300 or 180ppi?

[poledark]

Checked out my Olympus 3mpx and it shows 72 dpi ............. still produces super pics, Personally I would forget about dpi

 

Den

[Sharkbyte]

What on earth is this dissecting of ppi all about?

 

It's merely an arbitrary figure that has no relevance to the quality contained within an image file.

 

If you want more or less ppi use photoshop to adjust. It wont make any difference to the quality of the captured image, least of all on a monitor.

 

Sensors have nothing to do with the ppi in this context and they are not limited to 180 / 300 ppi or anywhere near it. I guess the sensor on my camera is roughly around 1" square and produces 8.2m pixels. A compact with the same no. of Mp's will produce images with even more pixels per square inch of sensor due to the sensor itself being much smaller. I would guess that Cliff's compact produces somewhere in the order of 20m pixels per square inch of sensor.

 

Ppi and dpi are only really relevant to the printing of images. Photo sites per sq" of sensor is another subject entirely.

 

My files in Jpeg are 3504 x 2336 pixels.

 

Set to 72 ppi / dpi this would give a print size of 123.61cm x 82.41cm.

 

If I converted an image to 72000 ppi / dpi I'd in theory get an image of 0.12cm x 0.08cm but what's the point if you neither print nor display at this resolution?

 

The fact is that 10mp cameras produce 10m pixel files regardless of ppi / sensor size. If you want A3 prints great, if you want to seriously crop images and still have enough pixels to produce quality prints great. Memory is so cheap now that 4/5 Mb files in Jpeg are not a problem.

 

I am certainly agreed that huge numbers of pixels from small sensors being more marketing hype than anything else. I'd say most compact users would be better off with half the no. of (but greater sized) pixels and the resultant lower noise characteristics at higher ISO's.

 

However the image quality if I zoomed in is only as good as 180 ppi, the more pixels per inch the better the eye perceives the picture, it will become grainy much sooner than the same picture from a 300ppi sensor.

 

Nope, if you had two 10Mp images, one set at 1 ppi and another at 1000 ppi they would both appear exactly the same on a monitor display. Zooming in or out would make no difference to what you see as monitors are fixed in the number of pixels they display, for instance 1024 x 768. ppi settings are disregarded hence we resize our pictures to 800px max length for the comps..

 

This image is set at 72 ppi (according to the old 'web display' myth) 600px longest side.

 

Here's the same file but set for 2000 ppi, again 600px longest side.

 

I would completely dismiss the ppi issue as an irrelevance, as far as cameras go.

 

Edit - I can't believe how desaturated and flat those pics look once resized and posted. New thread coming up!

Edited September 6, 2007 by Sharkbyte