Image stabilization shoud be stabilized

Le 20/08/2013 23:45, sid a écrit :
Ghost-Rider wrote:

http://cjoint.com/13au/CHusUl3JPft_d7000_07890.jpg
http://cjoint.com/13au/CHutJicQBXe_d7000_07896.jpg

Well they look focused well and plenty sharp. Second one is the better one,
better angle on the dragon fly. A bit of post and they'll come up lovely.
How big were these dragonflys? What sort of magnification are you getting
with your setup? just curious

Here is a spreadsheet where I put all my measures.
http://cjoint.com/13au/CHvm0CNm2dS_m...nification.jpg
One can see on line 17 that using the 18-300 at 300 mm and one Olympus
MCON-35 add-on lens (2.85 dioptries), the magnification ratio obtained
is between 0.48 and 0.91, depending on the focus distance set on the barrel.
Surprisingly, the maximum magnification and distance from the subject
are obtained when the distance is set at infinity and not 0.45 m. That
is due to the internal focus system of the zoom.
The distance recorded in the EXIF does not take into account the add-on
lens. Therefore, it is misleading but useful though.

The head of this dragon-fly had a diameter of say about 5 millimeters if
I remember well.
Let's see if we can calculate it.
The distance read in the EXIF is 70.79 meters in the first photo, 18.84
meters in the second, nearly the infinity.
The first photo is therefore very close to the maximum magnification of
0.91, say 0.9.
The width of this photo can roughly contain 5 heads across.
As the width of the sensor is 23.6 mm, the head's diameter is
23.6 / 5 / 0.9 = 5.24 millimeters.

The spreadsheet shows many scenarios with my two successive cameras :
D90 + 18-200 and D7000 + 18-300, with one, two, three or four add-on
lenses and at different distances set on the barrel. I usually only use
one and not more than two since finding the subject and hand-help
focusing become very difficult as I pile-up lenses and I lose the extra
details because of bad focusing and the minute depth of field.
With two add-on lenses I can reach a magnification ratio of 1.57 which
is quite nice.

On 8/21/2013 7:05 AM, Ghost-Rider wrote:
Le 20/08/2013 23:45, sid a écrit :
Ghost-Rider wrote:

http://cjoint.com/13au/CHusUl3JPft_d7000_07890.jpg
http://cjoint.com/13au/CHutJicQBXe_d7000_07896.jpg

Well they look focused well and plenty sharp. Second one is the better
one,
better angle on the dragon fly. A bit of post and they'll come up lovely.
How big were these dragonflys? What sort of magnification are you getting
with your setup? just curious

Here is a spreadsheet where I put all my measures.
http://cjoint.com/13au/CHvm0CNm2dS_m...nification.jpg
One can see on line 17 that using the 18-300 at 300 mm and one Olympus
MCON-35 add-on lens (2.85 dioptries), the magnification ratio obtained
is between 0.48 and 0.91, depending on the focus distance set on the
barrel.
Surprisingly, the maximum magnification and distance from the subject
are obtained when the distance is set at infinity and not 0.45 m. That
is due to the internal focus system of the zoom.
The distance recorded in the EXIF does not take into account the add-on
lens. Therefore, it is misleading but useful though.

The head of this dragon-fly had a diameter of say about 5 millimeters if
I remember well.
Let's see if we can calculate it.
The distance read in the EXIF is 70.79 meters in the first photo, 18.84
meters in the second, nearly the infinity.
The first photo is therefore very close to the maximum magnification of
0.91, say 0.9.
The width of this photo can roughly contain 5 heads across.
As the width of the sensor is 23.6 mm, the head's diameter is
23.6 / 5 / 0.9 = 5.24 millimeters.

The spreadsheet shows many scenarios with my two successive cameras :
D90 + 18-200 and D7000 + 18-300, with one, two, three or four add-on
lenses and at different distances set on the barrel. I usually only use
one and not more than two since finding the subject and hand-help
focusing become very difficult as I pile-up lenses and I lose the extra
details because of bad focusing and the minute depth of field.
With two add-on lenses I can reach a magnification ratio of 1.57 which
is quite nice.

The results are nice, and I would be reluctant to change. But,
have you tried extension tubes?



--
PeterN

Le 21/08/2013 22:29, PeterN a écrit :

The results are nice, and I would be reluctant to change. But,
have you tried extension tubes?

Not yet. I'll do that some day I think but I have postponed it so far
for several reasons.
- I have not yet exhausted all the possibilities of my present
contrivance, far from it.
- Although I use a long zoom lens, I would have to limit the
magnification on the zoom itself to use it as a shorter focal lens to
get a bigger overall magnification, but I don't know which. What happens
then ? Vignetting ?
- In any case, the aperture of my zoom is f3.5 to f5.6. If I double it's
extension, I'll get f7 to f11 where the autofocus will probably no
longer work (properly).
- My zoom is a G lens and the Nikon extension tubes, which are quite
short, do not work with G lenses, so I'll have to find compatible ones
(Kenko ?) or buy a shorter lens compatible with the Nikon extension tubes.
- I have read that for optical reasons (increase of extra-axial
aberrations : coma, field curvature), the quality obtained with
extension tubes is slightly diminished, which is not the case with
add-on lenses (apart from their own would-be aberrations).
- Last but not least, I don't envisage buying something without being
reasonably sure that I'll get acceptable results.
So...

On 8/22/2013 7:20 AM, Ghost-Rider wrote:
Le 21/08/2013 22:29, PeterN a écrit :

The results are nice, and I would be reluctant to change. But,
have you tried extension tubes?

Not yet. I'll do that some day I think but I have postponed it so far
for several reasons.
- I have not yet exhausted all the possibilities of my present
contrivance, far from it.
- Although I use a long zoom lens, I would have to limit the
magnification on the zoom itself to use it as a shorter focal lens to
get a bigger overall magnification, but I don't know which. What happens
then ? Vignetting ?
- In any case, the aperture of my zoom is f3.5 to f5.6. If I double it's
extension, I'll get f7 to f11 where the autofocus will probably no
longer work (properly).
- My zoom is a G lens and the Nikon extension tubes, which are quite
short, do not work with G lenses, so I'll have to find compatible ones
(Kenko ?) or buy a shorter lens compatible with the Nikon extension tubes.
- I have read that for optical reasons (increase of extra-axial
aberrations : coma, field curvature), the quality obtained with
extension tubes is slightly diminished, which is not the case with
add-on lenses (apart from their own would-be aberrations).
- Last but not least, I don't envisage buying something without being
reasonably sure that I'll get acceptable results.
So...




Just to be clear, I am talking about Extension tubes, not
tele-extenders. The old Nikon extension tubes do not give you autofocus.
I use Kenko pro and they work fine on my 70-200.



--
PeterN