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comparing depth of field

 
 
Bob Williams
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      06-07-2008
bucky3 wrote:
> Is there an objective spec that can be used to compare depth of field
> for different cameras/lenses? Would hyperfocal distance be able to
> serve this purpose?
>
> I'm not an expert on photography. I would like to get a non-SLR camera
> that can produce good bokeh (shallow depth of field), but I would like
> to be able to compare specs.



Most small sensor P/S cameras give pretty deep DOF.
I doubt that there would be significant differences between brands or
models at the same aperture........BUT.......
You can get a pretty convincing out of focus effect with Photoshop or
third party digital "filters". The nice thing about, say Photoshop's
Gaussian Blur Filter, is that you can very easily control the AMOUNT of
"bokeh" that you apply to the image.
Bob Williams
 
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ben brugman
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      06-07-2008

> I agree with this approach... works surprisingly well for normal
> shooting situations.
>
> Note that focal length plays NO ROLE contrary to what many think,
> provided the framing of the image is the same.
>


Not that focal length plays a LARGE ROLE if the subject distance is
near or beyond the hyperfocal distance. With modern small sensors
the hyperfocal distance is close so the focal length plays a role in
most day to day pictures.

ben
 
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Don Stauffer in Minnesota
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      06-07-2008
On Jun 7, 6:09 am, "ben brugman" <(E-Mail Removed)> wrote:
> > I agree with this approach... works surprisingly well for normal
> > shooting situations.

>
> > Note that focal length plays NO ROLE contrary to what many think,
> > provided the framing of the image is the same.

>
> Not that focal length plays a LARGE ROLE if the subject distance is
> near or beyond the hyperfocal distance. With modern small sensors
> the hyperfocal distance is close so the focal length plays a role in
> most day to day pictures.
>
> ben


Unless you are doing macro work.
 
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Archibald
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      06-07-2008
On Sat, 7 Jun 2008 13:09:59 +0200, "ben brugman" <(E-Mail Removed)>
wrote:

>
>> I agree with this approach... works surprisingly well for normal
>> shooting situations.
>>
>> Note that focal length plays NO ROLE contrary to what many think,
>> provided the framing of the image is the same.
>>

>
>Not that focal length plays a LARGE ROLE if the subject distance is
>near or beyond the hyperfocal distance. With modern small sensors
>the hyperfocal distance is close so the focal length plays a role in
>most day to day pictures.
>
>ben


Yes, this is true... but not much of an issue for most since the DOF
is so great. Basically everything is in focus.

Well, not everything. So if the near focus limit is critical for your
picture, this needs to be taken into consideration. But I don't see
many degrees of freedom here.... what if you are shooting a mountain
scene but the log in the foreground is not sharp (out of the DOF
zone). What would you do about it? Go to wide angle focal length?
Don't you think that would change the composition?

I think your only option is to stop down, if you want to keep your
composition.

Archibald
 
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ben brugman
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      06-08-2008

"Don Stauffer in Minnesota" <(E-Mail Removed)> schreef in bericht
news:(E-Mail Removed)...
> On Jun 7, 6:09 am, "ben brugman" <(E-Mail Removed)> wrote:
>> > I agree with this approach... works surprisingly well for normal
>> > shooting situations.

>>
>> > Note that focal length plays NO ROLE contrary to what many think,
>> > provided the framing of the image is the same.

>>


Not should be read as NOTE (sorry).
>> Not that focal length plays a LARGE ROLE if the subject distance is
>> near or beyond the hyperfocal distance. With modern small sensors
>> the hyperfocal distance is close so the focal length plays a role in
>> most day to day pictures.
>>
>> ben

>



> Unless you are doing macro work.

This exception was allready there in the sentence: Note the part 'near or
beyond', macro work normally is not near or beyond the hyperfocal distance
but closer.

ben


 
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ben brugman
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      06-08-2008

"Archibald" <(E-Mail Removed)> schreef in bericht
news:(E-Mail Removed)...
> On Sat, 7 Jun 2008 13:09:59 +0200, "ben brugman" <(E-Mail Removed)>
> wrote:
>
>>
>>> I agree with this approach... works surprisingly well for normal
>>> shooting situations.
>>>
>>> Note that focal length plays NO ROLE contrary to what many think,
>>> provided the framing of the image is the same.
>>>

>>
>>Not that focal length plays a LARGE ROLE if the subject distance is
>>near or beyond the hyperfocal distance. With modern small sensors
>>the hyperfocal distance is close so the focal length plays a role in
>>most day to day pictures.
>>
>>ben

>
> Yes, this is true... but not much of an issue for most since the DOF
> is so great. Basically everything is in focus. \

Well I think that is the issue everything being in focus.

>
> Well, not everything. So if the near focus limit is critical for your
> picture, this needs to be taken into consideration. But I don't see
> many degrees of freedom here.... what if you are shooting a mountain
> scene but the log in the foreground is not sharp (out of the DOF
> zone). What would you do about it? Go to wide angle focal length?
> Don't you think that would change the composition?
>
> I think your only option is to stop down, if you want to keep your
> composition.

Go to a smaller format is an option as well.

But I do agree with you that given a small sensor there is not a large
degree of freedom for the DOF.

ben


 
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Paul Furman
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      06-08-2008
bucky3 wrote:
> Is there an objective spec that can be used to compare depth of field
> for different cameras/lenses? Would hyperfocal distance be able to
> serve this purpose?
>
> I'm not an expert on photography. I would like to get a non-SLR camera
> that can produce good bokeh (shallow depth of field), but I would like
> to be able to compare specs.


The DOF calculators are a good idea. I wouldn't really try to boil it
down to one number, it's really 3 numbers:
-focal length (35mm equivalent is easier)
-f/stop
-sensor size

If you want to have a soft background, use a longer focal length at the
widest aperture, so a longer zoom will help with this.
http://www.cambridgeincolour.com/tut...h-of-field.htm


--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam
 
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