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

-- Loke Kun Tan (tan@broadcom.com), February 02, 1998

Answers

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

-- Steve Rasmussen (srasmuss@flash.net), February 06, 1998.

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

-- Steve Rasmussen (srasmuss@flash.net), January 20, 2000.

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).

Reinhar

-- Reinhard Becker (becker@astro.uni-tuebingen.de), February 12, 1998.

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.

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

Hope I can help you with this results

The notes are :

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

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

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

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

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

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

7.distorsion (15 points max)

The two stops down values are at: 2,4 - 5,6 ; 2,8 - 5,6 ; 3,5 - 8 ; 4 - 8 ; 4,5 - 8

The tested lenses are :

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

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

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

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

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

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

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

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

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

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

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

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

I hope you can now read the results better!

Reinhard

-- Reinhard B. (becker@astro.uni-tuebingen.de), February 14, 1998.

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.

-- Deron Chang (dchang@choate.edu), January 20, 2000.

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

-- Bobby Mahaffey (mahajen@prodigy.net), January 26, 2000.

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.

-- Michael Tolan (mjtolan@kbjrmail.com), August 10, 2001.

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".

-- Miles Stottard (p67shooter@yahoo.co.uk), August 15, 2001.

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

-- Bobby Mahaffey (mahajen@prodigy.net), August 15, 2001.