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Full Version: next PZ lens test report: Sony FE 70-200mm f/4 G OSS
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Guest

Quote:The lens will be tested on the NEX7. I doubt that many people come here just to read our thoughts on AF performance.
 

Them don't make statements like AF will never match DSLRs in the review if you are not going to test it with newer cameras with fast AF. 
Ok, I will point out that the NEX 7 has a poor AF (just like I did in the A7R and X-E1 tests).

Guest

You made definite statements regardless of cameras used with statement like "However, it's realistic to state that the system performance will remain inferior to DSLRs in the foreseeable future."

 

This is a ridiculous statement when you even refuse to test the lens with faster AF cameras.  

Example AF sensitity range:

 

Sony A6000: 0-20EV

Nikon D7100: -2-19EV

 

Now you may ask yourself why's the D7100 so much better in low light ? We are talking about a sensitivity that is 200% higher on the DSLR. Maybe think about the size of the AF photodiodes in these different approaches. 

 

This is a DSLR AF module:

http://imaging.nikon.com/lineup/microsit..._n3_03.jpg

Solely made for just one purpose.

 

Just a technical explanation, please. Thus why is a dedicate AF sensor array worse than an embedded AF sensor array in the image sensor ?

 

I am always willing to learn something new.
Quote:Example AF sensitity range:

 

Sony A6000: 0-20EV

Nikon D7100: -2-19EV

 

Now you may ask yourself why's the D7100 so much better in low light ? We are talking about a sensitivity that is 200% higher on the DSLR. Maybe think about the size of the AF photodiodes in these different approaches. 

 

This is a DSLR AF module:

http://imaging.nikon.com/lineup/microsit..._n3_03.jpg

Solely made for just one purpose.

 

Just a technical explanation, please. Thus why is a dedicate AF sensor array worse than an embedded AF sensor array in the image sensor ?

 

I am always willing to learn something new.
 

Pretty much any current mirrorless body focuses fast enough for anything except action photography.

Since I don't shoot action, I'd take mirrorless AF vs DSLR any day for one single reason: perfect accuracy.

Yes, for the majority of shots, what matters the most is AF accuracy. DSLRs suck big time at this since they require body + lens calibration.

I'd never go back to PDAF as implemented in DSLRS. I couldn't care less if they focus in -2 EV given they can't focus as accurately as CDAF in daylight conditions.
Folks, when did I start to propagate mirrorless cameras instead of DSLRs ? 3-4 years ago ? Something like that and this isn't really news for the readers in this forum. Ever since the Panasonic GH2 I am only using mirrorless cameras for my private sessions. I've never had issues with the AF performance from there on - I also mentioned this several times. A fast AF from a mirrorless cameras is also hardly a new concept. Most MFT and 1 Nikon users never had issues (except for 1st gen models ) - it's just fairly new for Sony. On the NEX-6 things improved but they weren't really impressive. Things changed at last with the A7 and A6000 albeit not with the A7R & A7s. So it's mostly better now - cool! No worries!

 

However, Mr. Wild came up with some aggressive statements and I'd like to hear a technical explanation from him why multiple 48-bit line sensors with dedicated amplifier circuitry (citing e.g. Canon regarding DSLR PD-AF) are inferior to much smaller, embedded photodiodes in a 42-bit sensor. The the CPU processing power of an EOS 1D X or D4s should also be quite bit higher than on an A6000.

 

This discussion is, of course, a joke, I know that. 

 

Depending on the camera model, modern DSLRs have have a small advantage but the advantage is there and I don't think that this gap can be completely closed in the next few years.  Just take the EOS 70D as an example. It has both on-chip as well as conventional PD AF. If the on-chip version was just as good then why would they have bothered with the conventional one at all ? Technically the AF photodiodes in a conventional PD-AF are just bigger thus more sensitive (better signal/noise quality).

 

Does it matter for most mortals - no. Does it matter for a few - maybe.

Guest

Quote: 

Depending on the camera model, modern DSLRs have have a small advantage but the advantage is there and I don't think that this gap can be completely closed in the next few years.  Just take the EOS 70D as an example. It has both on-chip as well as conventional PD AF. If the on-chip version was just as good then why would they have bothered with the conventional one at all ? Technically the AF photodiodes in a conventional PD-AF are just bigger thus more sensitive (better signal/noise quality).

 
 

This is invalid argument as DSLR lenses are designed to work  with PDAF only. The lenses for mirrorless cameras are designed to work with hybrid AF system, and there is no reason why hybrid AF with newer lenses can't eventually perform better than DSLR 

 

We aren't talking about lowlight AF but AF tracking so all your other arguments aren't relevant here
Good, your's are.

 

At least for you.  Tongue

 

Who told you that bullshit "as DSLR lenses are designed to work  with PDAF only."? It's the other way round, DSLR lenses AF with PDAF and CDAF, but mirrorless systems lack of PDAF. Which doesn't have to be a bad thing anyway.

 

Maybe you aren't talking about lowlight AF but for some people exactly that feature is opposite of "irrelevant". One could say "what good is PDAF for if you have to microadjust it first?", nonetheless I'm quite happy to get sort of sharp pictures while your slow AF with slow lens might get no focus at all...  Wink

Quote:This is invalid argument as DSLR lenses are designed to work  with PDAF only. The lenses for mirrorless cameras are designed to work with hybrid AF system, and there is no reason why hybrid AF with newer lenses can't eventually perform better than DSLR 

 

We aren't talking about lowlight AF but AF tracking so all your other arguments aren't relevant here
 

Canon STM lenses are meant to work with CD-AF. 

 

The CD-AF has advantages as far as accuracy is concerned. I am not aware where this has benefits for AF speed.

Guest

Quote:Good, your's are.

 

At least for you.  Tongue

 

Who told you that bullshit "as DSLR lenses are designed to work  with PDAF only."? It's the other way round, DSLR lenses AF with PDAF and CDAF, but mirrorless systems lack of PDAF. Which doesn't have to be a bad thing anyway.

 
 

 

If you are ignorant about a topic, I suggest, you tone down your post a bit. CDAF requires AF motors and optical design that can do for very shot but fast  movement so the camera can check focus quickly. The DSLR PDAF lenses have different requirement, design and AF motors. 

 

That's why DSLRs are much slower in CDAF than mirrorless cameras as lenses are not designed for CDAF. 

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