Tag Archives: Resolution

Getting down to pixel level

Getting down to the pixel level in your pictures.

Getting your image sharp is more about your photography technique than where the pixel level is in the image.
Click image to view large.

Viewable images need sharpness.

Viewing an image on your computer is easy. Just open it up. Actually, that is not the full image in most cases. It’s a tiny version of it. A control on your image viewer will allow you to view it at 100%. It is at that resolution that you will know what the sharpness is really like.

What you see normally

When viewing a full image on a screen you normally see the picture reduced. Most people have the image viewer set to show the full picture. To fit it on the screen the computer does a throw-away exercise. It looks at the image file data. It finds as much detail as it can to discard but still leave a picture you would recognise. To do that it will lose some of the picture detail. But to compensate the image is sharpened up. That means the computer will emphasis any lines and edges it finds. This helps you to see detail and make up the rest.

We are very good at that – making up the rest. After all, every image we see is in two dimensions. But we still perceive it in three dimensions – because we make it up. So it is with the lost detail. We still see the image as pretty complete and can imagine it. The picture above was taken on a 21 mega pixel camera. The original picture is 5616 x 3744 pixels = 21,026304. So as you see it, at 800 × 488 pixels (scaled to 473px × 288px) it is pretty sharp. You can see it at 1000px wide if you click the image to get a larger version.

Most cameras take at least 8 mega-pixel images

What eight mega pixels means is that the sensor has approximately eight million photosites (sometimes pixelsites) on the digital image sensor. A pixel site is one individual sensor point. It senses the light. Each pixel site translates into an individual pixel in your image. You can see how to calculate the different mega-pixels on this page  Camera mega-pixel calculator - External link - opens new tab/page.

See the pixels as they are – get sharpness

A picture at one hundred percent of its size is at its proper resolution. It is the picture that the digital sensor was able to capture. If you view the picture at this resolution your image should be sharp. If it is not then your photography technique needs some work. Sharpness at the 100% size of an image is the tale-tell. It tells you if you are really getting a sharp result. Any smaller resolution and the sharpness is created by the computer, not your technique.

Seen at 100% resolution each pixel will fall into the visual position that you expect and the image will appear sharp. If on the other hand you are viewing the image at 100% and it is not sharp you will see lines and edges that are blurred. They will appear ‘soft’ – as if the lines and edges are not really as thin as they are when you see them in real life. The image below is a section of the image from the top of the page. It is shown at its 100% resolution. Of course it is cropped to fit the space. So you are not seeing the full picture. However, you should be able to see the detail.

The image from above at 100% resolution. (Pixels are not visible as individual points)

A section of the Christmas tree from above showing the sharpness when viewing at 100% resolution. The detail is clear and recognisable.

When you blow them up pixels are messy

If you open an image up at more than one hundred percent you are asking the computer to lie to you. An image file can only reproduce an image at the resolution it was taken at. If you ask it to blow up the image further it will try to do it. What you actually see will be a best guess. Your computer will try to show the current pixels replicated outwards. Each pixel will be surrounded by replicas of itself. This will make your picture look blurry. If you continue to blow it up you will get a pixelated version of the picture. Squarish artefacts and lines appear. The picture will look increasingly blocky as it gets more blown up.

A blown up section (500% resolution). Look carefully you can see individual pixel points. The quality is poor.

This image is blown up to 500% of the proper resolution. It is still taken from the image at the top of the page. You can see individual pixel points and the quality is lost

What is the point?

The point, that is what a pixel is. When blown up large enough it shows as a single point on the picture. It comes from one point on the image sensor – a pixel site. At normal resolution a pixel is too small for the eye to see individually. Mixed with all the other points it helps create a picture. The eye views all the different pixel positions as a mass. Not individually. Together they form an image. But that image is the result of your minds eye assembling them to resemble reality. That is what you see. It is an imagined facsimile of reality run together from a mass of dots.

When you next see an image you have made, stop. Change it to 100 percent view size. See if it is sharp. If it is not, work on your photography technique (see: The Zen of sharpness). If it is sharp, then bless your imagination because you have created a wonderful thing in your head. You have created a real image.

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Damon Guy - Netkonnexion

Damon Guy (Netkonnexion)

Damon is a writer-photographer and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photogs.
See also: Editors ‘Bio’.
By Damon Guy see his profile on Google+.

Simple mistakes to avoid in photography

The quick way to improve:

…Is undoubtedly to listen to the mistakes that others made. Here are some easy things you can do to improve your photography in leaps and bounds. Getting lots of practice is the first step. The more you shoot the more you will get to know what works and what does not. However, going further than that takes a little diligence. So here are some things to do for quick improvements…

1. Not reading the manual

Get the manual out. Learn a technique from the manual. Then go out and use that technique.

2. Not reading the manual again in six months

Repeat (1) in six months. Using your camera will become easier and your memory will be refreshed.

3. Not making friends

The most fun you can have in photography is with friends. Join a club, find some other camera owners, join a website that shares comments… whatever you do – get people to look at your photos and help you with tips and tricks.

4. The equipment you own

Read “Seven deadly photographic sins” and realise that you should concentrate on learning everything about the equipment you own. Once you are an excellent photographer with your current equipment then consider new stuff, but not before.

5. File resolution

Shoot with the largest file size and highest resolution. If you do not know how to do that consult the manual. This is important. Using tiny files and low resolution will really frustrate your improvement.

6. Not checking the image

Beginners often click away without checking the image. Shoot-and-hope mostly fails. Check your screen, check and check again. Reduce the number of shots you take. Concentrate on composition – make the images you do take higher quality. Read up on “Chimping” the gentle art of screen checking!

7. Deleting in camera

Do not delete in camera… There are many good reasons for this…

  • Constant deleting shortens the life of your memory card – only ever format the card.
  • Unless very experienced you are probably not qualified to say if a shot is good or bad.
  • You cannot possibly tell if an image is good enough in the low resolution of a camera screen.
  • As your ‘eye’ develops you will change your idea of what is a ‘delete’. I have seen an image voted Best-shot-of-the-day but listed as a deleter by the author before the vote.
8. Not looking at the image in full size

There is only one sure test of sharpness, look at the image in full resolution. When you pull the image up on screen it is reduced and sharpened. Expand it to 100% to see it as you took it. Read your software manual to see how.

9. Ignoring the light

Find out all you can about light – all types of light and all sorts of lighting situations. You can find a whole range of resources here… Light and Lighting – Resource pages on Photokonnexion. Your knowledge of light will make you a great photographer if you focus on that alone.

10. Not using a tripod

The best sharpness tool is using a tripod. Never forget your tripod and you will always have sharp images!

For more on this subject and some detail of how to get past these mistakes read: Mistakes beginners make and how to overcome them

Here is a short video with four more great tips for you to take on board…

Mistakes to Avoid as a Beginner Photographer

startphotography channel External link - opens new tab/page

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By Damon Guy (author and Photokonnexion editor)

Damon Guy - Netkonnexion

Damon Guy (Netkonnexion)

Damon is a writer-photog and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photogs.
See also: Editors ‘Bio’.
By Damon Guy see his profile on Google+.