300D, 450D, 500D IQ

I have had the 300D and the 450D for a while now and just recently picked up the 500D. I took some shots the other day with all three bodies using a 18-55 IS lens all within 1 min of each other and exactly the same settings. I printed the images out 12x18 and was not able to tell which camera produced what print. Should there have been a visual IQ difference between the three? I then took all three images down to my local camera store. The owner of the business also could not distinguish a visual IQ difference between the images. Maybe if I was to plot out 16x20 or bigger but not at 12x18 and lower. Am I missing something here? I guess maybe I wasn't expecting that much of a difference between the 450D and the 500D but I was expecting to see a difference in IQ between the 300D and the 450D and 500D.

jtack wrote in post #10023354
I have had the 300D and the 450D for a while now and just recently picked up the 500D. I took some shots the other day with all three bodies using a 18-55 IS lens all within 1 min of each other and exactly the same settings. I printed the images out 12x18 and was not able to tell which camera produced what print. Should there have been a visual IQ difference between the three? I then took all three images down to my local camera store. The owner of the business also could not distinguish a visual IQ difference between the images. Maybe if I was to plot out 16x20 or bigger but not at 12x18 and lower. Am I missing something here? I guess maybe I wasn't expecting that much of a difference between the 450D and the 500D but I was expecting to see a difference in IQ between the 300D and the 450D and 500D.

I don't think Canon Inc. appreciates your inability to discern differences in image quality in their DSLR models. Suffice to say, keep this restricted info to yourself... or buy a better lens and redo your "tests"!
the differences are obvious, just look here:
http://www.imaging-resource.com/IMCOMP/CO​MPS01.HTM

Post up the 100% crops and let's have a go.

Seriously, it depends on how things were printed and how the images were processed to fit the 12x18 sheet. There are a lot of variables that determine image quality but I do generally agree that images printed on paper hide many imperfections and discerning different resolutions is extremely difficult unless there is something in the image that can act as a resolution tester.

There are a lot of things to be considered when you're making prints. You'd have to take into account printer resolution as well as image resolution.

For example, take an image shot w/ a 5MP dslr and the same image shot w/ a 15MP dslr. Print them both at 4x6 and you won't notice the difference in either. The only time you'd notice a difference is when printing the 5MP image to more than its intended maximum size given the printer resolution. You'll end up w/ interpolated data at best when you do that.

I don't like using Ken Rockwell's info but I googled and it came up... here.

Anyways, if you're happy w/ your prints at 12x18 with a 300D, that should be good enough. There are differences in these models but you won't see it in print unless you print really really big or start cropping images like mad.

gjl711 wrote in post #10023484
Post up the 100% crops and let's have a go.

Seriously, it depends on how things were printed and how the images were processed to fit the 12x18 sheet. There are a lot of variables that determine image quality but I do generally agree that images printed on paper hide many imperfections and discerning different resolutions is extremely difficult unless there is something in the image that can act as a resolution tester.

When you go to purchase a print at a gallery, do you ask them to show what the images look like at 100% crop before making your purchase. I am quite sure that at 100% crop there will be differences between the 3 images as there should be.

Oh and I also tried the same test with a 17-40 L lens as well....same outcome.

And the printer used was a pro 9000

That sounds normal, honestly. All 3 cameras have enough resolution to print a 12x18 image just fine.

watt100 wrote in post #10023428
I don't think Canon Inc. appreciates your inability to discern differences in image quality in their DSLR models. Suffice to say, keep this restricted info to yourself... or buy a better lens and redo your "tests"!
the differences are obvious, just look here:
http://www.imaging-resource.com/IMCOMP/CO​MPS01.HTM

Wow, thanks for the link! On the XSi and the T1i comparison, I can't tell a difference. Oh and I really don't care what Canon Inc. thinks about my inability to discern the differences between the image quality and obviously (read the other posts in this thread) it would be hard to tell the difference between the three unless the images are plotted at a size beyond the limitations of the lowest MP camera, that being the 6.3.

sigh

at low ISO's you wont see a difference no. You also wont see a difference on the xxd range or the 7d. possibly even full frame wont look different at that size.

The larger you print and the more you push the cameras ISO etc etc is when you start to see noticeable IQ differences. The improvements with bodies are often things like high ISO, burst speed, focus system, video and resolution. low ISO quality has been at a high standard for a long time now and isn't the area that needs improving.

jtack wrote in post #10023525
When you go to purchase a print at a gallery, do you ask them to show what the images look like at 100% crop before making your purchase. I am quite sure that at 100% crop there will be differences between the 3 images as there should be.

Oh and I also tried the same test with a 17-40 L lens as well....same outcome.

And the printer used was a pro 9000

Of course not, in fact my favorite image I have hung on my wall was taken with a 4mp P/S. But that was not your question. You had asked if there would be any visual IQ difference and i answered, possibly not, it all depends on how the images were printed. I guess subject matter would come into play as well as would processing of the image and any resizing done to get the image to 12x16. I can easily see taking a 6MP image, sending it to the printer, the printer uses bi-cubic resampeling to scale the image to 5400x3600 and it doing the same to the XSi image as well. Printer applies a little sharpening, vivid up the colors, and prints.

I am sorry, I guess I should have rephrased my original question to go something like this...I print out my images no larger than 12x18 and I do not study 100% crops to determine image quality. So given that information, should I see an IQ difference between the 300D, 450D and the 500D? Anyway, thank you all for your input.

No you probably wont if you expose properly and process them well.

BTW, this discussion can apply to film just a readily. I have a 35mm camera and a medium format camera. If I blow up the image to 12x16 should I see a difference in IQ? After all the only difference between a 135 film and 120 film is resolution.