How can I set my Cybershot DSC-W350 to take pics. of at least 300dpi?

[penelope2448]

How can I set my Cybershot DSC-W350 to take pics of at least 300dpi?

[Blencogo · Accepted solution]

DPI is a printing resolution measurement and pixels are the photographic sensor capture measurement.  Some printers can interpolate the DPI but here we will assume you need 1 pixel for 1 dot.  The answer to your question depends on the print size you are using.

To print a 10"" x 8" photo at 300dpi requires a photo of 3000 X 2400 pixels = 7.2 megapixels

To print a 6" x 4" photo at 300 dpi requires 1800 X 1200 pixels = 2.1 megapixels

To print a large 30" X 24" photo at 300dpi requires 9000 X 7200 = 64.8 megapixels

If I were you, I would always shoot pictures at the highest resolution available on your camera - this gives you the greatest flexibility when printing and allows you to crop the image if required.  Just set your camera to 14 megapixels and then you can print pictures at 300dpi up to 4320 X 3240 which is up to a picture size of 14.4" X 10.8".  This is the maximum size you cam print at 300dpi.

Just set the Image Size to the maximum 14MP.

[penelope2448]

Hi,

Thank you for that information - I will do what you suggest.

[penelope2448]

Is there a formula to equate the pixels into kb etc?  I have images that I believe are too small to be printed at the required 300dpi.

[Blencogo]

What size are they to be printed at?

[Blencogo]

Just roughly for your camera: -

A 14MP image will be around 6.4 MB

A 10MP image will be around 5MB

A 5MP image will be around 3.2MB

It will depend what size they are to be printed at to calculate if 300dpi is possible.

[penelope2448]

Thanks for the reply.  I don't know what size they will be printed - they are for an article in an A5 size journal.  Should I ask what MB they need to be - it was the editor that asked me for jpgs of at least 300dpi when printed!

Are you able to answer this question for me - If I take a number of jpgs one after the other of the same subject why does the KB or MB differ?

Could you recommend a book which would help me understand these issues?

Thanks

[Blencogo]

penelope2448 wrote:
 
Are you able to answer this question for me - If I take a number of jpgs one after the other of the same subject why does the KB or MB differ?

We are getting onto complicated ground now! All the pictures from your camera are JPEGs and are compressed by the camera to produce a smaller file size.  More advanced cameras allow you to shoot in RAW or TIFF format, which saves ALL the information from the camera's sensor.  The downside is that the files are very large and you get relatively few on your memory card. Because of their size, they are also difficult to edit and take a long time to print.  Nearly every camera will allow JPEG compression.  The JPEG compression algorithm is complex but in simple terms it compresses areas of the same tone and texture more than the rest of the picture.  JPEG is a discrete algorithm, and for a given quality setting different input images may give widely differing file sizes. An image with lots of texture and fine detail will produce a large JPEG file, while one consisting only of blue sky will be very small.  Consequently all JPEG images will be a slightly different file size.

penelope2448 wrote:
 I don't know what size they will be printed - they are for an article in an A5 size journal.  Should I ask what MB they need to be - it was the editor that asked me for jpgs of at least 300dp

A5 paper is 5.83in × 8.27in

To print a double-page spread (A4) @ 300dpi needs 3498 X 2481 = 8.7MP (Landscape)

To print a full-page (A5) @ 300dpi needs 1759 X 2481 = 4.4MP (Portrait)

To print a half-page (A6) @ 300dpi needs 1759 X 1240 = 2.2MP (Landscape)

I hope this gives you an idea.

I don't know a book that covers this in an understandable way.  Perhaps someone else can recommend one.  If I think of a suitable one I wil let you know.

[Blencogo]

Try going to Amazon and search for 'Digital Photography' in 'Books'.

Click the dropdown box to choose to sort by 'Bestselling' and see which of the top 10 appeals to you.

You can try the same method but using 'Digital Camera'.

Or have a look here: -

http://www.digital-photography-school.com/12-great-digital-photography-books-for-your-christmas-stoc...

[penelope2448]

Thank you for all your feedback - difficult territory but you have given me a better understanding.

Thanks once again.