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Small, yet perfectly formed...
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This is probably a set of stupid questions but hey! I know one of you lot will know the answers. Probably Tim!

The first lot of pics i took i had the camera set to the default quality which is HQ and 2569 x 1920. The results and resolution were ok but if you crop and blow up a lot you can see pixellation. You do get 200 shots on a 256 card though.

I tried a few on SHQ but didnt twig at the time that the resolution was still 2560 X 1920. The files are approx 4 times bigger though so i assume that the difference between HQ and SHQ is more to do with the compression algorithm used? IS this right? in this mode you get about 50 pics to a 256 card. I notice on the menu there is also an enlargement option. what's that then? It doesnt give the pixel count.

This weekend I wanted to take some good portraits of the kids, really top notch so that i can get them printed as poster size for their Dad's 40th birthday present. I set the camera to TIFF, and again 2560 X 1920 because that was the highest resolution. The camera said it would do 17 pics this size to my 256 card. Actually it only did 10 and then said card full. When i looked at the pics they werent that impressive and I couldn't really see any difference between them and the ones i had taken previously on SHQ. As i understand it TIFF doesnt use any compression??

So firstly have i understood how this works correctly? And more importantly what is the best settings to use for taking pictures that you want to blow up really big (especially in this case where you dont mind filling the card).

Also can anyone recommend places where they do prints in poster sizes say A3 or A2, assuming i ever get a picture good enough to do that big, at reasonable cost

Oh and one last question, is there a handy lookup guide anywhere for picture limits for enlargements. you know such as , if its X pixel by Y pixel you can only blow it up to size Z??

again i know most of this is an RTFM problem but I dont find the user manual very friendly (yeah i know it's cos I'm and engineer and we arent used to reading them..)
Thanks.
I still think it's a very sexy bit of kit!

jules
 

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To dive or not to dive - that's not even an option
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Hi Jules

As I understand it, you are mostly right in what you think, but what you also must remember is that you cannot see the difference in quality most of the time because your eye is not sensitive enough. Enlarging pictures is like writting on a baloon and then stretching it, only when it starts to strech will you see the flaws in th text.

I have attached an image which will explain more.

As for getting big pics? The cheapest way to get an A3 would be to print an A4 in high resolution on photo paper and take it to your local "STAPLES" or similar store who can blow it up to A3 for a couple of quid. Otherwise some Jessops type places will do print from disk to a larger size, you'll know where you live and what's around.

James  
 

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Snap Happy
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Yeah, wot James said.

Don't forget RAW tho.  This is data straight from the CCD so doesn't have any of the in-camera changes applied - also, no compression.  You will need a utility that can read and translate the files produced tho beacuse you can't load them directly into a photo editing package (unless you have Photoshop CS).  I know this is stating the obvious but, as the files are larger, then clearly they will eat up more of your flash memory space (tho oddly not as much as a TIFF) and take longer to write - not a problem if you want to take los of photos of anenomes but a pain if a basking shark happens to swim past and you want lots of piccis.


More info on formats as well as converters for RAW
can be found at www.molon.de/5050.html
 

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Small, yet perfectly formed...
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Guys, thanks for that, it seem Tiff on 3:2 might be the "best " for my needs. There is so much to learn about this camera but then it's fun too!
cheers
jules
 

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Small, yet perfectly formed...
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for underwater I will stick to HQ since it writes quickly and you get 200 chances to take one good pic!
 

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How high should the resolution of the digital picture be?

The quality of the photographic print depends to a large extent on the resolution of the original file. The standard digital camera models differ in the possible resolution and usually define quality in terms of mega pixel. Please also note that the possible resolution of the digital camera can be influenced by individual camera settings.

The following table describes the possible print sizes for the reproduction on photographic paper of standard digital camera models.

Image Size in
Pixels,     Mpixels, image format @300dpi, Print Size inch

768 x 512      0.4         6.5 x 4.33cm      4 x 6
1024 x 768    0.8         8.67 x 6.5 cm     5 x 7
1536 x 1024  1.6            13 x 8.67cm     6 x 9
2304 x 1536  3.5         19.51 x 13 cm     8 x 10
3072 x 2048  6.3       26.01 x 17.34cm   10 x 15
3072 x 2048  6.3       26.01 x 17.34cm   12 x 18

What effect does data compression have on the quality of the reproduction?

The quality of the photographic print not only depends on the resolution but also on the data compression used.

The standard file formats offer different data compression options. The data compression process reduces the file size.
Very high rates of compression can lead to the formation of so-called artifacts or also color purity errors both on the screen and in the print.

In this regard the JPEG or JPG format offers the highest number of variants and is generally used by digital cameras. For more information on the data compression used by your digital camera, please consult the relevant manual of your digital camera.

Professionals often use the TIFF format (Tag Image File Format). This format loses nothing in picture quality, but requires, because of this, a high amount of memory. The TIFF format (Tag Image File Format) additionally offers the option of LZW compression in order to reduce the file size. TIFF formats (Tag Image File Format) with LZW compression are not supported by this service at the present time.

The GIF format (Graphics Interchange Format) employs an extensive compression process. It is suitable only for representing pictures on the screen and not for photographic prints.



Hope this helps.... the above pixel data is based on 300dpi, but to be honest, I have seen people print poster size at 200dpi. Even though it is slightly more grainy (i.e. pixelated), with a large image you tend not to be as close to it as with a smaller one, so it evens out the image your eye perceives, if you see what I mean.  You wouldn't stand as close to a poster on a wall as you would examine a 4x6 print.
 

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Resolution of the original image is pretty much ‘fixed ‘ by the input device – be it a camera or a scanner. Enlarging the image causes problems because although you’re making the image bigger you’ve only got a set number of pixels to play with.

It’s like painting a chessboard onto a sheet of rubber and stretching it to twice its size. The pixels all become a lot bigger and you get the ‘ceefax’ effect. A nasty block result.

A way around this is to use interpolation. This is how most enlargement technologies work. When enlarging the image the device or software adds pixels between the existing ones. The pixels that are added are going to be a best guess at the colour. Often an average of the colours they fall between. But the problem is that it has to guess what colour the pixels should be. This often works well in organic graduated images but can be a problem with images like our chessboard. In this case at the joins between the black and white squares you will get grey pixels. This gives you a fuzzy – soft image.

Generally you should always aim to set the resolution at 1.5 to twice the resolution you are going to be printing at. Therefore to print an A4 at 150lpi (Commercial print) you need a camera that can take an A4 at 300ppi. (Big camera!) If you need to then enlarge the image to twice A4 size – your image still needs to be A4 but ideally taken originally at 600ppi (Even bigger camera!!!)

Enough theory - Some tricks I use with big digital images.

If you want to enlarge an image greatly use the highest resolution the camera can offer. Try to avoid any image processes within the camera or scanner. (Raw images or uncompressed Tiffs. Try not to use JPEGs). Enlarge the image yourself in PhotoShop and then use a sharpen or an unsharp mask filter carefully. Don’t oversharpen as the output device will often the sharpen the image itself somewhat when it turns it into dots for printing.

If the result still aren’t great then reducing the output resolution of the printer can often help. If it’s set to output at 600dpi – try it at 300dpi or lower. While the dots become larger the image becomes sharper.

Hope that helps – these are all general tricks rather than directed at one particular camera.

If you need any more info PM or email me.
 
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