# Question on depth of field

Discussion in 'Digital Photography' started by jean, Feb 22, 2004.

1. ### jeanGuest

If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?

Jean

--
jeandr at bigfoot dot com

jean, Feb 22, 2004

2. ### Tal FucusGuest

Jean,
I'm not sure I understand you, but you'll have larger depth of field with
smaller aperture.
f3.5 is smaller then f1.8 (At least in this case

Tal

"jean" <look_for@my_email.org> wrote in message
news:%E9_b.2604\$...
> If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
> the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?
>
> Jean
>
>
> --
> jeandr at bigfoot dot com
>
>

Tal Fucus, Feb 22, 2004

3. ### Lisa HortonGuest

Yes. 50mm at 3.5 is 50mm at 3.5

Lisa

jean wrote:
>
> If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
> the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?
>
> Jean
>
> --
> jeandr at bigfoot dot com

Lisa Horton, Feb 22, 2004
4. ### Ken WeitzelGuest

Durn new math

I still think 1.8 is smaller than 3.5

Ken

Tal Fucus wrote:
> Jean,
> I'm not sure I understand you, but you'll have larger depth of field with
> smaller aperture.
> f3.5 is smaller then f1.8 (At least in this case
>
> Tal
>
> "jean" <look_for@my_email.org> wrote in message
> news:%E9_b.2604\$...
>
>>If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
>>the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?
>>
>>Jean
>>
>>
>>--
>>jeandr at bigfoot dot com
>>
>>

>
>
>

Ken Weitzel, Feb 22, 2004
5. ### al-FarrobGuest

jean wrote:

> If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
> the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?
>
> Jean
>
>

Yes, you can see it as 50/3.5 in both cases

--
al-Farrob
--
http://www.al-farrob.com

al-Farrob, Feb 22, 2004
6. ### Rudy GarciaGuest

In article <%E9_b.2604\$>,
"jean" <look_for@my_email.org> wrote:

> If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
> the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?
>
> Jean

Absolutely the same when both are set to the same aperture and subject
distance.

--
Rudy Garcia

Rudy Garcia, Feb 22, 2004
7. ### David Dyer-BennetGuest

"jean" <look_for@my_email.org> writes:

> If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
> the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?

The depth of field is determined by the focal length of the lens, the
size of the film, the degree of enlargement (if you're making your
judgement from a print), the distance the lens is focused at, and the
aperture the lens is set at.

So if you're talking about taking the same photo with the same camera
with a 50mm f3.5 lens set at f3.5, and a 50mm f1.8 lens set at f3.5,
and otherwise doing everything the same, then yes, they'll have the
same depth of field. It's the aperture *used* that's relevant.
--
David Dyer-Bennet, <mailto:>, <http://www.dd-b.net/dd-b/>
RKBA: <http://noguns-nomoney.com> <http://www.dd-b.net/carry/>
Photos: <dd-b.lighthunters.net> Snapshots: <www.dd-b.net/dd-b/SnapshotAlbum/>
Dragaera/Steven Brust: <http://dragaera.info/>

David Dyer-Bennet, Feb 22, 2004
8. ### Ed RufGuest

On Sun, 22 Feb 2004 17:02:58 -0500, in rec.photo.digital "jean"
<look_for@my_email.org> wrote:

>If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
>the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?

As long as you are comparing apples to apples it is the same. By this I
mean the same camera. You can not compare settings from a film to a digital
camera,
________________________________________________________
Ed Ruf Lifetime AMA# 344007 ()
http://members.cox.net/egruf
See images taken with my CP-990 and 5700 at
http://members.cox.net/egruf-digicam

Ed Ruf, Feb 23, 2004

Yes - if you are focused at the same distance.

--
http://www.chapelhillnoir.com
home of The Camera-ist's Manifesto
The Improved Links Pages are at
A sample chapter from my novel "Haight-Ashbury" is at
http://www.chapelhillnoir.com/writ/hait/hatitl.html
"jean" <look_for@my_email.org> wrote in message
news:%E9_b.2604\$...
> If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
> the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?
>
> Jean
>
>
> --
> jeandr at bigfoot dot com
>
>

10. ### Don StaufferGuest

No. Well, sort of. The depth of field in relative amount (that is,
PROPORTIONAL to focal length, or percentage of focal length), will be
about the same, but not in absolute measurement scale.

Also, diffraction will alter the depth of field a bit, increasing the
relative depth of field by a small amount.

jean wrote:
>
> If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
> the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?
>
> Jean
>
> --
> jeandr at bigfoot dot com

--
Don Stauffer in Minnesota

webpage- http://www.usfamily.net/web/stauffer

Don Stauffer, Feb 23, 2004
11. ### Ken BurnsGuest

Yes 1.8 is smaller than 3.5. But 1/1.8 is larger than 1/3.5 and 1/3.5 is
smaller than 1/1.8. If you knew the basics of lens apertures, you would
know this and not make foolish remarks.

KB

"Ken Weitzel" <> wrote in message
news:...
> Durn new math
>
> I still think 1.8 is smaller than 3.5
>
> Ken
>
>
>
> Tal Fucus wrote:
> > Jean,
> > I'm not sure I understand you, but you'll have larger depth of field

with
> > smaller aperture.
> > f3.5 is smaller then f1.8 (At least in this case
> >
> > Tal
> >
> > "jean" <look_for@my_email.org> wrote in message
> > news:%E9_b.2604\$...
> >
> >>If I take pictures with a 50mm lens with a maximum aperture of f3.5,

will
> >>the depth of field be the same as an f1.8 50mm lens stopped down to

f3.5?
> >>
> >>Jean
> >>
> >>
> >>--
> >>jeandr at bigfoot dot com
> >>
> >>

> >
> >
> >

>

Ken Burns, Feb 23, 2004
12. ### Ken WeitzelGuest

Hi Ken...

I intended it as a nothing more than a teasing joke...

Ken

Ken Burns wrote:
> Yes 1.8 is smaller than 3.5. But 1/1.8 is larger than 1/3.5 and 1/3.5 is
> smaller than 1/1.8. If you knew the basics of lens apertures, you would
> know this and not make foolish remarks.
>
> KB
>
>
>
> "Ken Weitzel" <> wrote in message
> news:...
>
>>Durn new math
>>
>>I still think 1.8 is smaller than 3.5
>>
>>Ken
>>
>>
>>
>>Tal Fucus wrote:
>>
>>>Jean,
>>>I'm not sure I understand you, but you'll have larger depth of field

>>

> with
>
>>>smaller aperture.
>>>f3.5 is smaller then f1.8 (At least in this case
>>>
>>>Tal
>>>
>>>"jean" <look_for@my_email.org> wrote in message
>>>news:%E9_b.2604\$...
>>>
>>>
>>>>If I take pictures with a 50mm lens with a maximum aperture of f3.5,
>>>

> will
>
>>>>the depth of field be the same as an f1.8 50mm lens stopped down to
>>>

> f3.5?
>
>>>>Jean
>>>>
>>>>
>>>>--
>>>>jeandr at bigfoot dot com
>>>>
>>>>
>>>
>>>
>>>

>
>

Ken Weitzel, Feb 23, 2004
13. ### Rudy GarciaGuest

In article <>,
Don Stauffer <> wrote:

> No. Well, sort of. The depth of field in relative amount (that is,
> PROPORTIONAL to focal length, or percentage of focal length), will be
> about the same, but not in absolute measurement scale.

There is nothing relative about it. Two 50mm lenses set to the same
aperture and focuused on the same subject will yield the same depth of
field in the same film format.

> Also, diffraction will alter the depth of field a bit, increasing the
> relative depth of field by a small amount.

Diffraction effects will affect both lenses the same when set to the
same aperture.

> jean wrote:
> >
> > If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
> > the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?
> >
> > Jean
> >
> > --
> > jeandr at bigfoot dot com

--
Rudy Garcia

Rudy Garcia, Feb 24, 2004
14. ### Don StaufferGuest

But I thought the question was between DOF on two lenses of same
relative aperture, but different focal length. That is the case where
DOF scales as proportional to focal length.

Rudy Garcia wrote:
>
> In article <>,
> Don Stauffer <> wrote:
>
> > No. Well, sort of. The depth of field in relative amount (that is,
> > PROPORTIONAL to focal length, or percentage of focal length), will be
> > about the same, but not in absolute measurement scale.

>
> There is nothing relative about it. Two 50mm lenses set to the same
> aperture and focuused on the same subject will yield the same depth of
> field in the same film format.
>
> > Also, diffraction will alter the depth of field a bit, increasing the
> > relative depth of field by a small amount.

>
> Diffraction effects will affect both lenses the same when set to the
> same aperture.
>
> > jean wrote:
> > >
> > > If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
> > > the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?
> > >
> > > Jean
> > >
> > > --
> > > jeandr at bigfoot dot com

>
> --
> Rudy Garcia

--
Don Stauffer in Minnesota

webpage- http://www.usfamily.net/web/stauffer

Don Stauffer, Feb 24, 2004
15. ### KBobGuest

On Tue, 24 Feb 2004 02:30:36 GMT, Rudy Garcia <>
wrote:

>In article <>,
> Don Stauffer <> wrote:
>
>> No. Well, sort of. The depth of field in relative amount (that is,
>> PROPORTIONAL to focal length, or percentage of focal length), will be
>> about the same, but not in absolute measurement scale.

>
>There is nothing relative about it. Two 50mm lenses set to the same
>aperture and focuused on the same subject will yield the same depth of
>field in the same film format.
>
>> Also, diffraction will alter the depth of field a bit, increasing the
>> relative depth of field by a small amount.

>
>Diffraction effects will affect both lenses the same when set to the
>same aperture.
>
>> jean wrote:
>> >
>> > If I take pictures with a 50mm lens with a maximum aperture of f3.5, will
>> > the depth of field be the same as an f1.8 50mm lens stopped down to f3.5?
>> >
>> > Jean
>> >
>> > --
>> > jeandr at bigfoot dot com

Yes, but some cameras (e.g. the Sony 824) have their lenses marked in
terms of equivalent 35mm focal lengths, even though they have the
typically small (11mm) CCD. The actual F.L. varies from 7.1 to 51mm.
Certainly misleading when DOF is concerned.

KBob, Feb 25, 2004