Interesting Read: DXO Best lenses for the 20-MPix Sony Alpha A3000

My Fellow members,

I was looking at this article from DXO and it was interesting to note that the Sharpness score for a lot of the lenses tested on the Lowly A3000 with a 20 Mega Pixel Sensor was higher than the corresponding Sharpness score on the NEX7 with the 24 Mega Pixel Sensor. For e.g. Look at the Sigma 60 which scored 18Mpix on the A3000 while it scored only 16Mpix on the NEX7.

Is this due to the fact that the sensor in the A3000 is a newer generation sensor with better design that it gave sharper results from the same lens in spite of having a lower Megapixel sensor?

Usually what I have seen from DXO results are that lenses score more sharpness score on a sensor with more mega pixels than the one with lower mega pixels.


Going by this, I hope the latest sensor on the A6000 can deliver sharper results from the existing lenses.

Regards

JM

Could be something simple like different AA filter strength or different amount of sharpening to the RAW data.

It is entirely possible that the A6000 will do better or worse.

As you can see though none of the existing E lenses (besides the $1000 FE 55mm) are as sharp as the Sigma, they will all act as an AA filter of sorts to your 24 MP sensor. There is more to it than that, but looking at it at a basic level.

Nothing wrong with this, but you will need better lenses to make best use of 24 MP. My point here is I wouldn't buy the A6000 because it is 24 MP, I would buy it for features that you want (AF-C performance, etc).


Eric

I imagine you might see the score on the Sigma 60mm be even higher on A6000, but hard to say if the sensor is more similar to the 24 MP NEX 7 or the 20 MP A3000, what kind of AA filter they use if any, etc.

Looking at that list of lenses though, I wouldn't expect to see much change on any of them except for maybe the Sigma 60mm and ZEISS 55mm, the rest look lens limited. Increasing the sensor resolution on those will only have a small increase in overall resolution.

Removing the AA filter could have a fairly noticeable impact across the board, but this is just one of the reasons you shouldn't compare numbers too much detail between systems.

Eric

viking79 said:

Nothing wrong with this, but you will need better lenses to make best use of 24 MP.

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You also need better lenses to make the best use of 16MP. Or the 20MP A3000. Lens resolution is not a brick-wall. 24MP is slightly lower pixel density than 16MP MFT.

What amazes me is that Zeiss 12mm prime for $1250 scored less on sharpness than mediocre SEL20mm Sony's relatively cheap $350 prime. How can that be? Those DXO scores and very vague explanation of what they consider sharpness Mps is a mystery for me.

Donny out of Element here said:

What amazes me is that Zeiss 12mm prime for $1250 scored less on sharpness than mediocre SEL20mm Sony's relatively cheap $350 prime. How can that be? Those DXO scores and very vague explanation of what they consider sharpness Mps is a mystery for me.

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I agree the scoring is mystery to me as well, how ever I don't think we can compare sharpness scores across lenses with such varying focal lengths

Regards

JM

Donny out of Element here said:

What amazes me is that Zeiss 12mm prime for $1250 scored less on sharpness than mediocre SEL20mm Sony's relatively cheap $350 prime. How can that be? Those DXO scores and very vague explanation of what they consider sharpness Mps is a mystery for me.

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I wouldn't compare two drastically different focal lengths of lenses. You would do better comparing all 12mm lenses. You need a lens that is a certain focal length, you can look for the sharpest lens in that range, but I wouldn't buy a sharp 20mm over a 12mm if I needed a 12mm.

If you compare the 10-18mm and the 12mm you will find they are pretty close at 12mm.

Eric

Erik Magnuson said:

viking79 said:

Nothing wrong with this, but you will need better lenses to make best use of 24 MP.

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You also need better lenses to make the best use of 16MP. Or the 20MP A3000. Lens resolution is not a brick-wall. 24MP is slightly lower pixel density than 16MP MFT.

--
Erik

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I agree completely, system resolution is definitely set by both the sensor and the lens and is not a hard 12 mp or 16 mp figure to compare across systems, but looking at the best lens on a system isn't a bad starting point to see what to expect from other lenses. Clearly the 30mm f/3.5 isn't going to respond well to additional MP, but the Sigma 60mm f/2.8 should do better.

I wish DXO broke their score down from center to corners, since some lenses have lower MP score and I imagine it is mostly because of the corners.

Eric

JunzInc said:

My Fellow members,

I was looking at this article from DXO and it was interesting to note that the Sharpness score for a lot of the lenses tested on the Lowly A3000 with a 20 Mega Pixel Sensor was higher than the corresponding Sharpness score on the NEX7 with the 24 Mega Pixel Sensor. For e.g. Look at the Sigma 60 which scored 18Mpix on the A3000 while it scored only 16Mpix on the NEX7.

Is this due to the fact that the sensor in the A3000 is a newer generation sensor with better design that it gave sharper results from the same lens in spite of having a lower Megapixel sensor?

Usually what I have seen from DXO results are that lenses score more sharpness score on a sensor with more mega pixels than the one with lower mega pixels.

http://www.dxomark.com/Reviews/Best...ms/Best-prime-lenses-for-the-Sony-Alpha-A3000

Going by this, I hope the latest sensor on the A6000 can deliver sharper results from the existing lenses.

Regards

JM

Click to expand...

It all looks rather predictable, or standard.

At arms-length, the list basically shows longer FL stepping down to shorter FL, with the E30M being the anomaly, as it focuses on center sharp and close focusing distance.

Then, within the variances, the newer, and higher priced lenses drift upwards, and the older, and lower priced lenses, drift downwards.

The Sigma lenses use an impressive optical formula, and their sharpness, in 19, 30 and 60mm shows in this test as well.

Perhaps this also hints at a DxO test-weakness. A test that is designed for a normal, or standard FL, will force wide-angle to be 'close' - hinting of field curvature, and gives longer lenses a benefit of simply resolving more detail due to more (tele) magnification.

It does not reflect how you would shoot such lenses, I mean, a wide angle lens is to cover a broad view, not to capture lots of details.

The A3000 uses a 20Mp sensor, the A6000 uses a 24Mp sensor. If the AA filter is indeed weaker than on the Nex-7 (unconfirmed), we may expect improvements. For now, I would use the Nex-7 as the benchmark, and not expect the A6000 to dramatically improve (RAW) IQ. It will improve upon handling, JPG output, and so on.

viking79 said:

I wish DXO broke their score down from center to corners, since some lenses have lower MP score and I imagine it is mostly because of the corners.

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It's not just the corners:


From DXO

Curiously the dashed lines (sagittal?) are pretty close. Results like this sometimes make you wonder about a bad lens.

--
Erik

DXO shows the older Sigma 30 slightly better than the new version. I thought these two lenses were optically the same.

Can anyone explain?

Thanks, Lee

Sony got something really right with this sensor. I don't know how much of it is attributable to better design (or more likely QA) on the new black kit lens and how much is due to the sensor, but the A3000 + kit lens looks almost as good as a sharp prime. Basically, this sensor seems to really make even the kit lens perform great.

The SEL50, which was a great lens on the 16MP sensor, is just amazing on the A3000. The detail is just out of this world.

Initial reviews suggest even the 16-50 is very good (Alin's review says even better than the Zeiss and G zoom) on the A6000, so I suspect that whatever magic they worked on the A3000 sensor we will also see on the A6000 sensor.

DLeeT said:

DXO shows the older Sigma 30 slightly better than the new version. I thought these two lenses were optically the same.

Can anyone explain?

Thanks, Lee

Click to expand...

Probably within the margin of error of the test.

Erik Magnuson said:

viking79 said:

I wish DXO broke their score down from center to corners, since some lenses have lower MP score and I imagine it is mostly because of the corners.

Click to expand...

It's not just the corners:

Curiously the dashed lines (sagittal?) are pretty close. Results like this sometimes make you wonder about a bad lens.

Click to expand...

Thanks! I missed that they had the profiles for the sharpness on frame position, so they do have the information at least.

It looks like the dashed line is for vertical lines (if you look at single lens instead of comparison the legend at the bottom says dashed if for vertical), so it is saying the 30mm macro has a lot of astigmatism maybe? Or could be a bad lens.

Eric

blue_skies said:

Perhaps this also hints at a DxO test-weakness. A test that is designed for a normal, or standard FL, will force wide-angle to be 'close' - hinting of field curvature, and gives longer lenses a benefit of simply resolving more detail due to more (tele) magnification.

Click to expand...

I have a Voigtlander 12mm f/5.6 that kept testing horribly on my test charts but when I looked at images on a camera it seemed great. What I figured out was I was inside the minimum focus distance while focusing on my chart. 1:35 magnification is pretty far back for full frame on a 40x60" chart, but that is only like 0.4 meters for the area I was photographing and the lens only focuses to 0.5 m.

I was using a helicoid focusing adapter so had no issue extending it out some, but that lens doesn't perform well at minimum focus distance, so I decided my test chart was not a valid way to test sharpness on it. If my chart was the size of a large wall it would probably be fine.

So on some lenses it is wise to test them over a range of focal distances. When I test lenses my chart is only one focus distance, and that isn't valid for all lenses. Properties like distortion, focal length, etc, all vary with the focus distance.

I recall seeing people claim the Sigma 8-16mm had reasonable distortion, but the distortion on that lens dramatically decreased at minimum focus distance, where many might have been photographing their charts. At infinity it has very strong barrel distortion, but many reviews didn't underestimated the degree of distortion significantly for an infinity subject. That doesn't mean they are right or wrong, but it is important to consider how the lens is being used and how it is being tested and if they line up.

Eric

I like these DxO charts as one factor when I'm researching a lens.

But seriously the title should be, "Best Autofocus Lenses..."

Of course, they don't include any of the many lenses that can autofocus with adapters... but that would be useful information.

The way I see it is that the trump card of the Sony E-mount, IMO, is that you can use practically any lens that was ever made in front of leading sensors in the industry in small, lightweight mirror-less packages.

I bought into Sony FF and APS-c E mount to put better sensors behind my real investments....my lenses.

In my case with the Sony E-mount you could say, "I bought the cart before the horse."

DLeeT said:

DXO shows the older Sigma 30 slightly better than the new version. I thought these two lenses were optically the same.

Can anyone explain?

Thanks, Lee

Click to expand...

They probably got a bad copy of the Sigma 30mm. But I tried the Sigma 30mm art and thought I got a bad copy too.

Any comparisons involving the NEX-7 are probably meaningless because the sensor in that camera was optimized for that camera (short register) but for the original design application, the SLT A77. As a result, many lenses behaved somewhat differently compared to what should hjave been expected.

Now, if you repeat your comparisons using the NEX-6 you'd have something more meaningful.

The excellent score of the A3000 and Sigma 60 is quite amazing and I wonder why?

viking79 said:

I imagine you might see the score on the Sigma 60mm be even higher on A6000, but hard to say if the sensor is more similar to the 24 MP NEX 7 or the 20 MP A3000, what kind of AA filter they use if any, etc.

Looking at that list of lenses though, I wouldn't expect to see much change on any of them except for maybe the Sigma 60mm and ZEISS 55mm, the rest look lens limited. Increasing the sensor resolution on those will only have a small increase in overall resolution.

Removing the AA filter could have a fairly noticeable impact across the board, but this is just one of the reasons you shouldn't compare numbers too much detail between systems.

Eric

Click to expand...

Why is the score with the Sigma 60 so much higher than with the 30 or 19? I've seen DxO tests of these lenses before, on other bodies, but never any freal difference between the 30 and the 60. Maybe a typo over at DxO?

saintz said:

Sony got something really right with this sensor. I don't know how much of it is attributable to better design (or more likely QA) on the new black kit lens and how much is due to the sensor, but the A3000 + kit lens looks almost as good as a sharp prime. Basically, this sensor seems to really make even the kit lens perform great.

The SEL50, which was a great lens on the 16MP sensor, is just amazing on the A3000. The detail is just out of this world.

Initial reviews suggest even the 16-50 is very good (Alin's review says even better than the Zeiss and G zoom) on the A6000, so I suspect that whatever magic they worked on the A3000 sensor we will also see on the A6000 sensor.

Click to expand...

Just a reminder that the A5000 also uses the exact same 20mp sensor so the same should apply.