Optical tests of Pentax67 optics

[loke_kun_tan]

I was wondering if there has been any published optical

tests of Pentax67 lenses. If so could someone please

point me to such information.

Loke Kun Tan

[steve_rasmussen]

I believe there was one in Modern Photography some time back but I don't know which issue. There is very little in the way of medium format optical tests mostly because the majority of photographers use 35mm and magazines cater to the masses. Be assured that medium format manufacturers use the same general designs for lenses as in 35mm cameras. You'll notice the similarity between a normal lens in 35mm format and normal lenses in medium format, as an example. My results with P67 lenses have been excellent. I use the 45, 75,105, 200,300 &600. Steve

[reinhard_becker2]

There was a test about 67 (Pentax and Mamiya) lenses in a german magazin a few years ago. If somebody is interested in

the results, please mail me a short message. I will try to find the old magazine (1991, I think).

 

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Reinhar

[reinhard_becker2]

In the comment, the author said that all lenses have very good optics. The Pentax and Mamiya with great apertures (2,4 and 2,8) are not so good used full open, but two stops down they are at the same level as the other lenses.

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Following lenses got the "grade 1" sign as testwinners: KL 4/65, Sekor Z 4,5/50 , Pentax 67 4/55 , Zenzanon-PG 3,5/100 Sekor C 4,5/180

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Hope I can help you with this results

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The notes are :

 

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1.sharpness aperture full open (10 points max), center & edge

 

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2.sharpness two stops down (10 points max), center & edge

 

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3.contrast aperture full open (10 points max), center & edge

 

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4.contrast two stops down (10 points max), center & edge

 

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5.vignetting aperture full open (in EV, 34mm from center)

 

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6.vignetting two stops down (in EV, 34mm from center)

 

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7.distorsion (15 points max)

 

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The two stops down values are at:

2,4 - 5,6 ; 2,8 - 5,6 ; 3,5 - 8 ; 4 - 8 ; 4,5 - 8

 

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The tested lenses are :

 

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Mamiya KL 4/65 (RB) :

8,5 7,0 9,3 8,2 8,7 7,3 9,3 8,5 1,2 0,4 13,5

 

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Mamiya KL 3,5/90 (RB):

7,9 6,4 9,0 8,0 8,5 7,0 9,1 8,3 1,1 0,3 13,0

 

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Mamiya Sekor C 4,5/180 (RB):

8,5 8,2 8,8 8,3 8,8 8,6 9,2 8,8 0,7 0,3 13,0

 

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Mamiya Sekor Z 4,5/50 W (RZ):

8,6 7,2 9,2 8,1 9,0 7,6 9,3 8,3 1,3 0,5 14,0

 

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Mamiya Sekor Z 2,8/110 W (RZ):

7,0 5,5 9,2 8,7 7,8 6,3 9,2 8,4 1,0 0,3 13,0

 

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Mamiya Sekor Z 3,5/150 W (RZ):

7,8 7,4 8,4 7,5 8,2 7,6 9,1 8,2 0,6 0,2 13,0

 

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Pentax 67 4/55 :

8,6 7,1 9,2 8,5 8,9 7,5 9,3 8,7 1,3 0,5 14,0

 

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Pentax 67 2,4/105 :

7,0 5,9 9,2 8,1 7,9 6,6 9,2 8,4 1,2 0,2 13,0

 

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Pentax 67 2,8/165 :

6,9 5,8 8,8 7,2 7,9 6,8 9,2 7,9 1,2 0,2 13,0

 

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Zenzanon-PG 4/65 (GS1):

8,3 6,7 9,2 7,9 8,7 7,2 9,2 8,3 1,2 0,4 13,5

 

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Zenzanon-PG 3,5/100 (GS1):

8,5 7,3 9,2 8,5 8,8 7,8 9,1 8,5 0,7 0,2 13,0

 

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Zenzanon-PG 4/150 (GS1):

8,0 7,2 8,4 7,4 8,4 7,4 9,1 8,2 0,7 0,2 13,0

 

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I hope you can now read the results better!

 

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Reinhard

[jacks_dad]

Does anyone know what version of the 55 f/4 was tested in the report

above? Since the article was published in 1991, I expect that it was

the most recent version of the 55.

[steve_rasmussen]

It was most likely the second f/4 but be assurred that the first f/4

and the older f/3.5 were all quite sharp. The first f/4 was the same

design as the 45mm. SR

[bobby mahaffey]

Modern Photography published several lens tests shortly after the

Pentax 6x7 was introduced. The reports were generally very

favorable. For example, "The 105 f/2.4 Super Takumar normal lens is

surely one of the finest we have ever tested for any 2 1/4 camera.

Likewise, the 75mm f/4.5 Super Takumar ($249.50) is an

extraordinarily good wide angle lens focusing to 29 in. The teles we

checked were certainly no slouches either." Here are the report

dates: March 1971--75/4.5, 105/2.4, 150/2.8, 200/4. February 1972-

-35/4.5 fish-eye, 800/4. August 1973--55/3.5, 135/4 macro.

Bob

[michael_tolan]

If you are REALLY interested in P67 assessments and history (not just

lenses, but an overall assessment), you will not only want to read

the 1971-1973 lens tests listed above, but also go back to the debut

of this camera, and the articles which followed it. In 1969 Modern

Photography published �in abbreviated form- a translation of the

final report conducted by the magazine �Asahi Camera� (just for the

record: Asahi Camera, the magazine, is not in any way tied to, Asahi-

Pentax, the camera manufacturer). If you have never seen a quality-

control assessment from a group like this, you might find it

especially interesting � even beyond your P67 interest. In this

case �if I remember correctly- the �team� was made up of someone from

JCII (Japan Camera and Optical Instruments Inspection & Testing

Institute � the group responsible for safety and quality control of

all Japanese-made photographic devices subject to export and/or sales

to the public), 2 professional photographers, 2 professional camera

technicians/repairmen, 2 professors of optical science, and 2

laboratory technicians. Reading one of these reports is like reading

a police report, or autopsy, or something. Everything, less the

final concluding paragraph(s), is very matter-of-fact. Testers

almost always assess workmanship based on the assumption that the

buyer will use this camera regularly over the course of their adult

life (meaning they take build quality VERY seriously). They test and

comment on the things you would expect (are shutter speeds accurate?

In their test the 1/1000 was less than satisfactory offering a 1/875

or something; all other speeds were near-perfection). They also test

some things you might not expect. For instance, film flatness &

light tightness, etc. (they subjected the loaded P67 to an omni-

directional light source of 10,000 lux for 10 minutes and were quite

pleased with the results). The report often �explains� design

thinking (why the pentaprism reveals only 88% of the image area,

etc.); sometimes it questions it (trying to get 21 frames on 220

often results in frame #1 not being anywhere near acceptable film

flatness; the film-advance lever should have been bigger and

stronger; the interior has too many reflective parts, etc.). The

authors also point out when a design or �working� is rather unique

(P67 mirror quick-return mechanism, elec-controlled, giant cloth

shutter; etc.), as well as acknowledge which accessories can be

installed/switched by the user and which require a Pentax technician

(regarding the ground glass as an option they clearly identified

as �quite inconvenient� � and they pointed out a camera of

this �class� surely should allow photographers to do this themselves,

as the need calls for it). Overall, I found the report to be

excellent, and wish a greater number of the so-called tests you see

today were more like this one. The only thing I questioned, or at

least found a little odd, was the claim that any photographer well

accustomed to the P67 camera could take un-blurred, hand-held photos

at 1/15. Note, due to space limitations, Modern Photography did not

reproduce the entire report, and for whatever reason, offered a bland

one- or two-sentence summary of the lens tests (the 105mm & 200mm)

instead of reproducing the test-charts which appeared in the original

magazine article; both lenses tested very well. As a system, the P67

received very high marks. If you want the full report, and the lens-

test charts, you will have to resort to the magazine Asahi Camera

(10/69, I think), and brush up on your Japanese reading skills.

Although I have never seen them, I have heard that there is at least

one additional inspection/field test of the original P67 & lens line,

and that it was available the second time the camera was exhibitioned

at Photokina (1968), and also at the Tokyo Camera Show (1969). This

literature, too, might be in Japanese.

[miles stoddard]

Michael, Did you construct this entire reply from memory? If so,

excellent job. If not, then may I assume you have these articles or

copies of them? I guess what I was wondering was if you have the

actual articles, and if so, could they be scanned, and would they be

readable if you did so? I ask only because I tried to find these

articles years ago, and never was able to do so. I also tried to

find the articles from Asahi Camera, Minachi Camera [i might have

spelled this magazine title incorrectly], and CameraArt, and I never

found those either. I believe there is at least 1, and perhaps as

many as 3 tests of the P6x7 and accessories, in these Japanese

periodicals. Have you ever seen these other articles? I was also

told that there was a new round of tests/commentary on the camera

after the mirror lock-up function was added, but I am afraid I don't

have any citations for these tests. The Pentax 6x7 doesn't have

the "literature" surrounding it like many other cameras seem to have

(there are after-market user's guide for some cameras, and Hasselblad

even has its own monthly magazine!), and these articles are as close

as we come in some areas, and they are also historically

interesting. Just my, as you say "two cents worth".

[bobby mahaffey]

I have copies of the Modern Photography lens tests cited above, as

well as the reprint of the Asahi Camera report which appeared in

Modern, in addition to Modern's and Popular Photography's own tests

when the camera became available in the US. Anyone that would like

copies of my copies can email me your address and I will send them to

you. Bob