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ISF Calibration of HS50?

Discussion in 'Home Cinema Buying & Building' started by Boris Blank, Feb 11, 2005.

  1. Boris Blank

    Boris Blank
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    Anyone had their HS50 calibrated by Cine4home? Trying to find out if the results are as good as described (I think they are but wonder if contrast isn't maxed out or something).

    Could their calibration results be acheived by Gordon perhaps (prefer a home-grown calibration) - filters are the real problem rather than expertise (in case you wondered)!

    EDIT Hmm, just noticed this on the Cine4home website - "The Sony VPL-HS50 achieves a maximum contrast relationship of 6000:1, color calibrated still approximately 3000:1" which implies that you can have maximum contrast or colour calibration but not both.

    Thanks,
    Paul
     
  2. Gary Lightfoot

    Gary Lightfoot
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    Hi Paul,

    Quite often, to get maximum contrast means having the blue and green ramped up high - this is because the UHP lamp cannot produce as much red as it can green and blue.

    To colour balance the pj means ramping down the green and blue contrasts to match the red, hence the loss of CR.

    Now, if you can colour correct by finding a filter that will boost red/cut green and blue, then you may achieve both - an FL-Day will cut green but leave blue high. A lot of the light we see is green, so cutting blue won't affect the contrast as much as cutting green would.

    I have been experimenting with my Optoma H77 (and HT1000 beforehand), and found that some filters can cut green and blue, but the trick is to find one that cuts them the correct amount. You need Colorfacts to calibrate to D65, and this will help you see what filter is cutting the green and blue to match the red.

    I managed to increase the contrast on my H77 by 300:1 so that I now have around 2600:1 CR at D65. I'm using a combination of FL-Day and a skylight filter to help color correct and reduce the ft lamberts to 13.5. I prefer a dimmer image as I find it more film like and doesn't enhance image noise such as mpg artefacts.

    Gary.
     
  3. Boris Blank

    Boris Blank
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    Hi Gary,
    This all makes perfect sense to me, I was just thrown a bit by the "contrast or colour-calibration" comment by Cine4home but it does now indeed appear that the Sony can be colour-calibrated and have a high contrast in the 5k-6k:1 region.

    I'm torn between hiring Gordon/Cine4home or hiring Colorfacts at the moment but the filters are a sticking point, certainly for me. Did you have some knowledge of what sort of filters were needed or just trial and error (although given the cost of the filters, trial and error could be expensive!)?

    Having used Colourfacts before, I'm confident that I can get to D65 very easily, the filters though are another matter. Having had a look at the lens on the Sony, it doesn't have a screw-thread for the filters to attach to and the diameter of the lens housing is approx 75mm - does your H77 have a screw-thread, if not how did you attach the filters?
    Thanks,
    Paul
     
  4. Gary Lightfoot

    Gary Lightfoot
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    Hi Paul,

    You can use colour temp as an indicator of what filter to use, but this doesn't acurately take into account if the excess is too green or too blue, as both are in excess to varying amounts. As green tends to count for most of the light, an FL-Day is a good bet to get you on the right track - you just have to measure how much CR you are losing as you back off the blue and then decide if you need to add a yellow filter or find a single alternative. Something like an 81b might do the trick as well, but you'll need colorfacts to see by how much the colours are greater than red (using the RGB columns while in continuous reading mode), then place the filter in front of the lens and see how much it reduces the green and blue, and if it balances or not.

    Like my H77, if you don't have any threads in the lens, you can use some tape, or get a larger filter and hang it onto the lens via it's 'lip'. I've seen wide elastic bands used as well, and if the lens is the same diameter as a filter, then the elastic band can hold the filter onto the lens and look very neat. I was using two smaller filters tipped against the lens until I got the correct filter combination. The H77 lens sits inside the casing so that was easy to do, but currently I'm using 77mm lenses which are tipping forward but held back by the filter lip being under the lens. If that makes sense...

    I think the elastic band idea seems best myself.

    I think the only issue with filters is that they can dim the image too much for some people. Most reduce the lumens by a 3rd of a stop, which isn't too much really. An ND2 will reduce the output by half, and whereas that does seem a lot, once you've been viewing like that for a while, your eyes get accustomed quite quickly. My HT1000 was only reflecting 10.5ft lamberts, and that was fine for me. The H77 is currently giving 13.6 so is a bit brighter. Some calibrators aim for around 12 by using an ND filter, and that can help as the lamp dims with age - you remove it to get some 'free' brightness back.

    I can't see ISF people taking time to do this - it is quite labour intensive, so other than an FL-Day and an ND2 filter, they probably won't carry any others (if any at all).

    Gary.
     
  5. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    I did an HS50 a few days ago. No flters involved. I may have the pre-cal graphs I could send you Paul to aid working out what filter to try to get hold of.

    Gordon
     
  6. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Sorry scrub that....seem to have saved them to somewhere other than where they are supposed to be. From memory it was towards cyan through all the range. If you're ever coming down to Glasgow stick it under your arm and meet me at a shop and I'll bring the laptop so you can measure it.

    Gordon
     
  7. Gary Lightfoot

    Gary Lightfoot
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    You make it all sound so sordid... :clown:

    Gary.
     
  8. Boris Blank

    Boris Blank
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    LOL, 6 posts and the conversation degenerates to this! Its a disgrace I tell ya!

    I admit to being seriously torn between calibrating the HS50 myself (interesting and fun but may not get the best results and likely to get me hooked on tweaking the damn thing - this is your fault Gary, your posts are so interesting!), getting Gordon to do it (best results, sweet and simple) or getting Cine4home to do it (I'm intrigued to see the results and filter use but results not tailored for my own equipment)!

    Arrrghhh.

    If I may ask Gordon, what sort of contrast ratio have you been getting out of the HS50's? Around 4k or so? I would admit to being very pleased with the HS50, its not a crt killer but its sweet, simple and rather nice!
    Paul
     
  9. Gary Lightfoot

    Gary Lightfoot
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    Just in case anyone is interested, I found a combination of FL-Day and 81B filters was a good match for my H77, and I measured a CR of approx 2700:1. Unfortunately this also dimmed the image a little too much, so isn't really a viable option for the eco mode and a screen wider than 6 feet. It should be better in high lamp mode, but that also means reduced lamp life and a noisier fan.

    In theory you can get a much higher CR by putting a filter on the HS50, but some say it's already quite dim, so this won't help much in that respect. I wonder how dim it becomes when calibrated to D65 without a filter though. It may be closer than I think.

    Gary.
     
  10. alandbush

    alandbush
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    Just thought I would throw you further into confusion by mentioning the SMARTIII projector calibration toolkit:-

    http://www.enhancedht.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=EHT&Category_Code=S

    The creator of the software, Steve Smallcombe, reviews projectors for Secrets of Home Theater and there is reference to his use of SMARTIII in the reviews:-

    http://www.hometheaterhifi.com/volume_11_3/hitachi-pj-tx100-projector-8-2004-part-1.html

    Happy head scratching!!!

    Oh! I forgot this thread that relates to SMARTIII and a Sony HS20:-

    http://www.avforums.com/forums/showthread.php?t=178486&page=1&pp=15
     
  11. Gary Lightfoot

    Gary Lightfoot
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    SMART is excellent value, but can't see colour in the same way as the human eye, so SMART really only works well after Steve has used it with a partuicular projector and can supply the specific software. I have SMART III which came with a generic DLP software package, but it didn't work too well with my HT1000. Colorfacts is universal though. It's also very expensive in comparison.

    If he can get the HS50 and supply the software, you should get pretty good results though. It's a bargain at $300, but can be a bit drawn out and time consuming. For personal use, it's probably hard to beat though.

    Gary.
     

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