DSLR that adjusts shutter speed w/ focal length?

Discussion in 'Digital Photography' started by Richard H., Jul 22, 2007.

  1. Richard H.

    Richard H. Guest

    Do any DSLRs offer a mode to auto-adjust the shutter speed proportionate
    to the focal length? (i.e., if I zoom out to 2x the FOV, cut the
    shutter speed by 1/2 and open the aperture by 2x)

    When shooting motorsports, the ideal shutter speed is a balance between
    freezing the subject and conveying motion (e.g., blurred tires or panned
    background). Not a problem when using a fixed lens, but a problem if
    zooming in/out. (i.e., 1/2000 freezes more at 70mm than at 200mm).

    Do models like 1DsII or D2Xs offer such a feature? If so, what's it called?

    Richard H., Jul 22, 2007
    1. Advertisements

  2. Richard H.

    RichA Guest

    "DSLRs for Dummies"

    Seriously, do pro cameras ever have "idiot" modes?
    You know, like a little face logo for portraits, a mountain for
    landscapes, etc?
    When you see that on a Nikon D2Xs, you'll know their days are
    RichA, Jul 22, 2007
    1. Advertisements

  3. Yes, it is built in to the P mode (Program). For the last twenty years
    or more, P mode has been linked to focal length in all SLRs, whether pro
    or amateur.

    The camera can not tell whether you are shooting sports (unless it has a
    sports mode, which tends not to happen in pro models). But it can tell
    what focal length your are using, and will keep the shutter speed as
    short as possible at longer settings.

    David Kilpatrick, Jul 22, 2007
  4. Richard H.

    Pete D Guest

    I assume that program mode on the decent ones can be "programmed" to do what
    you you need, mine can.
    Pete D, Jul 22, 2007
  5. Richard H.

    Richard H. Guest

    Hi, David.

    Thanks for the reply. You're correct, of course. What I had in mind is
    very similar, but a bit of a hybrid.

    Put another way... Program mode but with a static exposure value,
    instead of auto-metering. (Like Nikon's AE Lock behavour, but without
    it being reset every time the meter turns off.) Ideally, it'd work with
    shutter-priority or manual (my preferred mode).

    The idea being to set the EV based on incident light (so different
    vehicle colors don't skew the metering) but preserve the visual effect
    by adjusting shutter speed across a range of focal lengths.

    Richard H., Jul 22, 2007
  6. Richard H.

    Richard H. Guest

    Hi, Pete.

    Which camera are you shooting with, and how much can the Program-mode
    behavior be customized?

    Richard H., Jul 22, 2007
  7. Richard H.

    Richard H. Guest

    Um, yeah. Maybe my follow-up to David makes it a bit clearer.
    :) Mind you, that's a great spot for user-programmed profiles (I
    believe the pro models do this). But the factory-set ones on prosumers
    are a waste of space.
    Richard H., Jul 22, 2007
  8. Richard H.

    Pete D Guest

    My K10D has four settings in hyper program mode.

    1. Normal
    2. Hi speed
    3. Depth of field
    4. MTF priority program is an AE mode that priorities the best aperture
    setting for the attached lens.


    Pete D, Jul 22, 2007
  9. Richard H.

    Doug Jewell Guest

    So you mean a "motion blur priority" mode? Kind of like shutter priority,
    but instead of keeping the shutter fixed, it maintains the shutter speed
    relative to the FL? so if the camera is at 100mm and I set the shutter to be
    1/50, it would move up to 1/150 if I zoomed to 300mm. Can't say I know of
    any that do it - shutter priority and dialling the shutter speed while you
    zoom would be the closest. Not all that hard to do.
    Doug Jewell, Jul 22, 2007
  10. Pentax has one similar thing and I suspect Samsung does. It's a mode
    where you set both shutter speed and aperture, and the ISO is varied,
    and when you reach the limit of the ISO (which you can pre-set to avoid
    using too low or high for the conditions) the camera will then alter the
    other parameters.

    However, I do not know of any camera which alters the plus-minus EV
    setting to cope with changes in the colour of a car - just manual mode.

    Nikon's better cameras use an external WB sensor on the prism, which
    avoids auto WB errors being caused by a coloured subject filling the
    frame. They do not use this sensor for exposure moderation though.

    Your idea is fundamentally a good one - an external incident light
    sensor on a probe, maybe, mounted on the hot shoe, to control the camera
    according to the light conditions - sun going in etc - and not using TTL

    So far it doesn't exist. Minolta bought in patents on a Zone System
    viewfinder display which allowed the use to target one of seven zones,
    and the camera would expose to match. They never used it.

    David Kilpatrick, Jul 22, 2007
  11. Richard H.

    John Sheehy Guest

    There's nothing "Dummies" or "Idiot" about the OP's request. It is a
    very logical feature that I desired as soon as I got back into
    photography a few years ago. In very low light, doing hand-held
    shooting, Av mode is extremely problematic. I tend to use Av mode when
    there is ample light for fast shutter speeds, and Tv mode when light is
    very low, and having a blurred long exposure is worse than having wide-
    open optics or a little under-exposure. The logical extension to the
    latter is to have a Tv-pri mode where you set a ratio to focal length,
    rather than a fixed focal length, very useful for zoom cameras, so you
    don't get unnecessary under-exposure at the wide end of the zoom range.

    An intelligent photographer can make good use of automation to their
    advantage, when they choose one that automates what *they* would do
    automatically, if they had remembered to do so and had the time.

    This feature would be more of a true "user-control" than the P mode,
    which the Pro cameras do have.

    John Sheehy, Jul 22, 2007
  12. Richard H.

    John Sheehy Guest

    Still not quite the same thing as the OP asked for; P mode *will*
    lengthen the exposure instead of under-exposing, when you reach the
    limits of light at the highest ISO. A mode that is unbending in SS is
    another thing.

    They don't make the most sales-worthy posters, but images under-exposed
    by 3 or 4 stops at ISO 1600 on my 30D are still usable to some degree,
    and properly downsampled are not much worse than well-exposed ISO 1600
    images for web-sized images.

    John Sheehy, Jul 22, 2007
  13. Richard H.

    John Sheehy Guest

    I'm not sure what you're implying here, but focal length has no effect on
    subject blur, at a given shutter speed. Someone swinging a golf club at
    1/100 will have the same angular blur at 8mm or 1200mm.

    I'd want a feature like you mention, but I'd want it for static or slow-
    moving subjects in compromised light (to avoid wasteful underexposure when
    zooming out).

    John Sheehy, Jul 22, 2007
  14. Richard H.

    John Sheehy Guest

    That's rather unfortunate. Exposure could be better gauged with three
    separate color meters. The brightest (RAW) color would dominate the
    exposure, and this could be extended to flash metering as well. WOuld be
    ideal, too, for exposure modes designed for maximum RAW exposure without

    The world of digital photography seems to be doiminated by very slow
    corporate thought processes.

    John Sheehy, Jul 22, 2007
  15. Richard H.

    Richard H. Guest


    I tend to shoot in manual mode, so I envision it as a menu option rather
    than a button, akin to "Track shutter speed with focal length". A bit
    of a hybrid between Program and Manual modes, if you will. (An
    alternative might be to allow a manual EV setting with Program mode.)

    Certainly this feature would be off by default - it's not the behavior
    anyone would normally expect when manually setting the shutter speed.

    Alas, it sounds like this might be a pipedream. Unfortunate, knowing
    that it'd be pretty easily implemented. Maybe one day camera firmware
    will go open source, and we can tweak away. :)

    Richard H., Jul 22, 2007
  16. Richard H.

    Gino Guest

    Why not buy a lens with IS? Then use Shutter Priority at 1/125 or even
    Gino, Jul 22, 2007
  17. Richard H.

    Matt Clara Guest

    That was my first thought, too, but here's another way of thinking about it:
    Imagine two 8x10s, one a wide angle of a golfer taking a swing, the other a
    close-up of the club head as it's in motion. Same shutter speed reveals the
    same amount of movement, let's say, a half an inch. In the wide angle
    image, that half an inch will occupy a tiny fraction of the print's surface,
    so little that it's a saleable image. In the close-up, it would occupy
    considerably more. So to get a saleable image with the close-up, he has to
    up his shutter speed.
    Matt Clara, Jul 22, 2007
  18. Richard H.

    RichA Guest

    Any such mode (like other such modes) would be only the roughest guess
    at what would be needed.
    There is no way you could ever make it even marginally precise. How
    does the camera know how fast the action is?
    Maybe in the future, a system of sensor feedback (could the sensor
    detect subject motion?) accelerometers in-camera could be used to
    facilitate something more accurate.
    RichA, Jul 22, 2007
  19. Richard H.

    acl Guest

    Sure it does: speed of image on sensor=speed of subject*magnification,
    and magnification depends on the focal length (amongst other things).

    Or thing of taking a photo of an airplane passing at a distance of
    200m with a) a 10mm lens and b) a 1000mm lens, everything else the
    acl, Jul 22, 2007
  20. Richard H.

    acl Guest

    acl, Jul 22, 2007
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.