simonw wrote:
Canon, I think, are very good at designing these kind of 'technical' lenses at longer focal lengths (such as the 85mm F1.2 and 135mm F2) so it doesn't suprise me that their new wideangle TSE's follow suit.
However despite this I still find myself drawn to lenses like the ZE 85mm F1.4 that are 'characterful' (soft glow wide open, biting sharp at F8) because they allow some artistic interpretation in how they are used.
I think that the Zeiss 25mm F2, while not as extreme as some of the other Zeiss offerings, has an interesting visual presentation.
Cheers, Simon W.
Yes, I really like the color and rendering I have seen thus far coming out of the Zeiss 25/2.
Thanks Simon. Do you mine posting some of the comparison shots with TS-E 24?
Interesting the TS-E 24 has even less CA.
Do you think the ZE 25/2 performs better at closer distances?
Unfortunately I still don't have any way of posting stuff online (still on my to-do list to set up a web presence) but if anyone is interested I could e-mail them a couple of images from the 24 TSE and ZE 25 to compare. Once again none of these comparisons are 'pretty' they are simply a couple of distance shots of the houses of parliament with the lens tilted up so the opposite bank of the river is running along the frame bottom.
A member called the 21mm Distagon clinical recently. I am taking poetry lessons at art school to compensate for this deficiency. One thing I like about Zeiss is that 'they' decide the trade-offs in the images their lenses produce - none of the good ones are faultless, but...
Field curvature is a possibility, considering that the most recent Zeiss lens before this one, the 35 f:1.4, also has that symptom. But it must be pretty extreme for it to be so visible even on a stopped down 25mm lens, with ample DOF...
To me, it does not look as bad as some of the previous examples but the extreme corner is blurry and clearly lacking the detail shown by the Canon lens.
FlyPenFly wrote:
The center crops looks better on the Zeiss with nicer colors and a bit more contrast.
Are those images corrected for exact brightness match and vignetting?
Otherwise I would not judge contrast, as a darker image gives the impression of more contrast.
edwardkaraa wrote:
To me it is not as sharp as the Canon in the extreme corners but I woukd certainly not call it blurry
I guess it just depends on expectations and what one considers "blurry" vs. "not as sharp".
For me:
Blurry = smearing of detail such that no amount of sharpening will bring back detail because it was not actually captured by the lens.
Whereas simply "not as sharp" might mean the detail is soft but sharpening might reveal it; the lens actually did capture the detail.
So, I say the very extreme part of the corner of the Zeiss 25/2 is blurry since there is detail not captured in this small area which is captured by the Canon.
Whether or not that actually matters to anyone is a completely different question of course but I think it is good to know a lenses capabilities and faults upfront. Simon is fortunate since now if he found himself in a situation where he actually required extreme corner detail, he could use the Canon lens. For some others (depending on their requirements), the fact that the Zeiss 25/2 is not as capable in this narrow/ specific situation might knock it off their list, particularly given it's price (it may be the only 24/25 some people own).
philip_pj wrote:
S, do you think Wayne's Nikkor so relatively inferior in those characteristics as to be responsible for the differences in the images he posted, and the luminosity handling he notes? It's a modern, high end Nikkor we are talking about...
It is a modern Nikkor, but it's one stop faster than the Zeiss (though they both have ten groups, I notice) and the coatings are different. The rear element of the Distagon is also much smaller, so it presents a smaller reflective surface for the image projected onto the sensor during exposure.
We're going by Wayne's comments here, and I don't know if he shot directly comparable images. Contrast is affected by many things. But if the Zeiss offers higher contrast than the Nikkor, that would be in line with my own general experience of the two brands.
It's S for Samuel, by the way.
wayne seltzer wrote:
What is interesting is that with the right bottom corner crop you can see the blurriness in the wall and the street lamps in the bottom right crops but the boat in the foreground is sharper. So it looks to me like field curvature causing the extreme corner blurriness.
I'm sure field curvature is at least partially to blame for the corners, but I think the boat is sharper – where it is sharper – simply because it's farther from the corner proper than the street lamps. The sharpness fall-off towards the corners is unusually abrupt for this Distagon, which means 1 mm in this area makes a big difference.
Most of the features of the boat are higher in contrast than the background on the far side of the Thames; this increases the perception of sharpness. Colours and atmospheric disturbances may also play a role.
In addition, the boat is far enough away to be at infinity for practical purposes. Field curvature would not cause a noticeable difference in sharpness between the boat and the far side of the river.
Finally, field curvature may swing away from the camera in the extreme corners, meaning distant objects would be imaged with better focus than close objects (when the lens is focused at infinity in the centre).
Other things to note:
The photos were taken at 1/125 second, which is a bit slow for careful comparisons unless a pretty hefty tripod is used.
Simon doesn't tell us where and how he focused. Since there's only sky in the centre of the images, this would be very useful information!
In these images, the Zeiss reveals slightly more subject detail throughout most of the bottom-middle crops, and on objects in the corner crops that are closest to the centre (i.e. not the extreme corners). But two factors complicate this comparison: (1) the Zeiss has a longer focal length (this puts the Canon at a disadvantage), and (2) because the Zeiss has a longer focal length, the same objects are positioned closer to the corners for the Zeiss than the Canon (this puts the Zeiss at a disadvantage).
In these images, the Canon has less chromatic aberration, distortion, and off-axis light fall-off than the Zeiss. The corners are obviously much better. Objective, indeed!
Thanks to Wayne for posting my images to the thread.
My shots were all taken using my largest gitzo (a 1325)/arca cube for support. I used 10X live view to focus on the bottom left corner each time and a 2 second self timer to try and mitigate any vibration. The images were processed through CameraRaw Neutral, no other adjustments to CA or vignetting, sharpening was set to 50% 0.5 radius.
As I mentioned I found it extremely difficult to compose normally and get meaningful detail in the corners so this is really an artificial test of just that one feature of the ZE25 compared to the TSE lens because so far this seems to be the most discussed aspect of the ZE 25mm design. This is also the reason why the images are a bit bright as I wanted to see exactly what was going on in the corners without paying much attention to what was happening in the rest of the frame.
S Dilworth wrote:
It is a modern Nikkor, but it's one stop faster than the Zeiss (though they both have ten groups, I notice) and the coatings are different. The rear element of the Distagon is also much smaller, so it presents a smaller reflective surface for the image projected onto the sensor during exposure.
Is it possible the explanation for the Z 25/2 corner softness/ blurriness might be something as simple as the interaction of the AA filter with the stepper angle of light rays striking it in the corners from the smaller rear element of the Zeiss 25/2? Even with retrofocus DSLR lenses, this can come into play I believe. It might be interesting to see how this Zeiss does on a FF camera which does not have an AA filter.
simonw wrote:
Thanks to Wayne for posting my images to the thread.
And thanks to you for taking them, Simon.
simonw wrote:
My shots were all taken using my largest gitzo (a 1325)/arca cube for support. I used 10X live view to focus on the bottom left corner each time and a 2 second self timer to try and mitigate any vibration.
Excellent. In the past we weren't able to assume that kind of diligence for early sample photos. It makes comparisons much more useful.
I have two further questions:
1. Do you remember where exactly in the bottom-left corner you focused? I ask because this throws new stuff into the mix, especially if the field of the Zeiss goes a bit wonky there.
2. Did you focus at the full aperture, the taking aperture, or something in between?
Tariq Gibran wrote:
Is it possible the explanation for the Z 25/2 corner softness/ blurriness might be something as simple as the interaction of the AA filter with the stepper angle of light rays striking it in the corners from the smaller rear element of the Zeiss 25/2?
Astigmatism induced by the filter pack might cause some more corner softness for the Zeiss than the Canon, if the chief ray angle is steeper for the Zeiss – which it probably is. But the majority of the softness is probably inherent in the optical design, judging from the MTF curves published by Zeiss. Notice that just inside the extreme corners, sharpness is very high for the Zeiss.
Oddly, despite the higher apparent lateral chromatic aberration of the Zeiss, it seems to show higher sharpness for tangential objects than the Canon, suggesting that any additional filter-pack-induced astigmatism in the Zeiss must be negligible or nearly negligible.
At 10X the tiny stone building at left (with steps leading down into the water) provided the highest contrast to focus on. I believe that using live view on the Canon means these would all have been focussed wide-open and then stopped down when the shot is taken (the image at the corner was certainly 'smeared' when focussing).
