[nandadevieast]

Hi,

I have read somewhere that lenses are optimized for distance. Like, i have read that Nikon AF-D 180 2.8 is not as good at infinity as it is for nearer distances, perhaps because they chose to design it for photojournalists. Macro lenses are also a case in point, where quite often they are better performers at macro distances.

What if someone wants to purchase a lens like 180 2.8, expecting to shoot landscapes with it, or a Sigma 150 2.8, expecting to use it as a telephoto over and above its macro function. If a particular lens is not optimized for something, how do you know that before buying it?

It will help if i know that lens A is better at infinity than lens B, though both have same focal length.

regards,

anurag

[Klaus]

[quote name='nandadevieast' timestamp='1343937304' post='19674']

Hi,

I have read somewhere that lenses are optimized for distance. Like, i have read that Nikon AF-D 180 2.8 is not as good at infinity as it is for nearer distances, perhaps because they chose to design it for photojournalists. Macro lenses are also a case in point, where quite often they are better performers at macro distances.

What if someone wants to purchase a lens like 180 2.8, expecting to shoot landscapes with it, or a Sigma 150 2.8, expecting to use it as a telephoto over and above its macro function. If a particular lens is not optimized for something, how do you know that before buying it?

It will help if i know that lens A is better at infinity than lens B, though both have same focal length.

regards,

anurag

[/quote]



PZ is testing the middleground. There is currently no serious way to test the quality at macro distances nor infinity.

[wim]

Hi anurag,



One can really only find out by reading a lot on lenses wanted, and testing this oneself.



Often different brands approach this in different ways, f.e., most Zeiss lenses, unless designed for a very specific function (macro, portrait) work best at middle to long distances, i.e, are great for general shooting and landscapes, but not so great for close-up shooting. A good example of this is the Zeiss 50 F/1.4, which is mediocre at best in close up, but is the one to beat at anything beyond 8-10 m from F/2.8 upwards.



This is also true for other lenses. Many Canon lenses are optimal at middle ground distances (for that particular FL), although L-lenses generally perform a bit better over multiple distances, and several are just excellent allround.



It really is a matter, if you want to go into that much detail, of figuring out what distance is most important for you, and select a lens specific for that.



In your case, if you want a 180 mm which performs exceptionally wel at or around infinity, an adapted Leitz 180 F/2.8 or F/2.8 is the way to go, for the middle ground the Nikon 180 F/2.8, and for the short distance any (150 to) 180 mm macro lens <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.



Of course there may be equally important characteristics for you, such as optical aberrations (CA, astigmatism, coma, flare, vignetting, etc.) and mechanical ones (mechanical vignetting - cats' eyes, manual focusing, aperture control), bokeh, general rendering, colour, contrast etc. If you buy any decent lens, the sharpness and resolution really become moot points, because lenses resolve more than any sensor, despite comments to the contrary on the internet (certainly at apertures larger than F/16 for FF and F/13 for APS-C), and what IMO becomes most important is whether one likes the overall rendering of a lens as influenced by the characteristics mentioned above.



From that POV, if you want quality, I reckon the Nikon 180 F/2.8 is one h**k of a lens, and absolutely nothing to complain or worry about.



As with all photographic equipment (and a lot of other things too), it really is just a matter of getting used to it and knowing how to work within its characteristics for your type(s) of photography. Or of course get several lenses for different types of shooting (as we generally already do with FLs <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />).



HTH, kind regards, Wim

[nandadevieast]

[quote name='wim' timestamp='1343989242' post='19678']

If you buy any decent lens, the sharpness and resolution really become moot points, because lenses resolve more than any sensor, despite comments to the contrary on the internet..

HTH, kind regards, Wim

[/quote]



Can a lens like 18-200 VR (brought out with D200) resolve more than today's 16 megapixel sensor?

Are discussions like "this lens vs. this lens?" a moot point then?

[Brightcolours]

[quote name='nandadevieast' timestamp='1343996135' post='19680']

Can a lens like 18-200 VR (brought out with D200) resolve more than today's 16 megapixel sensor?

Are discussions like "this lens vs. this lens?" a moot point then?

[/quote]

It is not like that.





You have to look at it a different way, really. One source of softness is the resolving power of the optics. Another source of softness is the sampling rate of the sensor. Those get added up.



So, while a 180mm f2.8 may give sharper results than that 18-200mm on a 12mp sensor, still the 18-200mm in combination with a 16mp sensor can resolve more than that 18-200 with a 12mp sensor.



You add up all causes of softness.

[nandadevieast]

There's no information or database on the net that you know of, which tells you which tele lenses are good for infinity or medium distances...?

[popo]

I think, outside of very special uses, this is a level of detail not needed even by pixel peepers.

[Brightcolours]

Only 50 years ago this was an issue. Back then, some macro lenses did great at macro distances, but got visibly soft at infinity. My micro NIKKOR 55mm f3.5 AUTO is an example of that.

My early version is virtually unmatched in sharpness by modern macro lenses at macro and close up distances, but not very well suited to be a normal lens because of its loss of resolution there.



A later version (micro NIKKOR 55mm f3.5 AUTO P and P.C) were redesigned already and focussed in a different way, making the lens more usable as "normal" lens, and only losing a little in ultimate sharpness at close up distances. I do not know of any modern macro lens that shows a difference in sharpness in close up and infinity like that 50 year old lens.

[Studor13]

[quote name='popo' timestamp='1344098720' post='19683']

I think, outside of very special uses, this is a level of detail not needed even by pixel peepers.

[/quote]

You don't have to be a pixel peeper to know that with landscapes and telephotos you want infinity to be sharp. On a number of lenses I recently tested on a D800 I found that most of the lenses were similar at mid distances. However, at infinity some were noticeably better than others.

[popo]

I'm not a landscaper, but I would have thought other factors like diffraction softening, intentional non-focusing on infinity (e.g. using hyperfocal distance) and even air quality would also be significant factors in perceived performance. How much influence any specific lens has in making or breaking a shot, I don't know.



Of course, if you really do need the maximum capability at infinity, you need it. Currently I'm most active in attempting astrophotography, so that's definitely at infinity with anything closer being irrelevant. But the optics are not my biggest problem at the moment...