Compact wide-angle lens system

A wide-angle lens system comprising:

• a first lens element which is a double-concave lens having a first refracting power .phi.1 which is negative;
• a second lens element which is a positive lens;
• a third lens element which is a negative lens, said second and said third lens elements having a second refracting power .phi.2 which is positive;
• a fourth lens element which is a negative lens;
• a fifth lens element which is a positive lens;
• a sixth lens element which is a negative lens, said fourth, said fifth and said sixth lens elements having a third refracting power .phi.3 which is positive;
• a seventh lens element which is a negative lens having a fourth refracting power .phi.4 which is negative;
• and
• a stop provided between said third lens element and said fourth lens element,
• said first, said second, said third, said fourth, said fifth, said sixth and said seventh lens elements being arranged in this order in a direction from an object side to an image surface side along an optical axis,
• wherein said first refracting power, said second refracting power, said third refracting power, and said fourth refracting power satisfy the conditions:
• 0.7<.phi.1/.phi.4<2.5 (1)
• 1.8<.phi.2/.phi.3<7.0. (2).

A wide-angle lens system comprising:

• a first lens component, a second lens component, a third lens component and a fourth lens component which are arranged in this order in a direction from an object side to an image surface side along an optical axis;
• and
• a stop provided between the second lens component and the third lens component,
• the first lens component comprising a double-concave lens, said first lens component having a first refracting power .phi.1 which is negative,
• the second lens component comprising a positive lens and a negative lens which are arranged in this order in the direction, said second lens component having a second refracting power .phi.2 which is positive,
• the third lens component comprising a negative lens, a positive lens and a negative lens which are arranged in this order in the direction, said third lens component having a third refracting power .phi.3 which is positive,
• the fourth lens component comprising a negative lens, said fourth lens component having a fourth refracting power .phi.4 which is negative,
• wherein I and J are integers and the J-th one of lenses in the I-th one of said first, said second, said third and said fourth lens components has a refractive index which is represented by N(I, J),
• wherein a refractive index N(3, 2) of the positive lens in said third lens component, a refrective index N(3, 1) of the negative lens in said third lens component and a refractive index N(3, 3) of the negative lens in said third lens component satisfy the condition:
• 0.1<N(3, 2)-{N(3, 1)+N(3, 3)}/2. (1A).