The original link is actually my article and lens.
I shaved the petals off the lens because I didn't want them to show up in the full frame camera images. Although I already have the 16mm fisheye, the 10mm shaved is a totally different look and although you don't get a full circle, it's better than spending more money for a new lens.
I wasn't concerned ...
The zoom helps with crop sensors but that's not the main reason. Basically on a full frame sensor the 8-15 is two lenses in one, at 8mm it's a full fisheye with a circular image and a 180 degree vertical field of view. At 15mm it's a diagonal fisheye, with 180 degrees corner to corner and no black areas.
Even if you don't want to shoot circular ...
I have not used Fulla myself but pulled this information together from various internet resources.
First you need to install Fulla, which is included in the Hugin package.
sudo apt-get install hugin-tools
Fulla is able to read in correction data from the last open-source PTLens database, available here. You have to point Fulla to the PTLens database ...
All lenses create a circular image, it's just that most of them have an image circle large enough that it covers the entire sensor. Vignetting at wide apertures is a manifestation of the image circle encroaching on the corners of the sensor as the circle edge is not as sharp as it would be with a narrower aperture.
With a fish-eye lens, the image circle is ...
By default, you are unable to place filters in front of those ultra-wide angle or fisheye lenses.
There are however, 3rd party accessories designed to tackle just this issue:
Fotodiox Pro. Filter Adapter (145mm)
Lucroit Hitech Filter Systems
I found this simple command with just rewrite all your gopro pics:
mogrify -distort barrel "0 0 -0.3" *.JPG
More information about imagemagick command can be found on http://www.imagemagick.org/script/command-line-options.php#distort
The method Barrel has the following arguments:
A B C [ D [ X , Y ] ]
An explanation how to set this four coefficients ...
There are several problems transforming the curvilinear perspective of the wide angle GoPro lens to a rectilinear one.
The transformation stretches the image in certain areas and compresses it in others. This lowers the image quality as new pixels are created as approximations and interpolations from the information in the original image.
There is also a ...
You could use the majority of software that handles barrel distortion, and just either setup a profile and save/reuse that profile, or reuse the settings by syncing the settings. An example of this software would be PTLens, but many solutions exist.
Since this is a fixed focal length lens, you don't need to worry about changing the settings for each image - ...
I've had limited use of a Composer and Muse. The build quality was acceptable, and I know they've held up well for the owners who use them regularly, though it's a pretty clear step below kit lenses in terms of fit and finish.
I think the amount of enjoyment you get out of a Lensbaby is most directly correlated to the optic you choose and your expectation ...
You really can't use filters with these due to the wide angle of view. You could try to rig up something along the lines of a Cokin style filter, but it would have to be a very large filter to avoid vignetting.
Some lenses, like 400mm and 600mm Nikon teles, have a "drop-in" filter which you slot into a gap in the middle of the lens. Not sure if any ...
The difference between a wide angle fisheye lens and a wide angle rectilinear lens is equal area projection versus straight line projection. Uncorrected, they will both demonstrate field curvature.
All simple lenses will demonstrate field curvature based on the angle of view the lens provides. Of course the sensor/film size is also involved in the angle of ...
It will work as expected. Any fisheye that projects a circular uncropped image on an EF-S camera does so also when attached to an EF-M mount with an EF/EF-M adapter. Correspondingly, the image of a full-frame circular fisheye gets cropped like it would with an EF-S camera. The sensor size being the same (APS-C), any adapted lens functions optically exactly ...
As far as free alternatives you can try Fred's defisheye script for ImageMagick, or Fulla, which is a command line tool that comes with Hugin.
Fisheye-Hemi is superior to these, though, as instead of using a standard remapping to a rectilinear projection that softens the edges and requires an aggressive crop it uses a custom mapping algorithm that preserves ...
The fisheye "effect" is dependent only on the angle between the camera and subject, it is thus totally independent of distance.
What you might be noticing is that a fisheye lens bends all straight lines unless they pass through the exact centre of the image.
In some natural scenes the horizon will be the only straight line in the image, thus if you happen ...
Wow, answered my own question:
There is a switch on the fisheye lens labeled "LIMIT" which will lock the maximum zoomed out state of the lens to a point where no negative space is captured on non-full-frame sensors. When this LIMIT switch is in the non-active position, the lens does not impose any artificial limits and the you are free to capture a ...
A fish-eye lens is not just a lens with a very short focal length, it also has a specific distortion (cf. fish-eye projection vs. rectilinear projection).
So while you can use a full-frame fish-eye on an APS-C body, it will still be a fish-eye lens.
You don't even need an expensive fisheye lens to produce this effect.
The linked image is a series of multiple shots and stitched in Photoshop
You can see more images like this at
I use Gimp and the
plugin, together with a few
scripts of mine
to convert the fisheye image into whatever projection better fits the subject: either rectilinear, stereographic, or Mercator. Mercator is my favorite: it's a kind of panoramic cylindrical projection that looks quite similar to the Fisheye-Hemi projection and is free of local distortions (...
This is actually all the same lens. Samyang makes them and they are sold under different brand names. The identical nature of the first two is kind of apparent from the specs, but actually the "6.5mm" is too — and apparently there's also a Vivitar 7mm. (See this web page for more.)
All of these companies have names which were historically legit camera gear ...
Consider this review of the Canon 8-15 f/4L USM fisheye, which can shift from circular at 8mm to diagonal at 15mm. Yes, it's circular because the lens's entire image circle is inside the area of the sensor, rather than covering the entire sensor. I'm not sure there's going to be an entire explanatory webpage other than Wikipedia on this, because it's such a ...
The fisheye effect does not come from the wide focal length, but it comes from using a lens that is not rectilinear.
A rectilinear lens is one that, despite the focal length, will still ensure that there is no barrel or pincushion distortion: that all straight lines remain straight, not curved. Technically, it ensures that the image is the image that would ...
If you want Hugin to auto-recognize and correct for the lens, then probably the right tag to use is Samyang 8mm f/3.5 Fish-Eye CS, because this is the entry in the lensfun database, which is now integrated into Hugin use. In the slr-samyang.xml file the entry is:
Michel Thoby's webpage has the following formula for the equal-area projection:
r = 2 f sin(θ/2)
where r is the distance from the centre in the projection plane of a point that is visible under angle θ.
For 10 mm focal length this gives r = 2 * 10 mm * sin(π/2 / 2) = 14 mm for the radius of the 180-degree image circle. This roughly ...
The link below reviews a Canon 8-15mm lens. It shows sample images from various focal lengths on both full frame and cropped sensors. According to these images, yes indeed will see the full circle when shooting at 8mm on a full frame camera.
Here is the ...
With the full-frame camera, should I expect to see the entire circular image?
It depends on what focal length you've set the lens to. The EF 8-15mm f/4L USM fisheye is unique in being circular at the wide end (at least on full frame it is), and diagonal at the "tele" end. Where you are in the zoom range determines how much of the frame is covered by the ...
Unlike "normal" (rectilinear) lens, there are many types of fisheye lenses, using different projections. The same focal length (f) can give different image size and/or different distortions, depending on the type.
Assuming your 8mm lens uses the most basic equidistant fisheye (180° degrees field of view = -90°..+90°)
R = f · θ
8mm · π/2 ≈ 12....
The EF 8-15mm f/4 L Fisheye lens has a gel filter holder in the rear of the lens. Gel, or other very thin media, can be cut to fit this holder. Gel ND filters are not as easy to find as they once were, but are still available from specialty companies such as B&H.
Here's a list of the Canon lenses with a 31mm rear gel filter holder:
EF 8-15mm f/4 L ...