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Old Feb 14, 2005, 7:06 AM   #1
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Does anyone have a price spec on the newly announced japan-only 20Da... Apart from the removal of the IR cutoff filter, the partial livepreview is something that given me quite a shock, and I think that is a must for future dSLR... and I know... you all wanted it too... So, any rumors?
If it passes the 2.5K we should go for an extra F828 instead, to pair the actual 20D...
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Old Feb 14, 2005, 8:41 AM   #2
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The S3 already has this 'livepreview': http://www.luminous-landscape.com/re...s/s3-pro.shtml

... This is a must for IR shooting (since the camera AF is 'tuned' differently)
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Old Feb 14, 2005, 10:42 AM   #3
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The IR cut filter is there for a reason on general purpose cameras. Only reason for removing it are for full spectrum IR photography and astrophotography. The IR filter can be removed for a $ from several normal consumerdslr's. But for normal shooting it is desirable to have it in place. Interesting that Canon would make a camera specific to a vary small targetaudience, very limited chance of generating much in the way of profits.

IMHO: the livepreview is of limited and dubious use in a DSLR,I'd place it as a marketing gimmick to get people chimping. The DSLR viewfinderworks very well giving a live ttl view that works in all light levels, the LCD is tough to see in daylight. I'd also preferto keep my LCD flat on the camera body and not have any easy to knock off swivel parts sticking out.

Peter.
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Old Feb 14, 2005, 10:49 AM   #4
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its specifically designed for astrophotography.
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Old Feb 14, 2005, 11:37 AM   #5
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FYI - Why 'livepreview' is neccessary for IR shooting: http://www.apogeephoto.com/mag1-4/mag1-4mfir.shtml

Also: http://www.sciencecenter.net/hutech/canon/
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Old Feb 15, 2005, 5:19 AM   #6
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I wouldn't mind a decent priced 20Da... but it is stated "specialized version" and probably will take long to hit the market... and hit hard on the pocket.
I am very happy with my 20D but wanted somehow the IR cutoff removed... someone told me it is not the "dust cover" like in other cameras... and it is the very AA filter... or worse... The "microlenses"... Still, the very classical 20D is recommended for astrophotography...

The partial livepreview can have many uses... not for the histogram :-( since it uses only partial mirror deflection, but to quickly correct exposures for a start...
NHL pointed to me in the past I think an Olympus 10something... a old dSLR with partial livepreview...
But if it is an bw preview like S3... it has no use to me... I wonder why after a mirror lookup I can't have a live preview implemented? I "promise" not to play in the sun with it, Mr. Canon... :-) and I think I just answered my question... they fear sensor damage during warranty, isn't it?...
Also, if the livepreview is done via an extra sensor "reading" the pentaprism via the mirror, not only that it would have a price impact but it will not be accurate...
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Old Feb 15, 2005, 4:15 PM   #7
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Pauza: In a DSLR, even with the mirror up the shutter curtainis still closed so the sensor does not see the light :-). Only way to get a preview feedbefore opening the shutter is to use a second sensor.

Used to be nice when the IR focus shift was etched right on the lens barrel of old cameras.

I wonder how big the specialized astrophotography market is for Canon to target it. I indulge in astronomy/astrophotography as a hobby, but not to the extent I would pay almost the price of a body to have its AA filter removed/replaced.

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Old Feb 15, 2005, 5:07 PM   #8
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They don't 'really' need a shutter... it could be 'sampled' just like other digicams, the shutter is there to prevent charges from the CCD from being contaminated when being shifted out from the CCD - but we have a CMOS here don't we?

The shutter can be opened the whole time during pre-view - only waste is the battery!


BTW B/W is all you need for composing and focusing - This is the luminance signal in your TV (the color info is not required) in fact in TV signals (even HD) the color are transmitted at a much lower bandwidth... :?
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Old Feb 15, 2005, 5:13 PM   #9
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Yes, but if you didn't have a shutter you would have to simulate the satisfying snick-thunk sound of an image being captured. So far I have not liked the almost apologetic anemic simulated sound produced by any of the P&S cameras. :blah:

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Old Feb 16, 2005, 4:33 AM   #10
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PeterP wrote:
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...In a DSLR, even with the mirror up the shutter curtain is still closed so the sensor does not see the light :-)...
Perhaps I am very wrong... but I think (at least for 20D) that it have an electronic shutter ("quick reading then stop" sensor)... the curtain is something "old" for highspeed (not fps) dSLRs (ok, not the film SLR) ... 1/8000 should be impossible I think, bellow 1/1500... maybe... but I don't really know if I am right...
And I recall seeing the someone's sensor during a mirror lockup... and why would Canon warn about not pointing at the sun during the memory lockup?
They stated I think damage to the sensor... so, anyone, am I right or wrong about the missing curtain? I would like to have this info right... thank you in advance.

About the built in filters: NHL pointed http://www.sciencecenter.net/hutech/canon/ , they sell modified Canon dSLR with those filters removed...
Did anyone heard about someone trying to remove those by himself? And succeeded... ;-)
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