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First Projection

Discussion in 'Projectors, Screens & Video Processors' started by Pyara, Jun 11, 2002.

  1. Pyara

    Pyara
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    I am a newbie at projectors, in fact I thought they were old out!!!

    Until my uncle lent me his projector which he very rarely uses now, I attached it to my digibox and watched last Fridays footie on it, I was job-smacked, I hope you good folks can answer a few questions for me....

    I currently have a philips 36" widescreen sony DD/DTS surround, Sky + & Toshiba SD-k320 DVD player.

    1) The project I was using is a few years old and had a noisy fan, am I correct in presuming newer models have more silent fans?

    2) The projecter had one lens at the front, am I correct in pressuming that top-spec models have three, R G B?

    3) LUNS- I think this is how bright the lens actually is, the higher this figure the less dark the room needs to be, hence go for a model with a high LUNS figure?

    4) Contrast Ratio- The higher this figure the more the difference between a bright and dark colour/area will be apparent, hence go for a model with a high contract ratio.

    5) Resolution- This is the actual screen area, the higher this figure the better the image will look.

    6) Widescreen- as an owner of a widescreen television I would obviously want a true anamorhpic lens, is there such a thing or do all projectors have a "wide screen mode"?


    Is there anything else I should look out for, I have budget of between £4,000 to £5,000, anyone have any suggestions (please could you state the model no). The reason for the high budget is because I was initially thinking of a 42" plasma. P.S. That budget is for the screen and projector, I already have all the rest of the AV KIT.

    I know this is a bit long-winded, but any help would be sincerely appreciated.
     
  2. LV426

    LV426
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    So many questions in one post!

    There are at least three different technologies use for projectors. Each has its advantages and disadvantages. Which you choose will depend on your own preferences, visual acuity and circumstances. This is a brief summary only.

    1: LCD. A popular and cost-effective type. LCD projectors have three tiny LCD panels inside, each of which produces one of the three primary colour components of the image. They are back-lit by a bright lamp. The three coloured images are combined inside the projector by a prism and the light is thrown out of a single lens, which you can zoom and focus just like a slide projector.

    Pro: Convenient to use, cost effective, transportable, easy to set up. Flexible positioning (most have a zoom lens). No image flicker (refresh rate), near-perfect geometry and convergence (ie pictures always the right shape, with no colour fringing due to bad alignment of the three coloured images). Often very small physically.

    Con: Have a cooling fan which can be noisy depending on model. Difficult to get dense blacks - tendency to be grey. Bulb will need replacing after several thousand hours (depends on model). Cheaper projectors have coarse LCD panels and the individual pixels can be seen in the picture - the "chicken wire" effect.

    2: DLP. More expensive like-for-like. Uses a single "chip" covered in tiny mirrors that tilt accordng to brightness. The chip is eneregised sequentially with the three colours of the image. A transparent coloured wheel rotates on front of the chip so that, when, say, the green image is on the chip, the green segment of the wheel is in front of it. The mirrors are illuminated by a bright lamp. The reflections pass through the coloured wheel and out through a single lens. So, what is projected is sequentially all green blue and red. However it all happens so quickly that in theory your brain merges the colours together and you get a full colour image in your mind.

    Pro: Convenient to use, easy to set up. Flexible positioning. Near-perfect geometry and convergence (ie pictures always the right shape, with no colour fringing due to bad alignment of the three coloured images). Better (darker) black than LCD. Often very small physically.

    Con: Have a cooling fan which can be noisy depending on model. Bulb will need replacing after several thousand hours (depends on model). Some users can see the sequential colours - referred to as the "rainbow effect".

    3: CRT. Three Cathode Ray Tubes mounted on the front of the projector each behind a coloured lens. Each one produces one colour component of the picture, and each throws its own image onto the screen.

    Pro: Can produce the best (darkest) blacks. Usually no cooling fan, so silent in operation. Can produce very film-like, smooth images if properly driven.

    Con: Need professionally installing and setting up. Cannot be moved once installed, because the three images have to be precisely "converged" onto the screen. No flexibility in positioning - no "zoom and must be firmly fixed, as must the screen. Convergence can drift over time, requiring further set up. Cheaper models can show up TV picture line structure and/or refresh rate flicker.


    There are many other factors, but these are the main ones. Everybody has their own preference. Mine is LCD but don't base your judgement on that. You really need to check these technologies out for yourself based on factors like, how "fast" your eyes are (you may see DLP rainbows or CRT refresh), whether you may want to move it or mount it on eg a coffee table etc.

    Yor other questions:
    LUNS - I guess this was LUMENS and is a measure of brightness. However, your eyes/brain are very adept at compensating for different conditions. It isn't something to be too bothered about IMHO.

    Contrast Ratio- The higher this figure the more the difference between a bright and dark colour/area will be apparent. CORRECT - but again, you do compensate, so, by all means, use it as a guide, but don't choose on the strength of a manufacturer's spec alone; they are rarely an accurate refection of real-life performance (like 0-60 figures for cars).

    Resolution - This a measure of the theoretical amount of detail the projector can resolve. It is normally only quoted for LCD and DLP devices and is the number of pixels or mirrors that are used to make the image. As a rule, more is better, but again, you can't use this in isolation; the quality of other components both inside and outside the projector can have a huge bearing on this.

    Widescreen: All but the cheapest projectors have a widescreen mode. The question you have to ask yourself is whether or not to choose a NATIVE widescreen projector. For all it matters, a NATIVE widescreen projector will show you any 4x3 (old TV shaped) images at the same height as, but narrower horizontally than, widescreen (16x9) material. Whereas a native 4x3 projector will show you 4x3 material taller than, and the same width as, 16x9 material. Because size is perceived by us more as a factor of height than width, a taller image looks "bigger". Hence, with a 4x3 projector, 4x3 images will look bigger than 16x9 ones. So, I'd choose a native widescreen (16x9) device.

    The best advice I can give is to first decide on a technology, by going and looking at each. If the fixed position, non-transportability of CRTs is a showstopping issue for you, discount that one straight away. Otherwise, get demonstrations of each. And take anyone else who will be enjoying your cinema with you. It may be, for example, that your "partner" is more sensitive to the DLP rainbow than you are.

    Once you have narrowed down which technology/ies suit you best, then draw up a short list of models based on price, and check each out thoroughly. Take into account the cost of replacement lamps if you choose DLP or LCD.
     
  3. Nic Rhodes

    Nic Rhodes
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    Good post.
     
  4. (GTV)Chris

    (GTV)Chris
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    I spent ages drafting out a reply to the original post....I deleted it having read the other reply :blush:

    The only useful bit of info I found was that The contrast ratio of the human eye averages about 1200:1.
    :p

    Chris
     
  5. Pyara

    Pyara
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    It would be a great injustice if I didn't express my gratitude for your reply post. Many thanks, I hope I can recipricate one day if you need any advice.

    I will look at various models and touch-up my knowledge on them...
     

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