I have been troubled for some time now trying to put into place what I’m told and what my eyes see in real life. I think I’m not the only one thinking about this, but I may be the one being most vocal. Rather than have the thoughts scattered around a 100 different threads it was suggested I start one specific to the questions I have and also the answers I have found for myself. To the mods I picked this forum not knowing the proper place for such a thread but feel it is appropriate because this is the starting point for many into front projection and where I see most of the questions this relates to. If you feel it is in the wrong place please feel free to move it to where it fits best. The majority of my conclusions regarding my own personal search for my answers came from this recent thread that was taken quite off topic, but with some really great input nonetheless. If the posters of that thread that helped me or the mods want to move any of the pertinent posts over here please do so. If not anyone that wants to see the back story just read thru this linked thread. https://www.avsforum.com/forum/68-dig...lp-please.html
The benefits of new technology are always many and front projection UHD will be no exception I’m sure. I’m not against change in any manner. Front projection is a hobby for most of us and most hobbies have a money cap and most of us here have a compulsion to want to stay up with the latest and the greatest. Right now we are being bombarded with lots of information about UHD and the benefits and many people are advocating it based around the improved resolution. I have read 50 different articles and seen 50 different charts showing the benefit of the improved resolution. I was getting confused as I know what my eyes see and in reading dozens of threads old and new on seating distance and having seen for myself where 720 crosses over for me and viewing a lot of 1080 content also and its crossover point. I kind of extrapolated in my head my benefits of UHD and came to the suspicion it was being over sold in terms of resolution benefits and only resolution benefits. I really don’t have a grasp on the rest of that advancements that will go along with it yet. If the chart and information is wrong they are not just wrong for UHD but they are wrong for all the lower resolution. All the information out there or at least the well quoted ones are based around human visual acuity and the Snellen findings and eye charts we all remember with the big E on the top. I believe that data to be true and it states that humans can resolve details in that test down to 1/60 of one degree in the control of that test. Black E’s on white test charts etc. based on that one measurement only the size of a pixel was assigned and that is the base of why we need UHD. A good source of information explaining this methodology and one of the many sources often quoted can be found here along with the current charts that are widely used. http://carltonbale.com/does-4k-resolution-matter/
I am in no way singling out just this site and I did try contacting them to get a better idea of the logic behind information posted and never got a reply back.
In no way am I trying to infringe on any copyrighted material and I have seen this chart and many identical on many different sites. I amended this chart only to uses as reference and to point out a few common screen sizes and seating distances to an amended set of numbers I show in red for the purpose of discussion or even debate based around the information I have gathered from the above linked thread and others plus my own visual acuity I have experimented with at home changing distance to view. If this was off a little I wouldn’t even bring up the point but the difference so small as 1/60 and 1/30 of one degree as a starting point changes seating a huge amount. I feel this revised chart still errors on the side caution, giving any benefit of the doubt to the new technology or those that have better than 20/20 vision.
I hope those reading will comment on their own findings on what works for them. I just wanted to put my thoughts out there and see what people a lot smarter than me have to say.
On edit 4/14/2016
I thought I would relate what I learned on this thread and summarize it on the opening post so anyone finding this thread wouldn’t have to read thru over 100 posts with a lot of them not pectinate to the topic.
These charts are all over the internet in different forms and my understanding and others were that they were suggestions when a screen size and resolution combination change would be recommended. For example someone using a 720P projector given close enough seating and large enough screen size should change to a 1080P projector as their viewing requirement is now compromised because of visual acuity and the size of one pixel in their field of vision. I assumed this is how it worked as the chart is based around well-known 20/20 vision testing and the Snellen eye chart. I also assumed this was the case because many times I was directed to use these charts to point out to me that my resolution was too low for the screen size I was using.
What these charts are really designed for is to point out the very first point when one resolution can be noticed compared to another by a person with normal vision. In the course of this thread I found out the charts are also wrong at doing that based on newer scientific studies. So the thread split into two different lines of reasoning one being when can an individual with normal vision first detect a difference between a lesser resolution compared to better resolution. The second item being when can an individual with normal vision condemn a resolution as not being minimally acceptable.
Both of these suggestions are only guidelines and of course anyone can watch any resolution from any distance they like and if you are a person that wants ultimate screen image that is indictable from reality you could adjust your resolution and screen size to the extreme first detection point or if you are more budget minded and are looking for a resolution guide that lets you know the point when you start to see individual pixels instead of an image blended together you could use the other guideline. People new to front projection without a projector resolution to look at and see for themselves might find this information useful. Different projector technologies display pixels differently and the information I have found on line leads me to believe LCD projectors begin to show pixels 10% to 20% sooner than DLP. The reason being DLP has a higher fill rate and thinner margins.
Based around what I found in the course of this thread is the original chart is off by a factor of 5. Meaning it is humanly possible to detect a better resolution 5x sooner than what the chart shows.
The second half of my question on when you could start to condemn as screens resolution based around pixel size I found for DLP to be roughly 2X later than the original charts starting point or 10x the corrected chart.
I tested the theory a few times now as quite a few retail stores are showing UHD flat screens next to 1080p flat screens of the same size. Up close watching ether of the displays they look totally usable but of course the UHD looks close to realism in side by side comparison but nothing condemning to the 1080P image by any means. As I moved away to the point the original chart suggests I shouldn’t be able to tell a difference I still easily could. As I got back closer to the 3X - 5X that distance there was no difference depending on content. These observations at those distances are really subjective as it is not at all about pixels anymore but other subtle qualities in the image. There is also great differences in the brightness and contrast of UHD demo content compared to the feed they send to most 1080P sets. So there is little scientific in my comparison by eye but I do trust the scientific studies done that suggest the greater distances.
As to the second aspect when you would likely say you are getting to close to any given resolution based on pixel size I feel the numbers I marked up on the attachment below are fairly correct for DLP and take off a little for LCD projectors. This is only a guideline I will use for my own comparisons and to point out to people my personal beliefs and anyone can feel free to agree or not agree as they wish.
When I get time I will make a new chart for the condemning limits and post it here with the disclaimer that it is only a reference point based around my best judgment.
On edit 2: I added the two attachments and they look similar but serve two completely different purposes. The first chart is my personal recommendation on when a jump in projection resolution is advisable if you are looking for a point where the image you watch will begin to fail due to pixel size becoming distracting and no longer blending. The second graph is for reference only pertaining to the study within this thread as to at what point a higher resolution can first be noticed In that chart I marked up the widely used chart to show what the points would be based on current science. To see the original published graph you will have to click on the link above in the opening post.
These two graphs are in some ways related as one is the starting point and the other a reasonable stopping point for any given resolution.