Toothwalker wrote:
From his description I reckon he is talking about optical vignetting, which decreases the blur of tangential details in the corners.
Can I hire you to be my translator this is what I tried to explain and not many understood from my desperate tries of writing it to text. Didn't think of it, but now when you say it's obvious the issue is that on tangential details are blurred on those shots where it happens - that is also why the blur looks so weird.
Toothwalker wrote:
All normal photographic lenses do that, some more than other ones.
Only ones I have found it to be distracting are 2/28 Z* (haven't owned C/Y version) and 2.8/25 CY (but only very very rarely this has been issue, I think it ruined one good forest photo - where 2/28 I'm losing >50%) .
PS. Once you got little more shooting with the lens, please report what you find out. Your descriptions of optical errors are always top-notch. Still zero availability in Finland, zeiss.de webshop also shows red and says "Available: 1st quarter 2012" (today is last day of Q1...)
Toothwalker wrote:
From his description I reckon he is talking about optical vignetting, which decreases the blur of tangential details in the corners. All normal photographic lenses do that, some more than other ones.
can you explain this a little further? i can understand how vignetting can change the detail in areas where bright and dark areas meet (i.e. thin branches against a white sky) due to the lower exposure but i can't visualize how vignetting could affect the actual blur itself.
simonw wrote:
can you explain this a little further? i can understand how vignetting can change the detail in areas where bright and dark areas meet (i.e. thin branches against a white sky) due to the lower exposure but i can't visualize how vignetting could affect the actual blur itself.
At full aperture, off-axis points in object space do not see a round aperture but a shape that resembles a cat's eye. The vignetting is due to off-axis points being confronted with a smaller aperture than points near the center of the image. The DOF effect is due to the fact that off-axis points are blurred more in the tangential direction than in the radial direction. In that case one should distinguish between sagittal and tangential DOF.
Samuli Vahonen wrote:
Can I hire you to be my translator this is what I tried to explain and not many understood from my desperate tries of writing it to text. Didn't think of it, but now when you say it's obvious the issue is that on tangential details are blurred on those shots where it happens - that is also why the blur looks so weird.
Only ones I have found it to be distracting are 2/28 Z* (haven't owned C/Y version) and 2.8/25 CY (but only very very rarely this has been issue, I think it ruined one good forest photo - where 2/28 I'm losing >50%) . ...Show more →
I think a lens like the MP 100/2 should be equally distracting in this regard, but maybe you don't take similar pictures with that lens?
PS. Once you got little more shooting with the lens, please report what you find out. Your descriptions of optical errors are always top-notch. Still zero availability in Finland, zeiss.de webshop also shows red and says "Available: 1st quarter 2012" (today is last day of Q1...)
Well, I am not much of a lens tester. I am more interested in optical phenomena than in lens tests or comparisons, but occasionally I join the test crowds. We'll see. The very first picture that I took with this lens was meant to answer the question whether it has onion-ring bokeh. And lo and behold, onion rings there are.
Availability in Norway was zero until last week. It seems that northern Europe is low on the new Zeiss lens distribution priority list.
Toothwalker wrote:
I think a lens like the MP 100/2 should be equally distracting in this regard, but maybe you don't take similar pictures with that lens?
Yes, in similar conditions 2/100 might be even worse, it's mechanical vignetting at long focus distances is ridiculous. However it's extreme difficult to arrange same conditions - why it's so visible is that with wide angle (28mm) if your subject is 2-3m and your background is 10-15m the background is not that much blurred. When I shoot wide open with 2/100 or 1.4/50 or 1.4/85 I always try to avoid situations that I have target for example 5m from camera and background 6m from camera since this same phenomenon happens then. With wide angle it's so much more problematic since the situation is so much hard to avoid in my typical environment, many cases impossible (the "branch" layer is constant above and there just might not way to avoid unless radically changing framing e.g. raising tripod 2m higher).
I'm not part of the group who believes MP 2/100 is somehow perfect, it's far from it, but like any tool you need to know how it behaves to use it's benefits and minimize/mitigate it's negatives.
Toothwalker wrote:
Availability in Norway was zero until last week. It seems that northern Europe is low on the new Zeiss lens distribution priority list.
I was on summer holiday at Friday (previous years summer holidays still remaining) I had time to research the topic. FYI for Finnish people: Color-Kolmio is no longer importing Zeiss to Finland, and Rajala (and other stores) said that they don't know who is importer and from Rajala they said they will sell the old stock but will not sell any new Zeiss or order new Zeiss models.
Thanks for Fred Miranda forum I got lens from Estonia. Thousand thanks for Jaan!!!
Long day; left home 6AM and got back little after midnight... I did personally fetch the lens from Tallinn, so I have spent majority of today in train between Tampere and Helsinki and ferry between Helsinki and Tallinn. Seems I really wanted the lens I was able to shoot few hours in Tallinn and some shots in Helsinki as well - and read almost 2 books - very exhausting day. Based on the initial shooting corners seem fine, some "infinity shots" I took seem to show much less blurring at f/8 than some samples in forum, it's not good in corners, but for most practical enlargements should be fine.
On the good side of things I think that now I finally have everything I need (and can buy, Zeiss still haven't made 200mm...) so I can concentrate just shooting for rest of the 2012 and not worry about the equipment.
The more I read and see example photos seem to confirm my earlier speculation of the lens having too small an image circle combined with strong field curvature. The close focusing distances increase the diameter of the image circle at the sensor plane, reducing the vignetting and sharpening corners.
Center sharpness seems like an excellent lens of for crop and M43 sensors, but a slight disappointment for full frame.
Gunzorro wrote:
The more I read and see example photos seem to confirm my earlier speculation of the lens having too small an image circle combined with strong field curvature. The close focusing distances increase the diameter of the image circle at the sensor plane, reducing the vignetting and sharpening corners.
Center sharpness seems like an excellent lens of for crop and M43 sensors, but a slight disappointment for full frame.
Yes, not perfect but the corners don't seem to get excessive contrast so they don't draw attention. Time will show, I have shot first 100 images so don't yet have that much experience, specially lacking any forest shots, only shoot in city.
Also bokeh shows some ugliness sometimes, shown in Siddhu's 2nd Jeep image. Here is sample image - f/2, 1/800s
Two bokeh crops:
And bottom right quarter of image, sharpened aggressively to show the field curvature in gravel, as you can see when closing image's right border the part of gravel, which is sharp, goes further away:
As initial impression this lens seems to be very similar to C/Y 2.8/25, just better in aspects but all characteristics are almost same!!! Bokeh have to be seen, the wide open bokeh of C/Y is definitely better, MUCH better, but I haven't checked how ZE version behaves f/2.8. I liked the C/Y version very much, so most likely this will become my favorite wide angle lens (21 too wide for me, 28 corner issue).
You are welcome Samuli. You really surprised me for what people are ready to have a Zeiss glass
Sorry about the weather, it was really cold and windy, hope I was not too eager tour guide. At least I wish you found some interesting details in Tallinn's Old Town to compensate you all-day trip
Samuli Vahonen wrote:
And bottom right quarter of image, sharpened aggressively to show the field curvature in gravel, as you can see when closing image's right border the part of gravel, which is sharp, goes further away:
This is a distinguishing characteristic present in almost all Zeiss lenses, old and new. The field curvature in the extreme corners is always in a U shape.
wayne seltzer wrote:
Ok, well the statement about being optimized or better at closer distances would have to be proved by shooting targets at different distances like I said before to prove or disprove.
The 2nd point about the heavy blurring in the extreme corners or corner smearing even at stopped down apertures like f8, that only happened to me on shots that were focused far away near infinity and not on closer shots like upper corners of my bar shot or the Chili's table tile shot I just posted. I am not talking about the gradual fall off sharpness to the corners but the case when all of sudden near the extreme corners all detail quickly gets much much blurrier. I don't see that in the Chili's shot which is very close focus. ...Show more →
Samuli Vahonen wrote:
Yes, in similar conditions 2/100 might be even worse, it's mechanical vignetting at long focus distances is ridiculous. However it's extreme difficult to arrange same conditions - why it's so visible is that with wide angle (28mm) if your subject is 2-3m and your background is 10-15m the background is not that much blurred. When I shoot wide open with 2/100 or 1.4/50 or 1.4/85 I always try to avoid situations that I have target for example 5m from camera and background 6m from camera since this same phenomenon happens then. With wide angle it's so much more problematic since the situation is so much hard to avoid in my typical environment, many cases impossible (the "branch" layer is constant above and there just might not way to avoid unless radically changing framing e.g. raising tripod 2m higher). ...Show more →
That is clear. Most wideangle lenses will be problematic in this regard if used at full aperture.
Long day; left home 6AM and got back little after midnight... I did personally fetch the lens from Tallinn, so I have spent majority of today in train between Tampere and Helsinki and ferry between Helsinki and Tallinn. Seems I really wanted the lens I was able to shoot few hours in Tallinn and some shots in Helsinki as well - and read almost 2 books - very exhausting day. Based on the initial shooting corners seem fine, some "infinity shots" I took seem to show much less blurring at f/8 than some samples in forum, it's not good in corners, but for most practical enlargements should be fine. ...Show more →
Well. I don't see any detail in the extreme upper corners. Furthermore the image magnification is in the regime 0.005 - 0.01, which is close to infinity as far as lens performance is concerned.
EDIT: Notice, focus on doors and they are quite deep inside the wall - not the best possible sample...
Pixel peeping is boooooooring...I have seen enough, this quality in corners is very usable, sure it's softer than in center, but I would assume with practical enlargements (e.g. A3 print) there isn't difference in sharpness, but you can notice the contrast difference between center and corner.
Full (notice 0.5 degreed turned to straighten image - corner 100% crops naturally from RAW image without straigtening [causes aliasing = softness - never rotate images if trying to figure out something about 100% pixel quality])
It is falling off a little in the corners but not as bad as some of the shots I show because you are shooting the corner of the building and the FC in the corners is benefiting. Take the shot of this building straight on to one side of it and lets see the corners then. Also, how close were you to infinity setting on the focus ring?
Like I have said a lot of times in this thread, this new Z* 25/2 lens is a good lens and will be fine for a lot of people which depends on shooting style etc. and if the corner smearing bothers you even at all when it does show up. It is well corrected for CA and has nice Zeiss colors. Personally, I just wish the lens was f1.4 instead of f2 and didn't have this extreme corner issue. For me I prefer the 21 and my faster 24G/1.4.
IMHO the 25/2 is better than the 28/2 and will a be a popular lens here.
wayne seltzer wrote:
It is falling off a little in the corners but not as bad as some of the shots I show because you are shooting the corner of the building and the FC in the corners is benefiting. Take the shot of this building straight on to one side of it and lets see the corners then. Also, how close were you to infinity setting on the focus ring?
I chose this image since distance differences were meaningless, for such short focal length on so big focus distance. Not sure how the focus ring was turned, but distance to center of image was about 8m (~24ft) and distance to bottom corner was about 11-12m(~33-36ft) and I did focus between these two distances using live view. So if average focus was in 10m then we are talking about 400x of focal length, which from optics perspective is considered infinity.
Since I was visiting Tallinn (Estonia) I was not there to shoot test images, but to actually do some real shooting ---> I didn't take any straight on building shots (they look stupid 99% of time). The other shot I posted is "straight on" but naturally the ground in bottom of image is closer than the rest of the image.
Initial impression is that I will really like this lens;
- it won't have the Z* 28mm issue of ugly corner bokeh (at least I was not able to fabricate it)
- corners seems sharp enough for landscape
- focuses close and gives great image quality for close ups
- lack of CA and great colors
Only problem I have this far identified is bokeh quality wide open, but I took so small number of this kind of shots that I'll have to report later, will it affect in real life. In close-ups I was not able to produce bad bokeh, just when subject was 1-2m away.
A stone wall and painted door test shot ---> Samuli, are you sure that the wall in the middle of the frame is properly in focus? It seems that you nailed focus on doors that are located farhter ahead about 07-1.0 m.
Could you add a crop of the center part of wall (by height) left or right to the door and a door crop just to confirm focus accuracy?
this is what I tried to explain and not many understood from my desperate tries of writing it to text. Didn't think of it, but now when you say it's obvious the issue is that on tangential details are blurred on those shots where it happens - that is also why the blur looks so weird.
- very exhausting day. Based on the initial shooting corners seem fine, some "infinity shots" I took seem to show much less blurring at f/8 than some samples in forum, it's not good in corners, but for most practical enlargements should be fine. 
