8

When setting the aperture at f1.8 you are for sure going to overexpose the image. When I'm out at the beach I set my GH5 at f1.8 with the shutter speed 1/8000 and my iso at 200, but I still get an overexposed image. What can I do?

29

The easiest way to solve this problem is to use a neutral-density filter. They are essentially neutral grey filters that cut down on the light reaching the film or digital sensor. Good ones are fairly expensive, because they are surprisingly hard to manufacture.

Another option is to shoot in more favourable conditions, like overcast days or really early or late in the day, when light is less bright.

In a pinch, a polarizing filter (which is something most photographers carry with them most places they go) will cut down light by about two and a half stops, or a factor of about five, which can be the difference between overexposure and correct exposure in some situations.

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    An ideal polarizer would only reduce unpolarized light by a factor two or one stop. I haven't tried it but I would be surprised that a real one costs a factor five. If you have two of them you can get any factor you want above two by the angle of the axes. – Ross Millikan Jul 24 '18 at 3:03
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    @RossMillikan I've use two polarisers nearly crossed as a variable ND. photographic polarisers generally have a quarter waveplate on the back "circular", so you need to mount them front-to-front with a reversing ring or improvise something. With the polarisers nearly crossed I could get about ND10 at the red end of the spectrum, but so much more blue light got through as to not be very useful. I think (they're at home) I had one Hoya and one Hama; different brands may behave differently. – Chris H Jul 24 '18 at 9:34
  • @ChrisH You can get variable ND filters (which are basically just that - a fixed and rotatable polarizer) that aren't as thick as two stacked filters... if vignetting is an issue. This is a filter that can't really be cheaped out on, though - inexpensive variable ND filters can be highly non-uniform and lend bad colour casts. Good quality ones can be very effective, however. – J... Jul 24 '18 at 11:29
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    @RossMillikan - a polarizer reduces light in general by about 1 to 2 stops. However it will cut down large portions of unpolarized light even more on top. – Yaba Jul 24 '18 at 11:48
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    @Yaba By pure physics a perfect polarizer will eliminate half of randomly polarized light (one stop). Unless most of your exposure is specular reflections, this should generally be a typical estimate. Real filters have some additional losses, but a good polarizer should be much closer to one stop than two. The Hoya CIR-PL, for example, has an ND number of 1.1 (ie: 1.1 stops). Unless you're buying garbage cheap filters this should hold for most quality polarizers. – J... Jul 24 '18 at 13:13
11

Some considerations:

  1. Turn your ISO right down to the minimum value

  2. Do you really need f/1.8? Depending on the composition of your shot you can usually still get decent shallow DoF up to around f/4.0

  3. As people have already mentioned, use an ND filter. You can get variable ND filters fairly cheap online but be wary if you're using them at high settings or long exposures they tend to cause vignetting and other side effects. If you can, buy trusted brands which will be more expensive - but ultimately any ND filter is going to be an improvement (not just for exposure but for polarisation too).

  4. Check you in-body camera settings, there may be other variables in play that are causing what appears to be an over-exposed image.

  5. If you're not already - shoot in RAW. This collects more data and therefore makes it easier to correct an image in post.

  6. Shoot early in the morning or later in the evening ~ see Golden Hour ~ you'll get softer light which will make for better pictures anyway

  7. If you're shooting portraits, try and get the sun behind or at least to the side of the subject.

  8. Potentially more obvious one - look for cover/shade from objects and buildings. Shadows can be just as important to composition as light!

  • I strongly recommend to stay away from variable ND filters. Cheap variable filters are unusable, while you can get a set of various decent, constant ND filters for the same price as a still not as good variable filter. – Yaba Jul 24 '18 at 14:55
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    I disagree, I have had plenty of NDx filters in the past and even the cheapest ones I have only found unuseable on their highest settings. I use a variable ND filter on my 50mm that cost me about £20 and I've had no issues whatsoever with it. Constant NDs will always be better - but it's a trade off for cost. When starting out I always advise use variable ND because it a cheaper way to learn how to use them. – Sam Jul 24 '18 at 15:06
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    "Unusable" is pretty subjective. For someone that didn't even know what an ND filter was a day ago, I think they'd get quite a bit of use out of a cheap one and learn a lot. Of course they may eventually realize the pictures could be better, but now they know what an ND filter is capable of, and what they should look for in a more expensive model. – JPhi1618 Jul 24 '18 at 19:35
4

You can also force a shallow DoF using a long focal length, even at f/22, if you have the lens for it (either prime or zoom). Try upwards of 100mm.

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    Note however that a longer lens will have other effects as well, such as compressing the background. – Yaba Jul 24 '18 at 15:02
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    @Yaba Moreover, if you have a zoom lens like me (a cheap 28-200mm), its aberrations will become quite visible above 135mm. When zooming at 200mm in certain conditions, the aberrations will be even distracting. It's best to have a prime +135mm lens. – CamilB Jul 25 '18 at 8:13
1
  • Get a a non circular continuous ND filter with as many stops as you need and the adapter for your lenses from lee filters.
  • And start taking great pictures, properly exposed ones at large aperture, at the beach or anywhere.
  • Check their webpage for tutorials, examples and inspiration about what ND filters can do for your photography.
  • Remember the saying “Invest in good glass, and not so much in a camera.” Current cameras are just an specific purpose computer that will be obsolete by the time you buy it. On the other hand good glass will outlast you.
0

Easy, just use a neutral density filter.

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