can a lens form real and 'erect' image and if it can then how?
Answers
In total there are three cases for each converging or diverging optical element (M=-inf to -0, M=0 to 1, M=1 to inf). If you count special cases (M=-1, M=1) and split the first case into two (M=-inf to -1 and M=-1 to -0) you could count up to 6.
But for now only the first three matter.
The first is a projection, giving a real and inverted image when using a converging optical element. The object is outside of the focal point.
The second is a magnification, giving a virtual, magnified, erect image when using a converging element. The object is in between the focal point and the lens.
The second is a magnification, giving a virtual, magnified, erect image when using a converging element. The object is in between the focal point and the lens
The third one usually gets overlooked with converging lenses, since it is usually considered to belong to diverging lenses (where it is the usual case). For converging lenses it only occurs with the object in virtual space. Then the image is real and erect, but diminished
