Long Exposure Photos

Discussion in 'Beginner Questions' started by alex_lamond, Jan 1, 2017.

  1. I've had my camera for a couple of years now but the one thing I can never get correct is long exposure shots. I can set the ISO to 100 but when I'm shooting in light scenes anything over a second shutter speed becomes horribly bright. I don't think I can change the aperture on manual mode but even on shutter priority, where the aperture updates itself, they are really bright. Is there a trick to getting long exposure times to work?
    Camera: Canon EOS 1000D
    Lenses: Canon EFS 18-55mm & Canon EF 70 - 300mm
     
  2. I don't think I can change the aperture on manual mode but even on shutter priority​
    Yes, you can change the aperture in manual mode, also the shutter priority mode can autimatically choose the correct aperture for you. The problem is the required aperture is out of the range your lens can provide. You well know that your lens has a limit in maximum aperture (for your lenses, the max aperture is 3.5 or 4.0), but you should know that there is also a limit in minimum apertures which is often F22 or F32. If your scene is in bright daylight, ISO is 100, shutter speed 1 second will need an aperture smaller than F1000 which obviously out of the range of your lenses.
    For long exposure time and bright scene, we often use ND filters to make the scene darker. I rarely use those filters, but someone else or Google can help you find those
     
  3. Either wait for the night or use a strong ND filter, that eats a lot of f-stops of light. - The interesting ones should be 5 stops or more, to grant 1sec on a somewhat bright day. - Naming is occasionally confusing since a few manufacturers tell which fraction of the light gets through.
    Keep in mind that such exposure times demand a tripod. Figure out if a probably not cheap ND filter seems worth it to you and also prepare for a sluggish shooting technique that might involve setting up your camera and adding the filter just before you expose (since AF doesn't work too well in low light).
     
  4. You need three things.
    The first is, obviously, a dark /ND/ filter - or better, a set of them. I have a 4, 6 and 10 stop filters in my bag all the time.
    The seciond would be to know how to calculate the correct exposure. There are a lot of applications for that, but you can also calculate it. For example, if your camera shows you recommended exposure of 80ms without the filter, that would be 1000x more with an 10 stop filter. So you need 80 seconds
    The third think would be a programable cable release in order to get the well-calculated long exposure.
    Thats it. Happy shooting
    00eIde-567161684.jpg
     
    Randy Filkin likes this.
  5. When hooting using tripod I always use the 10 second delay release to give the camera time to settle down from my pressing the trigger. I also do not touch the rig during countdown and exposure. Tripod read firm support like wall etc.
     
  6. Understanding exposure is the key to solving the problem you are running into. Your question indicates (to me) that you don't understand exposure. So I suggest that you learn and understand exposure. Because everything people said above, and will say later, won't make sense unless you understand exposure.
    For a given scene light level, you have to balance the 3 variables: ISO level, shutter speed, aperture
    It is like an algebra equation; Light level = ISO + shutter speed + aperture
    These 3 variables have to be in balance. If the scene is at a certain light level, there is a limit to the exposure setting that you can use at any given ISO. You cannot arbitrarily set the camera to a 100 second exposure, if your cameras settings won't support that exposure. Then you get a burnt out pix as you have.
    CAUTION. The simple equation I wrote (Light level = ISO + shutter speed + aperture), is a concept equation. You cannot simply plug in the values from your camera. Again, once you understand exposure, it will make sense.
    You can probably find free books and lessons on the internet to learn exposure.
    gud luk
     
  7. BTW, I calculated for a daylight shot at ISO 100, at 1 second exposure, you need an aperture of f/192. And f/192 does NOT exist on any consumer camera/lens that I know of. The smallest aperture that I have on any of my lenses is f/32, which is 5 stops short of f/192.
    How did I get f/192 ?
    Again, you need to understand exposure.
    Full daylight at ISO 100 = 1/125 sec at f/16. The "sunny 16 rule."
    You have to then compute equivalent exposures at other shutter speeds and the matching aperture, to arrive at the 1 sec, f/192 combination.
     
  8. I need to get myself a neutral density filter ASAP. Nice sample picture Nick!
     
  9. You can also try photography with a full moon. With a digital camera, you can try until you get it right, but 30 minutes at full aperture and ISO 100 might be about right.
     
  10. I have a 10 stop ND filter on my list of things to get.
     
  11. The problem you may encounter with long exposures especially in the 4 or 5 minute range, is it eats up your battery. You can take a test shot that is properly exposed and extrapolate the needed change of stops needed to increase exposure. I tend first to increase iso to as high as I think I need and still with noise that is controllable in post. I take a reflective reading of the sky without the filter, then with it and it gets me in the ball park of how much I need to slow the shutter. I expect you could do the same with the filter off and on. That way you are close. Don't forget, even if the shot is so under exposed you can barely see anything on the lcd. you can pull back quite a bit from a raw file. Don't delete those shots in camera. Took a night photo class and the instructor told me to not delete such a photo. The next day, when he put it on the screen, he pushed the exposure slider and it is the closest thing I have seen to what it used to that amazing moment in the wet dark room as the image appeared on the print. I agree with him, noise can acceptable and even desired. It's your vision. Variable neutral density filters have come down in price and I use a 2-8 stop nd filter. I also use an infrared filter that eats about 8 stops of light. If your aren't a math person and your camera is set to third stop increments. Just count down the shutter speed, 3 clicks per stop eaten by the filter same for raising iso. I tend to want to be in the f/11 or 16 range so only start opening if absolutely necessary to preserve dof. Shooting with a wide angle lens helps with that. Another disadvantage with high density filters is you can't see through the lens for composing and focusing. Both need to be done and focus locked before screwing on the filter. A downside to a wide angle lens is it can get you a bit closer to your subject than you might like. Here's a shot where my foreground friend and bird in the trees gator final.jpg didn't move during the longer exposure, but you can see cloud movement.
     
  12. The scenes are too bright to expose them at 1 sec or more even if you use f/22, i.e. the lens can't stop down enough. You've run up against a physical limit of the lens. You need a ND filter.
     
  13. Alan, it is an infrared.image using an IR filter to block visible light below 720 nm and capturing IR light in the area above 720. . The (Robert) Woods effect is green plants reflect more UV rays so it turns them white. The filter eats 8 stops but is a deep red filter, not a neutral one.
     
  14. The eye is still sensitive past 720nm, just not as much. Some years ago, I worked in a lab with 780nm lasers, and we could easily see them in the dark. That is, from scattering and such. But for DSLRs, the built-in IR block filter drops pretty fast, at the same time that your 720nm filter is rising, so your picture is darn close to only about 750nm. Still, it is enough fun to go around with a DSLR and 720nm filter. There are plenty good enough Chinese made ones for low prices. (It isn't enough fun that I want to spend large amounts of money on it.)
     
  15. For the OP, one thing to consider with a ND filter: once on the lens, forget about AF - there will be too little light coming through the lens for AF to work reliably. So when using a ND filter, either focus manually, or mount the filter after focussing. Best really is to set your lens to Manual Focus, to block AF from even trying. In daylight, long exposures without a ND filter is hard. Do take care when shopping for ND filters that many use confusing descriptions to indicate their strength (a 8x ND filter, for example, is only 3 stops and often not enough). As for changing the aperture in Manual mode: press the set button on your camera. Use the up/down buttons to go to the 'setting' "Fxx" (xx will be a number, for example f8), then turn the wheel to change your aperture.
     

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