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Old May 10, 2003, 5:22 AM   #1
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Default Super Stumped By Manual Settings with Sony F717

Hi!
Thanks so much for any help.... I'm sure the solution is quite easy.

I am voraciously reading many photography books (such as Kodak's Joy of Photography) and am quite ready for some creative manually controlled shots, but........ here are enduring mysteries even after reading the manual and tinkering:

in ANY MODE (manual, P, AP, SP...): sometimes I can set the aperature to f2,0 and sometimes only to f2.4... what limits this capriciously?

second, the same goes for shutter speeds... Steve has indicated in his review that the shutter speed can reach 1/2000 and the f-stop to a wonderful f2.0... yet these both become limited at times no matter how much I fiddle... it's as though automatic settings/limits are somehow taking over.

third, the same holds true for Manual Mode: when I want to force extremes to darken shadows, overexpose light, play with depth of field... the settings become LIMITED as mentioned above AND seem to jump around after I set them... as though it's behaving in Aperature or Shutter Priority mode where one setting tries to balance out in relation with the other.

So, how can I take full control with MANUAL?

Thanks!
Sean Shimmel
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Old May 11, 2003, 1:29 AM   #2
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I don't know about the shutter speed issue, but I can tell you that the lens opens up to f2.0 at full wide angle, but that narrows to f2.4 at full tele. Almost all zoom lenses have narrowing apertures at higher zoom settings.
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Old May 13, 2003, 5:46 PM   #3
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The same is true of shutter speeds on digicams. At the largest aperture you usually are limited in the shutter speed choices. Your owners manual should have all this info
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Old May 14, 2003, 7:35 PM   #4
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Hello got a possible reason for shutter speeds not able to do 1/2000 second in manual mode.

Sony has limited it in the manual settings to 1/1000s. The only way to use 1/2000s is to use automatic programmed exposure modes. Do not know why Sony didi this.

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Old May 21, 2003, 5:24 PM   #5
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Default Manual 717

It is possible that the reason you cannot get certain combinations of shutter speed and apertures, may be that like the Canon Gx cameras and no doubt others, the aperture diaphragm doubles as the shutter. Thus it moves around a lot and cannot couple high speeds with some apertures, 'cos it just cannot move fast enough to do so.
And as another poster has said, at max telephoto the max aperture is f2.4. At max wide angle it is f2.

I hope this helps. Or is my assumption about the double duty of the diaphragm, not an accurate assesment? Sony technicians please comment.
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Old May 21, 2003, 7:16 PM   #6
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Well I'm no Sony technician, but I know a thing or two about this camera's CCD since it's of the same flavor as the one used on my D7 (as well as the CP5000/5700 and the E20).

1. There's no "shutter" as in the classical sense, otherwise how else do you guys see through the EVF or the LCD for that matter if the shutter is closed, or the CCD for that matter?

2. The shutter function is electronically controlled by a logic signal to the CCD, so the camera is well able to capture at the 1/2000 speed, but the manufacturer just decide not to offer it on manual (reasoning that the firmware will do a better job?) :twisted:

3. All that said however some cameras do sport a mechanical "shutter" but it works in reverse (page 9, note 4 & 5 of datasheet, and page 19 for the timing diagram) to shut-off the light for a brief period while data is being shifted out from the CCD:
Quote:
It reduced smear by 30 dB to a level of approximately 116dB by performing the following sequence:

Vertical register high-speed transfer -> Readout -> Mechanical shutter close -> signal output.
http://www.sony.co.jp/~semicon/engli...1/a6803214.pdf

BTW some cameras also use this "shutter" in low-light mode to reduce noise. At long shutter speed of several seconds, the camera takes two shots: ie the camera take a regular shot at 30s for example and then another one also at 30s with the shutter close to subtract out the dark current frame noise! 8) 8) 8)

Check the front of your lens @ several seconds slow shutter speed... :lol: :lol: :lol:
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Old May 22, 2003, 7:37 AM   #7
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There's no "shutter" as in the classical sense, otherwise how else do you guys see through the EVF or the LCD for that matter if the shutter is closed, or the CCD for that matter?

Because it is possible that when viewing, the imager might not be writing to memory, only to the viewer.
As for not having a shutter in the classical sense [there were shutters before focal plane types of course] please read the following:

I quote from Phil Askeys [dreview] review of the Canon G!:-

We asked Canon why the F8 limitation and this was their reply (direct from Tokyo):

The PowerShot G1 adopts a single mechanism that serves as both for the iris and the shutter. This mechanism releases the shutter by closing the iris diaphragm completely.

In this mechanism, the iris diaphragm must be closed quickly when releasing the high-speed shutter. The closing speed of the iris diaphragm, however, has a limit to keep the precision and the durability of the mechanism.


Because of the above-written limit of iris diaphragm closing speed, the iris aperture must be closed to some extent to shorten the moving distance of the iris diaphragm, when releasing the high-speed shutter. This is the reason why the aperture value is fixed to F8 when using the high-speed shutter of 1/640 sec. or higher in the PowerShot G1.
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Old May 22, 2003, 8:48 AM   #8
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First of all the G's are point and shoot with a separate viewfinder so what you see is independent from what the CCD see (except for the LCD of course). It's a different design with a different CCD and I'm not going to pretend to know anything about how that camera works.

The EVF based cameras of course need to "see" all the time with its CCD so it can convey this info either to the EVF or the memories/flash card. I just want to point out to everyone here the fundamental difference in this case between a film and a digital camera: A mechanical "shutter" is used to let the light-in on a film camera whereas it's used to shut the light off in a digital camera. ie the mechanical "shutter" remains mostly shut in a film camera and open briefly with the correct speed, whereas it remains mostly open in a digital camera and only shuts off for a brief period with no critical timing.

Bottom line is the actual shutter is electronically sample by the CCD independent from the mechanical "shutter" as shown on the 1st page of the Sony CCD data sheet :
Quote:
This chip features an electronic shutter with variable charge-storage time
The mechanical "shutter" is used as a blind instead to prevent smear from bleeding through to the CCD while data is being shift out as pictured in page 19 of the above datasheet. It's also used as a noise reduction feature at long exposure by cancelling out the dark frame... Just check the front of the lens at slow-speed and see how it works!
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