What next when the hyperfocal is wrong?

According the Lord of math, the hyperfocal distance of my 50mm lens is
25 feet at F/11. Supposedly everything from 25 feet to infinity will be
in focus. Unfortunately you can't tell if this is the case until you
examine the image on a computer.

Last week, I shot a wedding where I wanted the couple at about 25 feet
and a church at infinity plus all in between to be focused. I didn't get
the measuring tape out but I have a fair idea of how far away 25 feet is.

The picture is OK. The foreground is sharp but the church in the
distance is not as sharp as I'd have thought it would be considering the
maths of the matter. I reasoned any smaller than F/11 and the image
would start to lose sharpness and produce vignetting.

Anyway... Can someone offer a suggestion as to why the technical details
were right and the results with my 20D off? The same image from my 5D
was spot on. Have I missed something with the crop factor or are there
other considerations when the lens is on 1.6 crop camera?

Douglas

Dmac wrote:

According the Lord of math, the hyperfocal distance of my 50mm lens is
25 feet at F/11. Supposedly everything from 25 feet to infinity will be
in focus. Unfortunately you can't tell if this is the case until you
examine the image on a computer.

Last week, I shot a wedding where I wanted the couple at about 25 feet
and a church at infinity plus all in between to be focused. I didn't get
the measuring tape out but I have a fair idea of how far away 25 feet is.

The picture is OK. The foreground is sharp but the church in the
distance is not as sharp as I'd have thought it would be considering the
maths of the matter. I reasoned any smaller than F/11 and the image
would start to lose sharpness and produce vignetting.

Anyway... Can someone offer a suggestion as to why the technical details
were right and the results with my 20D off? The same image from my 5D
was spot on. Have I missed something with the crop factor or are there
other considerations when the lens is on 1.6 crop camera?

Douglas

Presuming your couple were at 25 feet and the church was near enough to
infinity, then the hyperfocal distance - your focus point - should be 50
feet. Focus on 50 feet and the dof will extend from half the HD, i.e. 25 ft
to infinity, at the correct stop, of course. If you focused on 25 feet then
there's your problem. Dof when focused at 25 ft and f/11 extends from 13.5
ft to 174 ft, so the foreground and couple will be sharp, but the church will
probably be outside the 174 ft limit (from Dofmaster calculator).

From the DofMaster website calculator for APS-sized sensors with a CoC of
0.025mm, focusing on 50 ft at f/8 will give a dof of 22.6 feet to infinity.
If you focused directly on the couple for maximum sharpness (which is what I
would do), and wanted the church in as well, then your HD is 25 ft, the point
you focused on, and the aperture to extend the dof to infinity will be
f/13.5. This would also extend the dof in front of the couple to 12.4 feet -
so your total dof would be 12.4 ft to infinity when focused on 25 ft, which
obeys the rule of acceptable sharpness from half the HD to infinity.

But, as I well know, doing this in your head while shooting a wedding is all
but impossible.

Did you not think of using the 'A-dep' function on the camera?

Colin D.


--
Posted via a free Usenet account from http://www.teranews.com

"C J Donoghue" wrote in message
...


Dmac wrote:

According the Lord of math, the hyperfocal distance of my 50mm lens is
25 feet at F/11. Supposedly everything from 25 feet to infinity will be
in focus. Unfortunately you can't tell if this is the case until you
examine the image on a computer.

Last week, I shot a wedding where I wanted the couple at about 25 feet
and a church at infinity plus all in between to be focused. I didn't get
the measuring tape out but I have a fair idea of how far away 25 feet is.

The picture is OK. The foreground is sharp but the church in the
distance is not as sharp as I'd have thought it would be considering the
maths of the matter. I reasoned any smaller than F/11 and the image
would start to lose sharpness and produce vignetting.

Anyway... Can someone offer a suggestion as to why the technical details
were right and the results with my 20D off? The same image from my 5D
was spot on. Have I missed something with the crop factor or are there
other considerations when the lens is on 1.6 crop camera?

Douglas

Presuming your couple were at 25 feet and the church was near enough to
infinity, then the hyperfocal distance - your focus point - should be 50
feet. Focus on 50 feet and the dof will extend from half the HD, i.e. 25
ft
to infinity, at the correct stop, of course. If you focused on 25 feet
then
there's your problem. Dof when focused at 25 ft and f/11 extends from
13.5
ft to 174 ft, so the foreground and couple will be sharp, but the church
will
probably be outside the 174 ft limit (from Dofmaster calculator).

From the DofMaster website calculator for APS-sized sensors with a CoC of
0.025mm, focusing on 50 ft at f/8 will give a dof of 22.6 feet to
infinity.
If you focused directly on the couple for maximum sharpness (which is what
I
would do), and wanted the church in as well, then your HD is 25 ft, the
point
you focused on, and the aperture to extend the dof to infinity will be
f/13.5. This would also extend the dof in front of the couple to 12.4
feet -
so your total dof would be 12.4 ft to infinity when focused on 25 ft,
which
obeys the rule of acceptable sharpness from half the HD to infinity.

But, as I well know, doing this in your head while shooting a wedding is
all
but impossible.

Did you not think of using the 'A-dep' function on the camera?

Colin D.


--
Posted via a free Usenet account from http://www.teranews.com


Our numbers differ

I used a CoC of .019 for the 20D (as shown on dofmaster), but you used
..025???

"POTD.com.au" wrote:

"C J Donoghue" wrote in message
...


Dmac wrote:

According the Lord of math, the hyperfocal distance of my 50mm lens is
25 feet at F/11. Supposedly everything from 25 feet to infinity will be
in focus. Unfortunately you can't tell if this is the case until you
examine the image on a computer.

Last week, I shot a wedding where I wanted the couple at about 25 feet
and a church at infinity plus all in between to be focused. I didn't get
the measuring tape out but I have a fair idea of how far away 25 feet is.

The picture is OK. The foreground is sharp but the church in the
distance is not as sharp as I'd have thought it would be considering the
maths of the matter. I reasoned any smaller than F/11 and the image
would start to lose sharpness and produce vignetting.

Anyway... Can someone offer a suggestion as to why the technical details
were right and the results with my 20D off? The same image from my 5D
was spot on. Have I missed something with the crop factor or are there
other considerations when the lens is on 1.6 crop camera?

Douglas

Presuming your couple were at 25 feet and the church was near enough to
infinity, then the hyperfocal distance - your focus point - should be 50
feet. Focus on 50 feet and the dof will extend from half the HD, i.e. 25
ft
to infinity, at the correct stop, of course. If you focused on 25 feet
then
there's your problem. Dof when focused at 25 ft and f/11 extends from
13.5
ft to 174 ft, so the foreground and couple will be sharp, but the church
will
probably be outside the 174 ft limit (from Dofmaster calculator).

From the DofMaster website calculator for APS-sized sensors with a CoC of
0.025mm, focusing on 50 ft at f/8 will give a dof of 22.6 feet to
infinity.
If you focused directly on the couple for maximum sharpness (which is what
I
would do), and wanted the church in as well, then your HD is 25 ft, the
point
you focused on, and the aperture to extend the dof to infinity will be
f/13.5. This would also extend the dof in front of the couple to 12.4
feet -
so your total dof would be 12.4 ft to infinity when focused on 25 ft,
which
obeys the rule of acceptable sharpness from half the HD to infinity.

But, as I well know, doing this in your head while shooting a wedding is
all
but impossible.

Did you not think of using the 'A-dep' function on the camera?

Colin D.


--
Posted via a free Usenet account from http://www.teranews.com


Our numbers differ

I used a CoC of .019 for the 20D (as shown on dofmaster), but you used
.025???

Yes, I saw that, and the reason is as you say a difference in CoC. On the
Dofmaster calculator I simply used the CoC applicable to APS-sized cameras,
which is 0.025mm, but after your post I hit the net and found that the 20D spec.
is 0.019, and using DM's custom COC's I got near enough the same as you.
Interestingly, the same CoC was quoted for the 300D with its greater sensel
size, perhaps a mistake in the list.

But, 0.025 or 0.019, Doug's problem is one of miscalculating the HD, I think.

Colin D.


--
Posted via a free Usenet account from http://www.teranews.com

ColinD wrote:

"POTD.com.au" wrote:


"C J Donoghue" wrote in message
...


Dmac wrote:


According the Lord of math, the hyperfocal distance of my 50mm lens is
25 feet at F/11. Supposedly everything from 25 feet to infinity will be
in focus. Unfortunately you can't tell if this is the case until you
examine the image on a computer.

Last week, I shot a wedding where I wanted the couple at about 25 feet
and a church at infinity plus all in between to be focused. I didn't get
the measuring tape out but I have a fair idea of how far away 25 feet is.

The picture is OK. The foreground is sharp but the church in the
distance is not as sharp as I'd have thought it would be considering the
maths of the matter. I reasoned any smaller than F/11 and the image
would start to lose sharpness and produce vignetting.

Anyway... Can someone offer a suggestion as to why the technical details
were right and the results with my 20D off? The same image from my 5D
was spot on. Have I missed something with the crop factor or are there
other considerations when the lens is on 1.6 crop camera?

Douglas

Presuming your couple were at 25 feet and the church was near enough to
infinity, then the hyperfocal distance - your focus point - should be 50
feet. Focus on 50 feet and the dof will extend from half the HD, i.e. 25
ft
to infinity, at the correct stop, of course. If you focused on 25 feet
then
there's your problem. Dof when focused at 25 ft and f/11 extends from
13.5
ft to 174 ft, so the foreground and couple will be sharp, but the church
will
probably be outside the 174 ft limit (from Dofmaster calculator).

From the DofMaster website calculator for APS-sized sensors with a CoC of
0.025mm, focusing on 50 ft at f/8 will give a dof of 22.6 feet to
infinity.
If you focused directly on the couple for maximum sharpness (which is what
I
would do), and wanted the church in as well, then your HD is 25 ft, the
point
you focused on, and the aperture to extend the dof to infinity will be
f/13.5. This would also extend the dof in front of the couple to 12.4
feet -
so your total dof would be 12.4 ft to infinity when focused on 25 ft,
which
obeys the rule of acceptable sharpness from half the HD to infinity.

But, as I well know, doing this in your head while shooting a wedding is
all
but impossible.

Did you not think of using the 'A-dep' function on the camera?

Colin D.


--
Posted via a free Usenet account from http://www.teranews.com


Our numbers differ

I used a CoC of .019 for the 20D (as shown on dofmaster), but you used
.025???


Yes, I saw that, and the reason is as you say a difference in CoC. On the
Dofmaster calculator I simply used the CoC applicable to APS-sized cameras,
which is 0.025mm, but after your post I hit the net and found that the 20D spec.
is 0.019, and using DM's custom COC's I got near enough the same as you.
Interestingly, the same CoC was quoted for the 300D with its greater sensel
size, perhaps a mistake in the list.

But, 0.025 or 0.019, Doug's problem is one of miscalculating the HD, I think.

Colin D.



You could be right Colin. One of my very real problems is still working
with film (MF) for critical portraits and using digital for the rest of
the shoot. Mental calculations on the fly are always likely to be
inaccurate when you use DOF calculations different between 3 cameras.

I did some pegged out checks of HF calculations on the local sports
field yesterday and it would seem that Russell's (POTD) 0.019mm CoC for
a 20D is pretty accurate whereas the figures quoted by a plethora of
"experts" vary as much as their opinions do. Surprisingly, 0.025 - The
Leica standard CoC is not as far off as it seems it would be. Certainly
closer than the 0.030 I used at the time. In fact, you could probably
work with 0.025 on both a 20D and 5D at a pinch... Give or take a few feet.

Dmac wrote:

Surprisingly, 0.025 - The
Leica standard CoC is not as far off as it seems it would be. Certainly
closer than the 0.030 I used at the time. In fact, you could probably
work with 0.025 on both a 20D and 5D at a pinch... Give or take a few feet


Nonsense. If you think you can work with one value of CoC for two
such widely differing formats, you are even more of an idiot than you
first appeared.

"Dmac" wrote in message
...
SNIP
I did some pegged out checks of HF calculations on the local sports
field yesterday and it would seem that Russell's (POTD) 0.019mm CoC
for a 20D is pretty accurate whereas the figures quoted by a
plethora of "experts" vary as much as their opinions do.

As I mentioned in threads earlier than this one, I use a COC (which
also includes an enlargement to output) assumption of either 1x to 2x
(+processing) the sensel pitch. There will be no detail smaller than
the sensel pitch and, given the AA-filter + Bayer CFA, color
resolution will be close to 2x the pitch as a worst assumption.

This coincides with what I see on screen when preparing for large
format output. Smaller output will obviously allow me to get away with
larger COC assumptions.

Bart

"POTD.com.au" wrote:

"C J Donoghue" wrote in message
...


Dmac wrote:

According the Lord of math, the hyperfocal distance of my 50mm lens is
25 feet at F/11. Supposedly everything from 25 feet to infinity will be
in focus. Unfortunately you can't tell if this is the case until you
examine the image on a computer.

Last week, I shot a wedding where I wanted the couple at about 25 feet
and a church at infinity plus all in between to be focused. I didn't get
the measuring tape out but I have a fair idea of how far away 25 feet is.

The picture is OK. The foreground is sharp but the church in the
distance is not as sharp as I'd have thought it would be considering the
maths of the matter. I reasoned any smaller than F/11 and the image
would start to lose sharpness and produce vignetting.

Anyway... Can someone offer a suggestion as to why the technical details
were right and the results with my 20D off? The same image from my 5D
was spot on. Have I missed something with the crop factor or are there
other considerations when the lens is on 1.6 crop camera?

Douglas

Presuming your couple were at 25 feet and the church was near enough to
infinity, then the hyperfocal distance - your focus point - should be 50
feet. Focus on 50 feet and the dof will extend from half the HD, i.e. 25
ft
to infinity, at the correct stop, of course. If you focused on 25 feet
then
there's your problem. Dof when focused at 25 ft and f/11 extends from
13.5
ft to 174 ft, so the foreground and couple will be sharp, but the church
will
probably be outside the 174 ft limit (from Dofmaster calculator).

From the DofMaster website calculator for APS-sized sensors with a CoC of
0.025mm, focusing on 50 ft at f/8 will give a dof of 22.6 feet to
infinity.
If you focused directly on the couple for maximum sharpness (which is what
I
would do), and wanted the church in as well, then your HD is 25 ft, the
point
you focused on, and the aperture to extend the dof to infinity will be
f/13.5. This would also extend the dof in front of the couple to 12.4
feet -
so your total dof would be 12.4 ft to infinity when focused on 25 ft,
which
obeys the rule of acceptable sharpness from half the HD to infinity.

But, as I well know, doing this in your head while shooting a wedding is
all
but impossible.

Did you not think of using the 'A-dep' function on the camera?

Colin D.


--
Posted via a free Usenet account from http://www.teranews.com


Our numbers differ

I used a CoC of .019 for the 20D (as shown on dofmaster), but you used
.025???

Yes, I saw that, and the reason is as you say a difference in CoC. On the
Dofmaster calculator I simply used the CoC applicable to APS-sized cameras,
which is 0.025mm, but after your post I hit the net and found that the 20D spec.
is 0.019, and using DM's custom COC's I got near enough the same as you.
Interestingly, the same CoC was quoted for the 300D with its greater sensel
size, perhaps a mistake in the list.

But, 0.025 or 0.019, Doug's problem is one of miscalculating the HD, I think.

Colin D.


--
Posted via a free Usenet account from http://www.teranews.com

"ColinD" wrote in message
...


"POTD.com.au" wrote:

"C J Donoghue" wrote in message
...


Dmac wrote:

According the Lord of math, the hyperfocal distance of my 50mm lens is
25 feet at F/11. Supposedly everything from 25 feet to infinity will
be
in focus. Unfortunately you can't tell if this is the case until you
examine the image on a computer.

Last week, I shot a wedding where I wanted the couple at about 25 feet
and a church at infinity plus all in between to be focused. I didn't
get
the measuring tape out but I have a fair idea of how far away 25 feet
is.

The picture is OK. The foreground is sharp but the church in the
distance is not as sharp as I'd have thought it would be considering
the
maths of the matter. I reasoned any smaller than F/11 and the image
would start to lose sharpness and produce vignetting.

Anyway... Can someone offer a suggestion as to why the technical
details
were right and the results with my 20D off? The same image from my 5D
was spot on. Have I missed something with the crop factor or are there
other considerations when the lens is on 1.6 crop camera?

Douglas

Presuming your couple were at 25 feet and the church was near enough to
infinity, then the hyperfocal distance - your focus point - should be
50
feet. Focus on 50 feet and the dof will extend from half the HD, i.e.
25
ft
to infinity, at the correct stop, of course. If you focused on 25 feet
then
there's your problem. Dof when focused at 25 ft and f/11 extends from
13.5
ft to 174 ft, so the foreground and couple will be sharp, but the
church
will
probably be outside the 174 ft limit (from Dofmaster calculator).

From the DofMaster website calculator for APS-sized sensors with a CoC
of
0.025mm, focusing on 50 ft at f/8 will give a dof of 22.6 feet to
infinity.
If you focused directly on the couple for maximum sharpness (which is
what
I
would do), and wanted the church in as well, then your HD is 25 ft, the
point
you focused on, and the aperture to extend the dof to infinity will be
f/13.5. This would also extend the dof in front of the couple to 12.4
feet -
so your total dof would be 12.4 ft to infinity when focused on 25 ft,
which
obeys the rule of acceptable sharpness from half the HD to infinity.

But, as I well know, doing this in your head while shooting a wedding
is
all
but impossible.

Did you not think of using the 'A-dep' function on the camera?

Colin D.


--
Posted via a free Usenet account from http://www.teranews.com


Our numbers differ

I used a CoC of .019 for the 20D (as shown on dofmaster), but you used
.025???

Yes, I saw that, and the reason is as you say a difference in CoC. On the
Dofmaster calculator I simply used the CoC applicable to APS-sized
cameras,
which is 0.025mm, but after your post I hit the net and found that the 20D
spec.
is 0.019, and using DM's custom COC's I got near enough the same as you.
Interestingly, the same CoC was quoted for the 300D with its greater
sensel
size, perhaps a mistake in the list

Cool, but both the 300D and 20D have the same sensor size (1.6x) ;-)

C J Donoghue wrote:

Dmac wrote:


According the Lord of math, the hyperfocal distance of my 50mm lens is
25 feet at F/11. Supposedly everything from 25 feet to infinity will be
in focus. Unfortunately you can't tell if this is the case until you
examine the image on a computer.

Last week, I shot a wedding where I wanted the couple at about 25 feet
and a church at infinity plus all in between to be focused. I didn't get
the measuring tape out but I have a fair idea of how far away 25 feet is.

The picture is OK. The foreground is sharp but the church in the
distance is not as sharp as I'd have thought it would be considering the
maths of the matter. I reasoned any smaller than F/11 and the image
would start to lose sharpness and produce vignetting.

Anyway... Can someone offer a suggestion as to why the technical details
were right and the results with my 20D off? The same image from my 5D
was spot on. Have I missed something with the crop factor or are there
other considerations when the lens is on 1.6 crop camera?

Douglas


Presuming your couple were at 25 feet and the church was near enough to
infinity, then the hyperfocal distance - your focus point - should be 50
feet. Focus on 50 feet and the dof will extend from half the HD, i.e. 25 ft
to infinity, at the correct stop, of course. If you focused on 25 feet then
there's your problem. Dof when focused at 25 ft and f/11 extends from 13.5
ft to 174 ft, so the foreground and couple will be sharp, but the church will
probably be outside the 174 ft limit (from Dofmaster calculator).

From the DofMaster website calculator for APS-sized sensors with a CoC of
0.025mm, focusing on 50 ft at f/8 will give a dof of 22.6 feet to infinity.
If you focused directly on the couple for maximum sharpness (which is what I
would do), and wanted the church in as well, then your HD is 25 ft, the point
you focused on, and the aperture to extend the dof to infinity will be
f/13.5. This would also extend the dof in front of the couple to 12.4 feet -
so your total dof would be 12.4 ft to infinity when focused on 25 ft, which
obeys the rule of acceptable sharpness from half the HD to infinity.

But, as I well know, doing this in your head while shooting a wedding is all
but impossible.

Did you not think of using the 'A-dep' function on the camera?

Colin D.



There is a presumption in your post Colin that the CoC is 0.025 when in
fact it could be anywhere between 0.025 and 0.035 for a FF camera,
producing widely varying HF distances. Add to this the varying opinion
of what CoC of a 20D actually is and you can see my confusion on the issue.

Add to that the idiots whose numbers are growing by the minute, chiming
in with their barbs aimed at getting their rocks off at my expense, and
you must surely ask: Why bother? The answer will never come from this
bunch of rabble.

Crop factor cameras are here to stay. Unfortunately the technical
information we used to be able to rely on, now cannot be relied on.
Worse than this is that none of the self proclaimed "experts" here can
agree on what the CoC for a 20D actually is and you have a classic
Usenet situation where no one knows the answer but everyone wants a
piece of the action anyway. 'A-dep' is not practical for me in this
situation. Thanks anyway.