10 Common Errors in Long Exposure Photography

Lead: I will make a small survey in all the seminars set up by me (Francesco Gola, the same below) in Italy on 20 15. At the end of the seminar, I asked all the participants to write down their three most common photographic mistakes before class and give them to me on a piece of paper. So I decided to choose the most common mistakes in 10 long exposure photography from all the collected materials to explain.

Error 1: The anti-shake system is set to on.

There are some lovely technologies that can help us get clearer images and reduce the blur caused by fuselage vibration. This technique is very useful when we take slow photography in low light. Although different brands have different names for this function, the functions are similar (Nikon and Canon cameras use lens anti-shake technology, Sony, Olympus and Pentax use body anti-shake technology). But in the final analysis, this damping technology can slow down the four-speed shutter speed while maintaining the same image quality.

Anti-shake technology uses sensors to detect jitter and compensate by moving the lens module or the sensor itself. The problem is that if the camera is placed on a relatively stable tripod (of course, if you are exposed for a long time, your camera must be placed on a tripod), then the possibility of vibration is very small. Maybe you know this, but your camera doesn't, so even if it doesn't move, this anti-shake system will try to compensate for the jitter by moving the lens or sensor, which actually causes jitter (or blur) instead of eliminating them. So, if your camera stays safely on the tripod, let's turn off the anti-shake function!

Mistake 2: Forgot to pre-lift with reflector.

In a SLR camera, the light will pass through the lens and then be reflected by the mirror to the viewfinder. When the shutter is pressed, the mirror will be put away so that the light can be directly projected onto the sensor. This action will cause slight vibration of the fuselage, resulting in blurred photos.

To avoid this vibration, you can activate the pre-lift function of the mirror. After activation, when the shutter is pressed for the first time, the reflector will be lifted, and shooting will only happen when the shutter is pressed again. Don't underestimate this short interval of a few seconds, it can prevent the fuselage from shaking! Of course, if you use a mirrorless camera, consider my suggestion nonsense!

Mistake 3: I didn't use the gradient filter because I was shy.

In some cases (when the light ratio is not very large), you only need a mirror with medium gray density to get the desired effect. However, in many cases, the light conditions require us to use a lens with a medium gray gradient to maintain the exposure balance. If you use spiral ND filter, you may think that the only way to use GND filter is post PS, but you are wrong!

You can grab the filter by hand and put it in front of the camera. For the shutter speed with exposure time of several seconds, your only problem is to adjust the filter in your hand correctly. A few minutes of photography, even if the hand is not so stable, the final effect is satisfactory (try it yourself). Of course, the filter holder is still needed, especially in the environment where multiple filters need to be used at the same time (or when the hand cramps).

Error 4: In order to extend the exposure time, set the aperture to f/22.

The rule is simple: the smaller the aperture, the longer the exposure time.

Driven by this rule, you may naively think that you can extend the exposure time from 30 seconds to two minutes by adjusting the aperture from f/ 1 1 to f/22 with your fingers. Theoretically, this is not wrong. Unfortunately, there is a physical phenomenon called optical diffraction, that is, when the aperture is less than f/ 16, the clarity of the image will be greatly reduced. If you have used f/ 1 1 and are eager for a slower shutter speed, lowering ISO or using a dimming filter will be a better choice.

Error 5: Forgot to adjust sensitivity

Sensitivity is very helpful in long exposure. Sometimes you may forget to adjust sensitivity and only care about aperture and filter. Remember, every camera has a sensitivity range, within which the output quality is almost the same. In advanced cameras, this range is usually from ISO 50 to ISO 200. This means that you will have two gears to adjust, while in long exposure photography, two gears mean several minutes of exposure time.

Mistake 6: Shoot like you used it in the studio.

When you shoot in a comfortable room or studio, no external factors will affect the quality of your photos. But if you stand on the rocks by the sea and face the magnificent storm at sea, it won't be long before your filter will be complete. Wet? . Don't forget to put a clean mirror cloth in your bag before you leave. You know, even the smallest water droplets on the filter can cause high diffraction and ruin the photo. Never underestimate the power of nature. Even if the sky is clear in Wan Li, the weather is just a cup of tea.

Error 7: Choose inferior filter.

Every time a filter is added in front of the lens, the overall quality of our optical system will inevitably decrease. It is true that some well-known filter brands are very expensive, but do you really trust to put a filter with dozens of pieces in front of the camera? No, never! So pay attention to quality: for the filter, quality is not weight! You don't need to collect all types of neodymium and GND filters. Try to understand your most commonly used filters, and then remember to supplement them with your ISO and aperture. Finally, remember how close the people are to high-quality filters. Make good use of the internet.

Mistake 8: underestimate the power of the wind

When you are exposed for a long time, your camera will be affected by the external environment because of a few minutes of exposure. Even a few seconds of accidental wind will make you fail. Buy a stable tripod and put it away. If necessary, hang extra weights on the tripod hook to increase the stability of the tripod. Avoid using tripod shaft, lifting shaft will reduce the stability of tripod.

Error 9: The viewfinder is not covered properly.

After three minutes of exposure, when I previewed the photo, I found that it was covered with strange purple edges and halos. Why is this? Although the camera only wants to let light in through the lens, unfortunately, there are still other potential ways to hurt your photos. One of the most famous is the viewfinder. In order to prevent light from entering here, remember to cover it after focusing. If your camera doesn't have a cover, you can use black tape. If there is no tape, chewing gum is better than nothing. The most typical result of light entering the viewfinder is halo. Yes, if you have a mirrorless camera, please ignore me again!

If you use a plug-in filter system, another possible way to leak light is the gap between filters (which is why many photographers like screw filters). In this case, the best solution is to use black tape. The most typical performance of filter light leakage is the appearance of purple edge.

Finally, if you use a shifting lens or install a lens adapter ring, the light leakage problem may appear on the lens. The best way to solve this situation is to cover it with a scarf.

Error 10: Trust filter manufacturer.

When you worked so hard to buy a six-notch ND filter and naively thought it would really give you six-notch effect. Unfortunately, you are wrong again. In my life, I have never found a filter that is absolutely consistent with the manufacturer's propaganda. Of course, this difference is usually small, but even a half-step difference means a few minutes error of long exposure.

To avoid these mistakes, you can try the following steps:

Choose a room, turn on the lights and close the windows. You need a place where the light is absolutely stable.

Set a camera to photograph the room until you get a perfect histogram. Record all shooting data (sensitivity/aperture/shutter speed).

Install the ND filter, and then adjust the body parameter settings to make the exposure consistent with the previous photos.

Take pictures with ND filter.

Observe and compare the histograms of two photos. If they are exactly the same, it means that the filter specifications marked by the filter manufacturer are accurate. If the new histogram is on the left, your filter is higher than he claims; On the other hand, if it is tilted to the right, it means that the actual specifications of the filter are lower than the manufacturer's label.

If the histograms can't overlap, change the shutter speed and take another one, so that the histogram that can overlap with the unfiltered sample can be obtained.

When you find a satisfactory filter, try to build your own shutter speed conversion table. Another possible method is to install the PhotoPills application software on your smartphone, which allows you to quickly get the correct shutter speed when using the filter.

The above ten mistakes need to be avoided in long exposure photography.