Maybe somebody can explain a little about this? Is it about bad quality control or a bad quality policy? Is it about bad karma or are all the 35i lenses like this? Why at one side only - is that a result from a polishing machine in need of some adjustment?
---
I have this strange experience from trying three different Sigma 35i lenses now: None of they manage to deliver a sharp image of a painting in the size 1.0x0.8 meters.
Lens No.1 was bad at the right half of the image, the second copy was better but not good. At that point I thought I should give up. Reading the Lenstip review told me their copy probably was something like the two I had tried. If true maybe all the 35i lenses are like this? Can't be right? Maybe it was about bad luck only. Here I was recommended to make a third try.
OK, one shouldn't give up! Alas, the third copy turned out to be the worst one of them all.
One of the first fast test shots i do when buying a new lens is to shoot a 80 cm wide shelf where seven small crops from the ancient USAF test chart are sitting permanently. That says something about me of course. But wth, shouldn't a lens advertised with a flat nice MTF curve allow me to get a sharp picture of a 80 cm wide bookshelf? Or a painting.
So, I have USAF charts spread from left to right border with all these lenses.
EDIT April 25 - all images/charts are moved to an updated post (page 19, post 5)
I can hear some of you.... don't shoot test charts, take images! Yeah, for sure, I do that. However, I want to know my gear and a quick three or four part test taking a total of less than half an hour lets me know if the lens is any good or not. And, yes, I sometimes need to take images of paintings among all the other things I'm interested in.
I think copy three is the same as the first two ones and then with some sideways tilt added.
Are the results above any good? No. Here they are again but compared to the Samyang AF35 F1.8. The SY35 has a little lower contrast but a higher and more uniform resolving power than the 35i. Like this when compared in the same graph:
EDIT April 25 - all images/charts are moved to an updated post (page 19, post 5)
As mentioned the Samyang contrast, to my eyes, is a notch lower but the result is way better than the Sigmas (one averaged black curve only now).
And finally, for you wanting to see it all at the same time:
[Quote] EDIT April 25: all images/charts are moved to an updated post (page 19, post 5)
Remember this is about eye-balling, USAF charts are representing a quite crude way to judge "sharpness" and a value can vary from one day to another depending on my mode. Yoyr result will vary and probably be better.
USAF charts do however offer a very fast and efficient way to discover faults some faults with a lens. I want my lenses to be reasonably sharp from border to border. I'm not as concerned about the corners when shooting with a lens wide open (and most of the time I'm not concerned at all).
The lenses seemed to work at longer distances, I liked the haptics (far better than the 35GM), the weight was OK and so on. But the darn thing has to be able to make for a sharp image when at about 1 meter away from a flat surface.
The Sigmas had the following serial numbers: 5528xxxx, 5530xxxx and 5531xxxx.
Maybe somebody can explain a little about this? Is it about bad quality control or a bad quality policy? Is it about bad karma or are all the 35i lenses like this? Why at one side only - is that a result from a polishing machine in need of some adjustment?
---
I have this strange experience from trying three different Sigma 35i lenses now: None of they manage to deliver a sharp image of a painting in the size 1.0x0.8 meters.
Lens No.1 was bad at the right half of the image, the second copy was better but not good. At that point I thought I should give up. Reading the Lenstip review told me their copy probably was something like the two I had tried. If true maybe all the 35i lenses are like this? Can't be right? Maybe it was about bad luck only. Here I was recommended to make a third try.
OK, one shouldn't give up! Alas, the third copy turned out to be the worst one of them all.
One of the first fast test shots i do when buying a new lens is to shoot a 80 cm wide shelf where seven small crops from the ancient USAF test chart are sitting permanently. That says something about me of course. But wth, shouldn't a lens advertised with a flat nice MTF curve allow me to get a sharp picture of a 80 cm wide bookshelf? Or a painting.
So, I have USAF charts spread from left to right border with all these lenses.
EDIT April 25 - all images/charts are moved to an updated post (page 19, post 5)
I can hear some of you.... don't shoot test charts, take images! Yeah, for sure, I do that. However, I want to know my gear and a quick three or four part test taking a total of less than half an hour lets me know if the lens is any good or not. And, yes, I sometimes need to take images of paintings among all the other things I'm interested in.
I think copy three is the same as the first two ones and then with some sideways tilt added.
Are the results above any good? No. Here they are again but compared to the Samyang AF35 F1.8. The SY35 has a little lower contrast but a higher and more uniform resolving power than the 35i. Like this when compared in the same graph:
EDIT April 25 - all images/charts are moved to an updated post (page 19, post 5)
As mentioned the Samyang contrast, to my eyes, is a notch lower but the result is way better than the Sigmas (one averaged black curve only now).
And finally, for you wanting to see it all at the same time:
EDIT April 25 - all images/charts are moved to an updated post (page 19, post 5)
Remember this is about eye-balling, USAF charts are representing a quite crude way to judge "sharpness" and a value can vary from one day to another depending on my mode. Yoyr result will vary and probably be better.
USAF charts do however offer a very fast and efficient way to discover faults some faults with a lens. I want my lenses to be reasonably sharp from border to border. I'm not as concerned about the corners when shooting with a lens wide open (and most of the time I'm not concerned at all).
The lenses seemed to work at longer distances, I liked the haptics (far better than the 35GM), the weight was OK and so on. But the darn thing has to be able to make for a sharp image when at about 1 meter away from a flat surface.
The Sigmas had the following serial numbers: 5528xxxx, 5530xxxx and 5531xxxx.
Maybe somebody can explain a little about this? Is it about bad quality control or a bad quality policy? Is it about bad karma or are all the 35i lenses like this? Why at one side only - is that a result from a polishing machine in need of some adjustment?
---
I have this strange experience from trying three different Sigma 35i lenses now: None of they manage to deliver a sharp image of a painting in the size 1.0x0.8 meters.
Lens No.1 was bad at the right half of the image, the second copy was better but not good. At that point I thought I should give up. Reading the Lenstip review told me their copy probably was something like the two I had tried. If true maybe all the 35i lenses are like this? Can't be right? Maybe it was about bad luck only. Here I was recommended to make a third try.
OK, one shouldn't give up! Alas, the third copy turned out to be the worst one of them all.
One of the first fast test shots i do when buying a new lens is to shoot a 80 cm wide shelf where seven small crops from the ancient USAF test chart are sitting permanently. That says something about me of course. But wth, shouldn't a lens advertised with a flat nice MTF curve allow me to get a sharp picture of a 80 cm wide bookshelf? Or a painting.
So, I have USAF charts spread from left to right border with all these lenses.
The results, if transformed into Excel graphs look like this:
I can hear some of you.... don't shoot test charts, take images! Yeah, for sure, I do that. However, I want to know my gear and a quick three or four part test taking a total of less than half an hour lets me know if the lens is any good or not. And, yes, I sometimes need to take images of paintings among all the other things I'm interested in.
I think copy three is the same as the first two ones and then with some sideways tilt added.
Are the results above any good? No. Here they are again but compared to the Samyang AF35 F1.8. The SY35 has a little lower contrast but a higher and more uniform resolving power than the 35i. Like this when compared in the same graph:
As mentioned the Samyang contrast, to my eyes, is a notch lower but the result is way better than the Sigmas (one averaged black curve only now).
And finally, for you wanting to see it all at the same time:
In the graph above we have the Sony 35GM at f/2 added to the soup. There is also a straight grey line showing the max result I used to get back in the days with the well-known Sony 6MP APS-C sensor.
Remeber this is about eye-balling, USAF charts are representing a quite crude way to judge "sharpness" and a value can vary from one day to another depending on my mode. Yoyr result will vary and probably be better.
USAF charts do however offer a very fast and efficient way to discover faults some faults with a lens. I want my lenses to be reasonably sharp from border to border. I'm not as concerned about the corners when shooting with a lens wide open (and most of the time I'm not concerned at all).
The lenses seemed to work at longer distances, I liked the haptics (far better than the 35GM), the weight was OK and so on. But the darn thing has to be able to make for a sharp image when at about 1 meter away from a flat surface.
The Sigmas had the following serial numbers: 5528xxxx, 5530xxxx and 5531xxxx.
Apr 18, 2021 at 03:05 PM
Previous versions of Jonas B's message #15570538 « Sigma 35mm f/2 DG DN Contemporary Review »
