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next PZ lens test report: Fujinon XF 50-140mm f/2.8 R LM OIS WR
#21
Well, the only person deciding which is lowlight and which is DoF centric, is you, Klaus. I say, DoF is by far less important than speed of a lens. DoF is nothing to be used with some precision. if I want everything sharp from  that stone to a branch 65 cm behind the stone - and I want it really sharp and not just sort of less blurry than the rest of the picture; i have to go either Scheimpflug or focusstacking, everything else I see as cooking fog.

 

I think, this is my main concern about that equivalencing business. Depending on lens type, aperture and focal length we get different bokehs, different to compare and to rate, at least I never saw a rating in points, numbers or even of a rough five star range, when it comes to different blurrs at different apertures. So, if you don't have a DoF rating scale (maybe you do and I just didn't pay attention to it), I simply see no reason why prioritizing DoF against speed should be valid. Speed is important  - it can make a difference bewteen "handheld" and "tripod necessary".

 

I don't know acting photographers closing the aperture for 1 1/3 stop more because that makes soooo much a difference in the resulting picture. That can effect only be seen in the final print, not on the camera LCD or in the viewfinder. I don't k now if any of us could detect the difference of 1 stop more or less in terms of DoF, but one stop faster makes a difference to me.

 

I also was looking at the other offers, the 70-200/4 and /2.8 and the Olympus 40-150 (which again is equivalented as 80-300 on FF). I think the offernings are roughly comparable in terms of price - the Nikon 70-200/4 comes without a collar, add that cost and you pay more or less the same - although it's not necessary or helpful, that Nikon collar. Due to the soft plastic tube, the stiff collar holds a soft tube which wobbles and is not helping to camera shake.

#22
Quote:Thanks for the review. Vignetting seems a little high for such a lens @ f2.8 as well as corner resolution at the long end but maybe these are good trade offs given that the lens appears to be nearly apo. Seems an interesting contrast to the m4/3 version but it is a bit on the heavy side.
 

760 gr on the Olympus side, 995 gr on the Fujinon? Or were you're looking at some other lens?
#23
He says the Fuji is a bit on the heavy side..

#24
Quote:Well, the only person deciding which is lowlight and which is DoF centric, is you, Klaus. I say, DoF is by far less important than speed of a lens. DoF is nothing to be used with some precision. if I want everything sharp from  that stone to a branch 65 cm behind the stone - and I want it really sharp and not just sort of less blurry than the rest of the picture; i have to go either Scheimpflug or focusstacking, everything else I see as cooking fog.
 

Speed = max. f-stop correlated with acceptable sensor noise

 

Whether I shoot

f/2.8 at 1/500sec @ ISO 400 (APS-C)

or

f/4 at 1/500sec @ ISO 800 (Full format)

is utterly irrelevant. The SPEED is 1/500sec in both cases. The result is the SAME (assuming the identical field of view, a perfect lens and comparable megapixels).

 

The speed of the lens alone is meaningless. A lens alone doesn't take pictures. I can have a look through the lens with my naked eye and enjoy (?) the "original" speed of the naked lens. That's it. What use case is that ?


The system of camera + lens (+ human) takes pictures. 

#25
"Speed" was an unlucky choice of term from my side. "Fast lenses" are a common expression and my "speed" is referring to the max. aperture. Which also has an impact on focus precision or the ability of the focus unit to see something to focus at in lowlight conditions. But of course, f/4 or f/2.8 don't make that superhuge difference. Nikon i.e. says something about the aperture and which AF-sensors are compatible with f/8. What they don't specifiy so clearly is, when even f/4 is too dark.

 

So, with the disadvatage of a CDAF system needing more light to focus quick and precise, fast lenses are welcome to improve AF.

#26
What the reason was for mechanical quality penalty?

#27
Quote:What the reason was for mechanical quality penalty?
 

It "rattles" when shaking it.

And it's too big and heavy compared to the rest of the gang.
#28
Quote:"Speed" was an unlucky choice of term from my side. "Fast lenses" are a common expression and my "speed" is referring to the max. aperture. Which also has an impact on focus precision or the ability of the focus unit to see something to focus at in lowlight conditions. But of course, f/4 or f/2.8 don't make that superhuge difference. Nikon i.e. says something about the aperture and which AF-sensors are compatible with f/8. What they don't specifiy so clearly is, when even f/4 is too dark.

 

So, with the disadvatage of a CDAF system needing more light to focus quick and precise, fast lenses are welcome to improve AF.
 

Well, compared to the Sony 70-200mm f/4 (on an A7x) even the AF argument isn't valid neither in terms of C-AF nor P-AF which are both located on/obtained from the image sensor. The 1 f-stop advance of the full format sensor and identical equivalent DoF (on the sensor planr) compensate the f/4 vs f/2.8 effects here as well.

 

The AF sensitivity argument is only valid on DSLRs because the AF photodiodes in the viewfinder are identical on APS-C and FF DSLRs (comparatively speaking). 
#29
This topic is getting really hot!


None algebra question:

Hi Klaus, how the current set up compares with OM-D + 40-150mm f2.8? I mean on the field.

#30
Well, the Oly has some bokeh problems whereas the Fuji is quite nice there.

So just in terms of the end result I'd prefer the Fuji.

On the other hand I prefer the construction of the Oly.

 

However, to play the equivalence game again - these are different lens categories.

The Oly is a "80-300mm f/5.6" vs the Fuji "75-215mm f/4".

  


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