[ElJamoquio]

If you understood resolution and Image quality you would understand that they aren't all that different..in fact the results would be practically indistinguishable.

I can distinguish between a picture taken by a FF camera with a 50mm lens, and a picture taken by an APS-C with 50mm lens.

FYI, resolution is part of image quality.

[ElJamoquio]

It doesn't need to be terrible just because it wouldn't give any obvious advantage over K-5 with DA16-45 and DA70.

At 70mm (or 105mm for the FF) I'm guessing the 70mm might have an advantage in bokeh. I'd have to look at the pictures.

For the 16-45... I think the 24-105 has better bokeh (from memory on both so don't burn my house down if I'm wrong). The 24-105 would also have another stop of control of DOF so there's another advantage.

[Digitalis]

I can distinguish between a picture taken by a FF camera with a 50mm lens, and a picture taken by an APS-C with 50mm lens.

Really? let's see you prove it...

[ElJamoquio]

Those are two different framings, sir. I was going with your original statement...

Here is a though experiement: if you reduce a 21Mp full frame image to 15Mp - and compare it to a 15Mp image from an APS-C format camera - (only the FF camera has an AA filter,the APS-C camera doesn't - both images taken with the same lens, at its optimum aperture) which image will have higher resolution?

Your pictures do not fulfill your statement. If they did fulfill your statement you'd easily see why I called it silly.

Nevertheless send me prints and I'll tell you which is which.

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Last edited by ElJamoquio; 10-18-2012 at 06:49 AM.

[rawr]

I can distinguish between a picture taken by a FF camera with a 50mm lens, and a picture taken by an APS-C with 50mm lens.

LOL. No matter how many times I hear this on the Internet, I still get a giggle out of it. It is part of the enduring 'romance' of FF, but there is no science to it.

For some, it doesn't matter if you are shooting an old clunker like a 5D 'Classic', using the kit lens, and mangling focus and exposure, as long as the body was FF, the image will still have some of that FF je ne sais quoi

[normhead]

Ya ya, if he sends you 13x19 prints you still won't be able to tell. But hey, who's going to spend that kind of money just to prove a point.

Back in the old days, my father passed on to me a study where someone studied whether beer sales were driven by marketing or taste. SO he took the best sellers from 5 different companies and brought in the die hards. To qualify for the taste test you had to be one of those guys who swore up and down on a stack of bibles that he loved one brand and despised it's competition because of the taste. The results. Of the five brands, the die hards averaged 1 in 5 of identifying their brand correctly. Exactly the same as random chance.

So my point is, people can't always do what they say they can do.

Your pictures do not fulfill your statement. If they did fulfill your statement you'd easily see why I called it silly.

So you are saying that if I'm shooting next to a guy shooting FF taking the same scene and I use different framings... people won't be able to tell which one was FF? Then I'm pretty much good with APS-c. You should have guessed, you had a 50 50 chance of being right (assuming one image was really FF and one was really APS-c) . You could have snowed us a bit longer.

[Buschmaster]

The top one is FF because of 50/50 chance.

[ElJamoquio]

So you are saying that if I'm shooting next to a guy shooting FF taking the same scene and I use different framings... people won't be able to tell which one was FF? Then I'm pretty much good with APS-c. You should have guessed, you had a 50 50 chance of being right (assuming one image was really FF and one was really APS-c) . You could have snowed us a bit longer.

You're saying that, if you're standing next to someone with a 50mm FF, and you're using your 50mm APS-C, you can't tell the difference between the two pictures?

[ElJamoquio]

LOL. No matter how many times I hear this on the Internet, I still get a giggle out of it. It is part of the enduring 'romance' of FF, but there is no science to it.

For some, it doesn't matter if you are shooting an old clunker like a 5D 'Classic', using the kit lens, and mangling focus and exposure, as long as the body was FF, the image will still have some of that FF je ne sais quoi

It's not indescribable. It's perfectly describable. He positioned a silly proposition.

[ElJamoquio]

The top one is FF because of 50/50 chance.

I actually think it's the bottom one, assuming either one is FF, but only an idiot would claim to be able to tell the difference with a 0.7 MP file.

[garyk]

Easy to tell. The guy with the FF has a flatter wallet. No brain er.

[glennbp]

Put a 75mm lens on the FF and a 50mm lens on the APS-C and then compare. Given that all other parameters are equal, the photos will be identical. This arrangement obviously takes the 'crop factor' into consideration.

[ElJamoquio]

Put a 75mm lens on the FF and a 50mm lens on the APS-C and then compare. Given that all other parameters are equal, the photos will be identical. This arrangement obviously takes the 'crop factor' into consideration.

Yup, this is the correct way to do it.

You also need to make sure the FF is set to have roughly one stop smaller aperture as well, to keep the DOF the same.

Then it's tough to tell the difference; you'd have to rely on the 30% better resolution for the FF (assuming you're using the zoom lens for the FF; if you can use a prime, then the number would be 40-50% better, depending on aperture, etc).

[normhead]

No, I'm basing it on knowledge of optics. All else the same, the FF lenses will have ~50% better resolution. It's tough to measure that across different cameras because the megapixels are not the same between cameras, in general.

Say no more, now I know where you're coming from. You're talking about what is true theoretically. Actually it's not even true theoretically. Because theoretically you'd have to establish a direct cause and effect link between image resolution and how much people enjoy looking at an image. And as far as I know that's never been done. Its a stretch to assume that given two different images people will prefer the FF based on a theoretical construct like image resolution.

It would be even further of a stretch that given two images, the determining factor in which image they preferred would be image resolution.IN fact prints are all made at the same resolution, you just blow the images up more. So to take my 4700 pixel wide images to print to 30 inches wide I need to expand to 9000 pixels or approximately twice to get to 300 dpi. Now I don't know what the specs are for a D800 but if memory serves me well it's somewhere between 6000-7000. So you still don't have 1:1 detail in your 300 dpi print. You still have to enlarge it.

So what you're saying is that you can see the difference between a 2x enlargement and a 1.2 enlargement printed at 300 dpi when the captured print resolution for one is 150 dpi. for one and 250 dpi from the other, standing at the distance you'd have to stand at to look at such a picture. I'm at least 6 feet away for a 30" picture. It's possible the "laws of optics" you're espousing say that you couldn't actually tell the difference.

Not only that , but if I print at 300 dpi and my 4700 wide image is printed at 4700/300 = 15.3 or less, and my 16 MP image is sharp, the FF image can't be any better. There can be no difference, because a sharp image printed at 300 DPI printed 1:1 is the best you can do. At that point and smaller It doesn't matter how big your sensor is, your sensor is overkill because you are going ot reduce the information to APS-c values in any case.

Then there's the whole issue of what the resolving power was of the lens that was used etc. The above "I can tell the difference " thing is so fraught with unknown x-factors that it's not even worth making, unless you've actually done the research.

The laws of optics simply haven't addressed many of these issues in any coherent fashion.

And even if they had, it wouldn't answer the question , what do people like. The laws of optics are completely incapable of even beginning to deal with that question.

So, you have to ask' if this theoretical "IQ" is not what people like, or not the determining factor in what people like, why do I even care about it?'

[ElJamoquio]

Say no more, now I know where you're coming from. You're talking about what is true theoretically. Actually it's not even true theoretically. Because theoretically you'd have to establish a direct cause and effect link between image resolution and how much people enjoy looking at an image. And as far as I know that's never been done. Its a stretch to assume that given two different images people will prefer the FF based on a theoretical construct like image resolution.

I've been very distinct in talking about the differences in IQ and resolution. It was someone else who said they were basically the same thing.

Regarding the differences between FF and APS-C, I've spoken about both theory and practice. In both theory and practice FF has much better resolution than APS-C, so much so, that when comparing a moderate/high priced ('prosumer') zoom against any (known to me, whether expensive or cheap) prime, the FF/zoom combo has better measured resolution than the APS-C/prime.

So, you have to ask' if this theoretical "IQ" is not what people like, or not the determining factor in what people like, why do I even care about it?'

Again, I'm not the one who equated IQ and resolution, I'm the one who separated the two.

I'm not silly enough to talk about preferences. Many people, myself included in some limited scenarios, like soft pictures. For most reasonable assumptions, you can make a 'soft' picture when starting with a setup that can make a sharp picture, but you can't make a sharp picture starting with a setup that can only make soft pictures.