How to use overlay image to simulate long exposure time averagely

2020-11-19 22:16:52  作者:About design, photography and literature

Smooth water effect , Streaked clouds , Motion smoothing , With an ethereal appearance ; As photographers discover the appearance that can be created , Long exposure photography seems to be very popular . There are many ways to achieve this . The basic thing is to buy a standard neutral density camera filter , It can reduce the light , Allows you to use a longer shutter speed without overexposure . You can do the exposure in a few minutes , Especially when using things like Lee Big Stopper In this way 10 level ND Filters or even 15 level Super Stopper when .

The author recently wrote an article about an alternative to making long exposure photos ,“ Try this one DIY Neutral density filters for long exposure photos .” The author encourages you to read this article , Learn how a piece of welded glass can be a more budget alternative to expensive photography ND Filter .

This is where the author uses some of the other shots in this article , But when the river is higher and faster . The biggest difference is that the author uses DIY Welding glass ND Filter to achieve this shot . author

This article will teach you a third way to make long exposure images without using filters . Different from the skill of welding glass , It almost requires that your final image be monochromatic , So you don't have to fight against heavy colors , This method is very suitable for full color , No filters at all , There's no color deviation . It's a good way to simulate long exposures .

The technology uses a stack of multiple images of the same scene , And then use what's called image averaging Photoshop Process . It's very simple , And ND The traditional method of filter has some advantages .

Use ND When you take a traditional long exposure shot with a filter , You will have a long exposure .( Uh !) There are some challenges :

If you collide with the camera or object during a long exposure, move through the lens without trying to blur , You need to shoot again .

A long exposure can usually be a few minutes . If you also have camera interior noise reduction enabled , Double the time . If exposure requires 2 minute , And noise reduction requires 2 Minutes to complete , You just need every 4 Shoot once a minute . This may slow down your work , If the light changes during that time , You may miss it .

For very dark ND Filter , Once the filter is in place , You won't be able to see anything through the lens . You have to compose the picture , Pre focus , Then install ND Filter and make images .

Determining the exposure will require some calculation . You will check the exposure without a filter , And then use a computing tool to determine ND The new shutter speed required for the filter . Usually this will require some adjustment after you see your lens ...... Yes , Another one needs to be redone .

If you go back to editing, you'll see the camera , And hope you have a longer or shorter shutter speed to change the look , That's too bad . You have to go back and shoot again - If possible .

In the bright sunshine , Even if ISO by 50, The aperture for f / 22,1 / 5 Second can also reach the shutter speed , At the same time, maintain proper exposure . No filter .

The advantages of using image stacking are basically the opposite of those mentioned above :

Instead of making multiple images . If there is a problem with one of the images in the group , You can remove it and use the rest of the image to create the effect successfully .

You can see what you're doing ! Shooting without a dark filter means that if you shoot with your hand , You can still see , Composition , Use autofocus , Auto exposure , Even the image is stable .

No calculation ! If you don't add dark filters , This step can be eliminated .

Adjust in post production “ Analog slow shutter ” The length of . Want to be more or less fuzzy ? You can change your mind later .

For standard long exposure shots , Whether the conditions are too bright ? Maybe you only have one 6 level ND Filter , The conditions of the day are too bright , Can't get you the exposure time you want . You can use both methods in combination to simulate more than using alone ND Filter for longer exposure time .

Does anyone want to delete ? Because they can move during multiple shots , When the average process occurs , They will disappear !

Let people disappear ! Notes on inserting people walking in the river , But in the finished shot ,15 Zhang image , Each sheet 1/5 second / 4 Second simulation . They're gone .

Set up and take images the average image you need to create is roughly the same as any photography . Here are the factors and steps to remember :

Just because you introduce long exposure blur doesn't mean you'll automatically create a good photo . Still thinking about how to compose the picture carefully . Considering that the moving object in the lens will blur , It seems to simplify , Less detail . Good long exposure shots usually emphasize static , Don't move objects ( building , Rocks , Trees, etc ) And moving objects ( Like clouds and water ) Contrast between . Included in your lens .

The author mentioned that you can do this PDA , ok ...... Maybe you can . however , Even with this technology , You still want to shoot at the slowest shutter speed . such , You don't have to make too many shots for the combination . Once you're slower than 1/30 second ( If you only drink coffee so fast ), Then a hand-held camera may damage your lens .

All images ISO 50,f / 22. top left corner - No filters - Every 1/5 Second has 20 Images = Total number of simulations = 4 second . Upper right corner - No filters - Each sheet 1/5 second 35 Zhang image = Total number of simulations = 7 second . Bottom - 6 files ND Filter - Every time 20 second 15 Zhang image = Total number of simulations = 5 minute .

The technology simulates long exposure by combining multiple lenses . The simple formula is :

(#Shots)x( The shutter speed per shot )= Simulate the total effect of shutter speed ( In seconds )

Let's insert some numbers and see the results . Set the camera to the lowest possible ISO. The author can put Canon 6D Down to ISO 50. Some cameras ISO 100 The minimum . Do what you can . Set the aperture to the smallest possible aperture . Use these settings for measurement , And see how long each shot takes , And expose it correctly . Suppose we can do this in the shadows :1/4 second ,f / 22,ISO 50. To get a minute (60 second ) Analog shutter speed of , We need to shoot 240 A picture .

240 Zhang x 1/4 second (.25)= 60 second

It's a little clumsy , stay Photoshop Middle stack 240 Zhang may cause the computer to suffocate . So what to do ? Maybe you don't have... In your bag ND filter , But you have a circular polarizer . It helps to reduce light . You install it , Now find out that you have lost 2 standing . So your exposure time can be 1 second ,f / 22,ISO 50. Insert it into the recipe , You will get :

60 Hair x 1 second = 60 second

If you shoot in dim light , You can start with a slower shutter speed . This means that you can reduce the number of shots .

To make your work easier ( And computers ), Always try to get the slowest shutter speed . This means that you can create simulated long exposures with fewer lenses .

There is an assumption in the suite that you 6 files ND Filter . You install it , Now it's your setting 16 second ,f / 22,ISO 50. Now? , To get simulated 1 Minute exposure , You only need about four shots . Why don't you make it in front of you 10 And it can simulate 2.6 minute (160 second ) Exposure ?

If you do this traditionally , And there's a 10 level ND Filter , You can take unfiltered exposure from 1/4 second ,f / 22,ISO 50 To 256 second (4.2 minute ),f / 22,ISO 50. , Use 6 files ND Filters can be obtained with average images using 10 The same effect of the file , shooting 16 A picture .

16 gun x 16 second = 256 second (4.2 minute )

Every time 1/6 Second combination 35 Images to simulate 6 Second exposure . Shot in the sun , If there is no filter , It may not work 6 Second exposure .

Forget math , Make a decision !

If all this math is a headache for you , Here's a simple way to get what you need , therefore Photoshop Can play its magic :

Use a tripod . You don't want to do all this , And get the shaky footage . It's a waste of all your work .

Use the equipment you own , Shoot what you need at the slowest shutter speed . In the camera , This usually means setting the lowest ISO And minimum aperture .

If you have a polarizer or ND Filter , If you can , Use them to get faster shutter speeds .

Make a large number of shots for each stacked image you will create . According to the speed you get the shutter speed , Dozens are not too many . In editing , You don't have to use them all , But having more will allow longer simulations .

This recipe assumes that you will use a combination of Adobe Lightroom and Photoshop. You do not have to use Lightroom. if necessary , You can put your individual images into Photoshop in ( Although the use of LR More easily ). however , Use Photoshop It's necessary . Besides , To use the intelligent object function described above , You need a version for 14.2 Or later Photoshop. The old version of Photoshop There won't be this .

There are ways to do this with older versions in a more manual process . If you have an old version , You need to do some online research to learn the technology . Let's have an intuitive look at this step-by-step process ......

  1. from Lightroom in , Select the image sequence you want to use . Edit the first... In the sequence to your liking . Then select all of these and use the sync function , So all settings are the same as the first one .

  1. Choose all , By going to Photoshop The picture in - > edit - > Turn on layers , Take the image from Lightroom Send to Photoshop.(Photoshop Will open the , The image will be displayed as a layer in the stack ). If you want to open and stack a lot of images , It may take a while . Let it work .

  1. After selecting all layers , Select layer from the menu - > Intelligent objects - > Convert to intelligent objects . It may take a while to complete its work . Please be patient .

  1. After selecting the intelligent object layer , Select layers from the menu - > Intelligent objects - > Stack mode - > Average . It also takes some work .

wait ...... wait for ...... then ......

Presto ! You will have a simulated long exposure image , It's made up of your stack of shorter exposures . Each in 3.2 second ,f / 22,ISO 50 Of 20 Images . Do not use filters . Simulate long exposure 64 second .

in any case , The water in this section is very calm , But look at the front and back areas of the arrow , The original shot is 3.2 second , And the combination 20 Shots 3.2 second = simulation 64 second .

  1. To complete the , Please go to layer - > Flatten the image . And then the documents - > Save as and save the finished image to your favorite location . If you want to make some extra adjustments to the finished image , You can use it just like any other image Photoshop or Lightroom.

This is the magic ! For best results , Keep the following points in mind :

Think about your composition and look for a scene , In this scenario, you will have some combination of static objects , These objects will not move during the sequence . The images of both will be more attractive .

Use a tripod . If necessary , This handheld computer can execute , But be aware that any camera movement will turn to blur in the final result .

Get the shutter speed of each image in the sequence as quickly as possible . take ISO To the lowest setting , Use a small aperture , And use a polarizing filter or anything ND Filter . The longer the exposure time per shot is, the less images are needed to create an analog long exposure .

Overshoot . If you decide not to blur as much as possible , You don't need to use all the images in the sequence . however , If you don't shoot enough , You may want you to have them .

In completing these steps , Some things can take a long time . Want to have patience , Make your computer work . If the process crashes , Maybe you don't have enough computer resources , And it has to satisfy a smaller stack .

5 Images , Every 6 second = Simulated exposure 30 second . No filters used .

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