Nikkor 105mm f/2.5

[Tristin]

The 105/2.5 gets better with distance.  It's shortcomings are really magnified at it's MFD.

[Akira]

The 105/2.5 gets better with distance.  It's shortcomings are really magnified at it's MFD.

Tristin, that is interesting.  My experiences with a couple of different versions of 105/2.5 (all were of Xenotar type.  Single-coated, multi-coated K, Ais) equally tell that they are sharper at MFD.  None I've had was satisfactory when focused at distant scenes.

[richardHaw]

some people say that a 100X multiplication factor of FL = distance is the optimum distance for a lens

example:

50mm = 5 meters
85mm = 8.5 meters

[Tristin]

Akira, I particularly mean the lense's field curvature and chromatic aberrations which are much more noticeable up close.  The sharpness of the 105/2.5 is good up close, but the area in which the field curvature will allow sharpness plunges strongly in the corners and brings increased CA with it making the image corners and borders look poor.  At farther distances the field curvature effects the image less prominently.

[Akira]

Akira, I particularly mean the lense's field curvature and chromatic aberrations which are much more noticeable up close.  The sharpness of the 105/2.5 is good up close, but the area in which the field curvature will allow sharpness plunges strongly in the corners and brings increased CA with it making the image corners and borders look poor.  At farther distances the field curvature effects the image less prominently.

I see.   I guess the lens designers thought the mid-teles would be used for the portraits more often than something flat in the entire frame when focused closer.  So, the field curvature could be a bit tolerated.

[Akira]

some people say that a 100X multiplication factor of FL = distance is the optimum distance for a lens

example:

50mm = 5 meters
85mm = 8.5 meters

I think the lenses without CRC at that time was basically designed for the infinity focus except for Micro Nikkors.  But the balancing of the aberrations in different distances should have been dependent on the designers' taste.

[Tristin]

I see.   I guess the lens designers thought the mid-teles would be used for the portraits more often than something flat in the entire frame when focused closer.  So, the field curvature could be a bit tolerated.

Precisely.

[simsurace]

some people say that a 100X multiplication factor of FL = distance is the optimum distance for a lens

example:

50mm = 5 meters
85mm = 8.5 meters

Do these people also explain why they think so?

[Akira]

some people say that a 100X multiplication factor of FL = distance is the optimum distance for a lens

example:

50mm = 5 meters
85mm = 8.5 meters

Are the "some people" the folks gathering at tokinon 50/1,4? 

[richardHaw]

Are the "some people" the folks gathering at tokinon 50/1,4? 

no, i think it was Sato Haruo himself who said that.
read the 5cm or the 5.8cm write up i think it's there

[richardHaw]

Do these people also explain why they think so?

I don't recall but I read it from a credible source. I just cannot remember where

[Akira]

no, i think it was Sato Haruo himself who said that.
read the 5cm or the 5.8cm write up i think it's there

Just checked "1001 Nights".  I couldn't find any of the notion at least in the sections for 58/1.4, 55/1.2, 50/1.4 or the rangefinder 50/2.0.  I'll look into other sections when I have time.

[richardHaw]

Just checked "1001 Nights".  I couldn't find any of the notion at least in the sections for 58/1.4, 55/1.2, 50/1.4 or the rangefinder 50/2.0.  I'll look into other sections when I have time.

me,too

[Akira]

me,too

 

[stenrasmussen]

Ai-S version at f/2.5.