Canon 400D Image Resolution

[Megapodius]

I have a Canon 400D which appears to take images at 72ppi. This is OK for general photography but if I want to crop and blow up a bird in a photo taken at extreme range it pixilates. Is it possible to increase the image resolution on JPEG photos? Using the RAW format gives me better resolution but is hungry on space.
I realise this maybe a dumb question but I am struggling to understand why the resolution is so low in this camera when my Coolpix P6000 takes images at 240ppi

[Roy C]

I have a Canon 400D which appears to take images at 72ppi. This is OK for general photography but if I want to crop and blow up a bird in a photo taken at extreme range it pixilates. Is it possible to increase the image resolution on JPEG photos? Using the RAW format gives me better resolution but is hungry on space.
I realise this maybe a dumb question but I am struggling to understand why the resolution is so low in this camera when my Coolpix P6000 takes images at 240ppi
The ppi has no bearing on IQ or file size it is just used for printing. 72 ppi is used for screen display but when you print just change to whatever you want. A image with 72ppi will be the same file size if you change it to 1000 ppi, the only difference will be the print size.

[postcardcv]

If you make sure that you set the camera to record the highest quality jpg then you'll get the same resolution as you do with RAW (the advantage of RAW is processing latitude, not increased resolution). The 400D is a decent camera that will give you lots of room for cropping if you want to use images on the web or will allow you to create big prints from uncropped images.

[Megapodius]

Thank you both for your prompt reply. I am having difficulty getting my head around this. I always use either RAW or Fine Large. I have taken a picture of a bird at extreme lens length which appears small in the context of the whole image. When I crop the bird to fill the scene it appears blurred. ie you can see the pixels. Are you saying that this will occur to the same extent irrespective of the ppi?

[Roy C]

Are you saying that this will occur to the same extent irrespective of the ppi?
Absolutely, as explained ppi is only relevant at print time.
It sounds as if you are trying to crop too heavily, the more you crop the less pixels you have left. Having said that if you have a good lens and the shot is sharp you can crop fairly heavily for web use - see attached which shows the original unprocessed shot shot and a heavily cropped final version. This is a 100% crop.

[petermallett]

Sounds like you need to get closer to your subject or use a larger lens. Sadly no matter what camera and lens you have if the subject is very small in the frame and you crop heavily to enlarge the subject image quality will suffer.

[Cactusdave]

That's a nice clean up job you did on the Godwit, Roy. It's true that a good dSLR plus a good sharp lens and a sharp focus will give you an image that can be cropped very heavily, almost to the level of 'actual pixels', and still be very acceptable at web display resolution (typically 72 dots per inch). They won't however look good when printed at anything more than postcard size, as much higher resolution (typically around 250 dots per inch or preferably greater) is needed for good prints. Heavy crops simply don't have enough pixels left in them to go around.

[Roy C]

That's a nice clean up job you did on the Godwit, Roy. It's true that a good dSLR plus a good sharp lens and a sharp focus will give you an image that can be cropped very heavily, almost to the level of 'actual pixels', and still be very acceptable at web display resolution (typically 72 dots per inch). They won't however look good when printed at anything more than postcard size, as much higher resolution (typically around 250 dots per inch or preferably greater) is needed for good prints. Heavy crops simply don't have enough pixels left in them to go around.
Yep, that's why I said "you can crop fairly heavily for web use".
BTW this is a 100% crop (e.g. the actual pixels).

[rockwright]

I hope this helps. When you bring up an image from the camera into photoshop or photoshop elements, and click on the image ->image size on the top toolbar, it will pop up a screen that says something like Width 54 inches, Height 36 inches, resolution 72 dpi. If you change the resolution to 300 dpi, the image size will change to about 8x12 inches. As a general rule, 300 dpi is the resolution to use for good prints. Some photo contests require that prints be submitted to this resolution. 72 dpi is ok for a web picture but will look terrible when printed on paper. You can change the resolution to any dpi you want - it will affect the final image size when printed.

When you bring the image up in your editing program, such as photoshop, make sure that under the "view" menu that "rulers" are cllicked on. Then a ruler will appear at the top and side of the picture. This will indicate the photo size when printed at the resolution you have chosen. When you crop the photo you will also get an idea of the size of the printed picture. This may be too basic but I hope it helps.

[Megapodius]

Great. I can put this to rest now. Thanks to all who replied. I have read numerous books on this without success and you have made more sense in less time.

[cab1024]

Last little thing. When you make all of these adjustments to the image size in Photoshop, make sure that the "Resample Image" box is UNchecked, otherwise Photoshop really will change the files size -- and resolution -- of you image. It will extrapolate (create) extra pixels when you enlarge, and remove pixels when you reduce.

Hope that did not add to your confusion...