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next PZ lens test report: Carl-Zeiss Vario-Tessar T* 24-70mm f/4 OSS ZA
#1
http://www.opticallimits.com/sonyalphaff...s2470f4oss

 

Not so good.

#2
Indeed!

And its a nuisance; I need a lens of this general size and specifications, and there isn't going to be an alternative for a long time.

And it may not be easy: it could be that the extra diameter and weight of the Canon F4 is what you need.

 

I remember in the early days of digital Olympus used to go on about the importance of telecentricity in lens design for 4/3 cameras because of the requirements of digital. Maybe that's right, and for all that mirrorless cameras have advantages, the flange distance is not really one of them (except for versatility) as the best designs will still be tele centric. 

 

One question: i wonder if I mightn't get better results on 36MP by shooting at 50mm and cropping rather than shooting at 70mm. Anyone care to crunch the numbers?

#3
Question:

Are the LW/PH figures between formats comparable, in the sense that they allow you to compare the total (sharpness related) quality of the lens/sensor system? So that getting the same numbers on a 16MP system and a 36MP system would give you the same overall quality (though obviously there would be something a bit disappointing about on the 36MP system)?

(I ask because my subjective thought was that I was getting better results on the whole with this lens on the A7r than I was with the Panny 12-35, and I see that the absolute numbers seem to bear this out, even if I'm getting nothing like the potential revealed by the 55)

#4
There's a scaling effect when moving towards higher density sensors.

Thus if there was a -say- 24mp MFT sensor the figures would be higher - this is not a linear relationship though.

As such it is very difficult to compare these numbers.

 

Klaus

#5
Very hard to compare numbers if what you want to do is compare lens performance, sure.

 

But the numbers do allow you to compare *system performance*  (i.e. the lens/sensor pair, even if you can't separate them from each other)   normalised to the same effective print size, right? Or am I missing something...
#6
You can compare the numbers within a test system - thus all tests performed with the A7R are comparable.

The -charts- are also roughly comparable between similar systems (same format, similar megapixels) if you ignore the numbers.

#7
I get that if you are interested in LENS performance you can compare numbers within a system, or to some degree charts.

 

My question was whether if you are interested in SYSTEM performance (i.e. lens+sensor) you can compare raw numbers. Thus if the we see the same numbers for a lens on a 16MP system an a different lens on  36 MP system we can infer that we will see similar resolution in a print of the same size (or if we normalise the two images and view on screen). 

 

This is supposed to be how perceptual megapixels work with DXO; if one lens+sensor gives you 13PMP at a certain location and a different lens+sensor gives you 13PMP they will look the same printed to the same size (at that location). Of course if the first sensor is 16MP and the second 36 you might want to say the second lens is 'bad' - it isn't giving you the potential of the 36MP sensor. But it's still giving you there same performance in one sense as the much better lens on the smaller MP sensor.

 

In some way these are the numbers that are of most interest: to me, for example, in figuring out if the a lens and sensor from one system can give the same appearance of sharpness in a certain print size and a different lens mixed with a different sensor.
#8
Quote:I get that if you are interested in LENS performance you can compare numbers within a system, or to some degree charts.

 

My question was whether if you are interested in SYSTEM performance (i.e. lens+sensor) you can compare raw numbers. Thus if the we see the same numbers for a lens on a 16MP system an a different lens on  36 MP system we can infer that we will see similar resolution in a print of the same size (or if we normalise the two images and view on screen). 

 

This is supposed to be how perceptual megapixels work with DXO; if one lens+sensor gives you 13PMP at a certain location and a different lens+sensor gives you 13PMP they will look the same printed to the same size (at that location). Of course if the first sensor is 16MP and the second 36 you might want to say the second lens is 'bad' - it isn't giving you the potential of the 36MP sensor. But it's still giving you there same performance in one sense as the much better lens on the smaller MP sensor.

 

In some way these are the numbers that are of most interest: to me, for example, in figuring out if the a lens and sensor from one system can give the same appearance of sharpness in a certain print size and a different lens mixed with a different sensor.
 

 

The tests are not aligned to this purpose. You can do so but in this specific scope the error margin is probably higher than over at DxO. e.g. we are using the RAW converter that yields the best results for the specific system whereas DxO probably just sticks to their own algorithm. That being said, the problem remains that e.g. demosaicing algorithms tend evolve over time. e.g. for Fuji X-Trans Adobe's first shot was rather poor but improved significantly with later versions. No idea how DxO handles these life-cycle dependencies.
#9
   Just goes to show that the name Zeiss and a hefty price tag does not always mean a good lens, after bringing out the one of the best lenses out there the Zeiss Otus  55 1.4 to great acclaim, they then bring out something more than average!

Dave's clichés
#10
Lots of CAs, reminds me a disco ball...all crazy colours. Not good for a company like Zeiss, especially at this price tag. Now you tell me why would I bother with any FF when I have razor sharp Ricoh GR!

  


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