long exposure and hdr questions

Discussion in 'Digital Photography' started by rweakins, Dec 30, 2007.

  1. rweakins macrumors 6502


    May 3, 2007
    i have just some general questions about long exposures and the settings and methods used to create them. the questions range from studio to landscape and every kind of photography

    1. i know if you are reading this you probably didnt take the picture below but if you can help and can answer please do. in the picture hows is only the top half of the apple lit and is it lit because of the light from the light source or was some other method possibly used?


    2. for pre dawn/post dusk pictures like the following what settings are optimum for long exposures such as ISO settings and F/? and so on...



    3. what light sources have you found to work best in long exposures such as.....



    4. for hdr's is it more beneficial to use one raw image or several source images?

    5. any additional tips or tricks you have for long exposures and/or hdr's would be greatly appreciated
  2. Doylem macrumors 68040


    Dec 30, 2006
    Wherever I hang my hat...
    I shoot a lot of pix at twilight and after the sun's gone down.

    Rule 1: use a tripod and cable release (vital for long exposures and HDR... to keep subsequent shots 'in regster').

    A tripod gives you the freedom to pick the best aperture/ISO/shutter speed combination for the job: no compromise, or wondering if you can hand-hold at 1/30 sec, etc. I keep ISO at the lowest (100) and seldom change it. Aperture: usually f8 or f11, to get the most out of the lens... and a good depth of field. This means the only 'variable' is the shutter speed. So my pix may typically be shot with exposures of 10secs or more. When the camera's on the tripod, I shoot 'manual'.

    The 'window' for shooting after the sun has gone down can be quite short. For the shot below (of a floodlit landmark) I set the camera on the tripod as the sun went down, and took a shot every five minutes for about an hour. It was interesting to see the light fade in the sky, and the way the floodlight 'appeared' to get brighter in comparison. Eventually, there was a moment when the two light sources were in a kind of balance... and this was the best shot. This is really useful exercise to try, and fun to review the pix afterwards.

    A lot of people shoot night shots when the sky is black... when, IMO, the pix could all be improved by shooting where there is still some light in the sky.

    For HDR I generally shoot 5 auto-bracketed shots (easy if your camera has this facility).

    Easy to do 'tricks' with hand-held lights, when camera is tripod-mounted, with a long exposure. I've had fun with sparklers, 'painting' with torches, etc. So much easier with digital, 'cos your failed experiments cost nothing. The challenge is to get a balance between ambient and artficial light, and that just takes practise and lots of frames. Hope this helps... :)

  3. rweakins thread starter macrumors 6502


    May 3, 2007
    so usually when you are looking to take pre dawn or post dusk is it best to do it with a little light on the horizon or not as much? i mean i know it all depends on how long of an exposure you plan on doing but in general what do people find to be best? less light and a longer exposure or more light with a shorter exposure?
  4. Doylem macrumors 68040


    Dec 30, 2006
    Wherever I hang my hat...
    This is where you need to experiment. :)

    Thankfully, with digital you can shoot loads of trial shots... to see what works and what doesn't. Twilight is a wonderful time for photography. I spend many a happy evening with camera clamped to the tripod, trying to balance artificial and ambient lighting. With a tripod it doesn't really matter if your exposures are in whole seconds (though by the time exposures are up to half a minute, that generally means the light has 'gone'). I'd just stress that pix look sooo much better with colour in the sky than when they're jet black.

    Go somewhere nice, put your camera on a tripod, and see what happens...
  5. Macerture macrumors member


    Jan 2, 2008
    Dirty Jersey
    There's more than one way to skin a cat, well, I wouldn't skin a cat but, here's some tips regarding long exposures..

    Decide what type of DOF you want (depth of field) first. A large aperture will give a very narrow DOF and a small aperture will give a very deep DOF.

    Example: If you want the foreground as well as the background sharply in focus, use an aperture of f22. If you want only one part of the scene or subject sharply in focus and the rest bokeh (the out of focus blurred area), use an aperture of f2.8. Tip: f8 to f11 is many lenses' sweet-spot or, the aperture in which it produces the sharpest images, not the narrowest or deepest DOF however.

    Any light source will do, just be sure to adjust your WB (white balance) for your light source. Nothing like using a tungsten lamp for a warm glow and you end up turning everything into a blue-cast because the WB was off.

    Use a STURDY tripod.

    Use either a remote release OR a camera timed release so the camera and lens has time to settle down after you press the shutter release and the image is taken. Tip: ALWAYS use mirror-lock mode, sometimes called, mirror-up mode, etc.. Basically, using mirror-lock and a timed release prevents any shake when the shutter is finally released as the mirror is put into the 'up' or 'lock' position when the timer is started so there will be no vibration when the shutter opens.

    Set your ISO to the lowest possible setting, ie; ISO100. This will help reduce noise levels in the image resulting in sharper images.

    Focusing. Well, if you have the ability to focus on the subject with the lights on, do so! Just remember to switch your camera to manual focus afterwards so that when you half-depress the shutter release your lenses doesn't go searching to infinity and back screwing up your focus in the first place. Also, it's a good idea to either focus manually or switch to manual after you have focus lock. Too many times the camera will have focused on the edge of something and even a minute movement causes the lens to go searching again and wrecks the shot when you depress the shutter or remote.

    Metering: Lots of personal preferences here but, for a large area landscape shot, I'd say multi-segmented metering is best.

    Flash: Well, this is preference as well but, say you have some interesting foreground stuff in the shot, there's nothing wrong with firing the flash at the beginning or end of the exposure to bring out some highlights. If you have a shoe-mount flash, fire it a few times during the exposure, experiment and see what you like. You can often balance a landscape shot if there are lights in the background by doing so.

    Finally; how are you going to tell the camera to take this long-exposure shot? You actually have three choices.. You can simply set the shutter speed to 2 seconds or more, usually up to about 30 seconds and check to see where the correct exposure you're looking for is. Or, you can set the camera to Bulb Mode. In Bulb Mode you hold the shutter down (remotely) for as long as you want. 1/4000 second to 5 hours, etc.. Or, you can simulate long exposures by using the multi-exposure feature. In multi-exposure you can take up to a set number of photos in quick (or slow, your choice) succession and the camera will merge all of the exposures into one final exposure when you've reached the preset number of shots. Tip: Use EV balancing when using multi-exposure or be good with math and adjust each shot's exposure in the series on your own. Trust me, EV balancing is best and will give flawless results each time.

    Now on to HDR..

    Go ask someone else about HDR:)

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