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Table I. Pro-Raptars
Table III. Mirrotel (Catadioptric Tele
Focal length
Diagonal Type and No. of //No. coverage elements
)
Focal length
Diagonal No. of //No. coverage elements
25 35 50 75 101 152
mm mm mm mm mm mm
//2.3 //2.3 //2.3 //2.3 //2.3 //2.7
61.2° 46.4° 33.0° 22.2° 16.8° 11.2°
6 6
6 6 6
4
Gaussian type
cc cc cc cc cc cc
cc cc
Modified Petzval
20 40 80
in. in. in.
//5.6 //14
3.4° 1.7° 0.85°
3 3 2
Table IV.
Wide-Angle
Lenses
for 16mm
Table II. Raptar Telephotos
Focal length
//No.
Diagonal No. of coverage elements
10 in.
//4.5
6.8°*
4
12 in.
//4.5
5.6°*
4
14 in.
//4.5
4.8°*
4
15 ;n.
//4.5
4.4°*
4
16 in.
//4.5
4.2°*
4
18 in.
//5.6
3.8°*
4
20 in.
//5.6
3.4°*
4
24 in.
//5.6
2.8°*
4
* Lenses marked with asterisk cover more than the angle specified for 35mm single frame with same high-quality performance.
Film
Focal length
//No.
Diagonal No. of coverage elements
3.7 mm
5.4 mm
12.7 mm
//I5 //1. 5 //1. 5
142° 84° 56°
8
8
11
Table V. Wide-Angle Lenses for 35mm Film
Focal length
//No.
Diagonal No. of coverage elements
8.3 mm 11.2 mm
//1. 5 //2.0
142° 84°
targets used. Strict control of the variables affecting the measurement is very necessary. Other ways to evaluate lens performance have been discussed also.11"13 Since the subject is well covered by these authors, no attempt will be made to discuss any of the methods as applied to the lenses which are the subject of this paper other than to state that the "Rayleigh-Conrady" tolerances14 were used as the basis for the comparison of these lens designs with other similar designs, as well as extensive photographic and optical bench comparisons.
Spherical Mirror Optics (Mirrotels)
Since catadioptric photographic objectives are recent developments in the
field it is felt that some discussion of the spherical mirror is necessary.
The advantages of the spherical mirror as an image-forming device have been known for many years. The spherical aberration of a single concave mirror is eight times smaller than that of a single lens of equal aperture and focal length even when the lens has the most favorable bending for minimum spherical aberration.2 Where high resolution is desired, spherical aberration is objectionable. Therefore, spherical mirrors have been made aspheric by hand correction to minimize the spherical aberration to acceptable limits. To have the advantage of large-aperture spherical mirrors with minimum spherical aberration, Schmidt1 in 1930
Gilkeson and Turula: Optical Aids
499