Why are Micro-4/3rds lenses SO MUCH SHARPER than full frame ones? Don't believe me?

Great Bustard · Feb 23, 2014

Anders W said:
After having followed SLR Gear results for quite a while now (not only the charts but also their sample images), I have come to the conclusion that their tests are biased in favor of MFT in cross-format comparisons with FF (which should certainly not be taken to mean that I think the bias is intentional). Consequently, I have refrained from using them in the many discussions about lens performance across sensor formats that I have taken part in on this forum (after first being alerted to the problems with using them for such purposes in a discussion with Jonas B about two years ago).

The results of other sites may be biased in the opposite direction. The only two I have reasonable confidence in for cross-format comparisons are LensRentals and Lenstip (although in the latter case, you need to convert the lp/mm values so as to make them comparable across sensors of different size). Possibly, the acutance measure (not P-MPix) of DxOMark is OK as well (although when I checked last they still had to make good on their promise to answer my request for further technical information about the measures and procedures used and although what they have so far said suggests that their results are biased against the aspect ratio used by MFT).

Of course, what you must always keep in mind when making these comparisons, even when there is no bias, is that image resolution is not just a matter of lens resolution but also of sensor resolution, and that no test site gives us perfect means to keep that factor constant. Note here that it is not only the pixel count that matters but also the presence/absence of an AA filter, and the strength of that filter when present.

Reasonable talk like that is not conducive to "entertainment"! By the way, how cool would it be if a new lens test site shot up where they mounted the lens in front of that 41 MP cell phone sensor, moved the sensor around to various portions of the image circle, and measured various portions of the test scene. I think that would do the trick.

Great Bustard · Feb 23, 2014

ApertureAcolyte said:
Once again, @ f1.8 the m43 prime lenses have much sharper corners than most FF lenses @ f1.8.

If the corners mattered, how often would someone be using f/1.8, especially with FF?

ApertureAcolyte said:
There is no such thing is "equivalent aperture".

In fact, there is:

http://www.josephjamesphotography.com/equivalence/#aperture

Understanding the fundamental concepts of Equivalence requires making important distinctions between various terms which people often take to mean the same thing. It is very much akin to making the distinction between "mass" and "weight", two terms which most people take to mean the same thing, when, in fact, they measure two different (but related) quantities. While there are circumstances where making the distinction is unnecessary, there are other times when it is critical.

The first of these distinctions that needs to be made is between aperture and f-ratio. The term "aperture", by itself, is vague -- we need a qualifying adjective to be clear. There are three different terms using "aperture":

The physical aperture (iris) is the smallest opening within a lens.
The virtual aperture (entrance pupil) is the image of the physical aperture when looking through the FE (front element).
The relative aperture (f-ratio) is the quotient of the focal length and the virtual aperture.

For example f/2 on a 50mm lens means the diameter of the virtual aperture (entrance pupil) is 50mm / 2 = 25mm, since the "f" in the f-ratio stands for "focal length".

Likewise, a 50mm lens with a 25mm virtual aperture has an f-ratio of 50mm / 25mm = 2. The same relative aperture (f-ratio) will result in the same density of light falling on the sensor (exposure) for a given scene luminance and shutter speed for all systems, whereas the same virtual aperture (entrance pupil) will result in the same total amount of light falling on the sensor for a given shutter speed (as well as same DOF for a given perspective, framing, and display size).

Thus, equivalent lenses are lenses that have the same AOV (angle of view) and virtual aperture (entrance pupil).

ApertureAcolyte said:
it is a myth spread via morons.

You must be confused with the "f/2 = f/2 = f/2" myth.

ApertureAcolyte said:
Does a 25mm @ f1.8 collect more or less proportional light than a 50mm @ f1.8 given the glass has the exact same optical properties...?

YES OR NO?

What's "proportional light" and why do we care?

Willy Chu · Feb 23, 2014

dennis tennis said:
Who are you trying to convince? Looks like the OP is trying to justify his decision.

I need everyone to agree with me that only mFT can make sharp lenses, the rest are crap?

The woman I married is the only woman worth marrying? All other wives are not as good?

My Big Mac, the one I'm eating, is the best Big Mac that McDonald's will ever make?

Begging for validation? Please.

No, I read the great reviews of the new Olympus 25mm and saw the edge to edge sharpness on Slrgear. I had never seen a FF prime that tested this evenly sharp across the image plane at maximum aperture, so I did a bit more research and "published" my findings as you see. It was a pattern I found at other focal lengths, too. Was it a coincidence or something inherent in a lens designed for a smaller sensor? It was not apparent to me why these graphs looked the way they do, so I was simply asking why? I also asked, if my analysis was right or not. We've had some good discussions so far.

I never said other lenses were "crap." I posted the charts; you can decide for yourself, if a lens' lack of sharpness reaches the level of "crap." And the topic of my post was limited to performance at maximum aperture, not other attributes of a lens. Maybe I did suggest the Leica was too expensive to justify the performance that was measurable by Slrgear's methodology. But they don't measure some variables, such as build quality or the quality of the bokeh that Leica's are known for. I would never call a Leica "crap."

If you have something constructive to add, please participate. Otherwise, don't.

sportyaccordy · Feb 23, 2014

zuikowesty said:
sportyaccordy said:

zuikowesty said:

sportyaccordy said:

amtberg said:

I have absolutely noticed that virtually all of the MFT lenses I own or have owned (11 lenses) are sharper wide open than the Canon and Sigma DSLR lenses I previously owned, including several Canon L lenses. I don't know if it's because Panasonic and Olympus are brilliant lens designers or if it's simply easier to make lenses for smaller sensors.

Click to expand...

Ding ding ding!!!!

Click to expand...

That may be true, but it also means the tolerances are that much smaller due to the much smaller elements and components.

Click to expand...

No it doesn't. The tolerances are the same.

Click to expand...

As a percentage, yes. But the dimensional tolerances will be smaller. That may not mean much with today's technology though.

ApertureAcolyte · Feb 23, 2014

Great Bustard said:
What's "proportional light" and why do we care?

2 stops of exposure. That's why

s_grins · Feb 23, 2014

Jack Hass said:
s_grins said:

I did not know that you have K5 IIS

Click to expand...

You didn't know that im 5'11", or that my hair is short, or that i weigh about 250, or that i own 2 cars. Welcome to the anonymous internet.

neil holmes · Feb 23, 2014

ApertureAcolyte said:
neil holmes said:

JeanPierre Martel said:

neil holmes said:

ApertureAcolyte said:

Willy Chu wrote:
m4/3 lens aren't designed for a larger sensor. They are designed to be just right for a m4/3 sensor, yet they are still sharper wide open.

Click to expand...

But they are NOT sharper wide open....

Click to expand...

Most FF lenses are mediocre wide open (look at the OP's message). Our lenses are definitively better wide open than them.

The M.Zuiko 12-40mm is even sharpest wide open on most of its focal range:
http://www.lenstip.com/392.4-Lens_r...l_12-40_mm_f_2.8_ED_PRO_Image_resolution.html

Click to expand...

The FF lenses have higher blur units when used on FF cameras than the m4/3 lenses when used on a m4/3 camera.

BUT...if you put those FF lenses on the m4/3 camera, in many cases the FF lens would now have LESS blur units than the m4/3 lens on the m4/3 camera.

Therefore you can not say the m4/3 lens is sharper because many of them are not....and the thing is you CAN put those larger sensor lenses on m4/3....and many people do.

Click to expand...

http://www.lensrentals.com/blog/2013/09/there-is-no-free-lunch-episode-763-lens-adapters

enjoy

Mostly agree that is. Some Nikon lenses have been seen to be better on the A7R than the Nikon FF cameras.

The 75 Oly would NOT be as good on a different mount now would it....and FF lenses may well not be as good on smaller sensor cameras to use.....but that is very different to lens sharpness as this thread is about IE "blur experience units" or whatever.

In fact, that is partly WHY I got a FF camera...to use some of the nice FD L lenses on what it was meant (size wise) to be instead of the crop cameras like m4/3 and Q mount.

But still, my 85 1.2 if tested on my A7 would no doubt have higher blur units than it would on my GX7....I would still prefer it on my A7 though.....and it does not change sharpness....it is still as was made.

Willy Chu · Feb 23, 2014

Great Bustard said:
Willy Chu said:

Or in other words, differences greater than a unit or so are significantly different. Full framers keep bashing the size of 4/3 sensors, but image quality is the sensor + the lens. Congratulations Olympus, your lens is WAY sharper than any full frame 50mm lens!

Click to expand...

...that we look forward to your stunning photos that are so much better than anything anyone using another format can do because of the wide open sharpness of f/1.8 at 25mm.

Please be kind, and refrain from entering in any challenges -- it would be unfair to the rest of the people entering with hopes of winning.

;-)

Are we reading the same thread?! I don't see how my photographic skills are an issue here. Did I say you could only take good photos with a m4/3 lens?

No, I read the great reviews of the new Olympus 25mm and saw the edge to edge sharpness on Slrgear. I had never seen a FF prime that tested this evenly sharp across the image plane at maximum aperture, so I did a bit more research and "published" my findings as you see. It was a pattern I found at other focal lengths, too. Was it a coincidence or something inherent in a lens designed for a smaller sensor? It was not apparent to me why these graphs looked the way they do, so I was simply asking why? I also asked, if my analysis was right or not. We've had some good discussions so far.

If you have something constructive to add, please do. Otherwise, don't. ;-)

Great Bustard · Feb 23, 2014

ApertureAcolyte said:
Great Bustard said:

What's "proportional light" and why do we care?

Click to expand...

2 stops of exposure. That's why

So why say "proportional light" instead of "exposure"? Are you trying to be confusing on purpose? Moving right along, why do we care about exposure for cross format comparisons? For reference:

http://www.josephjamesphotography.com/equivalence/index.htm#exposure

This section will answer the following four questions:

For a given scene, what is the difference in exposure, if any, between f/2.8 1/200 ISO 400 and f/5.6 1/200 ISO 1600?
What role does the ISO setting play?
What role does the sensor size play?
What does any of this have to do with the visual properties of the photo?

Let us know.

Great Bustard · Feb 23, 2014

Willy Chu said:
Great Bustard said:

Willy Chu said:

Or in other words, differences greater than a unit or so are significantly different. Full framers keep bashing the size of 4/3 sensors, but image quality is the sensor + the lens. Congratulations Olympus, your lens is WAY sharper than any full frame 50mm lens!

Click to expand...

...that we look forward to your stunning photos that are so much better than anything anyone using another format can do because of the wide open sharpness of f/1.8 at 25mm.

Please be kind, and refrain from entering in any challenges -- it would be unfair to the rest of the people entering with hopes of winning.

;-)

Click to expand...

Are we reading the same thread?! I don't see how my photographic skills are an issue here. Did I say you could only take good photos with a m4/3 lens?

Last line of your OP:

http://www.dpreview.com/forums/post/53175760

Congratulations Olympus, your lens is WAY sharper than any full frame 50mm lens!

So you're saying it has nothing to do with taking good photos? Then why the exuberance?

Willy Chu said:
No, I read the great reviews of the new Olympus 25mm and saw the edge to edge sharpness on Slrgear. I had never seen a FF prime that tested this evenly sharp across the image plane at maximum aperture, so I did a bit more research and "published" my findings as you see. It was a pattern I found at other focal lengths, too. Was it a coincidence or something inherent in a lens designed for a smaller sensor? It was not apparent to me why these graphs looked the way they do, so I was simply asking why? I also asked, if my analysis was right or not. We've had some good discussions so far.

If you have something constructive to add, please do. Otherwise, don't. ;-)

What scenes do you take photos of where corner sharpness wide open is important, especially on FF? I can think of some situations: astrophotography, and, when a tripod is not possible or too inconvenient, low light photos of paintings in a museum and low light photos of distance scenes where everything is within the DOF wide open.

Are these the types of photos you are excited about taking with this new lens?

G1Houston · Feb 23, 2014

$400 vs $197. May be this can partially answer OP's question?

Lights · Feb 23, 2014

Even though I've switched to M43.

1. For one thing I think comparing two systems, with different light gathering and at differing effective fstops is sort of confusing.

2. Does it really matter in the terms of what you can do, what can be bent through working around some shortcomings(in any system) if you want creativity? But of course this is a gear oriented forum. I really don't think lab tested sharpness means a damn (and who knows the methodology of testing many times?), besides passing interest...and an entertaining discussion.

3. In measuring sharpness at given fstops, a 135mm equiv. lens needs to be stopped down 2 stops, you can't comparatively measure them at the same fstop for equiv focal lengths.

4. Yes some of, a lot of the M43 lenses seem good. But my old Canon 89.00 50mm is damned sharp, but lacks in some other things

I haven't looked at any real comparisons, except what I can see with my eyes, and isn't that what really matters? Often times sharper lenses (unless generally very expensive designs, from all I've read) lack in the quality of background blur, if that is the photographers style or desire at the time. So there are many horses for many courses?

My Gallery is here -
http://www.pbase.com/madlights
The Joker: Why so serious?

Anders W · Feb 23, 2014

Great Bustard said:
Anders W said:

After having followed SLR Gear results for quite a while now (not only the charts but also their sample images), I have come to the conclusion that their tests are biased in favor of MFT in cross-format comparisons with FF (which should certainly not be taken to mean that I think the bias is intentional). Consequently, I have refrained from using them in the many discussions about lens performance across sensor formats that I have taken part in on this forum (after first being alerted to the problems with using them for such purposes in a discussion with Jonas B about two years ago).

The results of other sites may be biased in the opposite direction. The only two I have reasonable confidence in for cross-format comparisons are LensRentals and Lenstip (although in the latter case, you need to convert the lp/mm values so as to make them comparable across sensors of different size). Possibly, the acutance measure (not P-MPix) of DxOMark is OK as well (although when I checked last they still had to make good on their promise to answer my request for further technical information about the measures and procedures used and although what they have so far said suggests that their results are biased against the aspect ratio used by MFT).

Of course, what you must always keep in mind when making these comparisons, even when there is no bias, is that image resolution is not just a matter of lens resolution but also of sensor resolution, and that no test site gives us perfect means to keep that factor constant. Note here that it is not only the pixel count that matters but also the presence/absence of an AA filter, and the strength of that filter when present.

Click to expand...

Reasonable talk like that is not conducive to "entertainment"!

Sorry about that. ;-)

Great Bustard said:
By the way, how cool would it be if a new lens test site shot up where they mounted the lens in front of that 41 MP cell phone sensor, moved the sensor around to various portions of the image circle, and measured various portions of the test scene. I think that would do the trick.

Yes, I have been playing with similar thoughts myself. Should pretty much do the trick. While the resolution of such an amalgamated sensor is still not infinite, I think it would come sufficiently close to isolating the performance of the lens itself to be of interest.

neil holmes · Feb 23, 2014

mrc4nl said:
I was thinking, what woud be the best 50mm (ish) for m43? since all other formats can be adapted, lots of 50mm's to choose from.
too bad the ZE 55MM has a sony e mount, the reviews say its a sharp lens
lenses i want to see get compared:
1.Zuiko digital 50mm F2 macro
2.Minolta 50mm f2 (just for reference since have one)
3.Zeiss MP 50mm F2
4. Leica 50mm F2 ASPH
5.Upcoming Sigma 50mm ART (f1.4) @f2
i Think the zeiss has optics for good corners, but not the centre resolution to match The 16MP 43 sensors.

Non scientific test most at f2 (some at 1.7 or 1.8 one at much different)...just snaps...as taken but resaved to remove exif and I moved back and forward to account for focal lengths so the smallest may not be the shortest and vice versa...all hand held and not to be taken as a serious test..just focused using peaking with the GX7.

Guess which one is the 50 f2 MD?

I had others to try but this is enough for fun.

Edit...and one of these was with a clearly sharper native lens...

Lights · Feb 23, 2014

[No message]

dv312 · Feb 23, 2014

Not sure about sharpness as a blanket statement for it still depends on the lens

In general the MFT primes + fast zooms are pretty awesome

I notice my Nikon FF lenses tend to vignette, no exceptions

Telecentric design my have something to do with MFT sharpness

Cheers ,

Willy Chu · Feb 23, 2014

Anders W said:
After having followed SLR Gear results for quite a while now (not only the charts but also their sample images), I have come to the conclusion that their tests are biased in favor of MFT in cross-format comparisons with FF (which should certainly not be taken to mean that I think the bias is intentional). Consequently, I have refrained from using them in the many discussions about lens performance across sensor formats that I have taken part in on this forum (after first being alerted to the problems with using them for such purposes in a discussion with Jonas B about two years ago).

The results of other sites may be biased in the opposite direction. The only two I have reasonable confidence in for cross-format comparisons are LensRentals and Lenstip (although in the latter case, you need to convert the lp/mm values so as to make them comparable across sensors of different size). Possibly, the acutance measure (not P-MPix) of DxOMark is OK as well (although when I checked last they still had to make good on their promise to answer my request for further technical information about the measures and procedures used and although what they have so far said suggests that their results are biased against the aspect ratio used by MFT).

Of course, what you must always keep in mind when making these comparisons, even when there is no bias, is that image resolution is not just a matter of lens resolution but also of sensor resolution, and that no test site gives us perfect means to keep that factor constant. Note here that it is not only the pixel count that matters but also the presence/absence of an AA filter, and the strength of that filter when present.

Very good thoughts.

On the topic of test methods, I alway thought the Popular Photography SQF charts made sense. They don't seem to publish these any more. This is one I found after only a quick Google search:

The beauty of this is that you first decide what your end print size will be. So in the above example, if you are happy with A+ and A quality, any aperture at any focal length would be good up to 8"x10". If you were printing 11"x14"s, you may not want to shoot at much more than 200mm. If you print much larger than this, you may want to look at another lens. The weakness of this method is that the MTF measurements in the center, 1/2 way out, and in the corner of the frame are weighted to produce a single number. But it's quick and simple. No testing method is ideal.

It may be, for those who never print larger than 8"x10" or who only post photos at online sites, that all lenses at all apertures and all focal lengths will give indistinguishable sharpness results. How about that idea?

Would love to see a poll of what the largest size prints all our Forum members typically make. Maybe that should be appended to their profile, so we can see where they are coming from when they opine about image quality. Yes?

Anders W · Feb 23, 2014

PerL said:
ApertureAcolyte said:

PerL said:

Willy Chu said:

Slrgear.com has just tested the new Olympus 25mm f/1.8 and it's just awesome wide open:

From the website:

"Sharpness is probably the first characteristic anyone thinks of when considering lens quality, and it's here that the combination of DxO Analyzer with our own graphing and display software shows the most revealing results.

"Sharpness is a tricky parameter to nail down mathematically, as it involves not only the fineness of detail that can be captured, but the "crispness" of the images in question. In our camera-testing work at Imaging Resource, it's been clear for years now that cameras that perform well on resolution test charts don't necessarily produce images that we perceive as being "sharp."

"To address this issue, the image scientists at DxO came up with a measurement they call the "Blur Experience Unit," or "BxU." BxUs are a mathematical measurement that correlates very well with human perceptions of image sharpness. One BxU roughly corresponds to a "blur more" operation in Photoshop.

Click to expand...

Those BxU units are from DxO marks. On their own site DxO marks uses "perceptual MPix".

If you look at the scores of lenses/sensor combinations on DxO marks, you will see that FF lenses on FF sensors as a rule does get better scores than lenses on smaller formats, like APS-C or m43.

Click to expand...

Times the score by 4 to compare to full frame.

There;s no chance in hell that a 50mm f18 mkII is sharper than the top m43 primes.

Click to expand...

Dont blame me, blame DxO.

Canon 50 1.8/5DMkIII = score 28, Panasonic Leica 25 1.4/Olympus OM-D E-M1= score 24

(They have not tested the Oly 25 1.8 yet)

As far as I can tell, the discussion in which you intervened is about sharpness. So could you please explain to us all in precise technical terms how the DxO scores are derived, and how they are related to sharpness. While you are at it, please also explain to all of us how the two sharpness measures used by DxO (P-MPix and acutance) are defined in precise technical terms.

Great Bustard · Feb 23, 2014

Anders W said:
PerL said:

ApertureAcolyte said:

PerL said:

Willy Chu said:

Slrgear.com has just tested the new Olympus 25mm f/1.8 and it's just awesome wide open:

From the website:

"Sharpness is probably the first characteristic anyone thinks of when considering lens quality, and it's here that the combination of DxO Analyzer with our own graphing and display software shows the most revealing results.

"Sharpness is a tricky parameter to nail down mathematically, as it involves not only the fineness of detail that can be captured, but the "crispness" of the images in question. In our camera-testing work at Imaging Resource, it's been clear for years now that cameras that perform well on resolution test charts don't necessarily produce images that we perceive as being "sharp."

"To address this issue, the image scientists at DxO came up with a measurement they call the "Blur Experience Unit," or "BxU." BxUs are a mathematical measurement that correlates very well with human perceptions of image sharpness. One BxU roughly corresponds to a "blur more" operation in Photoshop.

Click to expand...

Those BxU units are from DxO marks. On their own site DxO marks uses "perceptual MPix".

If you look at the scores of lenses/sensor combinations on DxO marks, you will see that FF lenses on FF sensors as a rule does get better scores than lenses on smaller formats, like APS-C or m43.

Click to expand...

Times the score by 4 to compare to full frame.

There;s no chance in hell that a 50mm f18 mkII is sharper than the top m43 primes.

Click to expand...

Dont blame me, blame DxO.

Canon 50 1.8/5DMkIII = score 28, Panasonic Leica 25 1.4/Olympus OM-D E-M1= score 24

(They have not tested the Oly 25 1.8 yet)

Click to expand...

As far as I can tell, the discussion in which you intervened is about sharpness. So could you please explain to us all in precise technical terms how the DxO scores are derived, and how they are related to sharpness. While you are at it, please also explain to all of us how the two sharpness measures used by DxO (P-MPix and acutance) are defined in precise technical terms.

You may find this post of interest:

http://www.dpreview.com/forums/post/52637413

DonSC · Feb 23, 2014

I think the m.43 lenses are great but I don't think on a FL and aperture basis that they are better than the FF lenses. My experience with m.43 lenses is limited, but that limited experience suggests that good FF lenses on a high end FF body give you a somewhat better image quality. However, that slightly better quality comes at the cost of a whole lot more size and weight, and ultimately more size and weight means you are carrying too much gear. LOL

For example, I believe (and it's a belief and nothing more) that the Canon 600mm f/4 on a 1Dx body will produce a better image than the newly announced 300mm f/4 on a E-M1. But have you ever tried to use a 600mm f/4? It's gigantic and you need a vehicle to transport it to your tripod. It also costs what you'd pay for a small used car.

Given that after some point the quality of an image is "good enough" the choice between what I want to use isn't that difficult.

Why are Micro-4/3rds lenses SO MUCH SHARPER than full frame ones? Don't believe me?

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