- Applicant: Tamron Co., Ltd.
Publication number: P2023072281
Application number: P 2021184724
Publication date: 2023-05-24Title
of invention: Optical system and imaging device - Kind Code: A1 An optical system and an imaging apparatus having a larger aperture and a higher imaging magnification can be provided while maintaining a compact size as a whole.
- As these imaging devices have become more sophisticated and smaller, there has been a demand for their imaging lenses (optical systems) to have higher performance and smaller sizes, and macro lenses are no exception.
- Macro lenses are required to achieve high optical performance over the entire focal range by suppressing fluctuations in aberrations during focusing, such as fluctuations in spherical aberration and curvature of field. However, most macro lenses on the market today are around F2.8. Even with a zoom lens, it is possible to achieve a similar imaging magnification with a brightness of about F2.8, and there are cases where the zoom lens is used as a substitute for the macro lens. Therefore, there is a growing demand for macro lenses that are smaller, have higher performance, and have higher added value that pursue imaging expressions unique to macro lenses.
- However, although the optical system disclosed in Patent Document 1 has an F2.0 aperture and is intended to achieve a large aperture ratio, the weight and movement of the focus group are large. It is difficult to improve imaging magnification and focus speed.
- In addition, in the optical system disclosed in Patent Document 2, in order to further increase the aperture and improve the imaging magnification, another lens group must be configured in order to satisfactorily correct the aberration occurring in the third lens group. It is necessary to increase the number of lenses, resulting in an increase in the size of the optical system.
- SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an optical system and imaging apparatus with a larger aperture and a higher imaging magnification while keeping the overall size small.
- Example 1 (90mm F2 life-size macro)
Magnification 0 0.5x 1x
Focal length 92.7002 56.4352 38.4725
F value 2.110 3.200 4.200
Half angle of view 12.5792 6.5626 3.7783
Image height 21.633 21.633
21.633 back Focus 18.500 18.500 18.500
Optical total length 134.619 134.619 145.676
- Example 2 (90mm F2 0.8x macro)
Magnification 0 0.5x 0.8x
Focal length 92.7001 61.6892 46.4780
F value 2.1549 3.2000 3.8000
Half angle of view 12.5935 5.8338 5.7301
Image height 21.633
21.633 21.633 Back focus 18.500 18.500 18.500
Optical total length 136.903 136.903 136.903
- Example 3 (90mm F2.8 2x macro)
Magnification 0 1x 2x
Focal length 87.8766 39.7703 25.9505
F value 2.9000 5.8500 8.7000
Half angle of view 12.9523 8.4795 5.1482
Image height 21.633 21.633
21.6 33 Back focus 37.877 37.877 37.877
Optical total length 145.000 145.000 154.112
- Example 4 (90mm F2.8 1.5x macro)
Magnification 0 0.75x 1.5x
Focal length 91.6041 50.1114 35.1898
F value 2.9100 5.0000 6.5000
Half angle of view 12.7285 8.6295 5.5211
Image height 21.633 21.6
33 21.633 Back focus 53.033 40.589 40.589
Optical total length 143.520 143.520 154.229
Tamron 17-28mm f/2.8 Di III RXD FE:
B&H Photo / Amazon / Adorama
Tamron 28-75mm f/2.8 Di III VXD G2 FE:
B&H Photo / Amazon / Adorama
Tamron 28-75mm f/2.8 Di III RXD FE:
Amazon
Tamron 35-150mm f/2-2.8 Di III VXD:
B&H Photo / Amazon / Adorama
Tamron 70-180mm f/2.8 Di III RXD FE:
B&H Photo / Amazon / Adorama
Tamron 28-200mm f/2.8-5.6 Di III RXD FE:
B&H Photo / Amazon / Adorama
Tamron 20mm F/2.8 Di III OSD M1:2（Model F050):
B&H Photo / Amazon / Adorama
Tamron 24mm F/2.8 Di III OSD M1:2（Model F051):
B&H Photo / Amazon / Adorama
Tamron 35mm F/2.8 Di III OSD M1:2（Model F053):
B&H Photo / Amazon / Adorama
Tamron 17-70mm F2.8 Di III A-VC RXD:
B&H Photo / Amazon / Adorama
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