After reading Glenn Tanaka's earlier posts on this site about magazine test reports, I went to the local libray and checked out one copy of Modern Photography on which TC and three Hexanon lenses are tested - 50mm f1.7, 45-100mm f3.5UC, and 80-200 f4UC.

I have some questions regarding the contrast and resolution after reading the reports.

First, here are some numbers, for 50mm f1.7, the tested resolution is (at 1:50 magnification):

f/no, center(lines/mm), corner(lines/mm) 1.7---56----------------40 2.8---45----------------40 4-----50----------------50 5.6---64----------------64 8-----64----------------64 11----71----------------56 16----64----------------50

the tested contrast is: (at 30 lines/mm) f/no, center %, corner % 1.7---40--------31 2.8---60--------41 4-----64--------62 5.6---68--------64 8-----65--------62 11----58--------58 16----52--------52

My questions are: 1. Are these numbers high? :-) (knowing 50mmF1.7 is not the star lens in the Hexanon line) Are there benchmark numbers?

2. How did they get the contrast numbers?

For 45-100mm the contrast numbers are V/low 8-12% in the corner at 100mm end, low V/low to medium at 70mm, low to medium at 45mm. For 80-200mm the contrast numbers are V/low 8-16% in the corner at 200mm end, low at 135mm, and low to high at 80mm end.

However, the resolution numbers for both zoom lenses are from V good to Execllent (36-65 lpm).

So, my third question is: how to interpret these numbers?

Thanks!

Wenbiao

-- Anonymous, November 30, 2000

Answers

hmmm, the numbers are messed up...

the tested resolution is (at 1:50 magnification):

f/no, center(lines/mm), corner(lines/mm) 1.7---56----------------40

2.8---45----------------40

4-----50----------------50

5.6---64----------------64

8-----64----------------64

11----71----------------56

16----64----------------50

the tested contrast is: (at 30 lines/mm)

f/no, center %, corner %

1.7---40--------31

2.8---60--------41

4-----64--------62

5.6---68--------64

8-----65--------62

11----58--------58

16----52--------52

sorry...

-- Anonymous, November 30, 2000

Thanks for taking the time to post those results! Any more?

Thanks Wenbiao for posting those results. Are there anymore? Now I know to shoot my 50mm f1.7 lens in the f5.6 - f8 range! (well, I knew that before, but now I got stats!)

Mike.

-- Anonymous, November 30, 2000

two more lenses...

Hi, Mike, there were two more lens that got tested. 45-100mmf3.5UC and 80-200mmf4UC. some figures from the reports: resolution (contrast %), 45-100mmf3.5UC: f/no,center,corner (45mmend) 3.5--57(40)--40(21) 5.6--57(54)--45(31) 8----64(56)--45(36) 11---64(54)--51(34) 16---64(50)--51(32) f/no,center,corner (70mm) 3.5--53(37)--38(17) 5.6--60(56)--42(32) 8----60(58)--47(31) 11---60(56)--47(30) 16---60(51)--47(24) f/no,center,corner (100mm end) 3.5--53(50)--42(10) 5.6--53(60)--47(12) 8----47(60)--42(9) 11---47(58)--37(8) 16---53(53)--47(8)

resolution(contrast%)80-200mmf4 f/no,center,corner (at 80mm) 4----52(30)--41(13) 5.6--58(45)--41(20) 8----65(48)--52(36) 11---58(48)--52(46) 16---58(50)--52(44) f/no,center,corner (at 135mm) 4----41(28)--37(18) 5.6--52(34)--41(24) 8----52(40)--41(26) 11---58(42)--46(30) 16---46(42)--41(31) f/no,center,corner (at 200mm) 4----36(16)--29(8) 5.6--32(19)--26(11) 8----46(23)--36(15) 11---46(24)--32(16) 16---32(24)--29(16)

Any comments on the figures? Thanks,

-- Anonymous, December 01, 2000

I will gladly put this together

hi folks---

thanks wanbiao and glenn for bringing to light these test reports.

i will head off to the library today to get these reports, and i would like to make summary tables on the Web so that everyone can have access to this data.

it would be nice to have data from the entire line of hexanon's. but, i think this may not be possible. right now, as i understand it, there are reviews for:

28/1.8, 35/2.0, 40/1.8, 50/1.4, 50/1.7, 55/3.5, 57/1.2, 85/1.8, 100/2.8, 135/2.5 and right now i am not sure which of these (aside from the 50/1.4) has contrast/resolution data.

it would be nice to have data for all the 135's, the 28's, 24, 21, 200's, and some of the zooms. and then, maybe to compare this data with some other lenses (nikon's, minolta's, etc. of yesteryear and today).

my question: does anyone have any suggestions on where one can find this data?

paul.

-- Anonymous, December 19, 2000

I found those data in the local public library

Paul, The local public library has a magazine section which stores all the past issues they have. They don't have issues older than 68's... and I have to ask the librarian to get the magazines from the shelf, so after several times, they get a little tired of me -- especially when I don't know which issues have the Konica reviews... :-)

I think university libraries may allow you to browse the past issues yourselves?

In addition to the three lenses I posted here, I think I made copies of some issues in which 40/1.8, 100/2.8 and 28/1.8 are covered -- data are plot in a graph though (somewhat like MTF, and I had difficulty understanding those :-)) I will try to scan them once I get home...

Hope this helps... Wenbiao

-- Anonymous, December 19, 2000

status

hi wanbiao...

at boston university, where i am, i found many photography journals (including popular photo, british journal of photo, peterson's, etc.) that went way back (popular photo went back to the late 30's). boston public library has modern photography and practical photography (mentioned by Tim Hobson at this site's home page).

i will keep searching for data... and will organize it and post it.

does anyone know if konica ever published such contrast/resolution data?

if we were to obtain such data from someone at konica (someone here must have contacts, i just saw a post the other day regarding such a contact), it would be helpful to everyone, i think.

paul.

-- Anonymous, December 19, 2000

you may want to post a new message

Paul, I assume not so many people will watch this "older" thread, so it might be useful to create a new thread so more people can respond? :-)

Thanks, Wenbiao

-- Anonymous, December 19, 2000