PTNSYSTEMS NEWSLETTER MAY 2008

In this newsletter we will be looking at digital camera issues, resizing photos and industry developments which may be of interest to our customers.

Resizing photos and megapixel confusion

As digital photography has become more popular, and more and more people own digital cameras, we are seeing more problems relating to storage and the transfer of digital images via email etc. Many people find that they are running out of space on their hard drives because pictures are taking up a lot of space and when it comes to send an email attachment, with a picture file, it is not getting through or taking a long time to download.

Any form of information created and/or stored on your computer takes up space on the hard drive (please see previous newsletters on this). The more information stored in the picture the more space it occupies or the smaller the information in the picture the more we can save on our computer, it depends how you want to look at it.

Camera manufacturers have, for a long time, promoted their products based purely on the number of megapixels the camera uses to make images. A pixel (short for picture element) is the smallest component of the image, a small dot of information which makes up the entire image. In basic terms, the inside of the camera contains a small sensor with a grid of tiny light sensitive receptors, by multiplying the number of these, across and down, we arrive at a total number of pixels, normally in millions, or megapixels, so, if we believe the advertising, we simply buy the camera with the most pixels that we can afford. Now, 12 megapixel cameras can be bought for just over £200, so surely we would laugh at anyone paying £2500 for a 10 megapixel, Canon EOS 1D Mk III (and you don't even get a lens for that!). As you've probably guessed all is not what it seems, as computer manufacturers have focused the public's attention on faster processors equals faster computers so some camera manufacturers have used a misunderstanding of the market to promote products. Both scenarios stem back to a time when this was true, for computers the fun began when the processors ran at the same speed as modern microwave ovens and for cameras when a megapixel was a breakthrough. This doesn't mean all our digital cameras are massively over engineered, but it does mean that for 95% of the population they are probably making pictures far greater in size than they need to be.

Here are some guidelines for the size of image required to print certain size images at he highest quality:

• For a Photo quality 6 x 4in (15 x 10cm) print, your digital image needs to be at least 1800 x 1200 pixels, which is roughly 2.2 megapixels.

• For an A4 (21.0cm x 29.7cm) perfect photo quality A4 print, your digital image needs to be at least 2520 x 3564 pixels, which is just under 9 megapixels.

The figures above are a guide for printing pictures at a very high standard, and you would be generally not get the best results unless you were using professional paper on a professional grade printer. To print a good quality image on a piece of A4 to put on the wall you need about 2-3 megapixels or less.

Many people often remark that they never actually print any of their pictures, they either play them through their televisions or look at them on a computer screen, now we are talking about a much smaller file needed to display a good image on the screen. The most common resolution used on computer screens these days is 1024 x 768, this is probably the number of individual blocks of light which form the picture you are looking at now, if we want to look at an image which fills our screen we therefore only need an image which is less than 1 megapixel! If you download this image of the radio in our office (you may want to right click and select save target as to download for later) which was taken with a digital camera set at 1 megapixel, you will see it is perfectly adequate for viewing and, for storage interest, it is less than 200KB in size!!!!!

In short, large images are better for larger prints or if we need to crop the image and only use part of it. The downside is, they are slower to transfer on to our computers, take longer to send by email and they take up more space on our camera card or hard drive. If we reduce the size of the image the camera produces or reduce it afterwards it will take up less space and be far easier to manipulate, we will also be able to take more pictures before filling up the storage card on the camera. The easiest way to reduce image size is at the source i.e. the camera. Nearly every digital camera, I have seen, has this facility, within the settings menu, to reduce the picture size from say 6MP to 4 or 3, try it and see how many more pictures the camera can accommodate, try it and print some results (if you ever do) and see if the image looks any different.

If the thought of playing around with the camera settings isn't too attractive to you, or you already have large image files you want to make smaller, then we have to do some post camera processing. There are numerous photo editing software suites on the market, you often get something with the printer or scanner when you buy it, so if you're already familiar with something like Photoshop, it's probably best to stick with it. Within our chosen software, what we are looking for is the resize option and in the next part I'll explain how to do this with a built in piece of software on most computers, Microsoft Paint. This is a basic piece of software for image manipulation found on all Microsoft operating systems, we can open the software by selecting START-RUN and typing MSPAINT in the run box or look in START - ALL PROGRAMS - PAINT. Once open, we need to find the picture file on our camera or computer (please see previous articles for advice on browsing and file and folder navigation) to do this in Paint, select FILE, OPEN and select the image we want to resize (you could practice with our office radio image you downloaded earlier). Another method to open a picture file in paint is to navigate to the file and right click on the icon, then select OPEN WITH and select Microsoft paint.

The nice thing about MS Paint is that it opens the image in its entirety so you see the realistic size of the original image, to make the file smaller all we need to do is resize the original which should make it physically smaller and thus reduce the amount of space it requires on the camera and/or hard drive, it will also make it easier to send via email. Another point here is that if you are using dialup internet (as opposed to broadband) you don't want to be sending or receiving image files greater than a few hundred MB, unless you have a lot of patience and like big phone bills.

With our picture open in Paint, select IMAGE then STRETCH and SKEW, as long as we keep both values the same the image reduces in size equally so, in the stretch values, change the horizontal and vertical values from 100% to 50% (practice with this figure to see the results), at which point the image should shrink. Now select FILE then SAVE AS and save the original file as another name e.g. IMAGE-2.jpg now close Paint and look at the size of the image, it is nearly 4 times smaller than the original, and perfectly viewable.

Most of what has been covered here also applies to scanning and perhaps we'll cover more about digital imagery/photography, in later editions.

AVG FREE, VISTA SP1 AND XP SERVICE PACK 3

Many of you who have AVG anti-virus are probably getting reminders that support for earlier versions is coming to an end, there is no need to pay for, or buy anything, just download and install the new version which can be found here or here. We have found it is more successful to uninstall the previous version before installing the new one, it is also quite a large file so don't worry if it takes a while to download.

Those of you with Windows XP or Vista should also check your Windows updates are fully installed as there is a major upgrade to Windows XP available (service pack 3 or SP3), this is again a very large file, so you may want to leave it downloading while you do something else. If your machine is correctly configured for Windows updates you should get a yellow shield notification near the clock in the bottom right hand side of the screen prompting you to install updates. If you prefer, you can manually force the update process by selecting Windows or Microsoft updates from the start menu and following the prompts.

If you have multiple machines or need to save the file for later:

Windows XP Service pack 3 can be downloaded here (large download) please read instructions fully before proceeding.

Windows Vista Service pack 1 x86 can be downloaded here (very large download) please read instructions fully before proceeding.

Please feel free to email or call the office if you have any questions, or suggestions for future newsletters or know anyone who would like to receive notifications of new newsletters,

looking forward to your suggestions.

PTNSYSTEMS LTD