[Klaus]

Ok, done ...

http://www.opticallimits.com/sony_nex/901-sony1670f4oss

 

... and now let's forget about it.  :o

[youpii]

It's a special zoom designed for portrait photographers 

[Scythels]

The images don't look as bad as the numbers suggest.  I wonder if imatest is just particularly susceptible to astigmatism.  I suspect it is due to the closer focusing distance.  Astigmatism seems to be the ruling aberration here, in conjunction with chromatic issues.

[Klaus]

Look at the image of the Opera house. The borders have about the same resolution as from a Coke bottle.

[stoppingdown]

Thanks.

 

While I'm not entirely satisfied with the sharpness of this lens, and this review just confirms what others found in the past, that this lens doesn't deserve the blue badge and the high price tag, I must say that your copy performs quite worse than mine. I've checked the Opera House photo and compared with other shots at 70mm and it's definitely much worse than my borders - while _a few_ of my shots have a comparable border degradation.

 

Putting this together with the statement by Sony, I conclude that they have a quite liberal tolerance for this lens. 

 

 

PS "Sony E 10-22mm f4 OSS" should be "Sony E 10-18mm f4 OSS".

[davidmanze]

Ouch Mr Zeiss!

 

 At the Sony service center the "nice man" of course thoroughly checked it out,  he weighed it, spot on at 308 gms! 

[Guest]

Eek!

I think there probably is a role for a relatively compact constant aperture lens with high contrast and super high central resolution.

But not at that price! And they should tell you....if you bought this wanting to shoot architecture you'd be dissapointed.

 

I take it that it was deliberate; they made the same set of compromises on the FE 24-70 but less so. I'm hoping that the reception that got taught them it's not what most of us want. The 16-35 suggests maybe they learned.

[Guest]

Hmm. Interesting. I don't think it's a good lens but I also don't think Sony Australia (is that where you sent it Klaus?) know what they are talking about. I just had a look at the (calculated) MTF charts for the lens. Now of course these are calculated, but one thing they tell you is that it ought be better in the corners wide open at 70 than at 16. So this copy is far from the design goal.

 

Is there a way I can upload the chart?

[Scythels]

Regarding the opera house image, it is certainly a poor image but imatest suggests the resolution is about 1/3rd that in the center - I am doubtful of that simply because of the flags that go up in design when that is the case (aberration plot scale would need to vary considerably as you move towards the center for example).  It also looks like a simple defocus, so astigmatism and chromatic issues seem to be the issue.  Certainly a bad performance, but imatest suggests it is more awful than it is, imo. 


Regarding computed MTF tests - Optical Design Software produces exceedingly accurate MTF charts - the software prediction will be within 1% of a well assembled lens on a real MTF bench.  I am quite adamant about this, but the reason will come into view soon enough. 

 

Some variables that go into the disparity between reality and software:

 

* ODS defaults to MTF at best focus for each plane, so this makes the lens look better than it really is.  I.e it removes astigmatism in the form of a mismatch between the focusing position of the meridonal and sagittal planes. 

 

* ODS MTF plots tend to be weighted 1:2:1 for red:green:blue, reality is not always in this ratio (though this is done to mimic the eye)

 

* ODS plots are for the nominal design.  Nominal designs are never manufactured - there is some manufacturing tolerance in all cases.  At times it is quite large. 

 

* ODS plots are for the bare lens, the sensor can have a rather enormous impact on the performance in many cases.

[Brightcolours]

Even at f8 at 19mm, the borders are not as sharp as one would expect from just about any standard zoom, but that might be due to CA (it then not having been corrected, but masked rather). 

My guess is that this lens is one of those examples where at MTF tests (distances) it has strong astigmatism, but at "normal" (read: medium to infinity focus range) it performs better than the measured numbers suggest. Like for instance the Voigtländer 20mm f3.5 SL II (N).

 

Not the worst results, but a bit silly that my EF-M 18-55mm f3.5-5.6 IS STM seems to outperform it. Considering that lens cost me, excluding shipping costs, $58 (for a new "grey box" copy).