Digital Advanteges in Macro

IMHO the greater Depth of field of the smaller sensor makes it easier
to work both with and without a tripod.

I was able to shoot 20 really good shots in the 1:2 range that I would
not have been able to hand hold previously because the DOF was so
precise that any camera shake would have ruined the image
 >> Stay informed about: Digital Advanteges in Macro 

In article <1125136355.645342.69620.TakeThisOut@o13g2000cwo.googlegroups.com>, rcrev
<rcrev.TakeThisOut@yahoo.com> writes
>IMHO the greater Depth of field of the smaller sensor makes it easier
>to work both with and without a tripod.

The DoF depends on the aperture and the length of the lens, not on the
size of the sensor (or film):

minimum = s/[1 + ac(s-f)/f^2]

maximum = s/[1 - ac(s-f)/f^2]

s — the focused subject distance (this is what is set on the lens
focus scale)
f — lens focal length
a — aperture (or F-stop), like e.g., 2.8
c — the diameter of the acceptable circle of confusion.

--
Ian G8ILZ
 >> Stay informed about: Digital Advanteges in Macro 

Prometheus <Prometheus.DeleteThis@127.0.0.1> wrote:

> In article <1125136355.645342.69620.DeleteThis@o13g2000cwo.googlegroups.com>, rcrev
> <rcrev.DeleteThis@yahoo.com> writes
> >IMHO the greater Depth of field of the smaller sensor makes it easier
> >to work both with and without a tripod.
>
> The DoF depends on the aperture and the length of the lens, not on the
> size of the sensor (or film):

DoF depends on the size of the final output print and how close it will
be to the viewer's eyeballs.
 >> Stay informed about: Digital Advanteges in Macro 

In article <slPbdZo7zDEDFwBu.TakeThisOut@newbrain.demon.co.uk>, Prometheus
<Prometheus.TakeThisOut@127.0.0.1> writes
>In article <1125136355.645342.69620.TakeThisOut@o13g2000cwo.googlegroups.com>,
>rcrev <rcrev.TakeThisOut@yahoo.com> writes
>>IMHO the greater Depth of field of the smaller sensor makes it easier
>>to work both with and without a tripod.
>
>The DoF depends on the aperture and the length of the lens, not on the
>size of the sensor (or film):
>
>minimum = s/[1 + ac(s-f)/f^2]
>
>maximum = s/[1 - ac(s-f)/f^2]
>
>s — the focused subject distance (this is what is set on the lens
>focus scale)
>f — lens focal length
>a — aperture (or F-stop), like e.g., 2.8
>c — the diameter of the acceptable circle of confusion.
>
The DoF calculation makes an assumption about the degree of enlargement
from film/sensor image to final output (screen or print). If you crop a
portion of the image and print the same size, the degree of enlargement
increases, and hence the acceptable circle of confusion size on the
image is smaller. Thus, logically, the DoF of an image on a reduced size
digital sensor should actually be less.

However, in reality with a macro subject it is likely that the image of
the actual subject will be the same size regardless of whether you are
using film or sensor; you will simply crop a little more in enlarging
the film. Alternatively, you will back off a little for the smaller
digital sensor, which will also increase DoF to cancel out the reduction
in my first paragraph Thus for most practical purposes the result will
probably be the same.

David
--
David Littlewood
 >> Stay informed about: Digital Advanteges in Macro 

In article <1h1yca0.14ygd8910itzk0N%usenet@mile23.c0m>, Paul Mitchum
<usenet RemoveThis @mile23.c0m> writes
>Prometheus <Prometheus RemoveThis @127.0.0.1> wrote:
>
>> In article <1125136355.645342.69620 RemoveThis @o13g2000cwo.googlegroups.com>, rcrev
>> <rcrev RemoveThis @yahoo.com> writes
>> >IMHO the greater Depth of field of the smaller sensor makes it easier
>> >to work both with and without a tripod.
>>
>> The DoF depends on the aperture and the length of the lens, not on the
>> size of the sensor (or film):
>
>DoF depends on the size of the final output print and how close it will
>be to the viewer's eyeballs.

The normal assumption is full frame viewed at a distance equal to the
diagonal; of course if you make it postage stamp sized and view at 10m
or A0 and view at 20mm with a loop the figures will be different, this
is why the conventional equation is used with the CoF taken to be on the
sensor or film. A proper photographer knows how the print will be viewed
and allows for that.
--
Ian G8ILZ
 >> Stay informed about: Digital Advanteges in Macro 

In article <1125208365.908398@ftpsrv1>, frederick <lost.DeleteThis@sea.co.zn>
writes
>???
>The difference in DOF is about 1 stop between 35mm and 1:1.5 ratio
>digital sensor (not a lot), but about 5 stops between 1:1.5 ratio and a
>compact camera with a 1 1/8" sensor.
>This is based on not the same magnification ratio, but for getting the
>same subject to fill the same area of the frame with the same
>acceptance of sharpness.
>A digital compact camera actually compliments a dslr quite nicely. The
>deepest available DOF from a dslr at the point where resolution is lost
>to diffraction is about the same as a compact camera at about f2.8,
>which gives you a further 3 or 4 stops with the compact before it in
>turn (assuming about 6mp) becomes diffraction limited.

You clearly reach this conclusion by ignoring the extra magnification
needed to bring the result from the tiny sensor up to the end result.
This is pretty meaningless.

David
--
David Littlewood
 >> Stay informed about: Digital Advanteges in Macro 

David Littlewood wrote:
> In article <slPbdZo7zDEDFwBu.TakeThisOut@newbrain.demon.co.uk>, Prometheus
> <Prometheus.TakeThisOut@127.0.0.1> writes
>
>> In article <1125136355.645342.69620.TakeThisOut@o13g2000cwo.googlegroups.com>,
>> rcrev <rcrev.TakeThisOut@yahoo.com> writes
>>
>>> IMHO the greater Depth of field of the smaller sensor makes it easier
>>> to work both with and without a tripod.
>>
>>
>> The DoF depends on the aperture and the length of the lens, not on the
>> size of the sensor (or film):
>>
>> minimum = s/[1 + ac(s-f)/f^2]
>>
>> maximum = s/[1 - ac(s-f)/f^2]
>>
>> s — the focused subject distance (this is what is set on the lens
>> focus scale)
>> f — lens focal length
>> a — aperture (or F-stop), like e.g., 2.8
>> c — the diameter of the acceptable circle of confusion.
>>
> The DoF calculation makes an assumption about the degree of enlargement
> from film/sensor image to final output (screen or print). If you crop a
> portion of the image and print the same size, the degree of enlargement
> increases, and hence the acceptable circle of confusion size on the
> image is smaller. Thus, logically, the DoF of an image on a reduced size
> digital sensor should actually be less.
>
> However, in reality with a macro subject it is likely that the image of
> the actual subject will be the same size regardless of whether you are
> using film or sensor; you will simply crop a little more in enlarging
> the film. Alternatively, you will back off a little for the smaller
> digital sensor, which will also increase DoF to cancel out the reduction
> in my first paragraph Thus for most practical purposes the result will
> probably be the same.
>
> David
???
The difference in DOF is about 1 stop between 35mm and 1:1.5 ratio
digital sensor (not a lot), but about 5 stops between 1:1.5 ratio and a
compact camera with a 1 1/8" sensor.
This is based on not the same magnification ratio, but for getting the
same subject to fill the same area of the frame with the same acceptance
of sharpness.
A digital compact camera actually compliments a dslr quite nicely. The
deepest available DOF from a dslr at the point where resolution is lost
to diffraction is about the same as a compact camera at about f2.8,
which gives you a further 3 or 4 stops with the compact before it in
turn (assuming about 6mp) becomes diffraction limited.
 >> Stay informed about: Digital Advanteges in Macro 

David Littlewood wrote:
> In article <1125208365.908398@ftpsrv1>, frederick <lost RemoveThis @sea.co.zn> writes
>
>> ???
>> The difference in DOF is about 1 stop between 35mm and 1:1.5 ratio
>> digital sensor (not a lot), but about 5 stops between 1:1.5 ratio and
>> a compact camera with a 1 1/8" sensor.
>> This is based on not the same magnification ratio, but for getting the
>> same subject to fill the same area of the frame with the same
>> acceptance of sharpness.
>> A digital compact camera actually compliments a dslr quite nicely.
>> The deepest available DOF from a dslr at the point where resolution is
>> lost to diffraction is about the same as a compact camera at about
>> f2.8, which gives you a further 3 or 4 stops with the compact before
>> it in turn (assuming about 6mp) becomes diffraction limited.
>
>
> You clearly reach this conclusion by ignoring the extra magnification
> needed to bring the result from the tiny sensor up to the end result.
> This is pretty meaningless.
>

With 35mm, 75mm lens, 500mm focus distance to subject, f2.8 total DOF is
about 7mm.
With 1:1.5 crop, 50mm lens, 500mm focus distance to subject, f2.8 total
DOF is about 11mm.
That is based on the same acceptability of sharpness for the same print
size - it does not ignore magnification ratio.
As I said, there is a little difference between 35mm and 1:1.5 crop ratio.
But the difference is big between 35mm and a compact camera with a tiny
sensor. If you have one with macro capability, then try it out yourself
instead of arguing with me.
 >> Stay informed about: Digital Advanteges in Macro