How to Measure Magnification of a Lens System with Liquid Surface

[Gleb1964]

The problem is that by the time the light passes through the bottom of the sample much of it has already been lost. Plus that will require modification of the camera end of the system since you have introduced a positive lens into it.

I haven't seen specification for the system, but I guess it not on a limit of signal/noise. The aim is to get evenly illuminated background field, not the best efficiency of using every photon. You may mention, there is a caple of apertures truncating a lot of light.

 

[Drakkith]

I haven't seen specification for the system, but I guess it not on a limit of signal/noise.

Indeed. That wasn't what I was trying to get at. My apologies for the confusion.

 

[HomeTinker]

I haven't seen specification for the system, but I guess it not on a limit of signal/noise. The aim is to get evenly illuminated background field, not the best efficiency of using every photon. You may mention, there is a caple of apertures truncating a lot of light.

There are two diaphragms in the system as per koehler design (field and aperture diaphragms) however to be honest they may very little difference here. Having them completely opened or closed do not improve on this situation.

 

[Gleb1964]

I have raytraced two options, with plano-convex lens above cuvette and below. Both options are working somehow, but not the same.
Variant with lens above cuvette does not give even illumination over entire field. Illumination is even at the central field but does not goes to the edge. Vignetting is increasing close to edge and at the very edge there is a dark rim because light undergo a total internal reflection and does not pass through.
Another option with the same lens under cuvette so the imaging optics is looking at cuvette bottom through the planoconvex lens. That does destroy telecentricity condition of imaging optics but makes possible to achive even illumination over entire cuvette bottom.
What trade of is preferable is at the topic starter choice.

 

[sophiecentaur]

Both options are working somehow, but not the same.

That doesn't surprise me too much. There is a right end and a wrong end for binoculars too.

 

[HomeTinker]

Many thanks for that, I will try to get hold of LA1859 and see what results that makes for both designs.