PanoTools NG:
Re: Aiptek A-HD+ mini fisheye camera mod
Hans Nyberg 2009-Apr-04 15:46:05
--- In #removed#, "Hans Nyberg" <hans@...> wrote:
>
> --- In #removed#, RomualdV <vromuald@> wrote:
> >
> >
> > Le 3 avr. 09 ?8:01, panovrx a ?it :
> >
> > > . an Aiptek A-HD+ hybrid camera and it came this morning and I
> > > replaced the lens with the fisheye lens from the GoPro Hero Wide --
> > > here is a still
> > > http://www.mediavr.com/aiptek1.jpg
> >
> > Sharper in the corners than in the center in this sample, as you set
> > it or it is a fov/distance effect...
>
> The focusplane of a fisheye is flat. This means that subjects in the periferal areas may have a focus distance of 10 cm even if they in real life are 10 meters away.
> So if you shoot on full aperture and focus at 10 cm you get sharp corners and no focus in centre.
> Of course it is also the same the other way around.
> http://www.panoramas.dk/panorama/fisheye-focus/fisheye-focus.jpg
>
Here is a real example showing this.
http://www.panoramas.dk/panorama/fisheye-focus/nikkor-0.4m.jpg
Distance to the floor and ceiling is 1,2 m and the distance to the white scale is 1 meter and the yellow is 0,7m. Lens is focused at 0.5m.
You can see that centre is out of focus after 0,7m but floor and ceiling is sharp.
This is why many have problems doing sharp nadirs, You actually may have to replace a diameter of 1 m with the Nadir shot even if your hole is just 50cm in diameter.
Hans
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