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02-17-2010, 10:03 AM   #16
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QuoteOriginally posted by frascati Quote
Is it me? Gooshin, are you deliberately trying to frustrate me? I stated, twice, with emphasis, that I'm not talking about having 8mp of information AVAILABLE TO ME!

I'm talking ONLY about viewing other's images on the web.

Stop mumbling into the air, put your espresso down for a sec, and just read the entire original question.
if you can only view 1.7 MP of pixels, then that is what you will see.

if load up a 1.7MP image and a 8MP image side by side, you will still see a 1.7MP image either way, its just that the 8MP one will be downsampled to 1.7MP

whether the 8MP image will look better depends on HOW it was down sampled. Which is an issue independent with resolution.

02-17-2010, 10:15 AM   #17
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................................

Last edited by frascati; 02-17-2010 at 10:21 AM.
02-17-2010, 10:37 AM   #18
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lets go over it one more time


But I often see pics on the web accompanied by something along the lines of "look at how sharp this photo is". My screen displays 1.76 megapixels of information. Unless someone identifies the photo as some percentage of a crop from the original, then doesn't it make little sense to comment on it's detail and sharpness?

technically you are correct, without knowing how large the original image is, what we see on the web is a poor representation of the actual photo if the ONLY variable we are going for is sharpness

on the other hand, even a web photo will show you the difference in sharpness of an FA Limited prime and a dinner plate.

also, on the other hand, there are web-sized photos that do in fact look sharp, so really the original poster has made no false claims.

Isn't, for the purposes of comparison on average laptop screens, such an image incapable of displaying sharpness and detail beyond what a 2 megapixel camera is capable of delivering?

it would have to be tested to see whether a 2MP APS-C DSLR camera can compete with a down-sampled 8 or 12 MP image.. but you would have to find us a 2MP camera first

Is my thinking off on this? And if, on occasion, shooting images for the express purpose of web posting with no intention of crop or revision then should the camera's range be set to no more than 2mp?

an 8MP camera will always shoot at native resolution, if you set the camera to 2MP, you are still shooting at 8MP then using the cameras processor to DOWNSAMPLE to 2MP.

However third party computer software does a BETTER job at downsampling, so your only incentive at setting the camera to a lower MP is if you are really running low on space.
02-17-2010, 10:49 AM   #19
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FWIW, I think the original question as asked (or as I interpreted it, anyhow) makes sense. That is, given that we are only seeing 2MP or less on screen, isn't it kind of silly for people to post images that have been resized that small and then brag about how sharp, noise-free, or otherwise great they are?

My answer would be, yes, it's a little silly. But not *completely* silly.

An unsharp and noisy image resized to 2MP might look less unsharp and noisy than it would otherwise, but there *are* differences that can be visible at that size, if you know what you're looking for. However, you'd pretyt much need to actually see the comparison to know for sure. That is, if you show me an image that you claim is unusually sharp or noise-free, but you only show it to me at 2MP, you should really post a comparable image from another lens/camera that you think illustrates the difference if you *really* want to convince anyone who wasn't already inclined to believe it. To some extent, I can compare what you posted to other images I have that I think might be comparable, but between the fact that it isn't a controlled test and the fact that we're viewing at 2MP, chances are pretty good you won't change my mind.

However, if you're just interested in preaching to the choir, not changing anyone's minds, then the simple 2MP image is fine for making me go, "yep, that's sharp and noise-free all right - at least, it looks exactly how I'd expect a sharp and noise-free image to look when resized to 2MP". Those thinking "yeah, but even a less sharp and noisier image might look as good resized to 2MP" won't be swayed, but if you're not trying to sway anyone, then who cares?

And of course, sometimes the point of posting images is that the differences we obsess about just don't matter in the "real world" of viewing on monitors or in 4x6" prints.

02-17-2010, 10:59 AM   #20
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for the purpose of optimizing for web viewing today (i.e. 1024x768), I most likely would take a perfectly sharp and noiseless (day or night) 0.79MP camera over higher mega pixels, provided that it is as advertised. (saves a lot of PP work)
02-17-2010, 11:01 AM   #21
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Funny. I was just over in the "kit lens club" going through the pages from the start and came across this

QuoteQuote:
Originally Posted by ea77 View Post

"I look at all of these photos of the kit lenses and they're average. Low in contrast and sharpness."

Amazing that you can judge sharpness at web resolution!
The retort there from Marc S himself. I copied the exchange and raced over here to post it and found Marc beat me to the space. Perhaps all of this is just the matter of a newbie overstating the obvious. In which case, I'm sorry if I overdid this. It's always difficult to balance too much with too little explanation and I might have been guilty of overstating things.
02-17-2010, 03:12 PM   #22
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Well let's see;

Without looking at the EXIF, can you tell which one of these was taken at 3200 ISO?

Which one was taken at F16?

Which one was saved as a JPG with a quality of 60 (out of 100)?

Technically, all three were taken with the exact same exposure values.

View Picture EXIF
Name:  GORE5019.JPG
Views: 85
Size:  43.3 KB

View Picture EXIF
Name:  GORE5020.JPG
Views: 86
Size:  52.7 KB

View Picture EXIF
Name:  GORE5021.JPG
Views: 91
Size:  35.1 KB

PS: those aren't compression artifacts or noise, my phone really is that dirty.
02-17-2010, 03:20 PM   #23
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the first one is clearly NOT the F16 one

the third one is ISO3200 (assuming the others are less)

and i cant really tell which one is 60/100 because at these resolutions it really is hard to tell such things.

02-17-2010, 03:40 PM   #24
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QuoteOriginally posted by Gooshin Quote
the first one is clearly NOT the F16 one

the third one is ISO3200 (assuming the others are less)

and i cant really tell which one is 60/100 because at these resolutions it really is hard to tell such things.
hehe, well power of deduction could've been used there too, since I mentioned that exposure stays constant throughout.

The first was at ISO 800, F5.6, 1/6 then resized to 640 wide with JPG quality set to 80.

The second was at ISO 1600, F11, 1/6 then resized to 640 wide with JPG quality set to 60.

The third was at ISO 3200, F16, 1/6 then resized to 640 wide with JPG quality set to 80 (same as first).

Personally, besides depth of field, I see very little difference between the three. Even the increasing noise is negligible, despite the fact that I'm pretty much at my camera's limit in that last one. The first looks a little darker, probably because the exposure stops didn't line up as precisely mathematically. All 3 are just the full-size full-quality JPGs from the camera.
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