This is a question that I have recieved seven PM's about and I would like to elaborate publicly to help dicern the difference.

The main thing is that the ELs have enhanced coatings relative to the SLCs.

This translates into better resolution (like an HD tv with a higher pixel count). The sharper resolution provides for better contrast – a birder can tell the differences between feathers easier. Colors are more true to nature in an EL and they pop out better.

The ELs all have “field flattening” lenses in them. The field flattener provides for true edge to edge distinction. For example, if you grab any pair of ELs, and put an object that goes straight up and down in the periphery of your field of view (such as a telephone or fence pole) you will see that it goes straight up and down. Only glass in the world to do this. SLCs don’t. While it’s nice that field flattening shows things they way they are (other glass bows or curves at the edges) it’s more important that the viewer’s eyes don’t constantly try and focus the periphery of your field of view, over and over and over again. Less eye strain with field flattening. ELs have more eye relief. That is, the 10x42 ELs have 20mm and the 10x42 SLCs have 16mm. ELs have open bridge design which makes them easier to grip (i.e. two hinges instead of one).

Now the SLCs beat the EL in one place, light transmission. ELs = 90%. SLCs = 91%. That’s because of the extra field flattening lenses in the Els.

I am comparing the new ELs versus the new SLCs. Over the years, there have been different versions of the ELs and SLCs with features constantly changing.

All ELs have HD glass. All new SLCs have or will have HD glass.