Why Did a Real Image Appear at 136cm in a Converging Lens Experiment?

[jnimagine]

hi i posted the same sort of question a few times before but this time it's a little different
we did an experiment with a converging lens and a candle to find an image. When the candle was placed at the focal point, which was 16.3cm, an image appeared at 136cm. I know in theory, no image should be appearing here. Last time when i asked the same question but with concave mirrors, some of the answers i got were that it was caused by the 3-D of the candle and spherical aberrations. But spherical aberration is not likely have caused it because the mirror was too small to cause that. So my question is, is it the same for a converging lens? the reason an image appears there is because of the three-dimensionality of the candle?

 

[OlderDan]

All the same principles apply to a converging lens that apply to a converging mirror. It seems very unlikely that this is purely a 3-D effect. Some of the flame would have to be more than 18cm from the lens to get a sharp image at 136cm if the focal length is indeed 16.3cm. Some distance measurement is probably a bit off, but that's the way real measurements are, subject to a certain amount of error.