New to Digital

In using 35mm film, I appreciated the various manual overrides to automatic
settings, such as apperature, shutter speed, and focus. Now I am looking at
digital cameras and I find the specs on these features not well explained. Is
there such a thing as a 30-second time exposure in digital? Is the equivalent
of shutter speed something that I can control manually? What about depth of
field?

Robert Scott
Ypsilanti, Michigan

Robert Scott wrote:
In using 35mm film, I appreciated the various manual overrides to
automatic settings, such as apperature, shutter speed, and focus.
Now I am looking at digital cameras and I find the specs on these
features not well explained.

Well, they work just the same way as on film cameras. In addition you can
also change the ISO settings without swapping films.

Is there such a thing as a 30-second
time exposure in digital?

Depends on the camera. High-end models have "B" (bulb), but the one drawback
with digital cameras is sensor noise, which can become quite significant
with long-time exposure.

Is the equivalent of shutter speed
something that I can control manually? What about depth of field?

Again, depends on the camera model. Better cameras allow you to control all
this and much more. Cheap consumer level "junk" typically does not.
It's just the same as with film cameras: those point-and-shoot or one-time
use throw-away film cameras you can buy in souvenir shops don't allow you to
adjust shutter speed or control DOF, either.

jue

On Sun, 02 Sep 2007 11:33:47 GMT, ---@--- (Robert Scott) wrote:

In using 35mm film, I appreciated the various manual overrides to automatic
settings, such as apperature, shutter speed, and focus. Now I am looking at
digital cameras and I find the specs on these features not well explained. Is
there such a thing as a 30-second time exposure in digital? Is the equivalent
of shutter speed something that I can control manually? What about depth of
field?

Robert Scott
Ypsilanti, Michigan

Robert,

The line-up of DSLR cameras operate like the film equivalent, with
full manual control, aperature priority or shutter priority for depth
of field, motion control, etc., or full automatic shooting. An
advantage is that DSLR's allow you to change ISO settings, allowing
you to shoot under a wider variety of conditions than you can with a
film camera without changing film.

The "point and shoot" variety don't generally offer as much manual
control as the DSLR cameras, but the higher end ones come close or may
even match the functionality.

Check out: dpreview.com and stevesdigicams.com for some pretty good
information.

HTH
Bill

---@--- (Robert Scott) writes:
In using 35mm film, I appreciated the various manual overrides to
automatic settings, such as apperature, shutter speed, and focus.

You find these on digital SLRs (DSLRs) and (higher end) digicams as
well. The Canon Powershot G9 is an example:
http://www.dpreview.com/news/0708/07082005canong9.asp

Now I am looking at digital cameras and I find the specs on these
features not well explained. Is there such a thing as a 30-second
time exposure in digital?

Most DSLRs have "bulb", but noise become an issue with longer
exposures (but there are ways to deal with this),

Is the equivalent of shutter speed something that I can control
manually?

Yes, and higher end models even use the same type of mechanical
shutter used in film cameras.

What about depth of field?

That depends on sensor size. A camera with an FX-size or film-sized
senor (e.g. Nikon D3, Canon 5D, will give you the same DOF as
135-format film. A DX-sized sized sensor (e.g Nikon D40) will give
about 1/2 stop more DOF at the same FOV and aperture

For instance, if use use a 50 mm lens at f/2.0 at a film camera, and
then move that lens to a camera with a DX-sized sesnor and set
aperture to f/2.0, the result will as if we've used a 75 mm lens at
f/3.0 at the film camera in terms of FOV and DOF. But not in terms of
speed, the f-stop would still be f/2.0.

Digicams have tiny sensors, and you will have problems getting
shallow DOF on them.

For more about how sensor sizes affect images, see:
http://hannemyr.com/photo/crop.html
http://hannemyr.com/photo/crop2.html

--
- gisle hannemyr [ gisle{at}hannemyr.no - http://hannemyr.com/photo/ ]
------------------------------------------------------------------------
Sigma SD10, Kodak DCS 14n, Canon Powershot G5, Olympus 2020Z
------------------------------------------------------------------------

Gisle Hannemyr wrote:
---@--- (Robert Scott) writes:
In using 35mm film, I appreciated the various manual overrides to
automatic settings, such as apperature, shutter speed, and focus.

You find these on digital SLRs (DSLRs) and (higher end) digicams as
well. The Canon Powershot G9 is an example:
http://www.dpreview.com/news/0708/07082005canong9.asp

Now I am looking at digital cameras and I find the specs on these
features not well explained. Is there such a thing as a 30-second
time exposure in digital?

Most DSLRs have "bulb", but noise become an issue with longer
exposures (but there are ways to deal with this),

While noise certainly can't be ignored, new concepts in
processing not only reduce the noise problem, the fact that
digital cameras have higher quantum efficiency than film
and no reciprocity failure means that digital cameras can
record much fainter subjects than film. Digital cameras
have become the choice for astrophotography, for example.
The key is to take shorter exposures and digitally add them,
and noise gets averaged away.
See (Gisle, I know you know this; this is for the OP):

http://www.clarkvision.com/photoinfo...ht.photography

Is the equivalent of shutter speed something that I can control
manually?

Yes, and higher end models even use the same type of mechanical
shutter used in film cameras.

What about depth of field?

That depends on sensor size. A camera with an FX-size or film-sized
senor (e.g. Nikon D3, Canon 5D, will give you the same DOF as
135-format film. A DX-sized sized sensor (e.g Nikon D40) will give
about 1/2 stop more DOF at the same FOV and aperture

For instance, if use use a 50 mm lens at f/2.0 at a film camera, and
then move that lens to a camera with a DX-sized sesnor and set
aperture to f/2.0, the result will as if we've used a 75 mm lens at
f/3.0 at the film camera in terms of FOV and DOF. But not in terms of
speed, the f-stop would still be f/2.0.

Digicams have tiny sensors, and you will have problems getting
shallow DOF on them.

For more about how sensor sizes affect images, see:
http://hannemyr.com/photo/crop.html
http://hannemyr.com/photo/crop2.html

Gisle,
These are excellent pages with a lot of great information.
But the DOF sections are classical views that don't fully
incorporate the properties of digital cameras with varying
pixels and their differing light gathering abilities.
See:
The Depth-of-Field Myth and Digital Cameras
http://www.clarkvision.com/photoinfo/dof_myth

Other articles that the OP may find of interest:
http://www.clarkvision.com/imagedetail

Roger

On Sep 2, 5:38 pm, Gisle Hannemyr wrote:
---@--- (Robert Scott) writes:

Now I am looking at digital cameras and I find the specs on these
features not well explained. Is there such a thing as a 30-second
time exposure in digital?

Most DSLRs have "bulb", but noise become an issue with longer
exposures (but there are ways to deal with this),

That there is noise buildup with longer exposures is true; to put it
into perspective, however, here's a 4 minute ISO 800 shot with a D200:
http://www.pbase.com/al599/image/84895056
This 's the camera jpeg, so it did its own noise reduction (it's not
hard to see it). The only thing I did to it is compress it a bit to
save space, so eg the white balance is off.

Frankly, I think the long exposure noise issue is irrelevant except
for astrophotographers. Certainly it's a non-issue in comparison to
what happens with ISO 800 films when exposed for 4 minutes...

"Roger N. Clark (change username to rnclark)" writes:
Gisle Hannemyr wrote:

For more about how sensor sizes affect images, see:
http://hannemyr.com/photo/crop.html
http://hannemyr.com/photo/crop2.html

Gisle,
These are excellent pages with a lot of great information.
But the DOF sections are classical views that don't fully
incorporate the properties of digital cameras with varying
pixels and their differing light gathering abilities.
See:
The Depth-of-Field Myth and Digital Cameras
http://www.clarkvision.com/photoinfo/dof_myth

Ok, I've updated DOF-section of my cropping page somewhat and
included a brief summery of your point (I hope, please let me know
if you think the summary are inaccurate), and also included a link to
your "myth" article.

OK?

Anchor to the revised section:
http://hannemyr.com/photo/crop.html#dof
--
- gisle hannemyr [ gisle{at}hannemyr.no - http://hannemyr.com/photo/ ]
------------------------------------------------------------------------
Sigma SD10, Kodak DCS 14n, Canon Powershot G5, Olympus 2020Z
------------------------------------------------------------------------

Roger N. Clark (change username to rnclark) wrote:

While noise certainly can't be ignored, new concepts in
processing not only reduce the noise problem, the fact that
digital cameras have higher quantum efficiency than film
and no reciprocity failure means that digital cameras can
record much fainter subjects than film. Digital cameras
have become the choice for astrophotography, for example.
The key is to take shorter exposures and digitally add them,
and noise gets averaged away.
See (Gisle, I know you know this; this is for the OP):

In astrophotography, the sensors are cooled to allow long
exposures with little noise buildup. It isn't practical in
a digicam.

In film photography, high-ISO films are grainier. The noise
in digital photography has a different cause, but the end
product looks similar to the viewer.

Marvin wrote:
Roger N. Clark (change username to rnclark) wrote:

While noise certainly can't be ignored, new concepts in
processing not only reduce the noise problem, the fact that
digital cameras have higher quantum efficiency than film
and no reciprocity failure means that digital cameras can
record much fainter subjects than film. Digital cameras
have become the choice for astrophotography, for example.
The key is to take shorter exposures and digitally add them,
and noise gets averaged away.
See (Gisle, I know you know this; this is for the OP):

In astrophotography, the sensors are cooled to allow long exposures with
little noise buildup. It isn't practical in a digicam.

Right, and I was referring to astrophotography with
digital cameras. E.g. see:
http://www.clarkvision.com/galleries...y.astrophoto-1

In film photography, high-ISO films are grainier. The noise in digital
photography has a different cause, but the end product looks similar to
the viewer.

It is not just grain/noise; it it total sensitivity and
no reciprocity failure that propel DSLRs cameras above film.

Roger

Gisle Hannemyr wrote:
"Roger N. Clark (change username to rnclark)" writes:
Gisle Hannemyr wrote:

For more about how sensor sizes affect images, see:
http://hannemyr.com/photo/crop.html
http://hannemyr.com/photo/crop2.html
Gisle,
These are excellent pages with a lot of great information.
But the DOF sections are classical views that don't fully
incorporate the properties of digital cameras with varying
pixels and their differing light gathering abilities.
See:
The Depth-of-Field Myth and Digital Cameras
http://www.clarkvision.com/photoinfo/dof_myth

Ok, I've updated DOF-section of my cropping page somewhat and
included a brief summery of your point (I hope, please let me know
if you think the summary are inaccurate), and also included a link to
your "myth" article.

OK?

Anchor to the revised section:
http://hannemyr.com/photo/crop.html#dof
OK.

I'll ad a link to your page from mine.

Thanks
Roger