8 mm Peleng fisheye and Canon EOS 5D DSLR


 


This page is a brief note about the Russian 8-mm focal length f/3.5 Peleng fisheye. For a complete review of the lens read the excellent paper by 
Cyril Cavadore here. All the essential comments about the Peleng 8-mm are given by C. Cavadore. The present page add only an information about the use of these lens with a Canon EOS 5D.

Compare the two following images, one taken with an EOS 350D, and one taken with an EOS 5D:


Peleng 8 mm fisheye @f/8 on a Canon EOS 350D (sensor nearly identical to the 20D).


Peleng 8 mm fisheye @ f/8 on a Canon EOS 5D. 

The 350D image is more detailed because the smallest size of the pixels (6.42 Ám for the 350D/20D, 8.2Ám for the 5D), but the 5D full frame sensor is a real advantage with this type of lens. However, one can note that even a 24x36 mm detector, the circular field misses slightly along the small direction of the image. But the loss remains very weak with the 5D ; the 180░ field is nearly complete.

I confirm the Cavadore's comment about the image quality: the sharpness is good for the price (but the use at f:8 relative aperture is recommended for an ultimate point image). Note also the limited sun flare. The ratio performance/cost is very favorable!


Another ESOS 5D view from my "observatory"...


... and a panoramic projection of the same image (Iris software, click here for details about fisheye projections and more about the topic).


A crop of the very far field of the fisheye for appreciate the resolution and diffusion of this part of the image (taken @ f/8). The test is severe. Some lateral color, but the chromatic aberration is well controlled.


A night version of the same point of view.


The panoramic projection.


Now the lens is directed toward the horizon. Canon EOS 5D + Peleng 8 mm @ f/8. Exposure 15 s @ ISO 500.


A view of the "Castanet" observatory, where the images are taken.


The Peleng lens is an ideal compagnon for evaluate the sky quality! The Toulouse city is in the north. 30 sec. exposure @ 400 ISO - Canon 5D.

A 360░ panorama extracted from the latest image.


 STAR TEST


Stack of 5 x 30 s. unguided exposure. Canon 5D + Peleng 8-mm @ f/8


Crop 100%


Crop 100%


The registered version of the 5x 30 seconds sequence. Peleng 8 mm @ f/8. EOS 5D @ ISO 400.


Of course, at full aperture the result is not so good. Some spherical aberration is present. Peleng 8 mm @ f/3.5. 30 secondes exposure.


Image quality near the border of the field at full aperture (f/3.5). Note the astigmatism. Remember, the DSLR is a full-frame 24x36.


Single guided shot of 240 seconds. Peleng 8 mm @ f/8. Crop 75%. Geminii/Orion region.


The setup used for take the guided image: A TG-SP Takahashi equatorial mount.


IMAGE PROCESSING DEMONSTRATION
Some celestial equatorial projections
See also the MAP documentation
(version en franšais ici)


The starting zenithal view - Single shot 30 seconds Peleng image. Canon 5D @ ISO 400.

First the Peleng image is projected onto a sphere (Fisheye... tool of Geometry menu):


Parameters of the spherical projection for a 5D equiped with the Peleng 8 mm.

Then, the spherical image is rotated by 90░ relative to its center (X=2193, Y=1460, i.e. the middle of the image) (command line >rot 2193 1460 90, or use Rotation... dialog box of Geometry menu). The meridian is now vertical: a facility for angles definition. The image is named SPHERE_PROJEC (it is an example):


The spherical projection. Equatorial system circles are drawed with an angular step of 10░.

For draw the circles, define the parameters file SPHERE.LST:

0
0.0  46  0
4386 2920
2193 1460 1460
0 0
-180 180 -90 90
0 0
0 0.5
10 10 3

Then

>GRID SPHERE 0

The value for PHIP (46░) is equal to 90░- (latitude of the observatory).

Now the result of a "Postel" polar projection (crop of the pole only):


Postel polar projection. Ursa Major, Ursa Minor and Cassiopea constellations.

The definition of the polar projection (POSTEL.LST):

7
0  0  0
0 0
0 0 0
0 0
-180 180 0 90
0 0
0 0.1
10 10 3


>LOAD SPHERE_PROJEC
>MAP SPHERE POSTER
>GRID POSTEL 200

Now an ideal projection for display intermediate declinaison:


Albers polar conic projection. The selected declinaison of the tangent point of the cone is +45░ (L1=L2=45░). Gemini, Auriga and Taurus constellations.

The ALBERS.LST file:

12
0.0  0  0
0 0
0 0 0
0 0
-180 180 -10 90
45 45
0 .1
10 10 3

>LOAD SPHERE_PROJEC
>MAP SPHERE ALBERS
>GRID ALBERS 240

And now, the equarorial contries:

demo5.jpg
Part of a Lambert cylindrar projection. Canis Major, Orion Gemini, and Taurus constellations.

Definition of the Lambert projection (file LAMBERT.LST):

1
0.0  0  0
0 0
0 0 0
0 0
-180 180 -75 75
0 0
0 .07
10 10 3

>LOAD SPHERE_PROJEC
>MAP SPHERE LAMBERT
>GRID LAMBERT 240

Here a detail of the Lambert projection, well adapted for examine equatorial zones.

Remember that all the images of the demonstration are derived from an unique single shot images!


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