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-   -   P & S and depth-of-field (http://www.velocityreviews.com/forums/t543228-p-and-s-and-depth-of-field.html)

Jeff Layman 10-10-2007 10:52 AM

P & S and depth-of-field
 
Some time ago in this group I asked about depth-of-field with a compact
digital camera. I was told that because of the small sensor size, this
isn't really a problem compared to 35 mm film cameras.

A friend using her new Fuji (A610, I think) asked me how to get shots with
the background blurred and only the object of interest (eg a flower) in
focus. I could be much mistaken, but I guess that this would be almost
impossible. I can't see how to do it with my Caplio R6 either. Maybe using
the lens in macro telephoto rather than wide angle would help, but even then
I doubt you'd get the same effect as using a 35 mm film camera with a 50 mm
macro lens set at f2.

It also set me wondering exactly how much the aperture of a P & S camera
changes when the lens specification is stated to be eg "f3 wide angle to
f5.3 telephoto".

Are there any P & S cameras where you can control the aperture over the sort
of range you'd expect with a 35 mm camera and standard 50 mm lens (about
f1.6 - 22), and so change depth-of-field?

--
Jeff
(cut "thetape" to reply)



Alex Monro 10-10-2007 11:09 AM

Re: P & S and depth-of-field
 
Jeff Layman wrote:

> Some time ago in this group I asked about depth-of-field with a
> compact
> digital camera. I was told that because of the small sensor size,
> this isn't really a problem compared to 35 mm film cameras.
>

It generally isn't a problem if you want lots of DoF, however,
restricting DoF, e.g. blurring distracting backgrounds, can be more
difficult.

> A friend using her new Fuji (A610, I think) asked me how to get shots
> with the background blurred and only the object of interest (eg a
> flower) in
> focus. I could be much mistaken, but I guess that this would be
> almost
> impossible. I can't see how to do it with my Caplio R6 either. Maybe
> using the lens in macro telephoto rather than wide angle would help,
> but even then I doubt you'd get the same effect as using a 35 mm film
> camera with a 50 mm macro lens set at f2.
>

Using tele macro is most likely to restrict DoF. For a detailed
tutorial see here:

http://www.cambridgeincolour.com/tut...h-of-field.htm

If you use the on-line DoF calculator, remember it needs the actual
focal length, typically arond 6-20mm for a 3x zoom compact, not the
35mm equivalent.

> It also set me wondering exactly how much the aperture of a P & S
> camera changes when the lens specification is stated to be eg "f3 wide
> angle to f5.3 telephoto".
>

Set the camera to manual mode and see what the largest aperture you
can select is for various zoom settings. There's no fixed rule for
how maximum aperture varies with zoom - it depends on each individual
lens design.

> Are there any P & S cameras where you can control the aperture over
> the sort of range you'd expect with a 35 mm camera and standard 50 mm
> lens (about f1.6 - 22), and so change depth-of-field?
>

I don't know of any P&S that has wider than f/2.4 max aperture, and
the minimum is usually about f/8, due to diffraction considerations
with the small sensor. If you need to control DoF, you need a larger
sensor, which means a DSLR, or the Sony R1 - a fixed lens ultrazoom
with an APS-C sized sensor.

Taylor Dawson 10-10-2007 12:52 PM

Re: P & S and depth-of-field
 
On Wed, 10 Oct 2007 12:09:09 +0100, Alex Monro
<nospamdeleteabusenews@argaty.org.uk> wrote:

>I don't know of any P&S that has wider than f/2.4 max aperture, and
>the minimum is usually about f/8, due to diffraction considerations
>with the small sensor. If you need to control DoF, you need a larger
>sensor, which means a DSLR, or the Sony R1 - a fixed lens ultrazoom
>with an APS-C sized sensor.


If you don't know of any P&S cameras that have a max aperture wider than f/2.4
then you shouldn't be posting such misleading information. Go do your homework
first. All of my P&S cameras are capable of f/2.4 or wider. One of my earliest
ones from 6 years ago has an f/2.0 lens on it. That's only 0.2 away from that
f/1.8 that DSLR owners always have an orgasm over, and they get that at only 1
focal length, mine is an f/2.0 zoom lens. You also need to learn what
"diffraction limited" means. If your lens is not configured to
diffraction-limited specifications that means it performs poorer than one that
is. Educate yourself instead of jumping up in class to show everyone what a
total fool you are.

DOF is a direct function of f-stop.

F-stop = focal-length of lens / diameter of lens

Change the diameter with the aperture control and keep the focal-length fixed,
you change the f-stop effects. The amount of light coming through as well as how
much is in focus, your DOF.

Change the focal length of the lens and keep the aperture fixed, you change the
f-stop. Increase the focal length by 2x and you change the f-stop effects by 2x.

There are two ways to control DOF effects. Aperture and focal-length. If your
camera has a zoom lens on it then you can get identical shallow DOF effects as a
larger sensor camera by just zooming in and moving further away from your
subject. If you want to stay in the same position then increase the focal-length
of your lens using a tele-extender to accomplish the same results.

Last but not least, you will get the most out of your P&S camera by starting to
ignore the DSLR morons who incessantly spread misinformation and misleading lies
to justify why they spend so much on their cameras, cameras that can't do
anything better than most P&S cameras.

I often wonder how these DSLR owners managed to buy cameras, learn to use a
keyboard, and even learn how to find which buttons to press, with that lobotomy
scar that the keep showing to everyone. I suspect they just didn't use a long
enough ice-pick and missed severing away their most damaged parts.

Don Stauffer in Minnesota 10-10-2007 01:18 PM

Re: P & S and depth-of-field
 
On Oct 10, 7:52 am, Taylor Dawson <spams...@nospam.org> wrote:
> On Wed, 10 Oct 2007 12:09:09 +0100, Alex Monro
>
> <nospamdeleteabusen...@argaty.org.uk> wrote:
> >I don't know of any P&S that has wider than f/2.4 max aperture, and
> >the minimum is usually about f/8, due to diffraction considerations
> >with the small sensor. If you need to control DoF, you need a larger
> >sensor, which means a DSLR, or the Sony R1 - a fixed lens ultrazoom
> >with an APS-C sized sensor.

>
> If you don't know of any P&S cameras that have a max aperture wider than f/2.4
> then you shouldn't be posting such misleading information. Go do your homework
> first. All of my P&S cameras are capable of f/2.4 or wider. One of my earliest
> ones from 6 years ago has an f/2.0 lens on it. That's only 0.2 away from that
> f/1.8 that DSLR owners always have an orgasm over, and they get that at only 1
> focal length, mine is an f/2.0 zoom lens. You also need to learn what
> "diffraction limited" means. If your lens is not configured to
> diffraction-limited specifications that means it performs poorer than one that
> is. Educate yourself instead of jumping up in class to show everyone what a
> total fool you are.
>
> DOF is a direct function of f-stop.



Part of the problem with this discussion is that folks are lumping
everything not a DSLR into a single catagory of compact point &
shoot. If one looks at cameras other than DSLR there is a wide
variety of specs. Some are very compact with small chips, others are
larger, some same size as DSLRs with larger chips.

DSLRs also vary in chip size. Mine has an APC sized chip, not full
frame.

We need to stop generalizing so much, and treat cameras as
"individuals", at least as far as brand and model.

Just like not all DSLRs are the same, not all non-DSLRs are the same.

In fact, we need to consider what we mean when we talk about a DSLR.
It merely means it uses a reflex (mirror) optical system for
viewfinding and focusing. Yeah, it is a fair generalization that most
DSLRs have interchangable lenses, but the term does not mean it has
to.



Jeff Layman 10-10-2007 01:26 PM

Re: P & S and depth-of-field
 
Alex Monro wrote:
> Jeff Layman wrote:
>
>> Some time ago in this group I asked about depth-of-field with a
>> compact
>> digital camera. I was told that because of the small sensor size,
>> this isn't really a problem compared to 35 mm film cameras.


>>

> It generally isn't a problem if you want lots of DoF, however,
> restricting DoF, e.g. blurring distracting backgrounds, can be more
> difficult.
>


>>

> Using tele macro is most likely to restrict DoF. For a detailed
> tutorial see here:
>
> http://www.cambridgeincolour.com/tut...h-of-field.htm
>


Thanks for the link. Very interesting and informative. Looks like there is
at least some possibility of restricting the DOF.

>> Are there any P & S cameras where you can control the aperture over
>> the sort of range you'd expect with a 35 mm camera and standard 50 mm
>> lens (about f1.6 - 22), and so change depth-of-field?
>>

> I don't know of any P&S that has wider than f/2.4 max aperture, and
> the minimum is usually about f/8, due to diffraction considerations
> with the small sensor. If you need to control DoF, you need a larger
> sensor, which means a DSLR, or the Sony R1 - a fixed lens ultrazoom
> with an APS-C sized sensor.


Probably best for her to get used to the Fuji first just to see what a
digital camera can do. Maybe then upgrade if it is too restricting for the
sort of photo she wants to take.

Thanks once again for the info.

--
Jeff
(cut "thetape" to reply)



M-M 10-10-2007 02:27 PM

Re: P & S and depth-of-field
 
In article <pghpg3psvmjmrpmecnt15gdv51scpamct5@4ax.com>,
Taylor Dawson <spamstop@nospam.org> wrote:

> DOF is a direct function of f-stop.



It is also a function of sensor size. A P&S camera will not give you
out-of-focus background like a DSLR.

Here is proof:

http://www.mhmyers.com/temp/4500-d80.jpg

--
m-m

Glenn Ramsen 10-10-2007 03:01 PM

Re: P & S and depth-of-field
 
On Wed, 10 Oct 2007 14:26:20 +0100, "Jeff Layman" <jmlayman@thetapetcp.co.uk>
wrote:

>Alex Monro wrote:
>> Jeff Layman wrote:
>>
>>> Some time ago in this group I asked about depth-of-field with a
>>> compact
>>> digital camera. I was told that because of the small sensor size,
>>> this isn't really a problem compared to 35 mm film cameras.

>
>>>

>> It generally isn't a problem if you want lots of DoF, however,
>> restricting DoF, e.g. blurring distracting backgrounds, can be more
>> difficult.
>>

>
>>>

>> Using tele macro is most likely to restrict DoF. For a detailed
>> tutorial see here:
>>
>> http://www.cambridgeincolour.com/tut...h-of-field.htm
>>

>
>Thanks for the link. Very interesting and informative. Looks like there is
>at least some possibility of restricting the DOF.
>
>>> Are there any P & S cameras where you can control the aperture over
>>> the sort of range you'd expect with a 35 mm camera and standard 50 mm
>>> lens (about f1.6 - 22), and so change depth-of-field?
>>>

>> I don't know of any P&S that has wider than f/2.4 max aperture, and
>> the minimum is usually about f/8, due to diffraction considerations
>> with the small sensor. If you need to control DoF, you need a larger
>> sensor, which means a DSLR, or the Sony R1 - a fixed lens ultrazoom
>> with an APS-C sized sensor.

>
>Probably best for her to get used to the Fuji first just to see what a
>digital camera can do. Maybe then upgrade if it is too restricting for the
>sort of photo she wants to take.
>
>Thanks once again for the info.


psssst.....

http://farm3.static.flickr.com/2271/...fb8fa792_o.jpg

The framed area in focus is about 12x15 inches or so in size. The background is
only about 1 foot away from the flowers. Don't show this to the DSLR people. It
was taken with a P&S camera. If they find out that a P&S camera can do shallow
DOF effects too then they'll have to find another reason for buying their
cameras. Let's just keep it our little secret so they don't get all depressed
over how much money they spent. Okay? I have tons more photographs like this one
some with much shallower DOF in them, but I liked the orchids in this one, a
very unusual variety. When using shallow DOF effects you should only keep it
shallow enough to keep all parts of your main focus in subject. That's the
mistake that so many DSLR people make with having only one small bit of their
subject in focus. But then they have to. If they stop down their lens enough to
get a deeper DOF to get all of the main subject in focus while blurring the
background they then have to use a tripod and such slow shutter speeds that
their subject has to be perfectly still. Or they have to use such high ISOs that
invariably introduce more noise. This is why they are so proud of those high
ISOs in the latest models that they pay a fortune for, because it finally allows
them to get photos that P&S cameras have been able to get all along. Otherwise
taking any of these kinds of photos are virtually impossible for them or at
least extremely difficult. These drawbacks to all DSLRS is also why they fail at
being the best option for any type of macrophotography. They just don't have the
kind of range needed for subjects of this nature. But as I said, don't let them
know this. They get all upset when they see proof to the contrary of what they
want to believe and were told to believe all their lives. Some people are so
touchy when you prove to them how much money they wasted. Oh well.








stuseven 10-10-2007 03:11 PM

Re: P & S and depth-of-field
 
On Oct 10, 6:52 am, "Jeff Layman" <jmlay...@thetapetcp.co.uk> wrote:
> Some time ago in this group I asked about depth-of-field with a compact
> digital camera. I was told that because of the small sensor size, this
> isn't really a problem compared to 35 mm film cameras.
>
> A friend using her new Fuji (A610, I think) asked me how to get shots with
> the background blurred and only the object of interest (eg a flower) in
> focus. I could be much mistaken, but I guess that this would be almost
> impossible. I can't see how to do it with my Caplio R6 either. Maybe using
> the lens in macro telephoto rather than wide angle would help, but even then
> I doubt you'd get the same effect as using a 35 mm film camera with a 50 mm
> macro lens set at f2.
>
> It also set me wondering exactly how much the aperture of a P & S camera
> changes when the lens specification is stated to be eg "f3 wide angle to
> f5.3 telephoto".
>
> Are there any P & S cameras where you can control the aperture over the sort
> of range you'd expect with a 35 mm camera and standard 50 mm lens (about
> f1.6 - 22), and so change depth-of-field?
>
> --
> Jeff
> (cut "thetape" to reply)


+ well, what you might want to try is one of the plug-ins for graphics
programs which [simulate] depth of focus changes... that is, if you
already have the picture, and it isnt practical to re-photograph.


Paul Furman 10-10-2007 03:36 PM

Re: P & S and depth-of-field
 
Taylor Dawson [TROLL] wrote:
> Alex Monro wrote:
>
>>I don't know of any P&S that has wider than f/2.4 max aperture, and
>>the minimum is usually about f/8, due to diffraction considerations
>>with the small sensor. If you need to control DoF, you need a larger
>>sensor, which means a DSLR, or the Sony R1 - a fixed lens ultrazoom
>>with an APS-C sized sensor.

>
> If you don't know of any P&S cameras that have a max aperture wider than f/2.4
> then you shouldn't be posting such misleading information. Go do your homework
> first. All of my P&S cameras are capable of f/2.4 or wider. One of my earliest
> ones from 6 years ago has an f/2.0 lens on it. That's only 0.2 away from that
> f/1.8 that DSLR owners always have an orgasm over, and they get that at only 1
> focal length, mine is an f/2.0 zoom lens.


That's cool, which camera? f/2 on the long end too?


> You also need to learn what
> "diffraction limited" means. If your lens is not configured to
> diffraction-limited specifications that means it performs poorer than one that


The practical application here is that the sensor limits the useable f/stop.


> There are two ways to control DOF effects. Aperture and focal-length. If your
> camera has a zoom lens on it then you can get identical shallow DOF effects as a
> larger sensor camera by just zooming in and moving further away from your
> subject. If you want to stay in the same position then increase the focal-length
> of your lens using a tele-extender to accomplish the same results.


Yes, this is the way to get selective focus: telephoto and/or macro.
It's not as much as a larger sensor camera though at long focal lengths
& particularly closeup, it's possible to get a similar look.

M-M 10-10-2007 03:37 PM

Re: P & S and depth-of-field
 
In article <auopg35frbm5febbfuhnhogda349pmj5vm@4ax.com>,
Glenn Ramsen <blocked@noreplies.net> wrote:

> http://farm3.static.flickr.com/2271/...fb8fa792_o.jpg
>
> The framed area in focus is about 12x15 inches or so in size. The background
> is
> only about 1 foot away from the flowers. Don't show this to the DSLR people.



You could not get that effect from a P&S if you were further away. In
fact, the only time you can get a shallow DOF with a P&S is when you
hold the lens right up to the subject.

Again, I'll refer you to this photo:

http://www.mhmyers.com/temp/4500-d80.jpg

I was about 100 feet from the sign and 200 ft from the background.

--
m-m


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