What Is The 500 Rule In Photography?

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    If you're into night sky photography in every capacity, you'll eventually hear someone mention about "500 Rule," otherwise known also as "rule of 500." Sooner or later, you will take photos of the night sky if you care about that sort of thing. Most seasoned photographers will memorise this moment rule of thumb so they can apply it when they're out shooting as night but want to get one of those spectacular shots of a Milky Way that tends to sweep audiences off their own and keep all stars nice and sharp.

    Beginner astrophotographers may find it challenging to get a sharp image with properly formed stars. Star trailing is an effect that can be captured in photographs of night sky that used a tripod as well as a lengthy exposure time. This is because, as seen from Earth, the night sky appears to be moving.

    When shooting astrophotography using a tripod setup that doesn't monitor the sky, the 500 Rule is among the most successful tactics for reducing the appearance the star trails in the final image.

    If you've ever dabbled with low - light photography, you know that taking pictures of a landscape at night is a very different experience from taking pictures of a landscape during the day. As soon as the sun goes dark and the sky fills with stars, you can put aside your knowledge of standard camera settings. Almost all of these will do more harm than good to your photographs.

    Instead, you'll need to go against every photography rule you've ever learned and use a high ISO, a wide aperture, and a slow shutter time.

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    Even though we go into great length in our night photography guide for beginners on the different settings, shutter speed is sometimes forgotten. Sure, you'll need a slow shutter speed, but what about keeping the ISO low, the aperture around f/11, and the exposure time at several minutes?

    We can certainly do that, however this will also impart an affect upon your images. This issue can be solved by applying the "500 Rule."

    What happens if we increase the shutter speed too much?

    The camera will capture any movement that occurs while the shutter is open. Thus, the camera will record any subject that moves while a shutter is open; for example, leaves blown by the wind during a five-second exposure will appear blurry because of the duration of time that shutter was open.

    What kind of effects does this have on night photography? Due to Earth's spin, the stars will seem blurry so when shutter speed is greater than a particular time. Those are the so-called "star trails" that everyone talks about.

    It's possible that you'll have to have a shutter of much more over 20 minutes if you stick with ISO 100 and aperture of f/11. The image file you end up with will be significantly cleaner (less noise and better front-to-back sharpness) because to the lengthy shutter speed, but it will include star trails.

    Now, while trying out different variations on this technique might be a great deal of fun, how should you do if you want the stars to be really sharp? How fast should the shutter be set? Allow me to introduce you to a concept known as the "500 rule":

    What exactly is the 500 Rule?

    When taking photographs of the night sky, the 500-second rule is used to establish how long an exposure can be before star trails emerge or the stars become indistinct. Photographs taken with a shutter speed longer than what is allowed by this guideline will not capture sharp stars.

    In order to determine the optimal exposure settings for a given lens on a full-frame and crop sensor camera, one only needs to consult a simple formula. If you follow those instructions to a T, the stars in your Milky Way and night sky photos will be razor sharp and won't trail.

    The 500 rule could be helpful when shooting the night sky with a fixed camera and tripod. This technique is applicable to photographs captured with lenses of varying lengths (up to roughly 200mm), but it shines when paired with a variable aperture to capture the Milky Way. Choosing the right wedding photographer in Melbourne to capture every moment on your wedding day.

    The 500 Rule Produces Razor-Sharp Stars

    Shooting at night is difficult because you have to settle for less-than-ideal conditions. You have to have a low ISO and a completely open aperture to get clear shots of the stars at night. This stipulation cannot be waived.

    While using star trails can be a fun approach on occasion, you should take every precaution to avoid star blur. As the stars gradually become blurrier, it becomes clear that the shutter is only little too slow at the this moment. It's now very evident that star trail wasn't really deliberately made, but rather was the result of a random occurrence. In times like these, the 500 Rule comes in handy.

    500 Night Photography Rules

    This simple rule of thumb, known as the "500 rule," can be used to calculate the longest exposure time that will prevent fuzzy stars in a shot. How perfect is it? No. However, it gives you a good idea of a shutter speed you can utilise with the gear at your disposal.

    The 500 Rule for Full Frame Cameras

    What Is The 500 Rule In Photography?  by Wild Romantic Photography Melbourne

    The 500 rule states that you should use an ISO of 3200 or 6400, an aperture of f/2.8 (and as wide as your lens will allow), and a shutter speed of 500 divided by that of the lens's focal length to achieve the best results with a full-frame camera.

    With such a full-frame sensor camera, the computation is simplified as much as possible, but you should still be ready for a shorter exposure. Since a crop factor is unnecessary, just divide 500 by the focal length to get the appropriate exposure. The reason for this is because there is no need to consider any elements related to the crop. For instance, if you were using a lens with a focal length of 50 millimetres, your shutter speed would indeed be two min (500 divided by 50 equals 10).

    The recommended shutter speed for a lens with a 24 mm focal length is about 21 minutes (500 divided by 24 equals 21).

    Think about how your camera's sensor reacts to low light to determine if you need to use a lower iso. Some cameras feature flawless sensors, allowing the operator to get excellent star photos at iso settings near 500.

    The 500 Rule for a Canon Camera with a Crop Sensor

    If you're using a Cannon crop sensor camera, remember that the crop factor is 1.6. After that, it boils down to:

    500 / (focal length x 1.6)

    500 divided by (50 times 1.6) yields 6 seconds when using a 50mm lens (approximately).

    Nikon's 500 Rule for Crop Sensor Cameras

    Considering that crop factor for just a Nikon cropping sensor camera was 1.5, you would do it as follows:

    500 / (focal length x 1.5)

    For a 50mm lens, the formula is 500 / (50 x 1.5) = 7 seconds (approximately).

    The 500 Rule Shutter Speed Settings

    Remember that this is just a suggestion and that, depending on the details of the scenario, some adjustments may need to be made. It's important to factor in light pollution or atmospheric haze in addition to the angle at which the stars are positioned.

    Depending on your camera and lens, you should use the following settings. It's important to remember that the 500-rule isn't infallible, and that you'll probably need to make some tiny adjustments that account for factors like light pollution, the position of the stars, and atmospheric haze.

    How to Use the 500 Rule to Calculate Shutter Speeds

    In that case, what exactly is the formula that determines the optimum shutter speed? It's elementary, really:

    Maximum Shutter Speed = 500 / Focal Length.

    The 14mm lens you're using is the industry standard for low-light photography. A shutter speed of less than 35 seconds should get crisp stellar images, with 500/14 giving you the absolute minimum.

    Just that? Finished? Just barely. There will be some people for whom the aforementioned formula doesn't work. The computed shutter speed above is designed for full-frame sensors, so if you're using an APS-C or Micro Four Thirds camera, you'll wind up with blurry stars.

    To determine the fastest shutter speed possible with an APS-C or Micro 4/3 sensor, multiply the focal length by the crop factor. It's common for APS-C sensors to have an crop factor of 1.5, while Micro 4/3 sensors get a crop factor of 2. The crop factor for Canon's APS-C sensors is 1.6, which is slightly different from other manufacturers.

    Maximum Shutter Speed (APS-C) = 500 / (Focal Length * 1.5)

    Maximum Shutter Speed (APS-C, CANON) = 500/(Focal Length * 1.6)


    When employing the 500 rule for night photography, use caution.

    The 500 rule is an excellent guideline for night photography, but caution should still be used. There is still a chance that you will see some haze in your stars even if you take all of the precautions that have been outlined above. This is because there are imperfections in the guideline.

    For crisp star images in your final product, it is highly recommended that you first take a test photo just at calculated shutter and then zoom into the preview. If not, the duration of their exposure should be reduced. A maximum exposure period of 30 seconds should be used for photographing the night sky.

    Why Do Photographers Follow The 500 Rule?

    Despite the fact that the 500 rule is much more of a guideline, it can nevertheless be put into effect. Taking images of a night sky can be greatly improved by using this straightforward procedure. If all goes as planned, your photographs of the stars will be clear the all way to a boundaries of the picture.

    The goal is to find out how long of an exposure may be used without losing detail in the stars or creating distracting star trails. Clearness in photographs is lost if the shutter speed is set for longer than is allowed by this guideline (the stars will appear as trails rather than dots).

    You'll need a solid grasp of mathematics to work with this formula, but you don't become a nuclear physicist to apply it well. This can be done easily, yet often the smallest changes have the biggest impacts.

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    How Does It Work?

    The regulation goes as follows:

    SS = 500 / (CF x FL)

    If this formula is confusing to you, take heart; all you need to do is learn the abbreviations. Shutter speed (SS) is given in seconds, crop factor (CF) is the ratio of your sensor's area to that of a full-frame sensor, and focal length (FL) is given in millimetres.

    The optimum shutter speed is determined by the following formula: 500 divided by the product of the crop factor and the focal length.

    Different crop-factor settings will be required depending on the camera model you use. If you need a reference, here it is:

    Full-frame cameras, times one

    Compact System Cameras from Nikon and Canon have a 1.5X (1.6X) magnification.

    The X-Micro 4/3 and a Second Camera

    Compact cameras with such a one-inch size sensor and magnifications of 2.7x and higher (or smaller)

    There is no special significance to the number "500" in this formula, despite its widespread use. Astrophotographers have merely determined that this particular value produces the greatest results for their shots.

    The magic of this method is in its ability to calculate your camera's optimal shutter speed on its own, allowing you to capture images with highest possible level of transparency. It finishes the job as quickly as feasible.

    Let's pretend for a second that you wanted to photograph the night sky yet had no clue how to avoid capturing star trails. For instance, you anticipate that the picture you take with a micro 4/3 camera with a remote lens adapter cable would turn out great because you choose a shutter speed of 60 seconds. On the other side, you'll get a hazy photo that doesn't do credit to how beautiful the sky actually is.

    The 500-Rule is a helpful tool for determining how long a picture must be exposed for when utilising a particular camera system. It's not precise enough to be called a science.

    The Science of It

    To estimate how much longer this exposure period can be before the stars' motion becomes visible, we need to come up with a simple formula.

    A full rotation of the sky takes 24 hours and occurs at a speed of 0.0042 arc degrees every second. The vertical field of sight will be 73.7 degrees when utilising a 24 millimetre lens on a full-frame camera.

    Suppose this camera's sensor contains 24 million individual photoreceptors (6000 x 4000). The aforementioned 73.7 degrees are reflected onto 6000 pixels, making the pixel density per degree 81.4. The 500 rule states that a glass of this sort requires an exposure period of around 21 seconds (500/24).

    The sky will revolve by about 0.09 degrees in 21 seconds (0.0042 degrees times 21 seconds). With this camera, 0.1 degrees is equivalent to 7.3 pixels (81,4*0.1).

    The amount of pixels which must pass well before stars as we see then in the sky became star trail in the picture is exactly 7.3 pixels; this is the maximum degree of motion blur that is permissible. But can you make out this sway in the photos?

    Most of the time, our visual attention is drawn to visuals on a screen. If you try to zoom in to 100% on your full-resolution shot, you'll discover that the stars are actually points of light. This is of course completely meaningless, as you could never see this with your naked eye.

    It's something to consider if you want to print your images in a very large format. When posting images online (Flickr, Instagram, etc.), the attention to detail is less important.

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    Is the 500 Rule Effective?

    If you were to use these shutter speeds in the real world, how well do you think they would perform? The right answer is "occasionally."

    When asked if they thought the 500 rules were reliable, respondents offered a range of responses, but most agreed that the system is highly effective in most situations.

    As noted by seasoned photographer Craig Stocks, the extent to which a picture taken with the "500 rule" is devoid of star trails depends on the camera's resolution and the quality of a lens. Higher resolution systems increase the likelihood of spotting star trails.

    This effect is more subtle with lower-resolution cameras, and therefore the 500-rule works better for them.

    As an additional note, if you take your images near the horizon, the stars may appear to move a bit quicker than they actually are. Because of its significance, this needs to be brought out.

    The 500 rule is a good place to start, but it's not a perfect measurement, so you'll need to play around with your own camera and lens setup to see what works best.

    Tools that are useful

    What Is The 500 Rule In Photography?  by Wild Romantic Photography Melbourne

    • Many different stacking programmes exist, and some of them are listed below. When need to stack untracked photos, We utilise either Adobe Photoshop or DeepSkyStacker. It's worth looking into the picture stacking script option in Adobe Photoshop, which automates the procedure.
    • Mr. Senator - As a bonus, it's completely costless for Windows users to make advantage of. It streamlines the process of picture stacking, allowing you to create a stunning image with no effort. The RAW format, crucial for the highest quality results, is now supported.
    • The trial version of Starry Landscape Stacker can be downloaded for free, but it's only compatible with Mac OS X. When utilising this programme, you can rest assured that your photographs will out out beautifully. The only real downside is that you can't use RAW files directly, therefore you'll need to use Adobe Flash RAW or another programme to convert it to TIFF before you can use them in the programme.
    • Another programme that works on Windows is called DeepSkyStacker. It streamlines the stacking process by handling registration and post-stacking tasks with minimal effort and storing the output as a TIFF. We have an exclusive range of wedding photography Mornington Peninsula services. Check them out here.

    Images of the Star Trail

    What do you do if you really want to schedule a time to display the star trails? Star trailing is a photographic technique that allows the stars' apparent motion across the sky to be artistically recorded. The procedure requires taking images with far longer exposure durations than those required by the 500 rule.

    Photographers will employ the longest exposure time feasible in order to record as much sky movement as available (without blowing out the highlights). As a rule of thumb, a tripod as well as a thirty-second exposure duration will do the trick. In order to create exceptionally lengthy star trails over time, the pictures are blended in Adobe Photoshop using the "lighten" blend option.


    The 500 Rule isn't foolproof, but it's a good rule of thumb to bear in mind when trying to capture the perfect shot of night sky with your camera. Like many amateur photographers, We started out with crop-sensor, entrance DSLR camera as well as a kit lenses (usually 18-55mm or similar).

    You should try out the 500 Rule the next time you set up your tripod, since We believe it to be an excellent solution for consumers in this situation. If your sensor has a higher megapixel count than 30, you should probably tone down the 500 Rule's recommendations and look at the NPF Rule instead.

    If you can grasp this concept, you'll have a far better grasp on how to picture the stars in the night sky, which are effectively moving targets.

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    Whether you're shooting with a full-frame or micro 4/3 camera, the 500 rule is a useful benchmark that may be applied in a variety of settings. The Milky Way, or your favourite constellation, may be captured in astonishing detail using image stacking and a variety of software tools.

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