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Remove lens flare

Lens flare are unwanted artifacts caused by internal reflection and scattering of sun rays inside the lens. It appears when the sun is near or within the shot angle.

How do I remove it ?

Please note that the techniques I suggest should work for limited-sized flares. Widespread or nested flares usually are beyond help.

Lens flare can be observed in two shapes : small colored bright artefacts, and low-contrast circles or hazes.

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The small artefacts are better removed using the clone stamp tool.

HowTo_Flare_tech1_p1 HowTo_Flare_tech1_p2

HowTo_Flare_tech1_p3 HowTo_Flare_tech1_p4

Circles and hazes are a bit more tricky but can usually be managed by retrieving the right color and contrast within the damaged zone.

In order to do this, select an area a bit larger than the flare. Copy the area in a new layer.

HowTo_Flare_tech2_p1

Bind a color-balance filter to this new layer and try to adjust to the color to find back the surrounding tones. Then add a contrast filter layer on top of that and adjust it to find back the surrounding contrast.

HowTo_Flare_tech2_p4b HowTo_Flare_tech2_p4a

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Then choose a soft brush approximately the size of the artefact and carefully erase the outer edge without revealing it.

HowTo_Flare_tech2_p5a HowTo_Flare_tech2_p5b

A few adjustments may be necessary to get the maximum blending, but in the end the original artefact should be barely noticeable.

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Some prevention

– Beware of the sun orientation
If you can, regarding your desired composition, avoid shooting facing the sun. It will protect your gear from potential damage and prevent you from dealing with back light.

– Use a lens hood
For each lens, constructors provide with a hood to be mounted to your front lens. It is specially designed to reduce flare caused by light coming sideways. It cannot stop you from shooting facing the sun though !

– Invest in better lens
The cheaper the lens, the cheaper the materials composing it. A better quality lens is built with improved glass and special coating which greatly reduce image aberrations.

 

Remove dust specs

That’s it, have you been wandering in wheat fields during harvest? Or was it hiking on windy cliffs? Or you just use your gear a lot, and it gets inevitably dirty? Anyway you got visible specs of dust on your photos, and here are a few steps to get rid of it.

Where is it?

The dust you see can be in different places in your camera. Where it actually is depends on a few observations:

– Is the dust spec visible from the viewfinder, but not on the photo? Then it must be either on the internal mirrors or directly on the viewfinder lens. Cleaning the viewfinder usually sorts it out.

– Is the dust grain visible on the photo? Are your front lens and filters clean? It is always useful to clean those once in a while with a microfiber cloth or a blower.

– Your gear was pretty much clean on the outside, but the dust is still visible? You sensor might be in cause.
Do a quick test to spot dust on your sensor: take a photo of a bright and clean zone (like the sky or a white wall) at the lowest aperture your lens provides (i.e. f/22). Low aperture is needed because of the lens optical properties, which will blur sensor dust specs to the point of hiding the smaller ones at high apertures. Carefully look at the resulting photo. Any dark dust specs should pop up pretty easily on the bright background.

How do I remove it from my photos?

You will need a tool that allows to cover the dark spot created by the dust blocking the light from being captured by the sensor. The most natural method to remove the spot is to blend it by covering it with the surrounding color and texture.

In Photoshop, tools capable of doing this are either the clone stamp or patch tools.

Patch tool retouches an image using sampled pixels or pattern.

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First, select with the tool one or several zones you wish to retouch, then grab the selection to an area that matches the content you wish to overlay.

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Once you release the selection, Photoshop runs the tool algorithm that will try to blend the selected areas as well as possible, using the matching area you provided as an input.

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This tool can come in handy but it is not flowless.  For example, it generates artefacts near the selection border, especially on noisy pictures (see below). It also does not blend delimited high contrast zones when the contrasted area is near the selection edge.

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That’s why I often prefer using the clone stamp tool for this task.

Clone stamp tool allows you to copy from one area of a photo to another using any type of brush.

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Start by sampling the area you wish to copy by maintaining the Alt key pressed (a target cursor appears), then click.

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Adapt the size and hardness of your brush to the size of the spec to cover. Edges may be too visible with a brush too hard. I usually use a brush somewhere between 0% and 50% hardness.

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Photoshop shows you a preview from the previously sampled area inside the selected brush so you can appreciate whether the color and texture would fit.

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The result is much more seamless in this case.

Some prevention

Keep in mind that a camera in use will anyhow naturally get dirty. However, a few things may prevent you from having to deal with unwanted dusty shots:

– Clean your gear !
Take the time to thoroughly clean your camera and your lenses before any travel. While on the road, check your gear every day, especially if you shoot in difficult conditions, and do some more cleaning if needed.

– Be careful of your gear in difficult conditions. Avoid changing lenses near places that produce dust (dirt paths, barns, you name it). Try to do so when the wind is low, or at least make the back of your camera face the wind so it won’t blow in the opening.

– For the most wealthy of you, invest in seal-weathered gear. Seal-weathered means hermetic. It is not only useful when it comes to wet weathers, it also works to prevent dust from entering your camera, though it will not prevent it from getting covered.

Enhance a boring sky

An empty or dull sky, whether white or blue, in a large part of an image is a vaste of space in a composition. You can’t necessarily wait on site for clouds to come or go, though ! One of our modern-days solution is to artificially replace parts of the sky.

Shoot “stock” skies

During a photo trip, we often focus on the landscapes around us, and less on the skyscapes above us. However, wonderful cloudscapes could happen while the land under might not be as interesting. Be sure to shoot some of those clouds, for they might be useful later. In other terms, build a cloud photos stock.

You may want to shoot skies from a variety of focal lengths and sun orientations. Any composition will look way more natural if all parts of the photo were shot with about the same light and focal length.

Boring_skies_ex1(16mm, sun from the left side)

Boring_skies_ex2(24mm, sun from above)

Software editing

Here is an example of a photo I like a lot, except it was taken under a light rain. Correct ground exposure required to over-expose the sky, but the clouds were quite uniformly grey and shapeless anyway. I decided to add a few strikes of blue and grey shades to fill the white void left.

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I chose to compose from a photo I shot earlier under grey-but-not-as-grey skies :

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First open both photos, then select the sky area you wish to move and copy it from the cloud reference photo to the base photo. Carefully align both horizons, so that the perspective won’t look unrealistic.

With a layer mask, smooth down the clouds layer lower edges to have a glimpse of what the result would look like. You can reduce the clouds layer opacity to better see what you are erasing. Use a soft edge brush to smooth the erasing.

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If you are still confident with the outcome, continue erasing the parts that overlay with the base photo. Don’t hesitate to shrink your brush when it comes to detailed areas, but in the end you may need to sacrifice some parts of the clouds layer if some details are too difficult to extract, like branches or grass.

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To correct this you can either adjust the levels of the under layer, adjust the levels of the clouds layer, delete more of the clouds with a large brush to ease the gray scaling, or a little bit of all that :

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I actually darkened the sky in the base layer, lightened a bit the cloud layer, and erased some of the clouds in the upper corners.

Boring_skies_ps4a  Boring_skies_ps4b

 

What about blue sky ?

This same technique also applies to fill a rather completely empty sky !

Boring_skies_ps5b  Boring_skies_ps5a

 

Simple exposure compositing

Did you know the human eye roughly has a 24-stops dynamic ? Well, that is about 2 times more than the best professional camera.

This explains why you are able to see more of a place where darkness and light combine with the naked eye than when you attempt to photograph it. A camera will require multiple exposures at different exposition parameters to render a highly contrasted scene. This is what HDR (High Dynamic Range) photography is all about.

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Many software components, internal to your device, or part of a post-processing tool, allow you to automatically combine multiple exposures into one HDR picture.
I personally prefer to control the whole process, judging by myself what zones need enhancement, adding in my own sensitivity to the result. Besides, some pictures are very easy to combine with a simple layer technique.

Tips to get the shots

– Use a tripod, or at least stabilize your camera so that the shots will be stackable.
– If available, use the multi-exposure function of your camera. Otherwise select the semi-automatic aperture priority mode and manage the exposure scale manually.
– Choose the average metering mode (“[  ]”), so that the metering will not favour any zone in the frame.
– Take as many shots as necessary to cover all the exposure range (a multi-exposure function may limit to 3 or 5). No over- or under-exposed zone must be left. Each shot should be separated by a same exposure value (EV), ideally comprised between 1 and 2EV

Post processing

In this example I got 3 separate photos, taken at -2, 0 and +2EV. This means the first shot was under-exposed by 2EV, the second one correctly exposed, and the third one over-exposed by 2EV.

 Exp_compositing_basethumb1 Exp_compositing_basethumb2 Exp_compositing_basethumb3

 

You can see the multiple-exposure was necessary, since the camera could not expose the inside of the cave, too dark, and the outside, too bright, within a same shot.

Start by opening all the photos as layers within the same project in Photoshop. Stack them from the more exposed to the less exposed.

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I am going to work with layer masks. This will allow us to discard specific parts of the layers. In this example, I wish to discard incorrectly-exposed parts.
Select the less exposed layer (the first one), and create a mask.

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One of the primary properties of a layer mask is that it links the layer to a transparency scale based on shades of grey : any “white” part will show the corresponding zone with 0% transparency, any “black” part will make it 100% transparent, letting the layer from under show.

Exp_compositing_ps3a    Exp_compositing_ps3b

 

A selected mask can be painted with any painting tool (brush, gradient, paint bucket…) but only accepts greyscale (white – grey – black) colors.

I will use these mask shades to select what zones of each layer to keep.
This first base image has the right exposure towards the outside of the cave but the inside is too dark, so I’ll use a black brush to exclude any under-exposed zone. The brush hardness must be low, so that the excluded zones won’t clash with the non-excluded ones.

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If I disable the other 2 layers’ visibility, you can see what is left of my first layer :

Exp_compositing_ps4b     Exp_compositing_ps4c

The cave entrance and the area surrounding it are now just fine, but the inside of the cave is still too dark, so I will mask the second image to reveal parts of the third layer.

Exp_compositing_ps5a    Exp_compositing_ps5b

 

And voilà !

Some adjustments regarding levels and colors may be necessary, but the base composition is now complete.

Limitations

This technique is just fine for compositions where the different exposure zones are easily distinguishable.

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If the different zones were too intertwined, the masks would be a lot more complex to detail subtly.

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