Technical question for the lens "gurus" out there...

[David Harper]

I'm still new to lens calculations, but I was wondering if 'point and
shoot' cameras can actually focus on objects at infinity?

I imagine camera designers design for the most frequent distance to
subjects (such as 15 or 20ft), and there's some range where the
subjects are 'close enough' to the ideal distance to the subject that
they appear in focus. Am I correct in this assumption?

I ask these questions as I recently started looking at cameras for use
on a high altitude project, and I'm selecting a camera based on
weight, field of view, auto-winding capacity, quality (including the
ability to focus at infinity). However, I'm worried that some "point
and shoot" cameras that look to be good candidates would result in
poor quality photos of the horizon / ground. Any advice on what type
of camera/lens would be good for high altitude photography would be
welcome!


Thanks in advance for any advice or information anyone has to offer!

Dave

[WinkenBlinken& Nod]

"David Harper" <achilles03@hotmail.com> wrote in message
news:fef44ceb.0306301317.2e3cceb0@posting.google.c om...

> I'm still new to lens calculations, but I was wondering if 'point and
> shoot' cameras can actually focus on objects at infinity?
>

No, they are too far away.

> I imagine camera designers design for the most frequent distance to
> subjects (such as 15 or 20ft), and there's some range where the
> subjects are 'close enough' to the ideal distance to the subject that
> they appear in focus. Am I correct in this assumption?

Study the term hyperfocal distance, and you will be amazed.

>
> I ask these questions as I recently started looking at cameras for use
> on a high altitude project,

Are you refering to aerial photography?

>and I'm selecting a camera based on
> weight, field of view, auto-winding capacity, quality (including the
> ability to focus at infinity). However, I'm worried that some "point
> and shoot" cameras that look to be good candidates would result in
> poor quality photos of the horizon / ground. Any advice on what type
> of camera/lens would be good for high altitude photography would be
> welcome!
>

Seriously is this a climbing activity, or is it from some sort of aerial
vehical as the cameras would be different.

>
> Thanks in advance for any advice or information anyone has to offer!
>
> Dave

[WinkenBlinken& Nod]

"David Harper" <achilles03@hotmail.com> wrote in message
news:fef44ceb.0306302055.3569c868@posting.google.c om...

> "WinkenBlinken& Nod" <spammelater@spam.com> wrote in message

news:<KF4Ma.30665$0v4.2249916@bgtnsc04-news.ops.worldnet.att.net>...

> > "David Harper" <achilles03@hotmail.com> wrote in message
> > news:fef44ceb.0306301317.2e3cceb0@posting.google.c om...

> > > I'm still new to lens calculations, but I was wondering if 'point and
> > > shoot' cameras can actually focus on objects at infinity?
> > >

> >
> > No, they are too far away.

>
> So why do they make the claim to be able to focus on a range of
> distances, such as 3.3ft to infinity, such as some of the Fuji models?
> Do they just use a very liberal circle of confusion (larger than
> .03mm) to be able to state ranges like that?
>

> > > I imagine camera designers design for the most frequent distance to
> > > subjects (such as 15 or 20ft), and there's some range where the
> > > subjects are 'close enough' to the ideal distance to the subject that
> > > they appear in focus. Am I correct in this assumption?

> >
> > Study the term hyperfocal distance, and you will be amazed.

>
> I have been in the past couple hours... so at infinity, the
> focus-quality for point and shoot cameras is right at the limit of the
> 'acceptable' focus quality based on the 'acceptable' circle of
> confusion?
>

> > > I ask these questions as I recently started looking at cameras for use
> > > on a high altitude project,

> >
> > Are you refering to aerial photography?

>
> Yes.
>

> > >and I'm selecting a camera based on
> > > weight, field of view, auto-winding capacity, quality (including the
> > > ability to focus at infinity). However, I'm worried that some "point
> > > and shoot" cameras that look to be good candidates would result in
> > > poor quality photos of the horizon / ground. Any advice on what type
> > > of camera/lens would be good for high altitude photography would be
> > > welcome!
> > >

> > Seriously is this a climbing activity, or is it from some sort of aerial
> > vehical as the cameras would be different.

>
> It's an aerial vehicle. Ideally, I'd like to set the focus to
> infinity for the duration of the flight. However, I imagine I'll have
> to settle for an autofocus camera (based on weight limitations).
>

> > > Thanks in advance for any advice or information anyone has to offer!
> > >
> > > Dave

Sounds to me like your planning on putting a camera in a radio controlled
model airplane right? If so and unless you are planning on taking close ups
while landing or some other such activity what difference does focus have to
do with the overall picture. I have taken hundreds of thousands of
photographs out of aircraft and never once used a camera that could be
focused at anything other than infinity. But that could even have been at
the hyperfocal distance, but I would think not.
If my assumptions are correct I would go for a cheap point and shoot that is
fixed focus, and that you are able to get to the contacts for the shutter
and connect them to one of the solenoid channels in order to control the
camera.

Ed

[David Harper]

"WinkenBlinken& Nod" <spammelater@spam.com> wrote in message news:<VnaMa.31012$3o3.2262074@bgtnsc05-news.ops.worldnet.att.net>...
<snip>

> Sounds to me like your planning on putting a camera in a radio controlled
> model airplane right?

Close, it's a high altitude balloon.

> If so and unless you are planning on taking close ups
> while landing or some other such activity what difference does focus have to
> do with the overall picture. I have taken hundreds of thousands of
> photographs out of aircraft and never once used a camera that could be
> focused at anything other than infinity.

Yeah, but "focused" at infinity with a point and shoot camera is
basically the same as "almost out of focus, but technically not
quite"... correct? For a camera fixed-focused at the hyperfocal
distance, a dot in infinity will appear the exact same size as the
circle of confusion, and not really perfectly focused... correct?

> But that could even have been at
> the hyperfocal distance, but I would think not.
> If my assumptions are correct I would go for a cheap point and shoot that is
> fixed focus, and that you are able to get to the contacts for the shutter
> and connect them to one of the solenoid channels in order to control the
> camera.
>
> Ed

Unfortunately, most point and shoot cameras I've taken apart are
spring-loaded with a mechanical mechanism directly linked to the
button, meaning no internal solenoid. So I purchased some solenoids
to be used externally to press the button... but not that it really
matters to the current discussion...


Dave