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Arial photographs

 
 
Chris W
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      11-06-2007
After being pleasantly surprised by the answer to my post on DOF
Cheating, I thought I would ask another somewhat similar question.

If you take several aerial photographs, like the satellites do, but from
an airplane, is there any software to help put all the photos together
into one large image?

Also am I correct in thinking that using a telephoto lens and flying
high, is better than using a wide angle lens and flying low, when the
goal is to piece the photos into one large image?


--
Chris W
KE5GIX

"Protect your digital freedom and privacy, eliminate DRM,
learn more at http://www.defectivebydesign.org/what_is_drm"

Ham Radio Repeater Database.
http://hrrdb.com
 
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Kinon O'Cann
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Posts: n/a
 
      11-06-2007

"Chris W" <(E-Mail Removed)> wrote in message
news:ah3Yi.4109$(E-Mail Removed)...
> After being pleasantly surprised by the answer to my post on DOF Cheating,
> I thought I would ask another somewhat similar question.
>
> If you take several aerial photographs, like the satellites do, but from
> an airplane, is there any software to help put all the photos together
> into one large image?


Yes, but keeping things still and aligned will be a challenge without a
gyro. However, I don't think this is any different than any other stitching
job, just more challenging.
>
> Also am I correct in thinking that using a telephoto lens and flying high,
> is better than using a wide angle lens and flying low, when the goal is to
> piece the photos into one large image?


Theoritically, but getting sharp images from a fast moving and potentially
bumpy flying object could prove impossible. But for firle flatness, a tele
is much better.

I've done a few aerials, but not like you describe, so I'm taking an
educated guess.


 
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Pat
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Posts: n/a
 
      11-06-2007
On Nov 6, 2:30 pm, Chris W <(E-Mail Removed)> wrote:
> After being pleasantly surprised by the answer to my post on DOF
> Cheating, I thought I would ask another somewhat similar question.
>
> If you take several aerial photographs, like the satellites do, but from
> an airplane, is there any software to help put all the photos together
> into one large image?
>
> Also am I correct in thinking that using a telephoto lens and flying
> high, is better than using a wide angle lens and flying low, when the
> goal is to piece the photos into one large image?
>
> --
> Chris W
> KE5GIX
>
> "Protect your digital freedom and privacy, eliminate DRM,
> learn more athttp://www.defectivebydesign.org/what_is_drm"
>
> Ham Radio Repeater Database.http://hrrdb.com


You will get a very different look from a big lens up high or a small
lens down low. The big lens compresses things and makes them look
flatter/closer.

Personally, I would probably use a small lens down low because of all
of them movement and vibrations. If you want with a bigger lens,
you'd need a corresponding higher shutter speed.

You might also want to look into a steadicam rig or something like
that.

 
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~^ beancounter ~^
Guest
Posts: n/a
 
      11-06-2007
under normal flight conditions...its not
that bumpy...i would be more concerned
about no glass / clear shot and correct positioning...

btw: i am a pilot w/plane avail in the denver / boulder
area if anyone needs a pilot/photographer for free lance
work....





On Nov 6, 2:11 pm, Pat <(E-Mail Removed)> wrote:
> On Nov 6, 2:30 pm, Chris W <(E-Mail Removed)> wrote:
>
>
>
>
>
> > After being pleasantly surprised by the answer to my post on DOF
> > Cheating, I thought I would ask another somewhat similar question.

>
> > If you take several aerial photographs, like the satellites do, but from
> > an airplane, is there any software to help put all the photos together
> > into one large image?

>
> > Also am I correct in thinking that using a telephoto lens and flying
> > high, is better than using a wide angle lens and flying low, when the
> > goal is to piece the photos into one large image?

>
> > --
> > Chris W
> > KE5GIX

>
> > "Protect your digital freedom and privacy, eliminate DRM,
> > learn more athttp://www.defectivebydesign.org/what_is_drm"

>
> > Ham Radio Repeater Database.http://hrrdb.com

>
> You will get a very different look from a big lens up high or a small
> lens down low. The big lens compresses things and makes them look
> flatter/closer.
>
> Personally, I would probably use a small lens down low because of all
> of them movement and vibrations. If you want with a bigger lens,
> you'd need a corresponding higher shutter speed.
>
> You might also want to look into a steadicam rig or something like
> that.- Hide quoted text -
>
> - Show quoted text -



 
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Jürgen Exner
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Posts: n/a
 
      11-06-2007
Pat wrote:
> On Nov 6, 2:30 pm, Chris W <(E-Mail Removed)> wrote:
>> Also am I correct in thinking that using a telephoto lens and flying
>> high, is better than using a wide angle lens and flying low, when the
>> goal is to piece the photos into one large image?

>
> You will get a very different look from a big lens up high or a small
> lens down low. The big lens compresses things and makes them look
> flatter/closer.


Something else to consider is mist/dust/smoke etc which will have an impact
on the hue and sharpness of photos with a long lens.

jue


 
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Pat
Guest
Posts: n/a
 
      11-06-2007
On Nov 6, 4:25 pm, ~^ beancounter ~^ <(E-Mail Removed)> wrote:
> under normal flight conditions...its not
> that bumpy...i would be more concerned
> about no glass / clear shot and correct positioning...
>
> btw: i am a pilot w/plane avail in the denver / boulder
> area if anyone needs a pilot/photographer for free lance
> work....
>
> On Nov 6, 2:11 pm, Pat <(E-Mail Removed)> wrote:
>
> > On Nov 6, 2:30 pm, Chris W <(E-Mail Removed)> wrote:

>
> > > After being pleasantly surprised by the answer to my post on DOF
> > > Cheating, I thought I would ask another somewhat similar question.

>
> > > If you take several aerial photographs, like the satellites do, but from
> > > an airplane, is there any software to help put all the photos together
> > > into one large image?

>
> > > Also am I correct in thinking that using a telephoto lens and flying
> > > high, is better than using a wide angle lens and flying low, when the
> > > goal is to piece the photos into one large image?

>
> > > --
> > > Chris W
> > > KE5GIX

>
> > > "Protect your digital freedom and privacy, eliminate DRM,
> > > learn more athttp://www.defectivebydesign.org/what_is_drm"

>
> > > Ham Radio Repeater Database.http://hrrdb.com

>
> > You will get a very different look from a big lens up high or a small
> > lens down low. The big lens compresses things and makes them look
> > flatter/closer.

>
> > Personally, I would probably use a small lens down low because of all
> > of them movement and vibrations. If you want with a bigger lens,
> > you'd need a corresponding higher shutter speed.

>
> > You might also want to look into a steadicam rig or something like
> > that.- Hide quoted text -

>
> > - Show quoted text -


The only time I did photos from a plane I was in my early 20's and the
primary shooter was the director of public information for the college
I did a lot of work for.

On cue the pilot rolled the plane on its side so we could get better
photos of what was under us. With the plane on its side, the window
open, the wind blowing and the guy leaning out to take pictures; all I
can remember is reaching forward and grabbing the neckstrap of the
camera -- just in case he let go for some reason. He was, after all,
using MY camera while his was safely in a bag in the back seat.

But as I remember it, there was quite a bit of vibration from the
engine.

 
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Mr. Strat
Guest
Posts: n/a
 
      11-07-2007
In article <(E-Mail Removed) .com>, Pat
<(E-Mail Removed)> wrote:

> The only time I did photos from a plane I was in my early 20's and the
> primary shooter was the director of public information for the college
> I did a lot of work for.
>
> On cue the pilot rolled the plane on its side so we could get better
> photos of what was under us. With the plane on its side, the window
> open, the wind blowing and the guy leaning out to take pictures; all I
> can remember is reaching forward and grabbing the neckstrap of the
> camera -- just in case he let go for some reason. He was, after all,
> using MY camera while his was safely in a bag in the back seat.
>
> But as I remember it, there was quite a bit of vibration from the
> engine.


Back in the early 90s, I worked part-time for a guy doing aerial
photography. I shot a Hasselblad EL straight down through a hole in the
bottom of the plane (FAA approved) in combination with a GPS unig (when
GPS was in its infancy).

We did mostly clearcuts to scale for the timber companies. We did a lot
of what are called stereo pairs. It's a series of three photographs
with a bit of overlap. The foresters then use a special viewing device
to get a stereo effect.

I suppose you could do the same thing with digital.
 
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Pat
Guest
Posts: n/a
 
      11-07-2007
On Nov 6, 9:54 pm, "Mr. Strat" <(E-Mail Removed)> wrote:
> In article <(E-Mail Removed) .com>, Pat
>
> <(E-Mail Removed)> wrote:
> > The only time I did photos from a plane I was in my early 20's and the
> > primary shooter was the director of public information for the college
> > I did a lot of work for.

>
> > On cue the pilot rolled the plane on its side so we could get better
> > photos of what was under us. With the plane on its side, the window
> > open, the wind blowing and the guy leaning out to take pictures; all I
> > can remember is reaching forward and grabbing the neckstrap of the
> > camera -- just in case he let go for some reason. He was, after all,
> > using MY camera while his was safely in a bag in the back seat.

>
> > But as I remember it, there was quite a bit of vibration from the
> > engine.

>
> Back in the early 90s, I worked part-time for a guy doing aerial
> photography. I shot a Hasselblad EL straight down through a hole in the
> bottom of the plane (FAA approved) in combination with a GPS unig (when
> GPS was in its infancy).
>
> We did mostly clearcuts to scale for the timber companies. We did a lot
> of what are called stereo pairs. It's a series of three photographs
> with a bit of overlap. The foresters then use a special viewing device
> to get a stereo effect.
>
> I suppose you could do the same thing with digital.


Lareo (I think that's how it's spelled) makes some stuff for doing
stereo. Also some other cute gadgets.

 
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C J Campbell
Guest
Posts: n/a
 
      11-07-2007
On 2007-11-06 11:30:13 -0800, Chris W <(E-Mail Removed)> said:

> After being pleasantly surprised by the answer to my post on DOF
> Cheating, I thought I would ask another somewhat similar question.
>
> If you take several aerial photographs, like the satellites do, but
> from an airplane, is there any software to help put all the photos
> together into one large image?
>
> Also am I correct in thinking that using a telephoto lens and flying
> high, is better than using a wide angle lens and flying low, when the
> goal is to piece the photos into one large image?


Experienced aerial photographers use a moderately long lens. The
narrower field of view makes it easier to keep things like struts and
landing gear out of the picture. The longer focal length makes it
easier to fly at a safer altitude.

Fly in the early morning, when the air is smooth, and use a stabilized lens.

I prefer small Cessna airplanes, since you can open the window
completely if you remove a small retaining screw. The air flow holds
the window up against the bottom of the wing unless the airplane is
flying very slowly.

You will get a lot of vibration from wind striking the lens if you poke
it too far out the window. You will want to wind your camera strap
tightly around your arm to hold the camera steady and keep from losing
it. Close the window when changing lenses.

There are several people doing professional work in digital mapping
such as you describe. The Cessna 206 is probably the smallest plane
being used for serious mapping work. The airplane is modified with a
hole in the floor so that the camera can point straight down.
Alternatively, you can mount a remote controlled camera on the side or
bottom of the fuselage. Another way to go is to use a plane that is
modified for skydiving and shoot out the parachute door while wearing a
safety harness and parachute. Overall, helicopters give you the most
visibility, followed by high-wing airplanes like Cessnas. Ultralights
and other planes with no cockpit body also provide excellent
visibility. The Kolb is a favorite for this kind of work; it is very
slow, easy to fly, and you can configure it with no windows, doors, or
any cockpit but a seat out in front of the propeller. There are people
doing some very fine photography in Kolbs. Arizona Highways has printed
some articles featuring these photographs. Since the Kolb is a
certified airplane, not an ultralight, it is also a nice, steady
platform, but you do need a pilot's license to fly it.

http://www.tnkolbaircraft.com/

But for just taking a few photos and pasting them together, just about
any airplane where you can open the windows will do. You want a skilled
pilot who knows how to slip the plane so that the wing strut is kept
out of your field of view. It does not matter if altitude varies a
little bit between shots since most stitching software can reconcile
mild perspective changes.

I generally prefer to fly over the area at 1000 feet, which is pretty
low, but not so low as to be unsafe. This minimizes problems with haze.
I use a Cessna 172RG for aerial photography. The gear is retractable so
it is out of the way and the high wing loading makes a very smooth
ride. It has big windows, too.

--
Waddling Eagle
World Famous Flight Instructor

 
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Don Stauffer in Minnesota
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Posts: n/a
 
      11-07-2007
On Nov 6, 1:30 pm, Chris W <(E-Mail Removed)> wrote:
> After being pleasantly surprised by the answer to my post on DOF
> Cheating, I thought I would ask another somewhat similar question.
>
> If you take several aerial photographs, like the satellites do, but from
> an airplane, is there any software to help put all the photos together
> into one large image?
>
> Also am I correct in thinking that using a telephoto lens and flying
> high, is better than using a wide angle lens and flying low, when the
> goal is to piece the photos into one large image?
>
> --
> Chris W
> KE5GIX
>
> "Protect your digital freedom and privacy, eliminate DRM,
> learn more athttp://www.defectivebydesign.org/what_is_drm"
>
> Ham Radio Repeater Database.http://hrrdb.com


The pros use fancy software that is impractical for the amateur. You
can use regular stitching programs, but you must do a lot of manual
rectification before stitching, so it is a lot of work.

Yes, you are correct- high altitude and long lenses are de riguer for
this use.

How much you need to worry about rectification depends on what you
will be using it for. If you are a civil engineer and using it to
plan road projects, that is one thing. If you are military and only
looking to see if there are tanks in the area, geometric distortion is
not much concern. The pro programs I mentioned are only for those who
need to make maps or use carefully measured distances. Otherwise, just
live with the distortion.

And, BTW, use red filters if you DO shoot from high altitude, or take
long range obliques.

 
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