Which one is the condenser fresnel?

[Iron Man]

Hi

Ive split my fresnel but ive forgotten which one is which. One of halves (lense A) requires u to be very close to the lense in order to see thru it completely. The other (lense B) allows u to be further away in order to see thru it completley.

1.Which one is the condenser fresnel?
2.And which one needs to be closest/facing the light source?

Thanks

 

[dewil]

1. The condenser is the one with the smallest Focal length. And based on your story, I think Lens A is the smaller one.
2. Lens A as it is the condenser fresnel.

Hope this helps 😀

 

[joemkal]

you could shine a bright light through it, move it until the light becomes a point

this should reveal the focus length of each lens