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Discussion Starter #1
I've seen lots of discussion on suggested standards for listing lumen output, contrast, etc... But the most vexing to me (and others from your posts) may be -- taking a decent screenshot.


I've seen amazing, crappy, and oblong pictures . We have variables with the camera, lighting, exposure, aperture, tripod vs handheld, and the type of camera (DIG VS 35 MM). Furthermore, what about the monitors upon which we view the screenshots? I checked my Dad's computer last month and it was set at 256 colors. That's got to hurt output.


Most screenshots come with the tag-line "looked much better in person". What graphics person has suggestions to best take pictures that routinely capture the true resolution of a pj? There is presently an innovative thread that has alternating screenshots of a CRT and LCD, with an overlay as well. That may be a good start.


What graphics person can suggest a somewhat standardized method that not only captures the output of a PJ, but also allows apples-apples comparisons to other pj's?


Looking forward to answers with my brownie,


Marshall
 

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What graphics person can suggest a somewhat standardized method that not only captures the output of a PJ, but also allows apples-apples comparisons to other pj's?


You're looking for the impossible. There are so many variables involved that it's illogical to try and do what you're asking.


All camera's are different. All computer monitors used to view the screen shots are different.


The end result is (I've said it a million times and I'll say it again):

Screen shots are an absolutely useless way to compare one projector to another.


Here's an analogy:


Trying to use screeshots to compare projector image quality is as logical as trying to compare loudspeakers by going to different hi-fi shops with a tape recorder and microphone and makign recordings of different speakers as they play, then playing back the tape at home through your own speakers so that you decide which sound best.


Another analogy:


TV commercials for televisions where they try to show you how good their TV's look on your own TV. Huh??


Kal
 

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Discussion Starter #3
hmm, why don't you send a screen shot of one of those commercials, Kal...


I think the first part (correct capture) is doable, but the second (apples to apples) is near impossible, but not illogical. The standardization would be massive! Funny similes.


Quote: "Screen shots are an absolutely useless way to compare one projector to another."


No, I think screen shots can do a pretty good job showing convergence, tube wear, etc.


Thanks, Kal for making it a million and one!


I think I saw your post (or reaction to your post) in another thread after I wrote this thread - (10'+ screens thread?) can't remember. Anyway, sounds like you've discussed this multiple times before. You sound pretty exasperated, but I understand what you are saying.


So, maybe someone that's had good results can suggest speed, aperture settings and such.


Thanks,


Marshall
 

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I agree that it's impossible to standardize screen shots... but I disagree that they are 'absolutely useless'. They do show some useful information, although it CAN also be misleading.


How about this... most screen shots I've seen have scenes from a DVD that really shows off the individual projector. (Everyone wants to convey their excitement about what they are experiencing.) That's really part of the problem.


For a slightly more scientific view we could photograph test patterns instead. I would suggest we pick a pattern that highlights both resolution and contrast.


A full screen capture should be shown along with a full-resolution snapshot of a defined section of the pattern (something that shows a diagonal line, for instance.) The section would be a zoomed in snapshot of something roughly 12"x12" to really show the detail. (The zoomed section should be optically zoomed in... not a digital zoom or resizing in photoshop...etc.)


Also, how about an additional shot of a white screen as a control? (This should be an actual white screen under full lights... not a projection of a white background.) Sort of like doing a white balance. This might show some of the issues introduced by the camera.


Okay, flame away at these ideas! It just seems to me we could get a lot more standardized with these shots and get more useful information out of them. Everybody should be aware they will never replace actually being there or comparing them side-by-side.
 

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Ok, ok, I've been a bit pessimistic I suppose! :)


My main reasons for the post above is that I see too many new people on this forum trying to use screenshots as a basis for comparison when making a purchase. Caveat Emptor! My experience is that when properly done, screenshots will more or less look the same and projectors all start to look the same. Seeing the units in person however shows that this is far from true.


Screen shots can serve a useful purpose when done correctly (see Bjeorn Roy's screenshots at http://www.videophile.info/ for a some great examples of how to correctly do screenshots), but as the above posters mentioned, you really need to understand the limitations of what you're looking at. Too many people however use screenshots to do an apples-to-apples comparison it seems.


I guess the problem is trying to get a $500-$1500 digital camera to capture and convey the colours, contrast range, depth of detail of a $20-40K (original price) CRT projector is just asking too much.


Kal
 

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Discussion Starter #6
Kal,


Three things...


1) Thanks

2) Holy Cow, Roy's setup and page is very nice / well explained

3) How can you be pessimistic with the setup you have? Very nice!


good tips in the above posts and on Roy's page.


Thanks,


Marshall





PS: Unless I missed it, I noticed you don't have any screen shots in your photos :)
 

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Quote:
Originally posted by Marshall F
PS: Unless I missed it, I noticed you don't have any screen shots in your photos :)
Nope! :) Because, in all honesty, they don't look anywhere as good as the real thing, so I don't bother!


Kal
 

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Discussion Starter #8
Kal, I just couldn't resist!


M
 

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They can be fun. And the better ones can capture some qualities of the image that are useful for comparisons. But they certainly should never be used to decide a purchase. When it comes to that there is no substitution for seeing the actual projected picture.


My one pet peeve is the screenshot's inability to convey black level. I've never seen a digital projector screenshot yet which has made black in the letterbox bars and the image to be what it really looks like. I've seen screenshots of pictures made with 400:1 contrast LCD projectors that make black look pitch black.
 
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