11-08-2011, 02:47 PM
[quote name='Studor13' timestamp='1320758938' post='12763']
I'll repeat what I wrote above:
According to PZ, the 18-35mm @35mm and f4.5 (D7000) gives:
2145(center); 1175(border); 1073(extreme)
vs 18-55 VR at f5
2588(center); 2131(border); 1929(extreme)
This simply can't be. Get these two lenses, shoot them side by side and look for yourself. There is no way that the 18-55 VR is sharper at 35mm. From the above, the border and extreme resolutions on the VR are almost double that of the 18-35!
When people rely simply on what PZ says as to how they should crop, then there is a fundamental problem with the way we shoot.
[/quote]
Actually, IMO, this is very well possible. WA and standard zoom lenses generally are sharpest in their mid ranges.
Other than that, what a lot of people seem to forget, that a lens is not all about sharpness, or some relatively minor optical aberrations. Any lens scoring Good in the relative ranges, actualy is that: Good. However, lenses here are compared to what is the theoretical best possible, which effectively is unobtainable, which makes it even better. What is truly amazing however, is that so many lenses these days not only manage to score "Good", but even "Very good" and "Excellent". This doesn't necessarily mean that one wil be able to get this sharpness out of the lens, into print or even onto screen for that matter, because quite a lot of factors do influence the end result as well. Generally speaking, it will be very hard to see the differences between good to very good lenses and excellent lenses, especially on th einternet.
I saw a good example recently, where pictures of the same onject, same distance, same exposure, same aperture were put next to each other, of a Canon EF 85 F/1.8 and a 85L II. Sharpnesss wise, they looked almost identical. If you check th etest here, you will find that the 85L II fares quite a bit better, apparently, than the 85 F/1.8. Mos tpeopel even couldn;t tell the pictures apart, except fo rthose who knew both well and the difference in rendering. Thsi si probably what you call the X-factor.
This is not related necessarily to the sharpness of a lens (even though it may help), but more to the way it renders stuf fonto the sensor, microcontrast, bokeh, colour, saturation, etc. Those are very difficult if not impossible to measure, but they do make a difference. And each photographer has his or her own opinion and emotion when it comes to the rendering. Thsi si also why some photographers have different lenses in the same FL, to be used specifically for the way they render, for certain subjects, to create certain moods, etc. On a technical test site you don't normally read anything about this, although Photozone does do a valiant effort at some stuff, like longitudinal colour aberrations and bokeh, and field curvature. Neither are easily measurable, but at least an effort is made to try and indicate the quality of these optical aberrations, which will effect image quality and rendering.
There are many more lenses tested here which don't come out all that well, one of them being my own favourite, the Canon 50L. Yes, it has its problems, but one can learn to work with those, or around those, and I find it is a very rewarding lens. Some of my best shots are made with this lens. And I do like it especially because of what you call its X-factor, the way it renders. It creates a unique look, often 3D-like, it is impossible to get a flare, and despite the problem bokeh displayed in one of the samples here, I always found the bokeh of this lens to be the best of any lens I have ever tried. And the image files created with this lens, do respond extremely well to sharpenign too - I accidentally shot a landscape once at F/3.5, I had to be fast, and didn't have time to check. A little edge sharpening, and the image was sharp from front to back, on FF. Asking a few people at which this image was shot (30 X 45 print), including professionals, I invariably got an answer of an aperture between F/8 and F/16! IOW, sharpness is relative. The X-factor and proicessing are easily as important.
Other than that, I honestly do think that a site like Photozone (and others) really only help in determining the things to look out for when acquiring a new lens, rather than determining how good or bad one's current lenses are. It helps to make an informed decision, why one chooses a particular lens over another. Factors in this of course are budget as well as perceived quality, and in the end those last two are the two most important factors, IMO. Some people shoot with very old large format lenses, basically because they like the way those lenses render, and I can assure you that even when contact printed the images don't look sharp, in contrast to your pictures here. In the end, if it works for you, does it really matter that the technical test results maybe are less than stellar?
Anyway, HTH, kind regards, Wim
I'll repeat what I wrote above:
According to PZ, the 18-35mm @35mm and f4.5 (D7000) gives:
2145(center); 1175(border); 1073(extreme)
vs 18-55 VR at f5
2588(center); 2131(border); 1929(extreme)
This simply can't be. Get these two lenses, shoot them side by side and look for yourself. There is no way that the 18-55 VR is sharper at 35mm. From the above, the border and extreme resolutions on the VR are almost double that of the 18-35!
When people rely simply on what PZ says as to how they should crop, then there is a fundamental problem with the way we shoot.
[/quote]
Actually, IMO, this is very well possible. WA and standard zoom lenses generally are sharpest in their mid ranges.
Other than that, what a lot of people seem to forget, that a lens is not all about sharpness, or some relatively minor optical aberrations. Any lens scoring Good in the relative ranges, actualy is that: Good. However, lenses here are compared to what is the theoretical best possible, which effectively is unobtainable, which makes it even better. What is truly amazing however, is that so many lenses these days not only manage to score "Good", but even "Very good" and "Excellent". This doesn't necessarily mean that one wil be able to get this sharpness out of the lens, into print or even onto screen for that matter, because quite a lot of factors do influence the end result as well. Generally speaking, it will be very hard to see the differences between good to very good lenses and excellent lenses, especially on th einternet.
I saw a good example recently, where pictures of the same onject, same distance, same exposure, same aperture were put next to each other, of a Canon EF 85 F/1.8 and a 85L II. Sharpnesss wise, they looked almost identical. If you check th etest here, you will find that the 85L II fares quite a bit better, apparently, than the 85 F/1.8. Mos tpeopel even couldn;t tell the pictures apart, except fo rthose who knew both well and the difference in rendering. Thsi si probably what you call the X-factor.
This is not related necessarily to the sharpness of a lens (even though it may help), but more to the way it renders stuf fonto the sensor, microcontrast, bokeh, colour, saturation, etc. Those are very difficult if not impossible to measure, but they do make a difference. And each photographer has his or her own opinion and emotion when it comes to the rendering. Thsi si also why some photographers have different lenses in the same FL, to be used specifically for the way they render, for certain subjects, to create certain moods, etc. On a technical test site you don't normally read anything about this, although Photozone does do a valiant effort at some stuff, like longitudinal colour aberrations and bokeh, and field curvature. Neither are easily measurable, but at least an effort is made to try and indicate the quality of these optical aberrations, which will effect image quality and rendering.
There are many more lenses tested here which don't come out all that well, one of them being my own favourite, the Canon 50L. Yes, it has its problems, but one can learn to work with those, or around those, and I find it is a very rewarding lens. Some of my best shots are made with this lens. And I do like it especially because of what you call its X-factor, the way it renders. It creates a unique look, often 3D-like, it is impossible to get a flare, and despite the problem bokeh displayed in one of the samples here, I always found the bokeh of this lens to be the best of any lens I have ever tried. And the image files created with this lens, do respond extremely well to sharpenign too - I accidentally shot a landscape once at F/3.5, I had to be fast, and didn't have time to check. A little edge sharpening, and the image was sharp from front to back, on FF. Asking a few people at which this image was shot (30 X 45 print), including professionals, I invariably got an answer of an aperture between F/8 and F/16! IOW, sharpness is relative. The X-factor and proicessing are easily as important.
Other than that, I honestly do think that a site like Photozone (and others) really only help in determining the things to look out for when acquiring a new lens, rather than determining how good or bad one's current lenses are. It helps to make an informed decision, why one chooses a particular lens over another. Factors in this of course are budget as well as perceived quality, and in the end those last two are the two most important factors, IMO. Some people shoot with very old large format lenses, basically because they like the way those lenses render, and I can assure you that even when contact printed the images don't look sharp, in contrast to your pictures here. In the end, if it works for you, does it really matter that the technical test results maybe are less than stellar?
Anyway, HTH, kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....