This topic is in the 2015 archive. You can read it and like its posts here. It is read only.
Archive 2015Zeiss Unveils the Loxia 21mm f/2.8
p.46 #1Zeiss Unveils the Loxia 21mm f/2.8
billsnature wrote:
Ah HA!!! The plot thickens
Ran another test of new Loxia 21mm. Used the same protocol as last time shooting 1 picture with camera in normal level position and then turned upside down.
First pair of two pictures was with optimal focus using 12.5X magnifier which resulted in focus a bit short of infinity hard stop. The second pair was shot with the lens driven to infinity hard stop. The results of the ideal focus were exactly the same as last time with top much sharper than bottom and the reverse when camera turned upside down. The pair shot at the hard...Show more →
What's that helicoid made of? Is there a design flaw?
Ah HA!!! The plot thickens
Ran another test of new Loxia 21mm. Used the same protocol as last time shooting 1 picture with camera in normal level position and then turned upside down.
First pair of two pictures was with optimal focus using 12.5X magnifier which resulted in focus a bit short of infinity hard stop. The second pair was shot with the lens driven to infinity hard stop. The results of the ideal focus were exactly the same as last time with top much sharper than bottom and the reverse when camera turned upside down. The pair shot at the hard...Show more →
What's that helicoid made of? Is there a design flaw?
Feb 27, 2016 at 07:16 PM
p.46 #2Zeiss Unveils the Loxia 21mm f/2.8
billsnature wrote:
The second pair was shot with the lens driven to infinity hard stop. The results of the ideal focus were exactly the same as last time with top much sharper than bottom and the reverse when camera turned upside down. The pair shot at the hard stop still showed the asymmetry, but to a much smaller degree. Now the top of the two images looked close and there was on a slight difference in the two bottoms.
This is expected if a lens isn't perfectly focused when testing. For the sake of simplicity, suppose that the bottom will be focused 20m closer than the top. So you focus the top perfectly on the subject at e.g. 100m, and the bottom is focused to 80m. When you turn it upside down, it will be out of focus by 20m and will look much worse. Now suppose you do it again, but this time you misfocus the top at 110m, so the bottom is focused at 90m, but the subject is at 100m. Both the top and bottom are now 10m out of focus and will look similar.
Note that this error can only ever make a bad lens look good, it can't make a good lens look bad. A good lens will always look the same both ways up, but a bad lens can look the same both ways up if misfocused such that the two shots end up roughly the same distance in front of and behind the correct focus distance.
The second pair was shot with the lens driven to infinity hard stop. The results of the ideal focus were exactly the same as last time with top much sharper than bottom and the reverse when camera turned upside down. The pair shot at the hard stop still showed the asymmetry, but to a much smaller degree. Now the top of the two images looked close and there was on a slight difference in the two bottoms.
This is expected if a lens isn't perfectly focused when testing. For the sake of simplicity, suppose that the bottom will be focused 20m closer than the top. So you focus the top perfectly on the subject at e.g. 100m, and the bottom is focused to 80m. When you turn it upside down, it will be out of focus by 20m and will look much worse. Now suppose you do it again, but this time you misfocus the top at 110m, so the bottom is focused at 90m, but the subject is at 100m. Both the top and bottom are now 10m out of focus and will look similar.
Note that this error can only ever make a bad lens look good, it can't make a good lens look bad. A good lens will always look the same both ways up, but a bad lens can look the same both ways up if misfocused such that the two shots end up roughly the same distance in front of and behind the correct focus distance.
Feb 27, 2016 at 09:15 PM
p.46 #3Zeiss Unveils the Loxia 21mm f/2.8
I gave up on the Loxia and just bought a like new ZE 21/2.8 for much less. Just tested it out and its a surprisingly excellent performer on my A7R (with my well tested and modified adapter). I couldn't find many examples of the ZE 21 on the A7R, but took the chance. Got a sharp and well centered copy 
I was getting the feeling that the Loxia 21 is not as robust as the ZE 21. The Distagon is an old-school robust design, and its not as large as I thought it would be. The weight difference is just over 200g. Love the ZE on my A7R!
I was getting the feeling that the Loxia 21 is not as robust as the ZE 21. The Distagon is an old-school robust design, and its not as large as I thought it would be. The weight difference is just over 200g. Love the ZE on my A7R!
Feb 27, 2016 at 10:09 PM
p.46 #4Zeiss Unveils the Loxia 21mm f/2.8
stevei wrote:
This is expected if a lens isn't perfectly focused when testing. For the sake of simplicity, suppose that the bottom will be focused 20m closer than the top. So you focus the top perfectly on the subject at e.g. 100m, and the bottom is focused to 80m. When you turn it upside down, it will be out of focus by 20m and will look much worse. Now suppose you do it again, but this time you misfocus the top at 110m, so the bottom is focused at 90m, but the subject is at 100m. Both the top and bottom are...Show more →
The lens was not focused at top or bottom. but was focused in center. The lens was held level both top to bottom and left to right. Therefore even if it was miss focused the two images should look identical. Maybe what I failed to mention, is that the images are auto rotated by the camera so that when you look at them they are both upright. Therefore if the focal plane was even, you wouldn't have the top sharp in one and the bottom sharp in the other. If the images were not rotated, then you explanation would be logical, but they are rotated indicating an asymmetry in lens focal plane.
billsnature wrote
The second pair was shot with the lens driven to infinity hard stop. The results of the ideal focus were exactly the same as last time with top much sharper than bottom and the reverse when camera turned upside down. The pair shot at the hard stop still showed the asymmetry, but to a much smaller degree. Now the top of the two images looked close and there was on a slight difference in the two bottoms.The lens was not focused at top or bottom. but was focused in center. The lens was held level both top to bottom and left to right. Therefore even if it was miss focused the two images should look identical. Maybe what I failed to mention, is that the images are auto rotated by the camera so that when you look at them they are both upright. Therefore if the focal plane was even, you wouldn't have the top sharp in one and the bottom sharp in the other. If the images were not rotated, then you explanation would be logical, but they are rotated indicating an asymmetry in lens focal plane.
Feb 27, 2016 at 11:19 PM
p.46 #5Zeiss Unveils the Loxia 21mm f/2.8
pdmphoto wrote:
I gave up on the Loxia and just bought a like new ZE 21/2.8 for much less. Just tested it out and its a surprisingly excellent performer on my A7R (with my well tested and modified adapter). I couldn't find many examples of the ZE 21 on the A7R, but took the chance. Got a sharp and well centered copy
I was getting the feeling that the Loxia 21 is not as robust as the ZE 21. The Distagon is an old-school robust design, and its not as large as I thought it would be. The weight difference is...Show more →
The old-school design can be adjusted and fixed as needed. I got mine fixed and it was BAD when I sent it in. And yes, it works on A7r and A7rII very well.
I gave up on the Loxia and just bought a like new ZE 21/2.8 for much less. Just tested it out and its a surprisingly excellent performer on my A7R (with my well tested and modified adapter). I couldn't find many examples of the ZE 21 on the A7R, but took the chance. Got a sharp and well centered copy
I was getting the feeling that the Loxia 21 is not as robust as the ZE 21. The Distagon is an old-school robust design, and its not as large as I thought it would be. The weight difference is...Show more →
The old-school design can be adjusted and fixed as needed. I got mine fixed and it was BAD when I sent it in. And yes, it works on A7r and A7rII very well.
Feb 28, 2016 at 06:16 AM
p.46 #6Zeiss Unveils the Loxia 21mm f/2.8
billsnature wrote:
The lens was not focused at top or bottom. but was focused in center. The lens was held level both top to bottom and left to right. Therefore even if it was miss focused the two images should look identical.
Yes, that's exactly what I said. With a good lens, the two images should always look identical, even if misfocused. With a bad lens, if it's correctly focused, there will be a difference between the two images. But if a bad lens is misfocused you can end up with the top and bottom (or left and right) looking the same if the misfocusing happens to result in them being on opposite sides of the correct plane of focus. So I'm suggesting that is why your images looked similar when you focused beyond the optimal point of focus.
The lens was not focused at top or bottom. but was focused in center. The lens was held level both top to bottom and left to right. Therefore even if it was miss focused the two images should look identical.
Yes, that's exactly what I said. With a good lens, the two images should always look identical, even if misfocused. With a bad lens, if it's correctly focused, there will be a difference between the two images. But if a bad lens is misfocused you can end up with the top and bottom (or left and right) looking the same if the misfocusing happens to result in them being on opposite sides of the correct plane of focus. So I'm suggesting that is why your images looked similar when you focused beyond the optimal point of focus.
Feb 28, 2016 at 10:15 AM
p.46 #7Zeiss Unveils the Loxia 21mm f/2.8
I received my copy today, ran a very rough decentering test, bordering on useless, but a quick glance at 500% didn't reveal anything criminal. I will put it through its paces on Wednesday, when I'll try to get some project shots in the Hermitage.
PS: the body itself I like more than the short barrel of the 2/35. I can comfortably rest the hood on my index finger. The focus ring I'm not sure about, as its travel seems quite short, but I was able to get precise shots very quickly nonetheless.
PS: the body itself I like more than the short barrel of the 2/35. I can comfortably rest the hood on my index finger. The focus ring I'm not sure about, as its travel seems quite short, but I was able to get precise shots very quickly nonetheless.
Feb 29, 2016 at 09:30 AM
p.46 #8Zeiss Unveils the Loxia 21mm f/2.8
I'm starting to get a bit stressed out about the lacking quality assurance on the FE mount lenses. Now we have problems with both the Sony Zeiss (like the 35mm f/1.4) AND issue with the Zeiss Loxia? 
I'm not sure I dare testing my FE 35 f/1.4, but I was at least hoping that the Loxia would be a safe choice?
I'm not sure I dare testing my FE 35 f/1.4, but I was at least hoping that the Loxia would be a safe choice?
Feb 29, 2016 at 09:42 AM
p.46 #9Zeiss Unveils the Loxia 21mm f/2.8
Cross posted from the FE images thread.
Sony a7R II + Loxia 21 @ f/2.8
Gunsmith Shop by Tim Devine, on Flickr
-Tim
Feb 29, 2016 at 09:48 AM
p.46 #10Zeiss Unveils the Loxia 21mm f/2.8
... but the Loxia 21 sure got the looks! 
Feb 29, 2016 at 09:52 AM
p.46 #11Zeiss Unveils the Loxia 21mm f/2.8
This is mildly offtopic, but I often find myself thinking that we've just developed this habit of obsessing over stuff and searching for possible flaws. In any and all craft. It has been developing as fast as the tech progress. I don't want to classify it as good or bad, it just is. A habit. And I often wonder if it detracts from the experience, if it gets in the way of what a person wants to achieve. We've made this gigantic technological leap in the last 10 years that people couldn't even dream of making only 15 years ago. And my point is, even though there sure are copies of the lens that have issues, it still produces wonderful shots. And in the majority of cases, people wouldn't have even bothered with checking corners. Sure, we want a great lens for this kind of money, but we might as well keep calm and put down the pikes.
Really hope everyone having issues gets their true copy in the end.
Really hope everyone having issues gets their true copy in the end.
Feb 29, 2016 at 10:02 AM
p.46 #12Zeiss Unveils the Loxia 21mm f/2.8
alksv wrote:
This is mildly offtopic, but I often find myself thinking that we've just developed this habit of obsessing over stuff and searching for possible flaws. In any and all craft. It has been developing as fast as the tech progress. I don't want to classify it as good or bad, it just is. A habit. And I often wonder if it detracts from the experience, if it gets in the way of what a person wants to achieve. We've made this gigantic technological leap in the last 10 years that people couldn't even dream of making only 15 years ago....Show more →
Excellent point.
http://rlv.zcache.com.au/keep_calm_and_carry_on_shooting_shirt-r5d51ee03b76d49c69a6d125aef47e44d_jf3ai_324.jpg
This is mildly offtopic, but I often find myself thinking that we've just developed this habit of obsessing over stuff and searching for possible flaws. In any and all craft. It has been developing as fast as the tech progress. I don't want to classify it as good or bad, it just is. A habit. And I often wonder if it detracts from the experience, if it gets in the way of what a person wants to achieve. We've made this gigantic technological leap in the last 10 years that people couldn't even dream of making only 15 years ago....Show more →
Excellent point.
http://rlv.zcache.com.au/keep_calm_and_carry_on_shooting_shirt-r5d51ee03b76d49c69a6d125aef47e44d_jf3ai_324.jpg
Feb 29, 2016 at 10:05 AM
p.46 #13Zeiss Unveils the Loxia 21mm f/2.8
alksv wrote:
This is mildly offtopic, but I often find myself thinking that we've just developed this habit of obsessing over stuff and searching for possible flaws.
I never understand why some people talk about "obsessing". As if there's something wrong with checking if you really got what you've paid for. I've done that all my life, with anything I've bought.
To me there's no point in accepting a lens that doesn't perform like it's designed. We're shooting these 42MP cameras now and some don't care that parts of an image aren't even in focus because of decentering?
BTW, many members on the FM alt forum are constantly splitting the tiniest hairs when it comes to differences in rendering between lenses, but apparently many don't care if their lenses are faulty or not. I think that's rather strange.
This is mildly offtopic, but I often find myself thinking that we've just developed this habit of obsessing over stuff and searching for possible flaws.
I never understand why some people talk about "obsessing". As if there's something wrong with checking if you really got what you've paid for. I've done that all my life, with anything I've bought.
To me there's no point in accepting a lens that doesn't perform like it's designed. We're shooting these 42MP cameras now and some don't care that parts of an image aren't even in focus because of decentering?
BTW, many members on the FM alt forum are constantly splitting the tiniest hairs when it comes to differences in rendering between lenses, but apparently many don't care if their lenses are faulty or not. I think that's rather strange.
Feb 29, 2016 at 01:11 PM
p.46 #14Zeiss Unveils the Loxia 21mm f/2.8
Since there are so many who are complaining about their Loxia 21 here, I can report that my copy is excellent. No flaws whatsoever. At least none that I have noticed.
I doubt that the actual lens quality variation is as high as one could get the impression of from reading this thread. Bare in mind that those that are unhappy about something are more likely to express that than those who are satisfied. This is only natural, just like the fact that people that are originally unhappy about a product, but then get their problems fixed by the seller or service provider, on average end up as more satisfied than those who didn't encounter any problems in the first place.
If i didn't already own a copy I would buy one again and again, even after reading this thread.
Ole
I doubt that the actual lens quality variation is as high as one could get the impression of from reading this thread. Bare in mind that those that are unhappy about something are more likely to express that than those who are satisfied. This is only natural, just like the fact that people that are originally unhappy about a product, but then get their problems fixed by the seller or service provider, on average end up as more satisfied than those who didn't encounter any problems in the first place.
If i didn't already own a copy I would buy one again and again, even after reading this thread.
Ole
Feb 29, 2016 at 01:17 PM
p.46 #15Zeiss Unveils the Loxia 21mm f/2.8
OleAndre wrote:
Since there are so many who are complaining about their Loxia 21 here, I can report that my copy is excellent. No flaws whatsoever. At least none that I have noticed.
I doubt that the actual lens quality variation is as high as one could get the impression of from reading this thread. Bare in mind that those that are unhappy about something are more likely to express that than those who are satisfied. This is only natural, just like the fact that people that are originally unhappy about a product, but then get their problems fixed by the seller...Show more →
Good for you Ole.
How did you test your lens exactly? Would you be kind to share the results of your test?
We should have a standard way to test these lenses to make sure other variables are not in play.
Since there are so many who are complaining about their Loxia 21 here, I can report that my copy is excellent. No flaws whatsoever. At least none that I have noticed.
I doubt that the actual lens quality variation is as high as one could get the impression of from reading this thread. Bare in mind that those that are unhappy about something are more likely to express that than those who are satisfied. This is only natural, just like the fact that people that are originally unhappy about a product, but then get their problems fixed by the seller...Show more →
Good for you Ole.
How did you test your lens exactly? Would you be kind to share the results of your test?
We should have a standard way to test these lenses to make sure other variables are not in play.
Feb 29, 2016 at 01:19 PM
p.46 #16Zeiss Unveils the Loxia 21mm f/2.8
Fred Miranda wrote:
Good for you Ole.
How did you test your lens exactly? Would you be kind to share the results of your test?
We should have a standard way to test these lenses to make sure other variables are not in play.
Well, let me emphasise that I am no expert, which is why i said "non that I have noticed"
But when reading this thread i went to this place called Nam Sham estate, to see how the corners performed at various apertures. I started at 2.8 and stopped the lens gradually down.
Here is one photo (f4) in full size:
https://www.flickr.com/photos/kjennerud/25266062862/sizes/o/
Here is another at f8, also full size:
https://www.flickr.com/photos/kjennerud/25016736799/sizes/o/
After that I asked myself whether i was happy about the lens, and yeah, i was. I found no reasons to be unhappy about the corner performance in these two images, or any of the other images i took at this location for that matter. But it might be that we have different definitions of what is acceptable and what is not.
I also did a very quick corner test by shifting the camera around the same subject (similar to what i have seen others have done in this thread). Here is the result of that simple test. Maybe i should have done it outdoors? Aperture at 3.5.
https://c2.staticflickr.com/2/1640/25266067182_02efa932c0_o.jpg
What do you think when seeing these, Fred? Do you come to a different conclusion than me? Would be great to hear
Regardless, i want to say that I have been very happy about my Loxia
Ole
Good for you Ole.
How did you test your lens exactly? Would you be kind to share the results of your test?
We should have a standard way to test these lenses to make sure other variables are not in play.
Well, let me emphasise that I am no expert, which is why i said "non that I have noticed"
But when reading this thread i went to this place called Nam Sham estate, to see how the corners performed at various apertures. I started at 2.8 and stopped the lens gradually down.
Here is one photo (f4) in full size:
https://www.flickr.com/photos/kjennerud/25266062862/sizes/o/
Here is another at f8, also full size:
https://www.flickr.com/photos/kjennerud/25016736799/sizes/o/
After that I asked myself whether i was happy about the lens, and yeah, i was. I found no reasons to be unhappy about the corner performance in these two images, or any of the other images i took at this location for that matter. But it might be that we have different definitions of what is acceptable and what is not.
I also did a very quick corner test by shifting the camera around the same subject (similar to what i have seen others have done in this thread). Here is the result of that simple test. Maybe i should have done it outdoors? Aperture at 3.5.
https://c2.staticflickr.com/2/1640/25266067182_02efa932c0_o.jpg
What do you think when seeing these, Fred? Do you come to a different conclusion than me? Would be great to hear
Regardless, i want to say that I have been very happy about my Loxia
Ole
Feb 29, 2016 at 02:39 PM
p.46 #17Zeiss Unveils the Loxia 21mm f/2.8
OleAndre wrote:
I doubt that the actual lens quality variation is as high as one could get the impression of from reading this thread. Bare in mind that those that are unhappy about something are more likely to express that than those who are satisfied.
If i didn't already own a copy I would buy one again and again, even after reading this thread.
Ole
I'm not sure this thread implies any "percentage variation" other than to make prospective buyers aware that this particular lens has "more" variation than other lenses. Some designs may be more prone to decentering, some lenses less capable of tweaking, etc - and it is good to know what range of outcomes may be possible.
Personally, this thread has been invaluable - particularly the feedback on field curvature - and i'm still in the process of considering how that suits me (i think it may actually be a benefit).
But the litmus test for me will be whether or not Guy can keep his for more than a month (which i've calculated to be his "mean dating time") - i have 2 trips to Italy this year (May, Aug) but given the lack of availability it may not even matter for this year's travels.
I doubt that the actual lens quality variation is as high as one could get the impression of from reading this thread. Bare in mind that those that are unhappy about something are more likely to express that than those who are satisfied.
If i didn't already own a copy I would buy one again and again, even after reading this thread.
Ole
I'm not sure this thread implies any "percentage variation" other than to make prospective buyers aware that this particular lens has "more" variation than other lenses. Some designs may be more prone to decentering, some lenses less capable of tweaking, etc - and it is good to know what range of outcomes may be possible.
Personally, this thread has been invaluable - particularly the feedback on field curvature - and i'm still in the process of considering how that suits me (i think it may actually be a benefit).
But the litmus test for me will be whether or not Guy can keep his for more than a month (which i've calculated to be his "mean dating time") - i have 2 trips to Italy this year (May, Aug) but given the lack of availability it may not even matter for this year's travels.
Feb 29, 2016 at 02:45 PM
p.46 #18Zeiss Unveils the Loxia 21mm f/2.8
OleAndre wrote:
I also did a very quick corner test by shifting the camera around the same subject (similar to what i have seen others have done in this thread). Here is the result of that simple test. Maybe i should have done it outdoors? Aperture at 3.5.
isn't that test (i.e. flipping the camera around) supposed to be done focused at infinity - not inside your kitchen?
I also did a very quick corner test by shifting the camera around the same subject (similar to what i have seen others have done in this thread). Here is the result of that simple test. Maybe i should have done it outdoors? Aperture at 3.5.
isn't that test (i.e. flipping the camera around) supposed to be done focused at infinity - not inside your kitchen?
Feb 29, 2016 at 02:47 PM
p.46 #19Zeiss Unveils the Loxia 21mm f/2.8
ecarlino wrote:
I'm not sure this thread implies any "percentage variation" other than to make prospective buyers aware that this particular lens has "more" variation than other lenses. Some designs may be more prone to decentering, some lenses less capable of tweaking, etc - and it is good to know what range of outcomes may be possible.
Personally, this thread has been invaluable - particularly the feedback on field curvature - and i'm still in the process of considering how that suits me (i think it may actually be a benefit).
But the litmus test for me will be whether or not Guy can...Show more →
I agree on that, but i still think that a thread like this will be more biased towards the errors than a neutral test would be, for example the testing done by the guys at LensRentals here: here. By just reading this thread, it is easy to overestimate the share of lenses that have errors. I general in statistics, one would need very a large sample, and most importantly a random sample, to more accurately evaluate whether it is plausible to say that a hypothesis is true or not (in this case whether the Loxia 21 has a higher frequency of decentered copies than other lenses).
That however, does not imply that a thread like this is of no value. Quite the contrary - I read this with great enthusiasm and learn a lot on practically every page. It is always necessary to evaluate what kind of lenses one might need, and which characteristics that is important.
In general I dont really think we disagree - I just like to point out to those who are evaluating whether to buy the Loxia should remember that there is a higher likelihood that you will get a good lens, than a bad lens (which doesn't really become clear in this thread). And yes - I'm an economist geek. I like these statistics stuff very much
I am also looking forward to see when (not if, right?) Guy will sell his Loxia. Thats probably the first thing i noticed here on FM - that Guy sells his lenses faster than I refuel my car
Ole
I'm not sure this thread implies any "percentage variation" other than to make prospective buyers aware that this particular lens has "more" variation than other lenses. Some designs may be more prone to decentering, some lenses less capable of tweaking, etc - and it is good to know what range of outcomes may be possible.
Personally, this thread has been invaluable - particularly the feedback on field curvature - and i'm still in the process of considering how that suits me (i think it may actually be a benefit).
But the litmus test for me will be whether or not Guy can...Show more →
I agree on that, but i still think that a thread like this will be more biased towards the errors than a neutral test would be, for example the testing done by the guys at LensRentals here: here. By just reading this thread, it is easy to overestimate the share of lenses that have errors. I general in statistics, one would need very a large sample, and most importantly a random sample, to more accurately evaluate whether it is plausible to say that a hypothesis is true or not (in this case whether the Loxia 21 has a higher frequency of decentered copies than other lenses).
That however, does not imply that a thread like this is of no value. Quite the contrary - I read this with great enthusiasm and learn a lot on practically every page. It is always necessary to evaluate what kind of lenses one might need, and which characteristics that is important.
In general I dont really think we disagree - I just like to point out to those who are evaluating whether to buy the Loxia should remember that there is a higher likelihood that you will get a good lens, than a bad lens (which doesn't really become clear in this thread). And yes - I'm an economist geek. I like these statistics stuff very much
I am also looking forward to see when (not if, right?) Guy will sell his Loxia. Thats probably the first thing i noticed here on FM - that Guy sells his lenses faster than I refuel my car
Ole
Feb 29, 2016 at 03:03 PM
p.46 #20Zeiss Unveils the Loxia 21mm f/2.8
ecarlino wrote:
isn't that test (i.e. flipping the camera around) supposed to be done focused at infinity - not inside your kitchen?
Probably yeah, but I didn't do that in Hong Kong, and in Norway it still gets dark before i get home from work. Hence the Kitchen test
isn't that test (i.e. flipping the camera around) supposed to be done focused at infinity - not inside your kitchen?
Probably yeah, but I didn't do that in Hong Kong, and in Norway it still gets dark before i get home from work. Hence the Kitchen test
Feb 29, 2016 at 03:04 PM