Hyperfocal distance

Guys

I am practicing up for an upcoming wedding shoot and have been looking at
the issue of hyperfocal distances for some of the after ceremony shindig.
I downloaded a program called Depth of Field 3 as it can work on my PDA.
When setting up the calculation I set the following and press calculate:


50mm focal length
5.6 f stop
30.0 LMM resolution
focus at 5 FT
teleconvertor 1.6 (for the fov on my 20D canon, - hope this is correct or
should I use 1?)

then press calculate. This gives the following:

4.5 near focus
5.6 far focus
44.1 hyperfocal distance (all above in feet)

It is the last figure I have problems with. I would have thought that the
hyperfocal distance would have been between the two near and far figures?
What's happening.

as always, look forward to some sage thoughts.

Don from Down Under
--
Don From Down Under

Hyperfocal distance is the distance you need to focus at to get
everything from half that distance and up to infinity in focus. It
depends on the focal length and the f stop.

In this case it tells you that if you focus at 44.1 feet everything
from 22.05 feet to infinity "acceptably" sharp
(http://en.wikipedia.org/wiki/Hyperfocal_distance)

"Don" wrote in message
...
Guys

I am practicing up for an upcoming wedding shoot and have been
looking at the issue of hyperfocal distances for some of the after
ceremony shindig.
I downloaded a program called Depth of Field 3 as it can work on my
PDA. When setting up the calculation I set the following and press
calculate:


50mm focal length
5.6 f stop
30.0 LMM resolution

Maybe it's a typo, but if it's 30 lines/mm (15 line-pairs/mm) it seems
a too strict definition of final output resolution. But then I'm not
familiar with the "Depth of Field 3" application, so maybe something
else is referred to?

focus at 5 FT
teleconvertor 1.6 (for the fov on my 20D canon, - hope this is
correct or should I use 1?)

Most "extenders/converters" apparently multiply the actual focal
length by either a 1.4x or a 2x factor. The 1.6 crop factor due to
smaller sensor is not a direct factor in most DoF calculators.

then press calculate. This gives the following:

4.5 near focus
5.6 far focus
44.1 hyperfocal distance (all above in feet)

It is the last figure I have problems with. I would have thought
that the hyperfocal distance would have been between the two near
and far figures? What's happening.

Again (not knowing the application), could it be that focus in front &
in rear of actual focus plane in meant? If so then adding them will
give total Dof, slightly more far than near.

Bart

"Don" wrote in message
...
Guys

I am practicing up for an upcoming wedding shoot and have been looking at
the issue of hyperfocal distances for some of the after ceremony shindig.
I downloaded a program called Depth of Field 3 as it can work on my PDA.
When setting up the calculation I set the following and press calculate:


50mm focal length
5.6 f stop
30.0 LMM resolution
focus at 5 FT
teleconvertor 1.6 (for the fov on my 20D canon, - hope this is correct or
should I use 1?)

There is no 1.6 teleconverter, leave that out. The lens stays a 50mm the
image is merely cropped by around 40%. THis is like making an 8x12" print
from 35mm negative, and then cutting out a 5x8" print from the middle.

Thanks for your comments. Changing the conversion rate to 1.0 so there is
no calculation for the FOV issue still raises the strange issue of the
output of (now) of 61.8 ft. The 30.0 lmm is evidently to cater for the
relevant COC given the 1.6 FOV issue (read the instructions further). The
issue here is to be able to manually set the focus point on the lens given a
set 50mm lens at F4 so I can know what will be the in and out focus range.
If I read it write what the calculation is telling me is that at the
settings I will have an "acceptable" range/dof of between 4.6 & 5.4 ft and
if I wish to set for hyperfocal I would focus at 61 feet and then have an
acceptable focus from 30 ft out to infinity? Does this seem right?

regards

Don.
"Darrell" wrote in message
...

"Don" wrote in message
...
Guys

I am practicing up for an upcoming wedding shoot and have been looking at
the issue of hyperfocal distances for some of the after ceremony shindig.
I downloaded a program called Depth of Field 3 as it can work on my PDA.
When setting up the calculation I set the following and press calculate:


50mm focal length
5.6 f stop
30.0 LMM resolution
focus at 5 FT
teleconvertor 1.6 (for the fov on my 20D canon, - hope this is correct or
should I use 1?)

There is no 1.6 teleconverter, leave that out. The lens stays a 50mm the
image is merely cropped by around 40%. THis is like making an 8x12" print
from 35mm negative, and then cutting out a 5x8" print from the middle.

Don wrote:
Guys

I am practicing up for an upcoming wedding shoot and have been
looking at the issue of hyperfocal distances for some of the after
ceremony shindig. I downloaded a program called Depth of Field 3 as
it can work on my PDA. When setting up the calculation I set the
following and press calculate:

My I make a suggestion. Lose the PDA, forget all about the formula and
maybe forget about doing the wedding.

To do a wedding you don't have time to think, let alone try to make
calculations on a PDA before a shot. You need to have that information
instinctive. You learn that by doing it over and over. Lots and lots of
experience. It is not something you should be thinking about when you are
using it.

Your question leads me to question the whole idea. I am not suggesting
you are a poor photographer, I have no way of knowing, but the question
indicates you are not ready to shoot a wedding as the primary photographer.
If you are scheduled to be THE photographer for this wedding, I suggest
backing out now so they can find someone who can do the job. Tell them you
will take photos, but they should hire a professional.

You, as a friend, can take may special photos that the professional is
not going to get. For example you are more likely to know that uncle Fred
and aunt Jane have not spoken to each other for thirty years do to that
little disagreement over the lamp, and today they are dancing together.
That would be THE picture of the day.

If you are not experienced in weddings (they really are different) and
you screw up (even the professionals do this, but far less often) you are
going to be hated for the rest of your life by people you wanted to consider
friends.


--
Joseph Meehan

Dia duit

"Don" wrote in message
...
Guys

I am practicing up for an upcoming wedding shoot and have been looking at
the issue of hyperfocal distances for some of the after ceremony shindig.
I downloaded a program called Depth of Field 3 as it can work on my PDA.
When setting up the calculation I set the following and press calculate:


50mm focal length
5.6 f stop
30.0 LMM resolution
focus at 5 FT
teleconvertor 1.6 (for the fov on my 20D canon, - hope this is correct or
should I use 1?)

then press calculate. This gives the following:

4.5 near focus
5.6 far focus
44.1 hyperfocal distance (all above in feet)

It is the last figure I have problems with. I would have thought that the
hyperfocal distance would have been between the two near and far figures?
What's happening.
Your equation is wrong.
Jim

as always, look forward to some sage thoughts.

Don from Down Under
--
Don From Down Under

"imbsysop" writes:

FWIW .. with an hyperfocal setting stored in a custom shooting mode you
don't have to calculate anything heck you don't even need to focus .. that's
the essence of hyperfocal :-)

The problem with using the hyperfocal distance is that what you really
want to show in the image is almost certainly not in best focus. The
hyperfocal setting guarantees that both infinity and the near limit,
whatever it is, are both bordering on visibly unsharp, and only
something about twice as far as the hyperfocal limit will really be in
focus.

In circumstances where you really will not have time to focus or
autofocus, it's the best choice available. But most of the time,
actually focusing on the intended subject (either in real time, or
prefocusing on your best guess of distance) will get the subject in
better focus.

Dave

"Don" wrote in message
...
Thanks for your comments. Changing the conversion rate to 1.0 so there is
no calculation for the FOV issue still raises the strange issue of the
output of (now) of 61.8 ft.

Yes. As in your original example, there is something drastically wrong
there. The hyperfocal distance is obviously located somewhere between near
focus and infinity, and the far focus cannot possibly be located somewhere
way short of the hyperfocal distance.


The 30.0 lmm is evidently to cater for the relevant COC given the 1.6 FOV
issue (read the instructions further). The issue here is to be able to
manually set the focus point on the lens given a set 50mm lens at F4 so I
can know what will be the in and out focus range. If I read it write what
the calculation is telling me is that at the settings I will have an
"acceptable" range/dof of between 4.6 & 5.4 ft and if I wish to set for
hyperfocal I would focus at 61 feet and then have an acceptable focus from
30 ft out to infinity? Does this seem right?

It's self-contradictory. If you have a DoF of 4.6 to 5.4 feet, then obvously
you are not focused on the hyperfocal distance, but on something near 5
feet. If your hyperfocal distance is at 61 feet and you're focused on that
then yes, your DoF is from 30.5 feet to infinity. In that case, what's the
relevance of the 4.6 and 5.4 feet business?

And yes, your DoF does need to be adjusted for the 1.6 focal length
multiplier, since the degree of final enlargement (which also affects DoF)
will be greater than if you were using the same 50mm lens on a 24x36 format.

Neil



regards

Don.
"Darrell" wrote in message
...

"Don" wrote in message
...
Guys

I am practicing up for an upcoming wedding shoot and have been looking
at the issue of hyperfocal distances for some of the after ceremony
shindig.
I downloaded a program called Depth of Field 3 as it can work on my PDA.
When setting up the calculation I set the following and press calculate:


50mm focal length
5.6 f stop
30.0 LMM resolution
focus at 5 FT
teleconvertor 1.6 (for the fov on my 20D canon, - hope this is correct
or should I use 1?)

There is no 1.6 teleconverter, leave that out. The lens stays a 50mm the
image is merely cropped by around 40%. THis is like making an 8x12" print
from 35mm negative, and then cutting out a 5x8" print from the middle.

"imbsysop" writes:

In circumstances where you really will not have time to focus or
autofocus, it's the best choice available. But most of the time,
actually focusing on the intended subject (either in real time, or
prefocusing on your best guess of distance) will get the subject in
better focus.

with only 2 conditions ..
fast focus and accurate focus .. and in mostly "bad" light .. aka only a
dSLR can do this ?

Maybe only a DSLR can autofocus in those conditions. But any camera
with manual focus can have focus preset.

I've use this with a Canon A80. Shooting in a restaurant where the
camera would not focus, and there was almost nothing visible in the LCD,
I estimated the distance to the subject, set that distance in manual
focus mode, and aimed using the optical finder. It worked fine.

Dave