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05-18-2009, 06:09 PM   #3421
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There is 1 thing which is buzzing in my mind right now: if there is 1/250 or 1/180. If the second one, its not improvements for photographers but only for occasional shutters and incidental clickers - it's mean pentax doesn't take seriuosly photographers. I can understand innovations... but if it is innovation for photographer... peopple there are some rules... you cannot take good pictures of a bride with the beautifull background of window without at least 1/250 synch speed...
1day4hours49min left

05-18-2009, 06:10 PM   #3422
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Flash sync time

In an attempt to sort out the possibilities with regard to the flash sync time, I computed the respective widths between shutter curtains:

Width between shutter curtains (vertical shutter):

K20D: APS-C, 1/4000, 1/180X: 0.70 mm
K-7 A: APS-C, 1/8000, 1/250X: 0.49 mm
K-7 B: APS-C, 1/8000, 1/180X: 0.35 mm
MX: VF, 1/1000, 1/60X: 1.44 mm
LX: VF, 1/2000, 1/75X: 0.9 mm
PZ-10: VF, 1/2000, 1/100X: 1.2 mm
PZ-1: VF, 1/8000, 1/250X: 0.75 mm

So, even 1/250X would be extraordinarily slow. So I assume that the flash sync speed is 1/250s at most. 1/180s probably is an mistake. Because it may be more expensive to make such a narrow gap between curtains than to make it faster.
05-18-2009, 06:16 PM   #3423
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Battery Grip Material

Does anyone know if the BG4 will be the same magnesium alloy as the body?
05-18-2009, 06:21 PM   #3424
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To buy or not to buy. That is the question.

And the basis for my answer to that question cannot be found in what information is thus far available. I'm presently using a K10D which for 90% of what I shoot (landscapes, macros, a few portraits, and still lifes) is all the camera I need. Unfortunately, it's the other 10%, which are action shots of my grandkids playing soccer, baseball, and basketball (and which are the ones that will be treasured most in the years to come) where the K10 is less than adequate. I don't need 1/8000 second shutter speed, video recording capability, a larger viewfinder, or some of the other new tweaks which are promised for the K-7. The two things I'm most interested in are the camera's ability to autofocus continuously and its IQ at higher ISO settings. Obviously, I'll have to wait a bit longer to find out about those. If Pentax comes through with autofocusing comparable to the D300 then I'll pull out my wallet in a heartbeat.

CN

05-18-2009, 06:40 PM   #3425
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QuoteOriginally posted by falconeye Quote
In an attempt to sort out the possibilities with regard to the flash sync time, I computed the respective widths between shutter curtains:

Width between shutter curtains (vertical shutter):

K20D: APS-C, 1/4000, 1/180X: 0.70 mm
K-7 A: APS-C, 1/8000, 1/250X: 0.49 mm
K-7 B: APS-C, 1/8000, 1/180X: 0.35 mm
MX: VF, 1/1000, 1/60X: 1.44 mm
LX: VF, 1/2000, 1/75X: 0.9 mm
PZ-10: VF, 1/2000, 1/100X: 1.2 mm
PZ-1: VF, 1/8000, 1/250X: 0.75 mm

So, even 1/250X would be extraordinarily slow. So I assume that the flash sync speed is 1/250s at most. 1/180s probably is an mistake. Because it may be more expensive to make such a narrow gap between curtains than to make it faster.
Shutter blade gap is irrelevant, You really need an electronic shutter. (Flash durations are in the 1/1000's sec range) That's really where the high synch's come from.
At great personal cost I present this link
Flash Sync Speed
The sync speed is the fastest speed at which the entire film or CCD can be open to light. This is determined by how fast the shutter curtains move.
At speeds faster than the sync speed the slit that travels across the film or CCD narrows. If you used flash at faster than the sync speed (you can't do this on modern cameras) you would only expose the part of the film behind the slit to the flash.
Nikon has done the world a great favor in the D1, D1X, D1H and D70 cameras by adding an electronic shutter to take care of the faster speeds. By doing this the sync speed becomes unlimited. The only reason the D1, D1X and D1H (and for all I know the D70) limit the speed to 1/500 is because of the loss of efficiency above that speed for shoe mounted flash.
Amateur digital SLR cameras omit the electronic shutter and are limited by the mechanical focal plane shutter.

Point-and-shoot digital cameras usually sync at high speeds like 1/500 because they also have electronic shutters.

Leaf shutters as used in professional cameras like the Hasselblad and large format cameras can sync at any speed. This is because their leaves open completely at all speeds, at which point the flash is fired. There is no slit or partial opening at the fastest speeds.
Personal note: If Pentax has all the movie bells and whistles they probably added an electronic shutter. MANUAL synch speed would be irrelevant.

Last edited by jeffkrol; 05-18-2009 at 06:46 PM.
05-18-2009, 06:45 PM   #3426
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QuoteOriginally posted by jeffkrol Quote
Shutter blade gap is irrelevant, You really need an electronic shutter. That's really where the high synch's come from.
At great personal cost I present this link
Flash Sync Speed
The sync speed is the fastest speed at which the entire film or CCD can be open to light. This is determined by how fast the shutter curtains move.
At speeds faster than the sync speed the slit that travels across the film or CCD narrows. If you used flash at faster than the sync speed (you can't do this on modern cameras) you would only expose the part of the film behind the slit to the flash.
Nikon has done the world a great favor in the D1, D1X, D1H and D70 cameras by adding an electronic shutter to take care of the faster speeds. By doing this the sync speed becomes unlimited. The only reason the D1, D1X and D1H (and for all I know the D70) limit the speed to 1/500 is because of the loss of efficiency above that speed for shoe mounted flash.
Amateur digital SLR cameras omit the electronic shutter and are limited by the mechanical focal plane shutter.

Point-and-shoot digital cameras usually sync at high speeds like 1/500 because they also have electronic shutters.

Leaf shutters as used in professional cameras like the Hasselblad and large format cameras can sync at any speed. This is because their leaves open completely at all speeds, at which point the flash is fired. There is no slit or partial opening at the fastest speeds.
Personal note: If Pentax has all the movie bells and whistles they probably added an electronic shutter. MANUAL synch speed would be irrelevant.
No can do with a CMOS sensor. CCDs can do electronic shutter for high flash sync, but CMOS can't.
05-18-2009, 06:48 PM   #3427
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QuoteOriginally posted by jeffkrol Quote
Shutter blade gap is irrelevant, You really need an electronic shutter.
That is all correct and interesting.

But I actually only tried to determine the most likely mechanical shutter sync speed in the K-7. I cannot see how your post helps in this regard.
QuoteOriginally posted by jeffkrol Quote
MANUAL synch speed would be irrelevant.
Almost.
There still would be an issue with long tele lenses imaging straight vertical lines as curvy because of shake during sync time, despite a short shutter speed.
05-18-2009, 06:56 PM   #3428
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It says the K-7 has a 14.6MP sensor, but is it the same as the one in the K20D or a newly developed one?

05-18-2009, 07:00 PM   #3429
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QuoteOriginally posted by GLXLR Quote
It says the K-7 has a 14.6MP sensor, but is it the same as the one in the K20D or a newly developed one?
The press text says:
QuoteQuote:
The K-7 incorporates a newly developed CMOS image sensor measuring 23.4mm by 15.6mm and featuring a high-speed, four-channel image data readout.
But AFAIK, its specifications are identical to the K20D sensor, incl. ISO range 100 - 3200/6400.
05-18-2009, 07:03 PM   #3430
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All revealed...

Pentax K-7, It IS Here! - ClubSNAP Photography Forums
05-18-2009, 07:10 PM   #3431
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MUCH more revealed here: https://www.pentaxforums.com/forums/pentax-news-rumors/60673-hands-pentax-k7.html

thank you skamaraju.
05-18-2009, 07:15 PM   #3432
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QuoteOriginally posted by mysterick Quote
and it could be like Hotel California, you can't check out!
More pedantry: I believe you can check out any time you like, but you can never leave ...
05-18-2009, 07:25 PM   #3433
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QuoteOriginally posted by illdefined Quote
Google only does a decent translation. native chinese speakers, please HELP:

https://www.pentaxforums.com/forums/pentax-news-rumors/60673-hands-pentax-k7.html

specifically the talk of "LCD viewfinder?"
05-18-2009, 07:26 PM   #3434
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QuoteOriginally posted by creampuff Quote
Looks like the same specs RH posted unless I'm missing something. Unless there's some wonderful feature that doesn't show up in the spec sheet can someone explain to me what Yvon Bourque was talking about when he said everyone else will have to play catch up? It looks as though Pentax has caught back up and possibly even moved slightly ahead of the D300 (the best current cropped sensor camera), but I hardly see anything that is going to cause Canikon to lay in bed awake at night. Pentax really should have tried to reign in the hype created by some of the people with NDA's.

The K7 looks like a wonderful camera, Pentax's best camera for sure; and it is obviously all the camera anyone really needs. But The D300, 50D, E-30, etc are really all anyone needs. I was hoping for something that made me drool like a Ducati 1198R does.
05-18-2009, 07:27 PM   #3435
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QuoteOriginally posted by illdefined Quote
Google only does a decent translation. native chinese speakers, please HELP:
https://www.pentaxforums.com/forums/pentax-news-rumors/60673-hands-pentax-k7.html
specifically the talk of "LCD viewfinder?"
There is not much new info in the text. He was comparing the viewfinder area vs Live View LCD and he finds them to be the same, thus confirming the 100% coverage.
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