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Discussion Starter · #1 ·
I recently joined this forum and enjoy all the helpful tips on equipment reviews-I notice many people complain about rainbow effects with projectors; however, there is never any mention of the conditions associated with your eye that can cause or increase this effect-corneal edema, glaucoma, mild amount of uncorrected astigmatism, dry eyes, larger then normal pupils can all distort how light enters your eye and the image is processed. My two cents would be to visit your eye doctor and get an updated prescription-you can have 20/20 vision but still have a slight prescription that creates distortion in dim lighting. Have the optometrist measure your pupil size and if they dilate above average in dim illumination he can prescribe an eye drop called Alphagan-this is used to lower eye pressure in glaucoma pts but has a secondary action of constricting the pupils in dark conditions; thus, decreasing excess light entering your eye from the peripheral cornea and decreasing halos, light diffraction also known as "abberations" to the eye, etc... It is mainly prescribed for post Lasik patients that see halos around lights at night...If you're sensitive to rainbow effects treating the above eye conditions could help solve your problems.
 

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It seems that as the colour strobe speed increases the "rainbow" effect decreases. There is only so much fooling that you can do to the human senses.


First the 2x speeds were obnoxious; 3x more bearable, and finally 4x speeds result in the effect significantly minimized. LED DLP appears to have the least (effects) of all.


I submit that the effect is a function of colour sensitivity. I believe that as more people buy this technology that more will notice and report the effect-particularly artists or anyone with a heightened sense of colour.
 

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In my experience with several projectors, both business and HT class, I have noticed the issue is worse if my eyes are fatigued.


With my old HT projector at 4x, I could always induce rainbows by looking back and forth quickly, and I also noticed that I was prone to headaches during extended viewings, very similar to looking at a CRT monitor at 60hz in the older computer days. However, others have no problem with a 60hz display. I think it's probably mostly due to genetics.
 

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Your logic is extremely confusing.


1. Exactly what you do “think” is due to genetics?

2. How do you measure (quantitatively) “worse”?

3. What was your “old HT projector at 4x”?


My experiences with the “Rainbow effect” are not a function of fatigue. I can see the effects on certain scenes regardless of my viewing habits.


LED DLP projectors display much less of the strobing effect. They don’t have the mechanical disadvantage of a spinning wheeling.


Let’s be clear “the rainbow effect” is the lag caused by strobing of the primary colours to create a full colour image. Some of us are annoyed by the lag. I suspect that the more sensitive a person is colour changes the more likely that person is to be annoyed by the lag. I also suspect that a greater light sensitivity can exacerbate the discomfort.


In the days of the 2x projectors, I simply could not watch anything displayed for more than a few seconds before I would become severely distracted.
 

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Discussion Starter · #5 ·
this "lag" and 'light sensitivity" is created by a delayed response of the P and M cells within our rods and cones that carry signals to the retina--they are being overloaded by sensory stimuli--light and diffraction from the above issues I mentioned...The eye fatigue issue can be remedied with vision therapy-essentially eye exercises to increase your eye muscle ability to converge and diverge on objects up close and far away-Vision therapy does wonders for kids with reading issues however adults can benefit too...see an eye doctor and i am willing to bet your eyes have an "exophoric posture"--in which prism in your eyeglass prescription can greatly remedy any eye fatigue along with the VT--it is not a genetic issue at all.
 

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Your eye fatigue hypothesis fails to explain why the effect is significantly diminished by INCREASING the colour strobe rate. Not only that but you also fail to quantify "overloaded by sensory stimuli" or give a base condition for non-fatigued eyes.
 
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