mawz wrote:
Zeiss ZE/ZF/ZM MTF's are measured not theoretical (ZA's are theoretical, but published by Sony not Zeiss), so it's both measured and from the published MTF.
i thought thesuede was using his own k-8 machine to measure the ZA MTFs?
AhamB wrote:
LoCA/bokeh fringing looks well controlled though in the shot of the yellow bus. Taken at f/2 and there is only a trace of cyan fringing in the high contrast parts.
I believe the proper term is optical vignetting. The cat's eyes are seen because of the image circle is too small to show full blur discs towards the corners -- i.e. because of the size of the optics, not because of mechanical obstruction. If the image circle was bigger there would be no cat's eyes, but if you'd put on a hood that was a little too long you would begin to see them and then it's called mechanical vignetting. http://toothwalker.org/optics/vignetting.html#optical...Show more →
If I remember right, I thought it is to do with the ratio of entrance pupil to exit pupil size.
My ZA seems to have rounder bokeh circles and smoother bokeh.
Jorgen Udvang wrote:
Correct, and for most portrait work, the 135mm would be stopped down anyway. 135mm at f/2 gives a very shallow depth of field, to shallow for most people's taste.
Wrong!
With the right distance to subject full and half body portraits can be shot with enough DOF.
Believe there are many uses for this lens to be shot more wide open and that is what the lens is designed for.
If you are going to only shoot this stopped down to f8, then just use a 70-200 zoom.
sebboh wrote:
i thought thesuede was using his own k-8 machine to measure the ZA MTFs?
"My own" is rather an overstatement, but yes - the ZA135 values are also real-world D50-weighed light actual measurements from a similarly equipped K-8 as the one Zeiss production uses. The main difference is that my figures are never optimized for center sharpness, the lens focusing is set to get the highest frame average rather than the highest center value. That's why the value is lower at OC than at 8mm image height.
AFAIK the Sony official theoretical values are based on a very green light, just like Leica's. This increases the values by quite a noticeable margin. **I would call that "cheating" if someone actually asked me... :-)
Jorgen Udvang wrote:
Why would it be more suitable for movie shooters? It does have clicks for the aperture stops, doesn't it? Also there is a dedicated cine version for almost 3 times the price:
The cine and Z* share the same optical design and so when they come out with one, they do it for the other.
For TV and film, a lens a little longer than 100MP which is fast and has smoother bokeh seems like a needed solution.
Makten wrote:
Why don't they give the lens to a good photographer? This sort of nonsense isn't really helping Zeiss sell their lenses.
Although I agree that these pics don't show off this lens very well, but isn't this the Zeiss marketing guy who took the first ZF35/1.4 pics and isn't he FM'r Vincent Kluwe?
wayne seltzer wrote:
If I remember right, I thought it is to do with the ratio of entrance pupil to exit pupil size.
My ZA seems to have rounder bokeh circles and smoother bokeh.
It has a lot "to do" with the pupil ratio, but for secondary reasons - it's not the ratio in it self, but rather other mechanical limitations that cut off the ray bundle. A lens with a high positive pupil ratio will have less trouble with mechanical restrictions behind the aperture, but often more in front of it (if we're talking about at least 50mm lenses, on a DSLR BFD distance from the sensor and a mirrorbox in the path...). But in front you can increase the lens diameters - you can't do that in the back, where you have a small square mirrorbox to fit the ray bundle through.
theSuede wrote:
The new 135 seems very interesting. Compared to the Sony lens it's much better controlled over the image height, and a lot sharper at wide open. Note how close the sagittal and meridonal lines follow each other, indicating very low astigmatism and very low amounts of coma, even at F2.0. The placement of the ED elements would also suggest a very well controlled LoCA, something that is hinted at in the (admittedly) very lacking sample images... :-)
theSuede wrote:
"My own" is rather an overstatement, but yes - the ZA135 values are also real-world D50-weighed light actual measurements from a similarly equipped K-8 as the one Zeiss production uses. The main difference is that my figures are never optimized for center sharpness, the lens focusing is set to get the highest frame average rather than the highest center value. That's why the value is lower at OC than at 8mm image height.
i didn't think you bought it with your own money and had it sitting your garage.
does zeiss normally optimize theirs for center sharpness?
theSuede wrote:
It has a lot "to do" with the pupil ratio, but for secondary reasons - it's not the ratio in it self, but rather other mechanical limitations that cut off the ray bundle. A lens with a high positive pupil ratio will have less trouble with mechanical restrictions behind the aperture, but often more in front of it (if we're talking about at least 50mm lenses, on a DSLR BFD distance from the sensor and a mirrorbox in the path...). But in front you can increase the lens diameters - you can't do that in the back, where you have a small square mirrorbox to fit the ray bundle through.
See the new 55mm distagon as a sample of this....Show more →
Does lens length have any effect on this too?
ZA is shorter and wider than new 135/2.
mawz wrote:
Zeiss ZE/ZF/ZM MTF's are measured not theoretical (ZA's are theoretical, but published by Sony not Zeiss), so it's both measured and from the published MTF.
I understand the difference in the published ZA and the other Zeiss MTFs. I just wonder if he actually measured these MTFs or he used the published one.
wayne seltzer wrote:
Wrong!
With the right distance to subject full and half body portraits can be shot with enough DOF.
Believe there are many uses for this lens to be shot more wide open and that is what the lens is designed for.
If you are going to only shoot this stopped down to f8, then just use a 70-200 zoom.
Oh, is f/8 where all lenses perform exactly the same now? It used to be f/11.
Lloyd Chamber just posted the MTF of all aperture from 2 to 16. Based on what theSuede has provided here, it seems the Sony Zeiss holds itself up better against diffraction.
20 lpmm is a the best all round measure, according to some. The 135/2 looks better behaved at f8 (where it takes a fair hit from f5.6, to be expected), at the expense of a little performance in mid-frame. The ZA looks quite sorry from mid-frame IH by comparison, irrespective of aperture.
The 20 lpmm for the new APO in theSuede's chart mirrors the CZ data at Lloyd's place, but a bit reduced to the measurement variations via explained methodology. Clearly a 'better' lens. Their best work goes into the ZE/F range it seems - past, present and future.
hiepphotog:
'yes - the ZA135 values are also real-world D50-weighed light actual measurements from a similarly equipped K-8 as the one Zeiss production uses.'
Indeed, it looked better behaved in term of astigmatism, yet the absolute value is lower. So it's not as resistant to diffraction. And we don't have the value of any other aperture of the ZA beside 1.8 and 8 to conclude that the "ZA looks quite sorry..., irrespective of aperture". I'm just stating the fact since I will get this new APO anyway.
I'm not sure as to which ZA135 values you're referring to, but the one provided here was measured by theSuede himself (as stated at the top). The published one by Sony is not. Just want to make sure we're on the same page.
