Comments on: LCOS vs DLP, .65″ DC3 DMD vs .95″ DC3 DMD – The Sharpness Debate http://www.videovantage.com/?p=11 The Independent Blog for Videophiles - Product Reviews, News, Interviews, How-To's, etc. Sat, 13 Feb 2010 19:06:04 -0500 http://wordpress.org/?v=2.9 hourly 1 By: MTF Revealed – Part I: The Samsung SP-A900B JKP Special Edition Projector | VideoVantage http://www.videovantage.com/?p=11&cpage=1#comment-172 MTF Revealed – Part I: The Samsung SP-A900B JKP Special Edition Projector | VideoVantage Sun, 03 Jan 2010 05:13:41 +0000 http://www.videovantage.net/?p=11#comment-172 [...] few months ago in this article, we took a close look at the sharpness differences between DLP and LCOS video projectors and in [...] [...] few months ago in this article, we took a close look at the sharpness differences between DLP and LCOS video projectors and in [...]

]]> By: Michael Lang http://www.videovantage.com/?p=11&cpage=1#comment-36 Michael Lang Tue, 04 Aug 2009 21:49:01 +0000 http://www.videovantage.net/?p=11#comment-36 That's exactly what I did because its the object plane that determines how hard the optical design is going to be. If you looke at the patents on projector lenses, you will have to come to the conclusion that the limits on sharpness are due to the resolving power of the lens and not the chip and improving the projector lens is extremely difficult. As a Videophile what I would like to see are videophile chips made which were 1.3 to 2 inches and then add a fourth chip. If some manufacture were to do that especially with the DILA chips You would see images coming out of those projectors which would set a new standard in quality and would justify a premium price. That’s exactly what I did because its the object plane that determines how hard the optical design is going to be. If you looke at the patents on projector lenses, you will have to come to the conclusion that the limits on sharpness are due to the resolving power of the lens and not the chip and improving the projector lens is extremely difficult. As a Videophile what I would like to see are videophile chips made which were 1.3 to 2 inches and then add a fourth chip. If some manufacture were to do that especially with the DILA chips You would see images coming out of those projectors which would set a new standard in quality and would justify a premium price.

]]> By: KonstantinMiller http://www.videovantage.com/?p=11&cpage=1#comment-18 KonstantinMiller Tue, 07 Jul 2009 04:55:51 +0000 http://www.videovantage.net/?p=11#comment-18 Hi! I like your srticle and I would like very much to read some more information on this issue. Will you post some more? Hi! I like your srticle and I would like very much to read some more information on this issue. Will you post some more?

]]> By: mark http://www.videovantage.com/?p=11&cpage=1#comment-10 mark Thu, 25 Jun 2009 21:15:29 +0000 http://www.videovantage.net/?p=11#comment-10 Thanks Michael, It's good to hear feedback like this from an experienced optical engineer like yourself. From what I've read, the limiting frequency (Nyquist cutoff) in a digital panel is dictated by the pixel count (on/off pattern) under the assumption that the optical system will be able to resolve at least this frequency. From your post it seems like you've worked backwards to determine the minimum cutoff frequency at the focal plane of the chip. But if we already know the frequency, we should be able to work forward using the chip size and cutoff frequency to determine the resolution needed in the lens. Is that basically what you've done in deriving 40 lp/mm, 58 lp/mm and 84 lp/mm for .95, .65 and .45 chips respectively? Thanks, Mark Thanks Michael,

It’s good to hear feedback like this from an experienced optical engineer like yourself. From what I’ve read, the limiting frequency (Nyquist cutoff) in a digital panel is dictated by the pixel count (on/off pattern) under the assumption that the optical system will be able to resolve at least this frequency. From your post it seems like you’ve worked backwards to determine the minimum cutoff frequency at the focal plane of the chip. But if we already know the frequency, we should be able to work forward using the chip size and cutoff frequency to determine the resolution needed in the lens. Is that basically what you’ve done in deriving 40 lp/mm, 58 lp/mm and 84 lp/mm for .95, .65 and .45 chips respectively?

Thanks,
Mark

]]> By: Michael Lang http://www.videovantage.com/?p=11&cpage=1#comment-9 Michael Lang Thu, 25 Jun 2009 19:52:47 +0000 http://www.videovantage.net/?p=11#comment-9 Mark, Great article It does not surprise me that a smaller chip would have a poorer MTF at the screen. This is because a .95 chip has Nyquist cutoff frequency of 40 lp/mm a .65 chip 58 lp/mm and the proposed .45 chip is 84 lp/mm at the focal plane of the chip. As the chips get smaller the lens quality has to get better and and in transferring an image with a cutoff of 84 lp/mm the lens has to be very good indeed. Mark,

Great article

It does not surprise me that a smaller chip would have a poorer MTF at the screen. This is because a .95 chip has Nyquist cutoff frequency of 40 lp/mm a .65 chip 58 lp/mm and the proposed .45 chip is 84 lp/mm at the focal plane of the chip. As the chips get smaller the lens quality has to get better and and in transferring an image with a cutoff of 84 lp/mm the lens has to be very good indeed.

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