Color shift from reading/computer glasses?

[Guillermo Luijk]

I have a pair of high-end progressive glasses from Seiko. I'm happy with them specially at work when having to look at presentations in office rooms at the same time as I type on my laptop. They are also very handy when using the mobile at the same time as looking farer places. They require to adapt, specially you need to move more your head than you used to.

They include a computer filter which hypothetically eliminates harming frequencies from computer monitors. The point is they create a visible warm cast on the screen which would ruin any accurate colour calibration. Luckily I don't really much care on my monitor calibration, but if I would, theses lenses wouldn't simply be usable on it.

I have done a simple check on how much colour cast these lenses produce. I shot twice a white screen, shooting with and without my glasses in front of the lens. Taking as a reference the WB needed to make the RAW data perfectly linear in the first shot (w/o the glasses), I have applied that white balance to both shots, linearly converted to sRGB, and then compared the relative exposure on the sRGB channels:



The differences are so subtle that are better viewed when zoomed (in the previous scale the right half of the plot corresponds to a single 1 stop):







Even if in the RAW space all three channels have reductions as expected, after the sRGB conversion R values remain nearly unaltered, while G are reduced by -0,018 EV and B are reduced by -0.115 EV.

So that -0.115 EV in the blues is the warming effect of my glasses put in numbers.



These are the 100x100 pixel central patches analysed. The width of the above histograms was pure Photon noise, being the R channel the noisiest (lowest RAW values and hence worst SNR and widest gaussian histogram).

Regards

[bassman51]

I went to their website and I see that now. So from what I can tell they are progressive but only correct for near and middle distances but not far vision. So I'm guessing that the focal 'zones' are broader, in other words they take up more space on the lens? This would then require less head movement to achieve focus. The image of the typical progressive wearer with her head tilted back is EXACTLY what happens to me with my current progressives. I'm excited about looking into these. Wonder if they really work as advertised. I do not relish the idea of having indoor and outdoor glasses but would really enjoy a dedicated pair for working at the computer.

The color shift is another matter altogether and I'm surprised not to see it mentioned more often in regard to color management issues, especially on a site in which ambient light and what clothes you are wearing when you work in post tend to be hot topics.

I was shocked to find how much warmer my monitor appears when seen through my glasses than without them. What can be done about this? Should we avoid antiglare coatings? Do these coatings even help? I have no way to compare since I only have one pair of glasses.

The bigger question is how to account for this in my workflow? My near/middle vision is rather poor but I can still see color casts etc without the glasses. Do I make color corrections without my glasses? What about when assessing prints?

I’m on my second pair of this type of “computer glasses” now, and they have saved my neck and shoulders. The current pair are progressives with the top/distance portion targeted at the screen distance - about 30” - and the bottom for reading.  They’re completely useless if I walk out of the office, as there’s not traditional distance portion at all.  I got them with no fancy options like anti-glare or the purple tint. 

Another hint - I got a completely different frame for these than my normal glasses; despite what I said above, I managed to walk out and even start driving with the old ones which had a similar frame to my daily glasses.  Really not a good idea 😱.