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DPI and image quality in programs like Windows Photo Viewer


I'll keep this as short as possible.  About 6 years ago I bought a Panasonic Lumix DMC-F28 digital camera (not DSLR).  It claims 10 MP.  After that my daughter bought a Canon Rebel (don;t know the model) which has 12 MP.  I would compare her pics with mine by looking at them in Windows Photo Viewer.  Hers always looked a lot fuzzier than mine.  Especially true if you zoomed in.   And I gave her a hard time, saying she had bought a knock off.


I just purcahsed a Rebel T5i with the usual kit  18/55 lens.  I took a picture with both the new and the old camera.  Guess what?  Given the same subject with the same lighting, the Panasonic still produces much clearer pictures in Windows Photo Viewer than the Canon.  The only difference I see is that the Canon states the DPI as 72 and the Panasonic as 180.  OF course, the Canon image has a lot more pixels.


I know that DPI matters only when a picture is printed.  But is it possible that the DPI property in the image file is telling Windows Photo Viewer how to present the image?  I hope so.  Otherwise I lucked out with my Panasonic and got the best camera in the world, or a Canon is not so great after all.


Do I need to apologize to my daughter? See attached images.


These images are opened in MS Paint and cropped to bring out the eye and hair detail.

Panasonic Image

Panasonic Image



Canon Image

Panasonic Lumix DMZ-FZ8





Who knows? Your sample images could be showing an apples and oranges comparison. 72 dpi is a fine "final" resolution for online posting but more dpi means more resolution and you're clearly set up to get more resolution from the Panasonic. What happens when you compare the pictures side-by-side at 100%, 150% or 200%? This is more important.

Thanks for the reply.  I did some more comparison pictures of static subjects under the same conditions.  The Panasonic is still better at any zoom level.  I had a chat with my daughter about it.  We came to the conclusion that while in all respects the Canaon is a superior camera the kit lens that you get in the bundle is not so good.  Both of us have kit lenses.  


I've also thought for a good while that the Leica lens in the Panasonic is a very fine one and as I say, I got lucky with the camera.


I'm planning to do some astrophotography.  The Panasonic is not really suited for this.   All the pros at that tell me that I'm going to need a prime lens anyway.  So when I get that lens I may be able to see how the Canon really performs.


My daughter tells me to stop zooming in.  I told her , thanks a lot.

I don't know exactly what you did to make the 2nd image but I have never seen one that bad from any Rebel.

A T5i can produce spectaular images which yours is not.  The 72 dpi reported is meaningless.

How high did you set the enlargement?  Try a different lens on your T5i.

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Your canon image is out of focus. So it's hard to tell. Even with kit lens, the T5i will perform better. I don't think your Panasonic even have superior lens. You will need a fast lens for astro-photography but you don't need to have a prime lens. Ironically, most prime lens are faster than zoom :). And DPI has nothing to do with it.

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You comparison method is seriously flawed. For 1 image to be at 72 DPI (a software supplied setting) & the other to be at 180 DPI it means that one image has been enlarged (180 divided by 72) 2.5 times more than the other to view it on screen. Zoom in on the good image until it's 2.5 times larger & see how it looks.

Next thing you need to know is that camera technique becomes more important as pixel count increases. an 18 Mpixel image will have an 80% increase in softness over the 10 Mpixel camera from identical camera shake. To make any accurate form of comparison you will need to eleminate the possibility of introducing camera shake into the test. You will also need very similar lighting & the subject must also be stationary for all test shots. (IE that eye (or the person it's attached to) may have moved during one shot but not the othern

"A skill is developed through constant practice with a passion to improve, not bought."

" All the pros at that tell me that I'm going to need a prime lens anyway."


This is the best but you don't need an especially fast lens to do astro photography.  And, you do need to figure out what is wrong with the samples you posted first.

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