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Mobile photo: # 1 Sharpness

Superuser II
Superuser II

Mobile photo: # 1 Sharpness

Mobile photography and SLRs are the basicaly the same. We want to capture a scene, to express an idea. Perhaps we only want a Facebook image or wallpaper, perhaps we want a picture on the wall of a living room or even aspire to a wall in the Louvre, we still need to know the rules and follow them, maybe know when we break them and why.

We will start with these basic rules and we will gradually work on the more complex ones.

# 1 The photo should be sharp

Exceptspecial cases, it is desirable in most cases for the photo to be sharp. It's not that simple, sometimes a is required to have sharp whole photo, typically with landscape photography, sometimes we want to emphasize the central theme, and only it will be sharp and the background should be blurred. This is called a depth of field.

 

OK - we want a sharp photo - how about it?

You need to realize why the photo is not sharp. The most common causes are:

  • Motion blur
  • Wrongfocus
  • Blur by moving the subject
  • Dirty lens

What with this? Motion blur, along with wrong focusing, is probably the most common cause of blurry photographs. Everyone of us shakes hands, more or less. Blurring of the image then depends on exposure time. Unfortunately, camera application does not show us the time, but if we switch to manual mode, we can not only see it but also change it. The shorter the time, the bigger the chances of a sharp photo. There is a rule that you can hold a time equal to the overturned value of the focus, in the case of mobile phones about 1 / 25s. Taking into account that we have effective stabilization available, we can get around 1 / 10s.

 

If the mobile is setting too long time, you can figure it out by increasing sensitivity (ISO), but mobile phones are very noising, and we do not want it. You can see that  ISO 50 photo is still without noise but blurry because the time was 1 / 4s. Next photo has been taken at ISO 800 for an acceptable time of 1/60s but the noise has increased:

 

50.jpgAperture: f / 2.4 Time: 1 / 4s ISO: 50 800.jpgAperture: f / 2.4 Time: 1 / 60s ISO: 800

If we photograph a static scene, we can use a tripod . It completely eliminates hand shake and small tripods such as GorillaPod are lightweight, and are not as expensive.

stativ.jpgSimple tripod with mobile phone adapter

If we do not have a tripod at hand, the mobile can lean on something or at least lean on its own.

 

In the case of Note9, it will also help trigger the trigger with S Pen. This eliminates the vibration of your mobile when touching the display.

 

Inappropriate focusing you have to check. Sometimes, however, the camera has trouble focusing. This happens most often when there is only few light on the scene or when we try to focus on a single area (white wall, sky, paper). The camera looks for contrasting elements on the scene and focuses on them.

We can help by finding something contrasting at the same distance as the subject, focus on it, and then compile it and photograph it without further focusing. But be careful that in automatic mode the camera also sets the exposure according to the focused scene, so if the scenes according to which we focused and the one we are shooting differs a lot, we get a badly photographed photo. This can be fixed a bit by manual exposure adjustment during sharpening, when we simply estimate the difference in scene brightness and shift the exposure correction accordingly.

 

Blurring of the subject's movement occurs when we take pictures of a tripod, for example, and a car will pass quickly.The whole scene will be sharp, but the car blurred. This can be avoided by focusing on a place where the car will go, then changing the composition to the moving car, keeping it in focus, and pressing the trigger in the spot where we have previously focused. All the time we have to keep the car in the picture and move by the phone! This will make the background behind the car blur, but the car remains sharp. I admit that this technique is quite complex on the mobile.

 

Dirty lens . You would not believe how frequent the problem is, especially since our wise manufacturers have moved the fingerprint readers alongside the camera lenses (S8 owners have something to tell). But the truth is that even if you are careful, somebody may sneak in the lens, drop a rain drop or a snowflake on it, etc. There is nothing left to watch out for and regularly clean the lenses with a special optic cloth.

I would still go back to what's supposed to be sharp on the photo. I have already mentioned the situation with the moving car, but there is more.

 

Portrait

eyes should be sharp, background blurred

Moving objects

the main object sharp, background, eventually surrounding, can be blurred both with depth of field and movement

Country

it should be all sharp

Macro

For a macro, a greater depth of field is difficult, the background may be blurred

Running water

the flow of water may be blurred for a long time, I will describe later

 

I have mentioned the depth of field several times. But what is it?

When you focus on a location, it will not be sharp only this, but it will also sharpen part of the image before and behind that focus. And this range, where we see the shot as sharp, is called the depth of field. (While the spot we're focusing on is called the plane of focus - it's not quite a plane, but rather a sphere, but it's all, just everything at that distance will be sharp perfectly and everything in the depth of field will actually be a bit fuzzy, but people they will still feel sharp).

 

The range of depth of field is affected by three parameters:

  • Aperture : The larger the aperture number, the greater the depth of field
  • Focal distance (zoom): The smaller the focal length, the greater the depth of field
  • Distance from the object: the greater the distance from the subject, the greater the depth of field

Unfortunately, mobiles do not allow for more intense work with the aperture and only limited with the focus (S9 + and the like have two or more cameras that differ in focal length.) It is called a portrait lens or a zoom in. It means in practice a greater focal length, zooming and less depth of field).

I have prepared a small demonstration of the use of the aperture. Note9 has a variable aperture, can be changed between 1.5 and 2.4, and it is beautiful to see how the background blur is changing.

15.jpgAperture: f / 1.5 Time: 1 / 15s ISO: 100 24.jpgAperture: f / 2.4 Time: 1 / 8s ISO: 100

I hope you like the first part and look at the exposition next time. Any questions I would like to answer. 

6 REPLIES 6
Superuser I
Superuser I
Thanks for sharing this information, I personally tend to use the easy mode because honestly - I'm quite horrible at making pictures.
Superuser II
Superuser II

I also prefer auto mode because it is faster.  But sometimes it fails and it is good to know why and how to figure it out. The will be more articles,  but I have to translate them from my native language

Big Cheese

Hi @Libb,

Is it worth all you are teaching us when using a camera phone?

Honestly...no it isn't. 

 

I'm sure most of people are not gonna spend time on it. Nowadays smartphone's cameras are "smart" enough.

 

One needs a real camera to enjoy what you are teaching us. There's not much "to play" in our "Galaxys.

 

Anyways... I liked! 

Superuser II
Superuser II

I hope there are still people who want to know how things work

Highlighted
Superuser II
Superuser II
Mastermind

Thanks very much @Libb for your knowledge.

 

Mr mifkop, this information will be useful for us for a mobile phone or a camera, in a close future, cameras will have more possibilities. Some months ago, I told you about addons to fix some problems you has say about pictures with mobile phones.

 

I don't want to extend much about it.

 

Cheers

 

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