mode a full body portrait is framed and shot at f1.4. If you then switch into DX and (keep the distance the same), the shot is now framing the torso only but the depth of field should be exactly the same. It should give the same result as if you took that FX image and cropped it in post. Then put that 50mm lens on a m4/3 camera and you frame only the stomach (same distance to subject), but the depth of field is again identical- the same as if the original full frame image had been cropped down to just the stomach

http://digitaljournalist.org/issue0710/tech-tips.html



it's all academic anyway, the advantage of digital over film is that you don't need to 'understand' this kind of theory anymore, we can step away from the textbooks and get on with the shooting, safe in the knowledge we can just shoot and shoot until we get the shot we desire. Until someone can point me to some data that proves me wrong, i'm sticking to my argument that sensor size does not effect DOF if all other variables (i.e. distance, aperture) are kept constant
 
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arad85 said:
:agree:

To put that in numbers... and assuming an S95 (which is a 1/1.7" sensor). It has a crop factor of 4.55. The 7D is a crop factor of 1.6. To get the same field of view (i.e. the same "picture") as 50mm on the 7D, you will need to use an 18mm focal length on the S95. Using an online DoF calculator (e.g. http://www.dofmaster.com/dofjs.html) and assuming a 2m distance to subject, the 7D/17-55 IS will have a depth of field of 8cm either side of 2m. Using the S95 at 18mm and f2, the DoF is 15cm either side of 2m. Basically, to counteract the smaller sensor size of the compact, you will need to drop to an f1 lens to get the same out of focusness. As far as I'm aware, these don't exist.

Your compromise will either have to be in depth of field or sensor size (and hence bulkiness of camera). Ye cannae change the laws of physics you know ;)
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This.

cambsno said:
The other issue with the s95 is the shutter lag compared to a dslr it is very slow.
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And this, are the key technical problems.

The third one, and it's rather harder to acquire, is considerable experience and shooting skills. Shooting kids on the move, with shallow DoF, will test even the best photographer with the best equipment.

That doesn't mean to say that you won't get great pictures with a compact, but they will not be as described by the OP.
 
mrjames said:
Instead of trying to blur the background into oblivion why doesn't she just try to think more creatively about the background, try to photograph the kids in front of some nicely textured backgrounds like a fence, the beach, a hedge. Without top quality equipment and an understanding of how to use it, it's unlikely that she will get in-focus images with a shallow depth of field.

I would look into a older DSLR 400d, 450d (both great), and a 50mm 1.8 to go with it. The kit lens should be ok for her too if she thinks about the background rather than just trying to make it disappear :D

as I understand it, even the link you posted says that in the 'same picture' comparison- the depth of field changes as a result of changing the focal length. I read this (and my own knowledge suggests) as saying that a 50mm lens gives a particular depth of field at a particular distance to subject irrespective of sensor size. I.e. on a d700 in fx mode a full body portrait is framed and shot at f1.4. If you then switch into DX and (keep the distance the same), the shot is now framing the torso only but the depth of field should be exactly the same. It should give the same result as if you took that FX image and cropped it in post. Then put that 50mm lens on a m4/3 camera and you frame only the stomach (same distance to subject), but the depth of field is again identical- the same as if the original full frame image had been cropped down to just the stomach

http://digitaljournalist.org/issue0710/tech-tips.html



it's all academic anyway, the advantage of digital over film is that you don't need to 'understand' this kind of theory anymore, we can step away from the textbooks and get on with the shooting, safe in the knowledge we can just shoot and shoot until we get the shot we desire. Until someone can point me to some data that proves me wrong, i'm sticking to my argument that sensor size does not effect DOF if all other variables (i.e. distance, aperture) are kept constant
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When you change the size of the sensor, the image (ie framing) changes completely so unless you also change focal length to restore equivalence, the comparison is meaningless anyway.

Apart from that, the proof you are seeking is the change to the circle of confusion in the DoF formula, which represents the size of the sensor.
 
mrjames said:
Until someone can point me to some data that proves me wrong, i'm sticking to my argument that sensor size does not effect DOF if all other variables (i.e. distance, aperture) are kept constant
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Nope - because Depth of Field is a perception thing. What you are forgetting is that DoF is only apparent when you render and view the image. Take any image with any camera and print it at different sizes and view from the same distance and the larger the image, the narrower depth of field it will appear have (assuming infinite pixels/perfect lenses). View them from different distances so that the print takes up the same field of view (that is, as the pictures get bigger, move further away), and the depth of field will appear to be the same. In this case, all I've done is print the captured image at different sizes and viewed them from different distances. Clearly, aperture, subject distance and sensor size haven't changed at all as the raw data for the prints are the same yet the DoF appears to change.

Goto http://dofmaster.com/dofjs.html and try keeping everything the same and JUST change sensor size (i.e. keep aperture, distance and focal length the same). You'll see that depth of field increases as sensor size increases. Why is that? The answer is to do with rendering the print. Assuming we just print the whole frame to 12"x8", any particular area of the image will be rendered smaller in the full frame image than from the APS-C image and when it is printed it will lead to a perception that more of it is in focus. The converse is also true, if you render the images so that the objects within them are rendered the same size (i.e. if you print the FF image larger than the APS-C image so that the subjects appear identically sized on the paper) the DoF will be perceived to be the same. This is the equivalent of cropping the full frame to APS-C size and printing the resultant images the same size.

In reality though, you don't keep everything the same, you change the focal length to suit the sensor size to get the same image. When you do that, the smaller format has a greater DoF (assuming the prints are rendered the same size). This is because with the longer the lens, the quicker the effects of becoming out of focus become apparent when rendering the image at a certain size.

If you want a more in-depth discussion of this, take a look here: http://en.wikipedia.org/wiki/Depth_of_field
 
Hahaha talk about hijacking a thread :0O i personally think looking for a shallow depth of field with fast moving kids (remember they move back and forth not just left and right) is a great way to get out of focus shots as the auto focus and lag on a compact isn't gonna keep up, id look for motion blur instead of focus blur, i taught my wife basic panning with her nex3 and she takes some awesome shots, she puts it in whatever mode gives her a medium aperture and a low shutter or just manually drops the shutter lower, theres a fairly hi trash rate on the images but imho you'd have that trying to catch fast moving kids at an open aperture anyway, just an alternative option..... ill let you get back to your mass debate ;)
 
I don't think this is OT becuase it's central to the OP.

woof woof said:
Hobby Horse time.

The size of the sensor doesn't affect DoF. DoF doesn't care about the size of the film or sensor.
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In itself, that is untrue. The DoF formula includes the Circle of Confusion which varies according to format. If you go to http://dofmaster.com/dofjs.html when you change the type of camera in the menu top-left, it changes the CoC in the box on the bottom right, according to the size of the sensor.

If you had one lens and you could use it on everything from a compact through to large format you'd get the same DoF on every format. The problem is that you can't use that lovely 85mm f1.4 that gives lovely shallow DoF on your full frame DSLR on a compact. On a compact you're stuck with something like a 6-20mm f2-4.9 and that will only give you shallow DoF in specific circumstances.
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The problem with that is, even if you could do it (which actually you could with the new interchangeable lens Pentax compact) is that you would end up with a completely different picture. The framing of an 85mm lens on a compact, would have the same field of view as something like a 400mm lens on full frame. So it's not a helpful or relevant comparison.

The only valid comparison* is - the same framing/field of view, from the same position to maintain perspective, and the same size print output viewed from the same distance. That's how we take pictures, and that delivers a print which is 'the same' in most people's understanding. When you do that, f/number for f/number, smaller formats deliver greater depth of field, but if you then adjust the f/number appropriately (ie by the crop factor) to restor equivalence in DoF, the two image are then, in fact, absolutely identical. So, IMHO, it is perfectly okay to express that in shorthand terms as "smaller formats give more DoF".

* You will notice I've not even mentioned the lens in that comparison. It's not relevant, because it's a given - the focal length obviously has to be adjusted to restore the same framing, and that is the cause of most disagreements on this. That, and the fact that many people forget the different degree of enlargement necessary to produce the same size print for viewing.
 
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HoppyUK said:
In itself, that is untrue. The DoF formula includes the Circle of Confusion which varies according to format.
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I know we've had this 100 times before so I'm almost sorry that I brought it up :lol: The reason that the CofC changes is not because of the sensor size AS SUCH. Think about it. Why does the Cof C change? It changes for other reasons than simply and only sensor size, so, I'll stick to my own belief that DoF is not decided by sensor size ALONE. I'm not the only one that says this and folk with far more knowledge (and ability:)) agree.

Getting back to compacts. The reason that the DoF is so deep has far more to do with the lens and the aperture than the sensor size although you could argue that the lens is decided at least in part by the sensor size. All else being equal (and I know they never can be) you could get shallow DoF from a compact if it had (for example...) a 85mm f1.2 lens.
 
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arad85 said:
Nope - because Depth of Field is a perception thing. What you are forgetting is that DoF is...
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I'm not forgetting anything. I've read the theory and tested it with different format cameras and I'm happy with what I believe and how it works. That's all we need actually, to decide what works for us and I know that I can get shallow DoF from FF, APS-C, MFT and in some circumstances compacts too.
 
woof woof said:
I know we've had this 100 times before so I'm almost sorry that I brought it up :lol: The reason that the CofC changes is not because of the sensor size AS SUCH. Think about it. Why does the Cof C change? It changes for other reasons than simply and only sensor size, so, I'll stick to my own belief that DoF is not decided by sensor size ALONE. I'm not the only one that says this and folk with far more knowledge (and ability:)) agree.

Getting back to compacts. The reason that the DoF is so deep has far more to do with the lens and the aperture than the sensor size although you could argue that the lens is decided at least in part by the sensor size. All else being equal (and I know they never can be) you could get shallow DoF from a compact if it had (for example...) a 85mm f1.2 lens.
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Haha! :D

The point is, changing the sensor changes the framing, so the lens must be adjusted to maintain equivalence. It's a given. But that's how we work - we change the focal length to adjust framing, because the sensor size is fixed. The sensor is central to everything and other factors must be worked around it.

"Why does the Cof C change? It changes for other reasons than simply and only sensor size." No, it only changes because of the sensor size.

"Folks with far more knowledge agree." Do they? None of the links posted above agree.
 
So the only reason that the CofC changes is format size? Are you sure that's what you mean?

What about resolution and pixel size? They can all change from sensor to sensor and format size to format size and yet they have nothing to do with the CofC? Come off it... :thinking::lol: At the mo I just can't see why you consistently overlook pixel size and resolution and the effects that these will have. Can you find a CofC calculator that does not include resolution or pixel size? It's not just format size.

Like I said, we've had this 100 times and if you want links look for them and you will find.

Granted you'll not find all things equal sensors in different format sizes but I still think it's worth saying even if some disagree that format size in itself and by itself does not decide DoF or CofC unless you go for really really small sensors and really really stupidly small images that would make the whole thing irelevant.

Perhaps I'm too much of a pedant on this so I'll shut up now :lol: I just thought it was worth saying.
 
From Mr Hogan :)

"The first problem with some of those tables is that the circle of confusion used is often larger than the photosite size of the camera. Do you think it might be possible that the photosite size actually dictates the smallest detail that can be resolved? Some of us think so. Digital is different than film in that we don't have overlapping recordings of light: we have distinct and separate recordings of where adjacent photons hit the sensor. Digital thus records the blur circle slightly differently than film. On film, the blur circle is pretty much always recorded as a circle (of blur). On digital, the blur circle is recorded as a point until it is larger than a photosite, then gets messed up a bit by the Bayer pattern as it starts to cover two photosites, then begins to get fully resolved once it occupies several adjacent photosites. The corollary is that setting a circle of confusion smaller than the photosite size is nonsensical: the camera can't distinguish any finer detail."

Later, I'll have a look at what Ken Rockwell says on that matter :lol:

Sorry I said I'd shut up.
 
I wonder if the OP is keeping up with this...
 
woof woof said:
So the only reason that the CofC changes is format size? Are you sure that's what you mean?
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Yes.

woof woof said:
What about resolution and pixel size?
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Immaterial. You seem to think that CoC is about a point in the image being captured sharply by a single pixel on the sensor. This is NOT what CoC is about. CoC is giving you the weighting of how much you have to expand the resultant image to get a given picture size. It is this that determines how sharp the resultant image appears.


woof woof said:
Can you find a CofC calculator that does not include resolution or pixel size? It's not just format size.
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Yes. All of them. Can you show me a CoC calculator that has. Have a look at: http://en.wikipedia.org/wiki/Circle_of_confusion There are 7 mentions of the word resolution and they are all to do with the output device. Not one mentions the sensor pixel size or sensor resolution....
 
woof woof said:
From Mr Hogan :)
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Sounds like it could be Paul Hogan based on the thinking behind it....

woof woof said:
"The first problem with some of those tables is that the circle of confusion used is often larger than the photosite size of the camera.
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That's immaterial. It depends on how that photosite is displayed and viewed that matters. If, when the image is displayed and viewed at normal viewing distances, the photosite is much smaller than the eye can resolve, the CoC can cover more sensor points and the image will still appear to be perfectly in focus. If you view that image closer than that distance, it may well start to appear less in focus.

CoC has NOTHING to do with pixel size (beyond the extremes), simply about sensor size.
 
woof woof said:
All else being equal (and I know they never can be) you could get shallow DoF from a compact if it had (for example...) a 85mm f1.2 lens.
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Yes, you could, but you would have the field of view of a 400mm lens on a full frame camera (assuming the S95 as elsewhere on the thread)....
 
odd jim said:
I wonder if the OP is keeping up with this...
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Then apologies. It's not off topic as such, but we are going into a bit of detail here. (You see what I did there? ;))

Andy is right, and I'm afraid WW is mistaken. The concept of depth of field has nothing to do with lens resolution or pixels. You could apply the same theory to a painting if you wanted.

That is, an image is deemed to be sharp when the level of detail (specified by the circle of confusion) is so fine that anything smaller cannot be detected by the human eye, in an average print viewed from an average distance. An 'average' print being something around A4, viewed at distance equal to the diagonal, ie 15in in this case. The exact size doesn't matter, only the viewing distance.

Resolution and pixels don't come in to it at all. They would be a relevant factor if indeed the pixels were actually larger than the circle of confusion, but they're not - they're several times smaller, so just not an issue.

At the end of the day, it boils down to this. If you take a picture with a full frame camera, and then take another shot with any camera with a smaller sensor - from the same spot, framed exactly the same - f/number for f/number the camera with the smaller sensor will deliver greater depth of field.

I don't think anybody would disagree with that (it's kinda hard to) and because that's how we work - with a camera having a fixed sensor and variable focal length lenses - it makes perfect logical sense. It's just confusing to get picky and say ah, but you've also changed this, and what if you changed the other. That's not how we work.
 
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