[Jeff Charles]

General rule of thumb, in terms of IQ:

1) Best/Most Expensive: Pro lens with FF camera
2) Second Best/Third Most Expensive (depends on assumptions of course): Consumer Lens with FF Camera
3) Third Best/Second Most Expensive: Pro Lens with APS-C camera
4) Fourth Best/Cheapest: Consumer Lens with APS-C Camera

If we're just talking resolution, and talking generically, 2) is 50% better than 3). 1) is 10-20% better than 2).

1. "IQ" is a general term. Please be more spedific about how FF IQ is better.
2. However "IQ" is defined, it is only meaningful in reference to the display medium and size. For example, at what print size, and of which subjects, would your number 1) be visually better than your number 3)?
3. If I shoot the same photo in good light with an APS-C camera and a FF camera, where both sensors have the same number of pixels, will the FF photo show more detail?

It's a given that FF is more capable if I want to limit DOF, or to shoot at higher ISOs. But when those are not in play, how much visual difference is there between an APS-C print and a FF print?

Jeff

[ElJamoquio]

1. "IQ" is a general term. Please be more spedific about how FF IQ is better.
2. However "IQ" is defined, it is only meaningful in reference to the display medium and size. For example, at what print size, and of which subjects, would your number 1) be visually better than your number 3)?
3. If I shoot the same photo in good light with an APS-C camera and a FF camera, where both sensors have the same number of pixels, will the FF photo show more detail?

It's a given that FF is more capable if I want to limit DOF, or to shoot at higher ISOs. But when those are not in play, how much visual difference is there between an APS-C print and a FF print?

Jeff

In other posts I've given a rough rule-of-thumb of ~1.5x linear resolving power (50% better). Bokeh is quite subjective of course and is more dependent on exact specifics of the lens used. Chromatic aberrations should be about 30% less for a given lens, I haven't thought too much about the improvement at a given DOF/AOV; feel free to pick some lenses, focal lengths, etc. at photozone or similar and let us know what you find.

[normhead]

"I looked into it (in my equivalency white paper) and it is a myth, an urban legend among photographers. The opposite is true. If you compare, e.g., the APS-C corners of an 31mm or 35mm at f/2.8 and the full frame corners of a 50mm at f/4, the latter wins by a significant margin (in absolute LW/PH resolution, not fall off from the center, to be clear here). Or any other equivalent combination."

Does that assume equivalent Mp? And how does the Mp of the different sensors affect that. How does the built in noise reduction in a camera affect that. SInce the the Nikon D7000 and K-5 use essentially the same sensor have different sensor ratings...what else affects these comparisons.

How useful is an analysis if it only looks at one element of a camera system at the exclusion of others and doesn't include factors such as sensor sensitivity, internal processing and Mp? Are they any use at all? And last, how is it that the K-5 sensor comes out rated above so many FF sensors, if it can't achieve the IQ of any of it's FF cousins.

Inquiring minds want to know.

[ElJamoquio]

"I looked into it (in my equivalency white paper) and it is a myth, an urban legend among photographers. The opposite is true. If you compare, e.g., the APS-C corners of an 31mm or 35mm at f/2.8 and the full frame corners of a 50mm at f/4, the latter wins by a significant margin (in absolute LW/PH resolution, not fall off from the center, to be clear here). Or any other equivalent combination."

Does that assume equivalent Mp?

The answer is true regardless of MP for reasonable numbers of pixels (i.e. not comparing 10x as many pixels). Photozone has a bunch of lenses tested on Nikon at ~12MP on both APS-C and FF that shows this is true at the same resolution.

How useful is an analysis if it only looks at one element of a camera system at the exclusion of others and doesn't include factors such as sensor sensitivity, internal processing and Mp? Are they any use at all? And last, how is it that the K-5 sensor comes out rated above so many FF sensors, if it can't achieve the IQ of any of it's FF cousins.

Inquiring minds want to know.

Without knowing what an equivalent picture is, you cannot determine which sensor is better. Not that anyone should care what sensor is better - they should care what picture is better, and these 'equivalency' equations show that even a relatively poor sensor on FF is better than a relatively better sensor on APS-C. If you're trying to compare between sensor sizes, you need to know equivalency to interpret the dxomark, etc, tests. Keep in mind, too, that measuring the sensor does not (or should not) measure the lens... and larger sensors demand far less from their sensors for an equivalent IQ.

FYI the k-5 sensor rates slighly better than the d7000 but I believe it's within the margin of error listed for the test. I don't argue that the k-5 is better.. but it's not that much better.

[ElJamoquio]

"I looked into it (in my equivalency white paper) and it is a myth, an urban legend among photographers. The opposite is true. If you compare, e.g., the APS-C corners of an 31mm or 35mm at f/2.8 and the full frame corners of a 50mm at f/4, the latter wins by a significant margin (in absolute LW/PH resolution, not fall off from the center, to be clear here). Or any other equivalent combination."

Does that assume equivalent Mp?

The answer is true regardless of MP for reasonable numbers of pixels (i.e. not comparing 10x as many pixels). Photozone has a bunch of lenses tested on Nikon at ~12MP on both APS-C and FF that shows this is true at the same resolution.

How useful is an analysis if it only looks at one element of a camera system at the exclusion of others and doesn't include factors such as sensor sensitivity, internal processing and Mp? Are they any use at all? And last, how is it that the K-5 sensor comes out rated above so many FF sensors, if it can't achieve the IQ of any of it's FF cousins.

Inquiring minds want to know.

Without knowing what an equivalent picture is, you cannot determine which sensor is better. Not that anyone should care what sensor is better - they should care what picture is better, and these 'equivalency' equations show that even a relatively poor sensor on FF is better than a relatively better sensor on APS-C. If you're trying to compare between sensor sizes, you need to know equivalency to interpret the dxomark, etc, tests. Keep in mind, too, that measuring the sensor does not (or should not) measure the lens... and larger sensors demand far less from their sensors for an equivalent IQ.

So a FF with a larger k5 sensor (in other words, the D800), would score 'off the charts' on the DxOMark test (which it did), but that still wouldn't account for the improvement in resolution likely from a same-cost-class lens (so the FF should be better still for many people).

FYI the k-5 sensor rates slighly better than the d7000 but I believe it's within the margin of error listed for the test. I don't argue that the k-5 is better.. but it's not that much better.

[northcoastgreg]

But when those are not in play, how much visual difference is there between an APS-C print and a FF print?

I can't answer the question as to FF vs. APS-C with identical MP sensors, but I have seen large prints from a Canon FF, and they have an extra bit of clarity over what you can get with an APS-C which can be impressive if you're into that sort of thing. It's sort of like the difference between a good zoom lens like the DA 16-45 and one of the FA limiteds. However, from showing my prints of my own stuff and doing volunteer work for a local art association/gallery, I find that most non-photographers aren't that impressed by mere resolution. If an image is not noticeably soft, they will tend to ignore how sharp it is and concentrate on the subject the image, its composition, and the distinctiveness of the image's color. It would be interesting to run a bit of a test with two identical landscape images, one taken with the Canon FF and an L lens, the other taken with the Pentax K-5 and a limited, and then have non-photographers choose which one they prefer. My money would be on the image taken with the Pentax glass. The limited lenses simply produce more distinctive colors than the L glass, and as long as an image is not distractingly soft, people will tend to favor the image with more distinctive color. At least that's been my experience.

FF has advantages over APS-C, but it is purely a subjective assessment as to whether those advantages are significant. I wouldn't put too much stock in resolution numbers. People perceive images, not numbers. It's the aesthetic experience that counts, not the number crunching and bean counting. Look, don't calculate!

[falconeye]

It is a strange experience ...

Bloggers around the world keep citing my recent blog article ( Falk Lumo: The full frame mystery revisited ).

Like petapixel.com, 1001noisycameras.com, sonyalpharumors.com, Japanese digicame-info.com and others.

Now, even Canon bloggers start to cite, like in [Rumor] Canon’s Entry-Level Full Frame Camera: Possible Specifications | CanonWatch where we learn that Canon may launch a similiar thing to the D600. Which ends with the words "Let’s hope Canon gets the message".

So, maybe that message now actually made it all the way to Ricoh I do hope in the interest of the K mount.

---

Last edited by falconeye; 07-18-2012 at 02:57 PM.

[eddie1960]

It is a strange experience ...

Bloggers around the world keep citing my recent blog article ( Falk Lumo: The full frame mystery revisited ).

Like petapixel.com, 1001noisycameras.com, sonyalpharumors.com, Japanese digicame-info.com and others.

Now, even Canon bloggers start to cite, like in [Rumor] Canon’s Entry-Level Full Frame Camera: Possible Specifications | CanonWatch where we learn that Canon may launch a similiar thing to the D600. Which ends with the words "Let’s hope Canon gets the message".

So, maybe that message now actually made it all the way to Ricoh I do hope in the interest of the K mount.

I've noticed the citations a few times Falk. I agree let's hope Ricoh is on top of things

[Timothy]

To interject in response to the original question:

Because I'm a wide-ish normal prime kind of guy.

I feel that any sensor of the past four generations has been capable of printing as large as any 35mm film and that it's totally reasonable switch to medium format (or some compromise such as the D800) if you want greater resolution than that. I'm relatively certain I've seen very good, sizable prints from even the most problematic modern DSLRs.

My issues with Pentax APS-C are all with "my" AOV and its status in the lens lineup now versus 15 years ago. If my preferred field of view was in the normal-long range there would be many fast, small, inexpensive options for me (how I envy those who actually like 50mm on APS-C--to me it's awkward and not worth the compromise) and I would be happy as a clam. If I liked zooms, the range would be covered by solid performers in almost every price range--for the record I would have no issue with my copy of the 16-50 if only, y'know, I liked zooms. If I liked wide primes Pentax has options. If I liked long telephotos I would delight in the extended 'reach' of APS-C.

But I like my primary lens as follows:

-Around 40mm in 135 terms (which would be around 27mm in APS-C terms).
-Fast-ish. 1.7? Great. 2.0? Cool. 2.4? Maybe with the next gen sensor. If it's small, usable wide open, inexpensive, and weather sealed. 3.2? No thank you.
-Small would be cool, but I'm not unrealistic. But I do not want a lens with comparable speed and angle of view to the Minolta 45mm/2.0 to be the size of a 2.8 zoom (Sigma 28/1.8 DG I'm looking at you).
-Since Pentax has done a great job convincing me that Star level weather sealing is a great idea and worth paying extra for: where is it?

Other than the sealing, the Sigma 30mm seems to fit these criteria pretty well. That's one option that I may want to look into replacing the Sigma 28DG with. Yet the key words here are one option. If we go 24x36 the number of options expands to many (albeit all with their own compromises):

DA 40
FA 43
FA 35
DA 35L
CV 40 Ultron

(For the record, the FA 31 is drifting too close to the price of say the Canon 35L or a late era Summicron 35 for me to consider it as a viable option, given the fact that it's a little long and not sealed.)

Basically I feel that in the focal length range I like to use, Pentax changed the use of the lenses rather than changing the lenses to the sensor. 135 would correct that.

Not a reason for me to want full frame: the bizarre (to me) depth of field equivalence debate. Yes, increased 'subject isolation' is another photographic tool in one's belt, and a 33mm f0.9 would be a more capable version of said tool, but to demand that one needs a certain depth of field (or shallowness of field) or it's not 'right', smells to me of tradition mixing with entitlement. If subject isolation is that important, by all means, shoot 6x9 or 4x5. Eighty years ago, 35mm was a small format. There is variation amongst DA35Ls, of course there's going to be variation amongst 35mm f2.0 lenses across manufacturers. To think that because they have the same depth of field a 35mm 2.0 on 135 and a 23mm 1.2 on APS-C are equivalent and should treated as such is a little ridiculous. The latter may some day be developed, but would then cost thousands of dollars, and likely only be bought by motion picture rental outfits. I would call that way less equivalent than a couple more inches of focus before and beyond the subject.

[falconeye]

To think that because they have the same depth of field a 35mm 2.0 on 135 and a 23mm 1.2 on APS-C are equivalent and should treated as such is a little ridiculous. The latter may some day be developed, but would then cost thousands of dollars ...

While I generally agree about the lack of good WA options, this statement is a little bit ironic.

Because there is a very good 24/1.4 in the Nikon lineup, at not so much difference in price to the Pentax 31/1.8. And a cheaper 24/1.4 from Samyang. Ironic because all lenses are full frame.

[Ayoh]

While I generally agree about the lack of good WA options, this statement is a little bit ironic.

Because there is a very good 24/1.4 in the Nikon lineup, at not so much difference in price to the Pentax 31/1.8. And a cheaper 24/1.4 from Samyang. Ironic because all lenses are full frame.

"Not so much difference in price"? The Nikon 24mm 1.4 is double the price of the Pentax lens.

[Wired]

what if you don't want to go super wide?
what if you like the extra reach that APS-C gives you?
what if you still want the brighter/bigger VF?
what if your happy with the DoF you can get from APS-C?
What if you can afford a FF?

what then?

[bossa]

what if you don't want to go super wide?
what if you like the extra reach that APS-C gives you?
what if you still want the brighter/bigger VF?
what if your happy with the DoF you can get from APS-C?
What if you can afford a FF?

what then?

I'd say WT... and just F it

oops.. left out an 'F' ;-)

[falconeye]

"Not so much difference in price"? The Nikon 24mm 1.4 is double the price of the Pentax lens.

1809€ vs. 1139€ which is a factor 1.59. That's in the middle between 1 and 2, nowhere near 2, for a faster lens ...

And then there is the Nikon 28mm f/1.8G at 719€, 0.63x the price of the FA 31/1.8.

[bossa]

1809€ vs. 1139€ which is a factor 1.59. That's in the middle between 1 and 2, nowhere near 2, for a faster lens ...

And then there is the Nikon 28mm f/1.8G at 719€, 0.63x the price of the FA 31/1.8.

Yes but that lens (28/1.8) is not great on a D7000 so why expect any more on a D800? Check out the Flickr samples and the DX & FX reviews on Photozone.

Also: The 24/1.4 is supposed to be 'soft' in the corners on a D800, unlike my Zeiss 21/2.8, which is sharp right up to the front element @ 2.8.