Pentax 67 Comparison Test Results

[turgut_tarhan]

I've recently made a comparison test. The results can be viewed at

this link: <a

href="http://www.turguttarhan.web1000.com/pentax67/test.htm"

target="_blank">www.turguttarhan.web1000.com/pentax67/test.htm</a>

Before this application, I also asked a question on this forum about

this subject. The link is:

<a href="http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=0058Vg"

target="_blank">www.photo.net/bboard/q-and-a-fetch-msg?

msg_id=0058Vg</a>

I'd be pleased to hear your comments.

[hunter_rose]

You should try a comparison of the Minolta 50mm and the Pentax with a 105 without cropping.

[www.antiquecameras.net]

Even if your test isnt flawed ( results should be tested MANY TIMES ), it makes no sense. It really doesnt matter if a Pentax 67 lens is "softer" than a 35mm lens on 24x36mm format. Even if the 67 is half as sharp, its gross film size of approx 4 TIMES larger, will easily make an enlarment "sharper" than the 35mm enlarged. It is fairly well known that the "sharpest" lenses, in order, are generally 35mm, med format, then lrg format. There is just no need to make med & lrg format lenses as complex as 35mm format because of the much larger area to record data on the larger film. Most med & lrg format lenses arent optimized for sharpness as much as coverage.. Try coparing a 5x7 image produced from p67 and minolta 35, if the p67 doesnt win, I will donate my P67 outfit to science...

[leonardo 144]

Turgut,there is also another reason why this comparison is not so useful: you are comparing a standard 35mm lens (one of the best in the whole line) with a medium format retrofocus ultra wideangle.

Ultra wide-angles are never as good as standard lenses.

That said, I think the Pentax 45mm is not as good as many on Photonet want us to believe. The specimen I tested also had a certain "glow" in the highlights and a "smearing" of lighter areas over darker areas (ie. trees against sky), especially at the edges.

Resolution in the center was tested in a Dutch Photo magazine as 90 Line pairs/mm (that in itself says nothing about contrast)

35mm standard lenses generally have a resolution over 120 line pairs/mm.(my 70's Nikkor 50mmF2 AI has 140+ lp/mm even with TMX)

If you want the highest resolution in in medium format, start saving

because the best is Zeiss.No other MF manufacturer makes lenses with

such high resolution.Unfortunately, Zeiss does not make 6x7 lenses...

[nicholas_t.]

Apart from the obviously blurry example, those tests are actually quite good - for the Pentax!

[jeff_drew4]

Generally, I agree with the above. 35mm lenses usually test out at higher resolutions and "sharper" numbers than MF lenses, no matter the brands. Yes, the film format makes a big difference! In fact, the entire chain of the photographic process needs care and consistency to make a good end product. That said, your tests are helping you learn about your tools and their pluses and minuses. Just an FYI: the Minox Complan lens with appropriate 8mm film outperforms all of the above - in terms of resolution! No matter what I do, my P67 negs will blow away my Minox negs at 4x5" and larger. Go figure . . . :-)

[george_rhodes]

Test

[george_rhodes]

Test #2. Long message would not register for second time, but "test" does.

[trooper]

I'm having the same trouble.... My response won't post.

[george_rhodes]

Test. Third try. Three strikes and I'm out.

[turgut_tarhan]

Thank you for all the answers, but I'm aware of what I did. I certainly know that 45mm in Pentax 67 is a wide angle lens, while the purpose of the test was some different. I already photographed the same frames by Pentax 105mm together with Minolta 50mm, but how could I show the image difference on the webpage? A 2500dpi scan of 6x7 frame(55x70mm) would produce a 25-30mb jpeg file which is almost impossible to transfer via internet (takes about 2 hours on modem rate), otherwise I need to invite people to see the two real enlargements, which is also impossible; while by this method a comparison is possible. The cropped Pentax film was scanned together with the original size from Minolta.

 

Even looking by naked eye, it is possible to say neither the 45mm nor 105mm slides have the same sharpness provided by Minolta 50mm lens. There is a considerable loss about 25%. Though the large film size far more compensates this, as the result max. enlargement won't be twice. I can have 30x40cm prints from Minolta, while 60x80cm prints from Pentax 67 won't likely have the same sharpness. And I didn't like the color palette. For 1.5 times improvement in enlargement , does it worth owning and carrying this camera? That was the essence of this test, as explained on the page in details.

[jean_marie_solichon4]

Then compare a 30x40cm print from the Minolta with a 30x40cm print from the P67 (any lens) and you will see why it's worth carrying it.

[george_rhodes]

I once heard of a brilliant man who was a scientist/philosopher/physicist, who started overanalyzing things and, as a result, started walking around his house in snowshoes. His good friend asked him why he was wearing the snowshoes. He answered that since everything in the universe is made up of atoms, nothing is actually as solid as it appears to us, so with the snowshoes on, he reasoned it would be less likely that he might fall through the floor. It all seemed perfectly reasonable to him. Sometimes real world results are more important than test results.

[gary_frost1]

As already mentioned: you are comparing a wide-angle retro-focus design to a standard focal length for the 35mm. If you want to do the

test this way, you might try using something like Mamiya 7II instead.

...Or use a 105mm on both the medium format and the 35mm camera.(?)

On your weight vs. lp/mm vs. film size comparison, you picked a big

one with the P67 as well: My 4X5 kit weighs less than a P67 + lens!

I think both your test and conclusions are skewed by this.

[ron_karpel]

To me, the biggest advantage of 35mm is flexibility. I like wide angle lenses, so I have a 16-35mm zoom for my Canon setup. I have been lucky enough on occasion to be able to get 20x30 inch prints which are tack sharp, but needed to get them scanned professionally at 6000 DPI. I get 18x24 inch prints most of the time with my 4000 DPI scanner.

 

I still am carrying my P67 around much of the time. With the P67 I can get 30x40 inch prints all the time (unless hand held). So the over all advantage is about 1.7 -- matches with your observation.

 

My biggest concern with my 45mm P67 lens is the poor sharpness at the edges. Here again, the Canon "L" far surpasses the P67.

 

Ron

[josh_goldstein]

Turgut, I don't mean to be disrepectful but, as others have pointed out, your test is absolutely meaningless. You're comparing lenses with different focal lengths to measure "resolution" and "sharpness", psuedo-digital terms which means nothing to a photographer, shot for some reason at F8!!! You should just borrow a MF camera and then go into the darkroom and print 16x20 images and the difference between MF and 35 will be immediately obvious. Better yet, for landscapes get a view camera (4x5) . . .

[xosni]

I think there is a misconception here: bigger formats are not made for larger prints, they are made for the same size prints with less degree of enlargement. That's why the ultimate print is a contact print. Also, sharpness in terms of lpi is not everything: tonality adds up to the overall degree of sharpness, lesser degrees of enlargements ALWAYS have better tonality.

 

Xosni

[turgut_tarhan]

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