smallest f-stop on digital cameras

I just bought a Sony DSC-F707, and discovered that the minimum (ie smallest aperture) f-stop that can be set on the camera is f-8.

Is this common on digital cameras? If so, why is this?

My brief survey seems to indicate that none of them have f16, or even f11.

It limits one's creativity a bit, as the depth of field is not very great with f8.

R

hardsuit said:

Rob K96859 said:

to date OLYMPUS has been unmatched in this catagory.
olympus has no fewer than three top rated digicams.
the 2040 2mp, 3040 3mp, 4040 4mp.
all have 3x optical zoom, aspheric and low distortion optics.
ISO is good also, up to 400/800 asa.

Click to expand...

Click to expand...

Rob K96859 said:

Rob K96859 said:

your are right that many digicams do not have this.
first you must have the optical engeneering, without this forget it.
olympus was and is allways a lensmaker first.
the engeneering part comes from implementing technology.
other digicam makers have access to tech but unable to bring it.
canon, nikon, minolta, fuji are all GOOD lens makers.

Click to expand...

Click to expand...

Rob K96859 said:

Rob K96859 said:

yes, for now it seems smaller aperatures are limited
to D-SLR like fuji S-2 and the like.
this is of cource is easy , since these cameras use 35mm SLR lens.
the D-SLR holds the best advantage in this aerna.
but there is hope......enter the D-ZLR.
that is DIGI zoom lens reflex , like fuji F602, min dimage 5/7.
with these you get the BEST of both worlds.
mini size , maxi zoom, maxi megapixel, low cost.

Click to expand...

Click to expand...

hardsuit

Hi Rob

There's more depth of field than you think. As the focal length decreases, depth of field increases, even allowing for the greater print magnification due to the smaller size of the CCD.

If you do the maths you'll find that the hyperfocal distance of a typical digital camera zoomed to 10mm (the 35mm equivalent of 50mm) is approx 4 feet at f8. ie a DoF of 2 feet to infinity. If you check the DoF scale on a typical 50mm lens from a 35mm camera, you'll see the hyperfocal distance at f8 is approx 20 feet giving a DoP of 10 feet to infinity. The real problem is that there's often too much DoF!

This is of course, all theoretical. I suggest you just get out there and take pictures.

David

Rob K said:

I just bought a Sony DSC-F707, and discovered that the minimum (ie
smallest aperture) f-stop that can be set on the camera is f-8.

Is this common on digital cameras? If so, why is this?

My brief survey seems to indicate that none of them have f16, or
even f11.

It limits one's creativity a bit, as the depth of field is not very
great with f8.

R

Click to expand...

Rob K said:

I just bought a Sony DSC-F707, and discovered that the minimum (ie smallest aperture) f-stop that can be set on the camera is f-8. My brief survey seems to indicate that none of them have f16, or even f11.

Click to expand...

+++

Hi Rob

Just for info, I'm using an Olympus E-20 which gives me a maximum setting of F11.

Best regards

Paul
--
Paul Jones
http://www.pauljones.org

You are thinking of the relationship between f-stops and dof on 35-mm cameras. For digitial you have to factor in the sensor sizes which, in general, are far smaller (i.e. less that 1/4 the physical dimensions) than 35-mm film. The true focal lengths are correspondingly sized compared to their 35-mm equivalents (which are generally quoted). The result is a gain of around 4 f-stops in dof. Although advantageous for those who want great dof, the more common complaint about digital cameras (below the D-SLR category) is that they do not permit the easy limiting of dof (selective focus). It is likely that, throught experimentation with you 707 you will have already found that large dof is the rule unless you subject is close and the lens set to its longer end.

Rob K said:

I just bought a Sony DSC-F707, and discovered that the minimum (ie
smallest aperture) f-stop that can be set on the camera is f-8.

Is this common on digital cameras? If so, why is this?

My brief survey seems to indicate that none of them have f16, or
even f11.

It limits one's creativity a bit, as the depth of field is not very
great with f8.

R

Click to expand...

--
Garry

Garry's Page: http://www3.mb.sympatico.ca/~gschaef

Most digital cameras use very small sensors which require very short lenses to achieve the usual fields of view/magnification. For instance my E10 has a 9-36 mm zoom which is equivalent in field of view (roughly) to a 35-140mm lens on a 35mm camera.

The short focal lengths lead to deep depth of field - in fact sometimes it is very difficult to get shallow DOF even at the longest tele setting wide open at F2.4.

The other consequence of the short focal length is that the physical diameter of the aperture hole is a lot smaller at any give f stop than you would get with 35mm equipment.

This means that degradation of image quality caused by diffraction effects of light "bending" around the edges of the aperture blades kicks in at wider apertures than you would expect from 35mm experience. An F22 setting on my E10 would probably degrade image quality as much a some ridiculous setting like F128 or somesuch on a 35mm camera.

Some consumer P&S cameras have even shorter focal length lenses than the E10 so the problem would be that much worse.

Rob K said:

I just bought a Sony DSC-F707, and discovered that the minimum (ie
smallest aperture) f-stop that can be set on the camera is f-8.

Is this common on digital cameras? If so, why is this?

My brief survey seems to indicate that none of them have f16, or
even f11.

It limits one's creativity a bit, as the depth of field is not very
great with f8.

R

Click to expand...

Vid M said:

Vid M wrote:
Hi Rob

There's more depth of field than you think. As the focal length
decreases, depth of field increases, even allowing for the greater
print magnification due to the smaller size of the CCD.

Click to expand...

NOT!

Generally speaking, focal length has no bearing on DOF. Aperture controls DOF.

http://www.luminous-landscape.com/dof.htm

Vid M said:

If you do the maths you'll find that the hyperfocal distance of a
typical digital camera zoomed to 10mm (the 35mm equivalent of 50mm)
is approx 4 feet at f8. ie a DoF of 2 feet to infinity. If you
check the DoF scale on a typical 50mm lens from a 35mm camera,
you'll see the hyperfocal distance at f8 is approx 20 feet giving a
DoP of 10 feet to infinity. The real problem is that there's often
too much DoF!

This is of course, all theoretical. I suggest you just get out
there and take pictures.

David

Rob K said:

I just bought a Sony DSC-F707, and discovered that the minimum (ie
smallest aperture) f-stop that can be set on the camera is f-8.

Is this common on digital cameras? If so, why is this?

My brief survey seems to indicate that none of them have f16, or
even f11.

It limits one's creativity a bit, as the depth of field is not very
great with f8.

R

Click to expand...

Click to expand...

You said!
Generally speaking, focal length has no bearing on DOF. Aperture

Silicon Junkie© said:

controls DOF.

Click to expand...

I guess you are not a photographer with real life experience so I suggest reading this web page again! You'll see that your statement is without foundation. If still in doubt, compare for yourself by taking two pictures, one wide and one tele with the same f stop. Look at them on your monitor both ate the same size.
Rinus

Silicon Junkie© said:

http://www.luminous-landscape.com/dof.htm

Click to expand...

DMillier said:

...
This means that degradation of image quality caused by diffraction
effects of light "bending" around the edges of the aperture blades
kicks in at wider apertures than you would expect from 35mm
experience. An F22 setting on my E10 would probably degrade image
quality as much a some ridiculous setting like F128 or somesuch on
a 35mm camera.

Some consumer P&S cameras have even shorter focal length lenses
than the E10 so the problem would be that much worse.

Click to expand...

Since the physical focal length of consumer digcams is about a factor of four less than their 35mm equiv, the smallest f/stop will be two stops more open, i.e. f/8 with a consumer digicam will have the same physical aperature as f/16 with a 35mm camera for the same field of view.

YES! Not really wanting to get in to an arguement on this but - traditionally DoF scales are based on the size of the circle of confusion seen on a full frame 10x8 enlargement. Bigger enlargement give less DoF.

The linked article http://www.luminous-landscape.com/dof2.htm states "if the subject image size remains the same, then at any given aperture all lenses will give the same depth of field." I agree completely. The problem is that the image has to be enlarged further on the W/A shots to show the distant object at the same size, and then, yes, it will appear just as out of focus as in the Telehoto shots. This is proof that bigger enlargement = less DoF, not that all focal lenghts give the same DoF.

Take a look at the DoF scale on an old manual focus lens. Did Nikon, Canon, Olympus, Pentax, Minolta, Sigma and Tamron etc etc get it wrong?

David
(In a Circle of Confusion)

Silicon Junkie© said:

Silicon Junkie© said:

Vid M wrote:
Hi Rob

There's more depth of field than you think. As the focal length
decreases, depth of field increases, even allowing for the greater
print magnification due to the smaller size of the CCD.

Click to expand...

NOT!

Generally speaking, focal length has no bearing on DOF. Aperture
controls DOF.

http://www.luminous-landscape.com/dof.htm

Silicon Junkie© said:

If you do the maths you'll find that the hyperfocal distance of a
typical digital camera zoomed to 10mm (the 35mm equivalent of 50mm)
is approx 4 feet at f8. ie a DoF of 2 feet to infinity. If you
check the DoF scale on a typical 50mm lens from a 35mm camera,
you'll see the hyperfocal distance at f8 is approx 20 feet giving a
DoP of 10 feet to infinity. The real problem is that there's often
too much DoF!

This is of course, all theoretical. I suggest you just get out
there and take pictures.

David

Rob K said:

I just bought a Sony DSC-F707, and discovered that the minimum (ie
smallest aperture) f-stop that can be set on the camera is f-8.

Is this common on digital cameras? If so, why is this?

My brief survey seems to indicate that none of them have f16, or
even f11.

It limits one's creativity a bit, as the depth of field is not very
great with f8.

R

Click to expand...

Click to expand...

Click to expand...

Rinus said:

Member said:

controls DOF.

Click to expand...

I guess you are not a photographer with real life experience so I
suggest reading this web page again! You'll see that your statement
is without foundation. If still in doubt, compare for yourself by
taking two pictures, one wide and one tele with the same f stop.
Look at them on your monitor both ate the same size.
Rinus

Member said:

http://www.luminous-landscape.com/dof.htm

Click to expand...

Click to expand...

Hi, Rinus...I am a photographer, but certainly not a pro - a hobbyist only. However, I've been involved in photography for over 25 years, so I do know a little bit about the principles of exposure and DOF.

Here are some excerpts, copied directly from the web page I cited above - pay particular attention to the sections I set off with asterisks...

==========

DOF / Focal Length & Image Size

At the beginning of this tutorial I wrote, "Most people also believe that wide angle lenses have more depth of field than telephoto lenses (false)." Why is this such a common misconception?

It seems logical. Wide angle lenses appear to have more depth of field than long lenses, don't they? Yes, they appear to but only when you don't take subject size into account.

Imagine a person in a photograph holding a flower in front of them, and with a mountain range in the background. Now set up the shot so that the person's head fills about half the frame. Take a series of shots with every lens in your arsenal, from a 14mm ultra wide to a 600mm ultra telephoto. As long as the head is the same size in each frame the Depth of Field will be the same. The flower and the mountains will be equally in focus or out of focus as you change lenses.

Though I don't use a model with a flower and a mountain, here is a link to a page that demonstrates a small test that anyone can do themselves so that they can see the validity of my assertion.

-----------------

And then copied from the linked page....

-----------------

Testing The Theory

Most photographers accept the common belief that short focal length lenses have greater depth of field than do long lenses. A wide angle lens, in other words, will give greater depth of field than will a telephoto. Right?

Sounds about right, but it's not the case. In fact, if the subject image size remains the same, then at any given aperture all lenses will give the same depth of field.

==============

The sharpness of objects in the field of view do not change relative to the size of the subject in the frame. Therefore the DOF is constant for all focal lengths given the same aperture. The fact that an object may "appear" in focus is an optical illusion created by the nature of a wide angle photograph.

Regards,
SJ©

Vid M said:

Vid M wrote:
YES! Not really wanting to get in to an arguement on this but -
traditionally DoF scales are based on the size of the circle of
confusion seen on a full frame 10x8 enlargement. Bigger enlargement
give less DoF.

The linked article http://www.luminous-landscape.com/dof2.htm
states "if the subject image size remains the same, then at any
given aperture all lenses will give the same depth of field." I
agree completely. The problem is that the image has to be enlarged
further on the W/A shots to show the distant object at the same
size, and then, yes, it will appear just as out of focus as in the
Telehoto shots. This is proof that bigger enlargement = less DoF,
not that all focal lenghts give the same DoF.

Click to expand...

No, that is not it at all...the depth of field has not changed at all. Perhaps the DOF scales printed on lenses refer to the reference 8x10 enlargement size you mention above. Of that, I do not know and cannot remark.

However, enlargement size has nothing to do with whether a distant object in the field of view is actually in focus or not. The fact that a large enough wide angle print will reveal that a distant object is OOF proves that the distant object is not within the DOF to begin with. The fact that a distant object at 400mm f4.5 appears way out of focus, and the same distant object at 50mm f4.5 appears to be in focus (given the size of your near-field in focus subject is the same size in both frames) is merely an optical illusion because of the circle of confusion mentioned in his aritcle. There is less resolution to make up the distant object, therefore, your brain interprets much of the background image, and it "appears" to be in focus, but actually is not.

If I'm wrong about all this, then I completely misunderstand Michael's article and the concept of DOF.

Cheerio,
SJ©

Vid M said:

Take a look at the DoF scale on an old manual focus lens. Did
Nikon, Canon, Olympus, Pentax, Minolta, Sigma and Tamron etc etc
get it wrong?

David
(In a Circle of Confusion)

Silicon Junkie© said:

Vid M said:

Vid M wrote:
Hi Rob

There's more depth of field than you think. As the focal length
decreases, depth of field increases, even allowing for the greater
print magnification due to the smaller size of the CCD.

Click to expand...

NOT!

Generally speaking, focal length has no bearing on DOF. Aperture
controls DOF.

http://www.luminous-landscape.com/dof.htm

Vid M said:

If you do the maths you'll find that the hyperfocal distance of a
typical digital camera zoomed to 10mm (the 35mm equivalent of 50mm)
is approx 4 feet at f8. ie a DoF of 2 feet to infinity. If you
check the DoF scale on a typical 50mm lens from a 35mm camera,
you'll see the hyperfocal distance at f8 is approx 20 feet giving a
DoP of 10 feet to infinity. The real problem is that there's often
too much DoF!

This is of course, all theoretical. I suggest you just get out
there and take pictures.

David

Rob K said:

I just bought a Sony DSC-F707, and discovered that the minimum (ie
smallest aperture) f-stop that can be set on the camera is f-8.

Is this common on digital cameras? If so, why is this?

My brief survey seems to indicate that none of them have f16, or
even f11.

It limits one's creativity a bit, as the depth of field is not very
great with f8.

R

Click to expand...

Click to expand...

Click to expand...

Click to expand...

I'm afraid you are wrong and you have misunderstood.

DOF is affected by the following factors:

1. Lens aperture

2. Subject distance

3. Focal length

4. Acceptable circle of confusion

In simple terms:

If you were to mount your camera on a tripod with a zoom fitted

and focus on the mid distance then take two shots, one at 24mm and one at 200mm at the same aperture, the tele shot will have blurred background, the wideangle a sharp background.

Michael was talking about a special set of circumstances - not what you come across in my typical example given above.

How do you explain the huge DOF possessed by small sensor digicams?

Silicon Junkie© said:

Silicon Junkie© said:

Vid M wrote:
YES! Not really wanting to get in to an arguement on this but -
traditionally DoF scales are based on the size of the circle of
confusion seen on a full frame 10x8 enlargement. Bigger enlargement
give less DoF.

The linked article http://www.luminous-landscape.com/dof2.htm
states "if the subject image size remains the same, then at any
given aperture all lenses will give the same depth of field." I
agree completely. The problem is that the image has to be enlarged
further on the W/A shots to show the distant object at the same
size, and then, yes, it will appear just as out of focus as in the
Telehoto shots. This is proof that bigger enlargement = less DoF,
not that all focal lenghts give the same DoF.

Click to expand...

No, that is not it at all...the depth of field has not changed at
all. Perhaps the DOF scales printed on lenses refer to the
reference 8x10 enlargement size you mention above. Of that, I do
not know and cannot remark.

However, enlargement size has nothing to do with whether a distant
object in the field of view is actually in focus or not. The fact
that a large enough wide angle print will reveal that a distant
object is OOF proves that the distant object is not within the DOF
to begin with. The fact that a distant object at 400mm f4.5
appears way out of focus, and the same distant object at 50mm f4.5
appears to be in focus (given the size of your near-field in focus
subject is the same size in both frames) is merely an optical
illusion because of the circle of confusion mentioned in his
aritcle. There is less resolution to make up the distant object,
therefore, your brain interprets much of the background image, and
it "appears" to be in focus, but actually is not.

If I'm wrong about all this, then I completely misunderstand
Michael's article and the concept of DOF.

Cheerio,
SJ©

Silicon Junkie© said:

Take a look at the DoF scale on an old manual focus lens. Did
Nikon, Canon, Olympus, Pentax, Minolta, Sigma and Tamron etc etc
get it wrong?

David
(In a Circle of Confusion)

Silicon Junkie© said:

Silicon Junkie© said:

Vid M wrote:
Hi Rob

There's more depth of field than you think. As the focal length
decreases, depth of field increases, even allowing for the greater
print magnification due to the smaller size of the CCD.

Click to expand...

NOT!

Generally speaking, focal length has no bearing on DOF. Aperture
controls DOF.

http://www.luminous-landscape.com/dof.htm

Silicon Junkie© said:

If you do the maths you'll find that the hyperfocal distance of a
typical digital camera zoomed to 10mm (the 35mm equivalent of 50mm)
is approx 4 feet at f8. ie a DoF of 2 feet to infinity. If you
check the DoF scale on a typical 50mm lens from a 35mm camera,
you'll see the hyperfocal distance at f8 is approx 20 feet giving a
DoP of 10 feet to infinity. The real problem is that there's often
too much DoF!

This is of course, all theoretical. I suggest you just get out
there and take pictures.

David

Rob K said:

I just bought a Sony DSC-F707, and discovered that the minimum (ie
smallest aperture) f-stop that can be set on the camera is f-8.

Is this common on digital cameras? If so, why is this?

My brief survey seems to indicate that none of them have f16, or
even f11.

It limits one's creativity a bit, as the depth of field is not very
great with f8.

R

Click to expand...

Click to expand...

Click to expand...

Click to expand...

Click to expand...

It all comes down to what is 'acceptably sharp', which can be defined as "...what is considered to be in good focus by the average eye...". As there's no such thing, here's a photo of my old boots, which looks sharpish to my non-average eyes...



David

DavidMillier said:

DMillier wrote:
I'm afraid you are wrong and you have misunderstood.

DOF is affected by the following factors:

1. Lens aperture

2. Subject distance

3. Focal length

4. Acceptable circle of confusion

In simple terms:

If you were to mount your camera on a tripod with a zoom fitted
and focus on the mid distance then take two shots, one at 24mm and
one at 200mm at the same aperture, the tele shot will have blurred
background, the wideangle a sharp background.

Michael was talking about a special set of circumstances - not what
you come across in my typical example given above.

How do you explain the huge DOF possessed by small sensor digicams?

Click to expand...

Actually, I don't think the WA shot's background will be sharp at all. It just "appears" that way because our brains are filling in information for us, given the prints are of an identical size. It is an optical illusion, pure and simple.

For example, take a tele shot of a particluar subject and a WA shot of the same subject. Make sure that the given in-focus subject, and aperture (wide open is better) is the same size in both shots. Now, enlarge the WA shot so that the background object is almost the same size as the telephoto shot - you will see that in both shots, they are OOF.

http://www.luminous-landscape.com/dof2.htm

Small sensor digicams have a greater depth of field because of that very thing - the area capturing the image is smaller, and therefore apertures are smaller. Take medium format for example. A f4 medium format is going to have a narrower DOF than f4 at 35mm. Just as f4 at APS is going to have a greater DOF than 35mm at f4.

Regards,
SJ©

Yes, but that is Michael's special circumstance. You don't normally go out and say, "now I could shoot at 200mm but I thnk I'll shoot at wide angle then enlarge the image just to prove the local DOF is the same."

No you think " Ah, I need to get the foreground sharp at the same time as the background and enlarge from the whole frame. I'll shoot with a wideangle from close range."

I think you have a point about the aperture diameter - I believe short focal lengths give more DOF at any given Fstop because the physical size of the hole in the lens for any given aperture is smaller with the shorter lens.

Don't forget though that if you crop and magnify a portion of an image you will also magnify the Circles of Confusion - I suspect that will have an effect on perceived DOF. However, to be frank, I can't be bothered to think it through any more because I know exactly how to control DOF in normal shooting using subject distance, F stop and focal length!

Silicon Junkie© said:

Silicon Junkie© said:

DMillier wrote:
I'm afraid you are wrong and you have misunderstood.

DOF is affected by the following factors:

1. Lens aperture

2. Subject distance

3. Focal length

4. Acceptable circle of confusion

In simple terms:

If you were to mount your camera on a tripod with a zoom fitted
and focus on the mid distance then take two shots, one at 24mm and
one at 200mm at the same aperture, the tele shot will have blurred
background, the wideangle a sharp background.

Michael was talking about a special set of circumstances - not what
you come across in my typical example given above.

How do you explain the huge DOF possessed by small sensor digicams?

Click to expand...

Actually, I don't think the WA shot's background will be sharp at
all. It just "appears" that way because our brains are filling in
information for us, given the prints are of an identical size. It
is an optical illusion, pure and simple.

For example, take a tele shot of a particluar subject and a WA shot
of the same subject. Make sure that the given in-focus subject,
and aperture (wide open is better) is the same size in both shots.
Now, enlarge the WA shot so that the background object is almost
the same size as the telephoto shot - you will see that in both
shots, they are OOF.

http://www.luminous-landscape.com/dof2.htm

Small sensor digicams have a greater depth of field because of that
very thing - the area capturing the image is smaller, and therefore
apertures are smaller. Take medium format for example. A f4
medium format is going to have a narrower DOF than f4 at 35mm.
Just as f4 at APS is going to have a greater DOF than 35mm at f4.

Regards,
SJ©

Click to expand...

Rob K said:

I just bought a Sony DSC-F707, and discovered that the minimum (ie
smallest aperture) f-stop that can be set on the camera is f-8.

Is this common on digital cameras? If so, why is this?

My brief survey seems to indicate that none of them have f16, or
even f11.

It limits one's creativity a bit, as the depth of field is not very
great with f8.

R

Click to expand...

Thanks to everyone who replied. The responses have completely answered my questions. I had completely forgotten to consider the fact that the CCD is much smaller than a 35mm frame (obvious to me now, considering that the focal lengths of the zoom lens are so small). And of course, it is diffraction that limits the ultimate size of the aperture.

Much appreciated.
R

DavidMillier said:

Don't forget though that if you crop and magnify a portion of an
image you will also magnify the Circles of Confusion - I suspect
that will have an effect on perceived DOF. However, to be frank, I
can't be bothered to think it through any more because I know
exactly how to control DOF in normal shooting using subject
distance, F stop and focal length!

Click to expand...

Don't the circles of confusion disappear when you put them on square pixels? As long as they're smaller than the pixels themselves?

It seems to be a digital "fact".. as to the why i think its cos the manufacturers have given up on the depth of focus factor.. its something to do with the shorter focal length.. thow there is photoshop to increase your "creativity" afterwards.. its a different world in many respects..

trog100

1. #####

Rob K said:

I just bought a Sony DSC-F707, and discovered that the minimum (ie
smallest aperture) f-stop that can be set on the camera is f-8.

Is this common on digital cameras? If so, why is this?

My brief survey seems to indicate that none of them have f16, or
even f11.

It limits one's creativity a bit, as the depth of field is not very
great with f8.

R

Click to expand...

trog100 said:

It seems to be a digital "fact".. as to the why i think its cos the
manufacturers have given up on the depth of focus factor.. its
something to do with the shorter focal length.. thow there is
photoshop to increase your "creativity" afterwards.. its a
different world in many respects..

Click to expand...

It has nothing to do with digital "facts", manufacturers giving up, or creativity. It can be explained by considering the wave nature of light and how it diffracts. Something no manufacturer can do anything about.