uneven sharpness

Nadar wrote:
I'm using a Fuji S2 PRO with a Nikon 12-24mm lens to take aerial photographs
(vertical aiming).
The camera is mounted vertically on a platform fixed on the door step of a
Cessna.
Usual settings are : zoom set to 16mm (eq. 24mm on 24x36), aperture between
5.6 and 11, shutter speed 1:1000 and sensibility 200 or 400 ASA depending on
the terrain. Focus is of course fixed on the infinity.
I use a GPS to know when I have to shoot, in order to acquire successive
pictures with 10-20 % overlap.
Along a flight line, photos are taken in "landscape" mode, to cover a strip
as wide as possible.
Flying altitude is usually around 2000 m (6000 ft), and the interval between
2 photos is around 20 seconds.
At this altitude, the relative movement of the ground is very slow, and the
target can be considered as non-moving.

Most of the time, I got excellent results, but sometimes, I observe a
strange problem on some series of pictures:
The "bottom" side of the images (if you hold the camera in a "normal"
position) is significantly less sharp than the "top" side.
This is very obvious when you place successive pictures with their
ovelapping area (one sharp "top" on top of one "fuzzy" bottom).

This is probably related to vibrations in the plane, but I don't understand
why shaking doesn't affect the whole image.
I had a similar problems earlier with a film camera used in the same
situation, and I interpreted then as the film being improperly pressed flat
by the plate located in the back of the camera.

To add to the confusion, the same problem occurs on some series of pictures
(always with the same magnitude), and other series are perfectly sharp.

How can you explain (understand / solve ) this problem ?

Will a stabilized sensor like the one found on Minolta Dimage A2 be
efficient in removing this type of vibration ?
Heard about a very wide angle (around 18mm) stabilized lens in (Nikon mount)
?

Any suggestion will be more than welcome.

Yves (from Belgium)


Hi Yves...

Just a shot in the dark from an old guy...

I'm pretty sure that the camera isn't held to the
plane by the threaded tripod mount on the bottom,
else you most likely wouldn't have it anymore

So, is it possible that it's mounted in some other
manner so securely that it's warping the camera?
Twisting the lens in the up/down direction?

It would take imperceptible movement in the lens
to film/ccd alignment to make a huge difference in
focus.


Take care.

Ken

Nadar wrote:
I'm using a Fuji S2 PRO with a Nikon 12-24mm lens to take aerial photographs
(vertical aiming).
The camera is mounted vertically on a platform fixed on the door step of a
Cessna.
Usual settings are : zoom set to 16mm (eq. 24mm on 24x36), aperture between
5.6 and 11, shutter speed 1:1000 and sensibility 200 or 400 ASA depending on
the terrain. Focus is of course fixed on the infinity.
I use a GPS to know when I have to shoot, in order to acquire successive
pictures with 10-20 % overlap.
Along a flight line, photos are taken in "landscape" mode, to cover a strip
as wide as possible.
Flying altitude is usually around 2000 m (6000 ft), and the interval between
2 photos is around 20 seconds.
At this altitude, the relative movement of the ground is very slow, and the
target can be considered as non-moving.

Most of the time, I got excellent results, but sometimes, I observe a
strange problem on some series of pictures:
The "bottom" side of the images (if you hold the camera in a "normal"
position) is significantly less sharp than the "top" side.
This is very obvious when you place successive pictures with their
ovelapping area (one sharp "top" on top of one "fuzzy" bottom).

This is probably related to vibrations in the plane, but I don't understand
why shaking doesn't affect the whole image.
I had a similar problems earlier with a film camera used in the same
situation, and I interpreted then as the film being improperly pressed flat
by the plate located in the back of the camera.

To add to the confusion, the same problem occurs on some series of pictures
(always with the same magnitude), and other series are perfectly sharp.

How can you explain (understand / solve ) this problem ?

Will a stabilized sensor like the one found on Minolta Dimage A2 be
efficient in removing this type of vibration ?
Heard about a very wide angle (around 18mm) stabilized lens in (Nikon mount)
?

Any suggestion will be more than welcome.

Yves (from Belgium)


Hi Yves...

Just a shot in the dark from an old guy...

I'm pretty sure that the camera isn't held to the
plane by the threaded tripod mount on the bottom,
else you most likely wouldn't have it anymore

So, is it possible that it's mounted in some other
manner so securely that it's warping the camera?
Twisting the lens in the up/down direction?

It would take imperceptible movement in the lens
to film/ccd alignment to make a huge difference in
focus.


Take care.

Ken

Nadar wrote:
I'm using a Fuji S2 PRO with a Nikon 12-24mm lens to take aerial photographs
(vertical aiming).
The camera is mounted vertically on a platform fixed on the door step of a
Cessna.
Usual settings are : zoom set to 16mm (eq. 24mm on 24x36), aperture between
5.6 and 11, shutter speed 1:1000 and sensibility 200 or 400 ASA depending on
the terrain. Focus is of course fixed on the infinity.
I use a GPS to know when I have to shoot, in order to acquire successive
pictures with 10-20 % overlap.
Along a flight line, photos are taken in "landscape" mode, to cover a strip
as wide as possible.
Flying altitude is usually around 2000 m (6000 ft), and the interval between
2 photos is around 20 seconds.
At this altitude, the relative movement of the ground is very slow, and the
target can be considered as non-moving.

Most of the time, I got excellent results, but sometimes, I observe a
strange problem on some series of pictures:
The "bottom" side of the images (if you hold the camera in a "normal"
position) is significantly less sharp than the "top" side.
This is very obvious when you place successive pictures with their
ovelapping area (one sharp "top" on top of one "fuzzy" bottom).

This is probably related to vibrations in the plane, but I don't understand
why shaking doesn't affect the whole image.
I had a similar problems earlier with a film camera used in the same
situation, and I interpreted then as the film being improperly pressed flat
by the plate located in the back of the camera.

To add to the confusion, the same problem occurs on some series of pictures
(always with the same magnitude), and other series are perfectly sharp.

How can you explain (understand / solve ) this problem ?

Will a stabilized sensor like the one found on Minolta Dimage A2 be
efficient in removing this type of vibration ?
Heard about a very wide angle (around 18mm) stabilized lens in (Nikon mount)
?

Any suggestion will be more than welcome.

Yves (from Belgium)


Hi Yves...

Just a shot in the dark from an old guy...

I'm pretty sure that the camera isn't held to the
plane by the threaded tripod mount on the bottom,
else you most likely wouldn't have it anymore

So, is it possible that it's mounted in some other
manner so securely that it's warping the camera?
Twisting the lens in the up/down direction?

It would take imperceptible movement in the lens
to film/ccd alignment to make a huge difference in
focus.


Take care.

Ken

Nadar wrote:
I'm using a Fuji S2 PRO with a Nikon 12-24mm lens to take aerial
photographs (vertical aiming).
The camera is mounted vertically on a platform fixed on the door step
of a Cessna.
Usual settings are :

Have you tried mounting the camera so another edge of the sensor is
leading on the flight path?

If the unsharp edge migrates with the change, it's in the camera; if
not, it's in the mounting or some other external influence, no?


Frank ess

Nadar wrote:
I'm using a Fuji S2 PRO with a Nikon 12-24mm lens to take aerial
photographs (vertical aiming).
The camera is mounted vertically on a platform fixed on the door step
of a Cessna.
Usual settings are :

Have you tried mounting the camera so another edge of the sensor is
leading on the flight path?

If the unsharp edge migrates with the change, it's in the camera; if
not, it's in the mounting or some other external influence, no?


Frank ess

Nadar wrote:
I'm using a Fuji S2 PRO with a Nikon 12-24mm lens to take aerial
photographs (vertical aiming).
The camera is mounted vertically on a platform fixed on the door step
of a Cessna.
Usual settings are :

Have you tried mounting the camera so another edge of the sensor is
leading on the flight path?

If the unsharp edge migrates with the change, it's in the camera; if
not, it's in the mounting or some other external influence, no?


Frank ess

Nadar wrote:

I'm using a Fuji S2 PRO with a Nikon 12-24mm lens to take aerial photographs
(vertical aiming).
The camera is mounted vertically on a platform fixed on the door step of a
Cessna.

Most of the time, I got excellent results, but sometimes, I observe a
strange problem on some series of pictures:
The "bottom" side of the images (if you hold the camera in a "normal"
position) is significantly less sharp than the "top" side.

where does the hot engine exhaust go past the plane?

top eliminate this as the problem,
try reducing the throttle to idle, and getting a quick shot.


Any suggestion will be more than welcome.

Yves (from Belgium)

Nadar wrote:

I'm using a Fuji S2 PRO with a Nikon 12-24mm lens to take aerial photographs
(vertical aiming).
The camera is mounted vertically on a platform fixed on the door step of a
Cessna.

Most of the time, I got excellent results, but sometimes, I observe a
strange problem on some series of pictures:
The "bottom" side of the images (if you hold the camera in a "normal"
position) is significantly less sharp than the "top" side.

where does the hot engine exhaust go past the plane?

top eliminate this as the problem,
try reducing the throttle to idle, and getting a quick shot.


Any suggestion will be more than welcome.

Yves (from Belgium)

I agree with you that if aircraft movement or vibration were the
problem, the blur would be somewhat uniform across the frame. These
results are indeed strange. If I get how you are mounting it, the
question about where exhaust comes wouldn't explain it, as exhaust
blowing back would make a blur that varies from side to side.

You are taking at a pretty wide angle, but if problem occurs only
sometimes that is not likely to be a factor.

While motion or vibration of plane is not likely to be the problem, is
it possible that vibration of camera itself, moving something INSIDE the
camera could be?

Nadar wrote:

I'm using a Fuji S2 PRO with a Nikon 12-24mm lens to take aerial photographs
(vertical aiming).
The camera is mounted vertically on a platform fixed on the door step of a
Cessna.
Usual settings are : zoom set to 16mm (eq. 24mm on 24x36), aperture between
5.6 and 11, shutter speed 1:1000 and sensibility 200 or 400 ASA depending on
the terrain. Focus is of course fixed on the infinity.
I use a GPS to know when I have to shoot, in order to acquire successive
pictures with 10-20 % overlap.
Along a flight line, photos are taken in "landscape" mode, to cover a strip
as wide as possible.
Flying altitude is usually around 2000 m (6000 ft), and the interval between
2 photos is around 20 seconds.
At this altitude, the relative movement of the ground is very slow, and the
target can be considered as non-moving.

Most of the time, I got excellent results, but sometimes, I observe a
strange problem on some series of pictures:
The "bottom" side of the images (if you hold the camera in a "normal"
position) is significantly less sharp than the "top" side.
This is very obvious when you place successive pictures with their
ovelapping area (one sharp "top" on top of one "fuzzy" bottom).

This is probably related to vibrations in the plane, but I don't understand
why shaking doesn't affect the whole image.
I had a similar problems earlier with a film camera used in the same
situation, and I interpreted then as the film being improperly pressed flat
by the plate located in the back of the camera.

To add to the confusion, the same problem occurs on some series of pictures
(always with the same magnitude), and other series are perfectly sharp.

How can you explain (understand / solve ) this problem ?

Will a stabilized sensor like the one found on Minolta Dimage A2 be
efficient in removing this type of vibration ?
Heard about a very wide angle (around 18mm) stabilized lens in (Nikon mount)
?

Any suggestion will be more than welcome.

Yves (from Belgium)

--
Don Stauffer in Minnesota

webpage- http://www.usfamily.net/web/stauffer

I agree with you that if aircraft movement or vibration were the
problem, the blur would be somewhat uniform across the frame. These
results are indeed strange. If I get how you are mounting it, the
question about where exhaust comes wouldn't explain it, as exhaust
blowing back would make a blur that varies from side to side.

You are taking at a pretty wide angle, but if problem occurs only
sometimes that is not likely to be a factor.

While motion or vibration of plane is not likely to be the problem, is
it possible that vibration of camera itself, moving something INSIDE the
camera could be?

Nadar wrote:

I'm using a Fuji S2 PRO with a Nikon 12-24mm lens to take aerial photographs
(vertical aiming).
The camera is mounted vertically on a platform fixed on the door step of a
Cessna.
Usual settings are : zoom set to 16mm (eq. 24mm on 24x36), aperture between
5.6 and 11, shutter speed 1:1000 and sensibility 200 or 400 ASA depending on
the terrain. Focus is of course fixed on the infinity.
I use a GPS to know when I have to shoot, in order to acquire successive
pictures with 10-20 % overlap.
Along a flight line, photos are taken in "landscape" mode, to cover a strip
as wide as possible.
Flying altitude is usually around 2000 m (6000 ft), and the interval between
2 photos is around 20 seconds.
At this altitude, the relative movement of the ground is very slow, and the
target can be considered as non-moving.

Most of the time, I got excellent results, but sometimes, I observe a
strange problem on some series of pictures:
The "bottom" side of the images (if you hold the camera in a "normal"
position) is significantly less sharp than the "top" side.
This is very obvious when you place successive pictures with their
ovelapping area (one sharp "top" on top of one "fuzzy" bottom).

This is probably related to vibrations in the plane, but I don't understand
why shaking doesn't affect the whole image.
I had a similar problems earlier with a film camera used in the same
situation, and I interpreted then as the film being improperly pressed flat
by the plate located in the back of the camera.

To add to the confusion, the same problem occurs on some series of pictures
(always with the same magnitude), and other series are perfectly sharp.

How can you explain (understand / solve ) this problem ?

Will a stabilized sensor like the one found on Minolta Dimage A2 be
efficient in removing this type of vibration ?
Heard about a very wide angle (around 18mm) stabilized lens in (Nikon mount)
?

Any suggestion will be more than welcome.

Yves (from Belgium)

--
Don Stauffer in Minnesota

webpage- http://www.usfamily.net/web/stauffer