A dSLR's fastest shutter-speed is really no faster than its flash-sync speed.

Discussion in 'Digital Photography' started by SelfImporantName, Jul 7, 2007.

  1. Ah .. you again, the guy going by "SockPuppet".
    Thomas T. Veldhouse, Jul 9, 2007
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  2. SelfImportantName == EdBancroft?

    Sock puppets? A little Free Agent for SelfImportantName and Outlook Express
    for EdBancroft and you have a nifty sockpuppet conversation going here ;-)
    Thomas T. Veldhouse, Jul 9, 2007
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  3. SelfImporantName

    SMS Guest

    Very few people are clamoring for AA powered cameras. As was pointed
    out, the NiMH proponents repeatedly misrepresent the facts, and I don't
    think anyone pays much attention to them.
    Hey, the original Prius used 240 consumer sized NiMH D cells in series
    to achieve 288 volts. You're not all that far off. I wonder if the same
    people that make up these ridiculous stories about NiMH batteries in
    cameras were upset when Toyota moved from D cells to proprietary NiMH
    modules. True the D cells they used were not button top, but solder-tab,
    so they would be harder to replace, but you can buy solder-tab NiMH
    cells without too much difficulty.
    SMS, Jul 9, 2007
  4. Many photographers use the shutter curtain for effect in their photography and
    it is a useful tool. With a flash, it can be used for interesting blurring
    and ghosting effects and it can also be used to enhance the background
    exposure in lower light. It just depends upon the curtain sync and your
    ability to utilize it.
    Photography is NOT about recording reality [necessarily], it is about creating
    art. For some people, like a photojournalist, that may not be true, but for
    most, it is about art.

    Without the mechanical shutter, you simply don't have this tool as an option
    for artistic creativity.

    I am sorry you feel so antogonistic about it.
    Thomas T. Veldhouse, Jul 9, 2007
  5. SelfImporantName

    SMS Guest

    I wonder why the D-SLR makers can't include both electronic and
    mechanical shutters. Nikon did it on the D70s.
    SMS, Jul 9, 2007
  6. SelfImporantName

    ASAAR Guest

    Wrong. That's just what the USB spec. assumes will be the
    minimum. But there are USB ports that provide less. And you have
    yet to back up your claim that most USB ports provide 1000mA. If
    that was the case, there would be no need for USB devices, such as
    Energizer's charger to drop down from drawing 500ma to only 100ma
    when it has to share the USB with other devices. If every USB
    socket is attached to a unique USB port, there would be no problem.
    But that's not the case, and though you many not be able to tell by
    looking at the connectors, they may be daisy-chained, sharing power
    and bandwidth. Do you really think that a low powered USB mouse or
    USB keyboard would need a dedicated USB port capable of providing at
    least 500mA to only that one device?

    Chargers don't have small, temporary surges. They operate for
    many hours, drawing current at a very uniform rate. If it was
    otherwise, the faster charging Energizer USB charger wouldn't be
    limited to being able to charge only two AA cells, and the Ultralast
    charger that can charge up to 4 AA cells wouldn't charge so much
    more slowly. Its charge rate, however, is still unknown. You only
    speculated that it is slow, adding that the package provided few

    No need to foam at the mouth, dog. What you called a data sheet
    is NOT the data sheet for Energizer's charger. It's the Duo
    Charger's manual, printed in English, French and Spanish. What I
    stated was copied from the Product Datasheet (CHUSB.PDF), which I'll
    paste below, again, since you didn't have the decency to quote it.
    It was downloaded within the last 24 hours, so you can still
    download it, and you have once more been proven to be a hot air
    blowhard, since what I posted has *not* been withdrawn by Energizer,
    nor was any part of it fabricated. Fabrication and wild speculation
    remain your specialties, not mine.

    You've also posted more of your bogus nonsense with the assumption
    that the problem is in any way related to USB 1.1 ports or hubs.
    Nowhere does Energizer have any caveats about using USB 1.1 vs USB
    2.0, it only states that their charger can drop to a very slow
    charge rate if other USB devices are used. Is Energizer fabricating
    a non-existent possibility? Here's my quote, that you referred to :
    To provide greater context, here's the more complete quote, again,
    copied from the Duo Charger (CHUSB) Product Datasheet :
    Your posts often contain some minor pieces of misinformation or
    deception, but this post of yours went *way* beyond merely pathetic.

    You? Humble? <g>

    (I couldn't honestly type "Don't make me laugh.")
    ASAAR, Jul 9, 2007
  7. SelfImporantName

    ASAAR Guest

    If you don't see that I continued it in a humorous vein (and I
    replied to Allen's post, which really didn't add any humor, not to
    yours), you need to re-examine what I wrote. I could have added
    much about using NiMH vs Li-Ion batteries, but recognized that it
    wasn't really appropriate. But I see that in SMS's reply to your
    message he's added his usual loony speculation, so I'll correct at
    least part of it, as well as something that you wrote :
    It doesn't make sense to want to use AA powered digital cameras?
    That was true several years (by now "many" years?), when AA powered
    cameras were often unable to take more than several dozen shots,
    sometimes as few as 10. For at least three years it has been
    possible to buy cameras that are able to take *many* shots using
    regular alkaline AA or NiMH batteries. The first set of alkaline AA
    batteries used in my 2004 Fuji S5100 was good for well over 600
    shots, more than 100 taken using the flash at full power. Using
    NiMH batteries it's now possible to take well over 1,000 shots per
    charge. Many Canon cameras do even better, getting up to 1,600
    shots per charge. This makes cameras using AA batteries much more
    capable now than they were years ago, and it would be quite
    inaccurate to say that they make little sense except for people that
    don't use their cameras much, or if used only as an "accident"
    camera. Several people have posted messages in the last year or two
    praising their Canon A610/A620 type cameras. Several of them noted
    that they'd taken up to several hundred pictures over periods
    ranging from 3 to 6 months, all on the first set of batteries. It's
    not exactly *heavy* use, but neither is it *light* use, and it is
    typical of many how many photographers use their cameras.

    If you're one of those that clamor for Li-Ion batteries, that's
    fine too. But you should realize that when evaluating batteries to
    find out which types are the most convenient or the cheapest to use,
    no one type always wins out. Much more depends these days on how
    the cameras are used than on which types of batteries are used, and
    you might be surprised by which types of batteries win out, and
    under which conditions. As even the most expensive battery types
    these days are quite affordable, most people don't care, making
    their sometimes unreasonable biases easier to remain intact. :)

    This is one of the stupidest statements SMS has ever made. He
    supposedly knows all about batteries, used not only in consumer
    products, but in heavy duty industrial products as well. If he
    wasn't trying to back up his usual bogus points, he would have
    recalled that solder tab (and welded tab) cells are NOT used to make
    replacement more difficult. They're used to make their use more
    reliable. Button top cells have relatively high contact resistance,
    and it increases over time, due to the effects of oxidations and
    grime. When used at the especially high currents demanded by
    electrical auto engines, they would waste more battery power and
    produce more heat at the contact points and make for less reliable
    operation. The addition of the contact springs alone, needed for
    240 button top D cells would also waste space, requiring the use of
    a larger battery compartment.

    This is no different in NiCD, NiMH and Li-Ion battery packs that
    use multiple cells for powering portable phones, cell phones, PDAs
    and laptops. They don't use button top batteries and spring metal
    contacts. They use cells that have been connected using soldered or
    welded tabs because it makes the battery packs more reliable. Almost
    all portable phones and cell phones use battery packs that can be
    easily replaced in seconds without using tools. Portable phone
    battery packs tend to be very inexpensive, but cell phone battery
    packs are usually far more expensive, but still easy to replace.

    I'm sure that the SMSpinmeister knows all of this, but when did
    facts ever get between him and the bogus points he tries to use to
    mislead the gullible?
    ASAAR, Jul 9, 2007
  8. SelfImporantName

    Guest Guest


    from the official usb spec,

    table 7-7 in section 7.3.2 (page 178) shows a *maximum* of 500ma per

    furthermore, a device is initially only guaranteed 100ma and must
    request 500ma from the host.

    kindly cease your disinformation campaign.
    Guest, Jul 9, 2007
  9. SelfImporantName

    SMS Guest

    Read page 171 of the USB 2.0 spec, section 7.2.1 under "Classes of
    Devices," that specifies when a low-power port is permitted.

    You cannot have a low power port on a computer, except under one
    condition specified in 7.2.1., a condition that is only ever taken
    advantage of in extremely small systems such as PDAs and UPCs. You _can_
    have a low power port on a bus-powered hub, and the available power per
    port is 100mA.

    Technically, it might be legal for a notebook manufacturer to detect
    when on battery power, and then reduce the available current to that of
    a low-power port, and only supply the higher current when on external
    power, but this is never done in practice as it would add a great deal
    of expense and complexity to the system, and lead to all sorts of
    technical issues when switching from external to battery power on-the-fly.

    You're reading table 7.7 incorrectly. Under "Supply Current" you're
    guaranteed a minimum of 500mA out of the hub, and the device (function)
    is supposed to draw a maximum of 500mA. In reality, the supply current
    is always somewhat greater than the 500mA minimum, and while it isn't
    really kosher to design a device that draws more than 500mA, many
    devices will take advantage of the higher current if available. They get
    around this apparent violation by supplying an external wall adapter to
    use if the USB port current is insufficient.

    Maybe Eveready was worried about someone plugging the Duo charger into a
    Bus Powered hub, so they put in that warning about charge current.

    Unfortunately they should have been more verbose as their wording
    apparently led some non-technical people to believe that plugging in
    multiple devices to their computer's USB ports will reduce the current
    on each port, which is completely false. Instead, they should have
    instructed users to only plug the device into a powered hub, or directly
    into the computer's USB port. At least this would not have confused
    people and led to all sorts of wild assumptions as to how USB power works.
    SMS, Jul 9, 2007
  10. SelfImporantName

    ASAAR Guest

    Nonsense. Energizer said nothing about the possibility of
    plugging the charger into a bus powered hub. They explicitly
    described what could cause the charger to draw only 100mA. You've
    now read the explanation from several sources, unless for some weird
    reason you're now trusting my quotes to be valid instead of the
    "fabrications" you earlier claimed them to be. The reason give by
    Energizer was that other USB devices drawing current from the port
    would be why the charger wouldn't draw the full 500mA. Once again
    you've posted misleading, deceptive speculation, disguised to appear
    as if it were fact. Is Energizer also mistaken, or is what they
    have said also a fabrication? Just rhetorical questions, since we
    know that you go to great lengths to avoid honest answers.

    Riiiight. If you actually believe this, you're in really bad shape.
    ASAAR, Jul 10, 2007
  11. SelfImporantName

    Guest Guest

    you mean this part?

    7.2.1 Classes of Devices
    The power source and sink requirements of different device classes
    can be simplified with the introduction of the concept of a unit
    load. A unit load is defined to be 100 mA. The number of unit loads
    a device can draw is an absolute maximum, not an average over time.
    A device may be either low-power at one unit load or high-power,
    consuming up to five unit loads. All devices default to low-power.
    The transition to high-power is under software control. It is the
    responsibility of software to ensure adequate power is available
    before allowing devices to consume high-power.

    or this part? High-power Bus-powered Functions
    A function is defined as being high-power if, when fully powered, it
    draws over one but no more than five unit loads from the USB cable.
    A high-power function requires staged switching of power. It must
    first come up in a reduced power state of less than one unit load.
    High-power functions must be capable of operating in their low-power
    (one unit load) mode with an input voltage as low as 4.40 V, so that
    it may be detected and enumerated even when plugged into a bus-
    powered hub. They must also be capable of operating at full power
    (up to five unit loads) with a VBUS voltage of 4.75 V, measured at
    the upstream plug end of the cable.

    maybe this?

    7.2.3 Power Control During Suspend/Resume
    Suspend current is a function of unit load allocation. All USB
    devices initially default to low-power. Low- power devices or
    high-power devices operating at low-power are limited to 500 mA of
    suspend current. If the device is configured for high-power and
    enabled as a remote wakeup source, it may draw up to 2.5 mA during
    suspend. When computing suspend current, the current from VBUS
    through the bus pull-up and pull-down resistors must be included.
    Configured bus-powered hubs may also consume a maximum of 2.5 mA,
    with 500 mA allocated to each available external port and the
    remainder available to the hub and its internal functions. If a hub
    is not configured, it is operating as a low-power device and must
    limit its suspend current to 500 mA. While in the Suspend state, a
    device may briefly draw more than the average current. The amplitude
    of the current spike cannot exceed the device power allocation 100 mA
    (or 500 mA).

    wikipedia has this to say:

    The USB specification provides a 5 V (volts) supply on a single wire
    from which connected USB devices may draw power. The specification
    provides for no more than 5.25 V and no less than 4.35 V between the
    +ve and -ve bus power lines. Initially, a device is only allowed to
    draw 100 mA. It may request more current from the upstream device in
    units of 100 mA up to a maximum of 500 mA.
    Some USB devices draw more power than is permitted by the
    specification for a single port. This is a common requirement of
    external hard and optical disc drives and other devices with motors
    or lamps. Such devices can be used with an external power supply of
    adequate rating; some external hubs may, in practice, supply
    sufficient power. For portable devices where external power is not
    available, but not more than 1 A is required at 5 V, devices may have
    connectors to allow the use of two USB cables, doubling available
    power but reducing the number of USB ports available to other devices.
    very few devices take more than 500ma because it is not guaranteed. in
    fact, i have heard of some devices failing to work, notably bus-powered
    hard drive enclosures, as well as causing port blowouts. a device
    requiring more than 500ma is out of spec. if this nimh charger needs a
    powered hub to supply necessary power, then the advantage of it being
    usb is totally lost.
    Guest, Jul 10, 2007
  12. SelfImporantName

    SMS Guest

    This part:

    "Root port hubs: Are directly attached to the USB Host Controller. Hub
    power is derived from the same source as the Host Controller. _Systems
    that obtain operating power externally, either AC or DC, must supply at
    least five unit loads to each port. Such ports are called high-power
    ports._ Battery-powered systems may supply either one or five unit loads."

    Every USB port on a desktop _MUST_ supply 500mA per port _minimum_.
    Using all the USB ports has no effect on the 500mA per port that must be
    supplied, though it can effect current _over_ 500mA because the power
    protection circuit has two cutoff modes. It will cut off individual
    ports at a certain level (typically 800-1000mA) but it will also cut off
    _all_ the ports, if the combined current exceeds 2.0A.

    What is true is that it would be _possible_ to design a laptop PC where
    the maximum current per port varied based on whether the notebook was
    plugged in or on batteries. You could legally reduce the USB current to
    100mA per port when operating on battery power. In practice this is
    _never_ done because a) it would increase the complexity and cost of the
    laptop, and b) it would cause problems during operation, i.e. if an
    external hard drive was in use during a power failure and suddenly
    disconnected due to lack of power.

    I think the Energizer was worried about someone plugging the NiMH
    charger into a bus powered hub. This is the only way that additional
    devices would affect the available current of other devices (at least in
    terms of the 500mA minimum). Unfortunately, they didn't communicate this
    very well to the technical writer.
    Every hub inside a PC is a Root Port hub and supplies 500mA per port,
    with no effect on the 500mA no matter how many of the ports are used.
    Don't think of a hub as only an external hub. It's only an external, bus
    powered hub that supplies only four units of power (one unit is used by
    the hub itself, and four units are available for devices).

    You're right that the devices that draw more than 500mA are out of spec.
    But if they're only a few hundred mA over the limit they'll usually
    work. I've never found an external notebook hard drive that wouldn't
    work on a USB port without the adapter. I've had an external DVD/CD RW
    drive that wouldn't work in some situations (writing) but would work
    fine in some situations. If it causes a port blowout then the USB power
    protection circuit is not working. Even a simply polyswitch will prevent
    port blowout. What we did on the Compaq machine with the guaranteed
    high-power USB port for Multibay (shown on the charger site) was to
    dedicate an entire root hub to that one port.
    The NiMH charger just requires a normal, 500mA USB port, as found on any
    computer manufactured in the last ten years or so. This isn't rocket
    science. Personally I'd like the option of a Y connector on these
    chargers to increase the available current per cell, but 250mA is
    sufficient for overnight charging.
    SMS, Jul 10, 2007
  13. SelfImporantName

    dj_nme Guest

    Some P&S digicams actually do have a high flash-synch speed.
    I had a Minolta Dimage 7Hi (it died at the time of the Sony 5mp sensor
    recall), it's highest shutter speed was 1/4000th in Program mode and
    1/2000th in Manual mode, it could flash-synch with it's pop-up flash at
    these shutter speeds.
    Because it had Minolta's proprietary flash shoe and no PC socket, I
    never got a chance to try an external unit flash with it.
    It had a mechanical iris shutter, so it didn't have separate shutter
    curtains which cause a black stripe if a FP shutter is used above it's
    flash-sych speed and because of the small diameter of the opening, it
    could have a fairly high shutter speed.
    I wouldn't call it an "ideal" camera, it had acceptable noise at ISO 100
    and ISO 200 and if you're in dim lighting, a bit too noisey at ISO 400
    and almost useless at ISO 800.
    The 7Hi was also a OK with AF and the 4x zoom on MF did help in good
    lighting; but in dim lighting it would hunt and the 4x zoom on MF just
    made the red/green noise in the image easier to see.

    I personaly can't see the point of "SelfImporantName"s rant, the
    trade-off between ultra-high flash-synch with a pop-up flash (P&S
    camera) versus low noise at high-ISO (DSLR & DRF camera) seems like a
    "no-brainer" as far as I can tell, because it means that pictures can be
    taken in low light without using the flash without getting an image
    that's a mess of noisey pixels.
    dj_nme, Jul 10, 2007
  14. SelfImporantName

    SMS Guest

    It's more than just low noise at high ISO. One of the biggest advantages
    of the D-SLR is the lack of shutter-lag.

    It's easy to live with the slower flash synch, after all, it's always
    been that way with SLRs, even film SLRs.
    SMS, Jul 10, 2007
  15. SelfImporantName

    dj_nme Guest

    SMS wrote:

    High-speed flash synch (pulsed flash) totally side-steps the problem.
    External flashguns that can send out a series of flash pulses to cover
    the whole exposure at high shutter speed (higher than the native "flash
    synch speed") has made the electronic shutter for DSLR cameras a thing
    of the past.
    If I remember correctly, there tended to be bit of image smearing if the
    electronic shutter was used for high-speed falsh synch.
    That's the only bit I can remember from the the D70s review on dpreview.com.
    dj_nme, Jul 10, 2007
  16. SelfImporantName

    Guest Guest

    maybe. no guarantees. might blow the port (i've seen it happen).
    i've seen numerous failures for the drive to spin up.
    if its out of spec, anything goes.
    Guest, Jul 10, 2007
  17. SelfImporantName

    dj_nme Guest

    1)no lag in the "live view" on the LCD or EVF that a P&S digicam usually
    2)very fast AF in most lighting conditions, right down to dim lighting
    in which manual focusing also isn't really possible (at least what I've
    found with Pentax DSLR cameras, ist-DS and K10D).
    3)the choice to be able to change lenses for a faster, longer or wider
    one as the situation demands.
    4)I'm sure there's more, but at 11:30pm I'm starting to run out of juice
    and suggestions.
    Then HS/FP flashguns came around and suddenly it's possible to flash
    synch all the way up to the top shutter speed with a DSLR while using
    the correct accessory flashgun, if you can put up with the reduced GN
    that comes with pulsed flash.
    dj_nme, Jul 10, 2007
  18. SelfImporantName

    SMS Guest

    I wouldn't design something that depends on a USB port delivering more
    than the guaranteed minimum of 500mA. The DVD/CD drives and hard drives
    don't really depend on it, as they always come with either an external
    power adapter, or a Y cable that lets them draw power-only from a second
    USB port. However the notebook drives (at least the recent ones) seem to
    always work fine from a single USB port, though I've only tried it on
    Dell and Compaq notebooks/tablets, and ASUS motherboards.

    The key point is that the root port hub inside the computer can deliver
    a minimum of 500 mA, on each port, even with all ports being used.

    It's a bizarre warning on the Energizer charger, which misleads people
    that don't understand how USB works. They should have just stated, "Do
    not plug this charger into a USB hub that does not have its own power

    Energizer has deluded people (or perhaps only one person) into
    statements like "If every USB socket is attached to a unique USB port,
    there would be no problem." I don't know what he was thinking, maybe he
    thinks USB is like the old 10BASE5 Ethernet or the Enhanced Parallel
    Port (1284.3), rather than a multi-level star topology like USB, where
    each USB socket _is_ attached to a unique USB port.
    SMS, Jul 10, 2007
  19. SelfImporantName

    ASAAR Guest

    Of course you don't know. You're too absorbed in your delusions,
    including the one where you stated that most USB ports are capable
    of providing close to 1000mA.
    ASAAR, Jul 10, 2007
  20. dj_nme wrote:
    1 - the EVF of a small-sensor camera can be brighter, although the DSLR
    offers finer control of framing.

    3 - can cause you to loose shots - better the full-range zoom on the ZLR
    than having to change between lenses. Changing lenses also introduces
    dust which causes problems for the DSLR. Lenses like the 18 - 200mm VR
    zoom from Nikon are perhaps better as general walking-around lenses, but
    they are expensive and somewhat heavier.

    "You pays your money and takes your choice".

    David J Taylor, Jul 10, 2007
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