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Distagon 3.5/15 versus SMC Pentax 3.5/15
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PostPosted: Fri Dec 28, 2012 3:46 pm    Post subject: Distagon 3.5/15 versus SMC Pentax 3.5/15 Reply with quote
Today my Distagon arrived and I must confess I was rather nervous opening the box. This is the lens I have been looking at and for, for a long time. I just love the enormous blob of glass. Until now I had the Pentax 15mm and I just love that lens as well. What I have read, here on the forum and in other places, the Pentax and the Zeiss are supposed to be the same, so I was very happy with my Pentax. There is a biiiig price difference between the 2.
I was lucky to find a reasonably priced Distagon and decided to buy it. All my other lenses are Contax's so the pentax was a little bit of a loner in my lens case.

First impression? What an incredibly beautiful, solid, well made, lovely, sexy, I can go on for a while, piece of art.
And completely different to the Pentax.

The Distagon is bigger, wider and heavier than the Pentax.














As you can see the glass is bigger as well, both the front-, as well as the rear element. Im not an optics expert, but this fact tells me that maybe (probably) the 2 lenses are not of the same design at all. The technical drawings may look very much alike but the dimensions are definitely not the same, so the recipe probably isn't as well. Interesting fact I think.

It is raining cats and dogs today so I am not going outside to take some pics, but I did some things inside. Especially the min focus distance interests me. The Pentax has 30 cm min focus, the Distagon only 16.

Here are a couple of pics to see the difference:


Distagon 1600 ISO, 1/80th, wide open, focus distance 16 cm


Distagon 1600 ISO, 1/80th, wide open, focus distance 30 cm


Pentax 1600 ISO, 1/80th, wide open, focus distance 30 cm


Distagon 1600 ISO, 1/30th, f8, focus distance 16 cm


Distagon 1600 ISO, 1/30th, f8, focus distance 30 cm


Pentax 1600 ISO, 1/30th, f8, focus distance 30 cm

The min focus distance is a biiiig difference. It's like WA macro on the Distagon.....
It looks like the Pentax is slightly wider.
The Distagon seems to be better adjusted for straight lines.
The Distagon has a beautiful OOF area with the min focus distance of 16 cm.

I am not drawing any conclusions apart from my feeling that these lenses are NOT the same design at all.

I will be making more comparisons, but from what I see now I will be very interested in comments from this knowledgable forum. I will not go into the difference in coatings btw .....Smile Twisted Evil

Please let me know what you would like to see in a test. The Pentax will have to leave soon.......


PostPosted: Fri Dec 28, 2012 4:24 pm    Post subject: Reply with quote
Looks also like the Distagon has warmer colors. To my eyes, the Pentax seems to have sharper detail in the wood grain, less detail on the blue bottle's text. Maybe the Pentax has slightly more contrast, which would make the wood grain appear sharper.


PostPosted: Fri Dec 28, 2012 4:47 pm    Post subject: Reply with quote
Please don't look at the colors. I forgot to adjust the White Balance, so I made some corrections after the shots were taken. But not very precise I'm afraid.....
Color and contrast comparison's will follow


PostPosted: Fri Dec 28, 2012 5:15 pm    Post subject: Reply with quote
What a beautiful lens and some very nice wood as well lol, Acacia ?


PostPosted: Fri Dec 28, 2012 5:30 pm    Post subject: Reply with quote
What a fantastic piece of glass! Congrats with that one! I was curious and checked ebay.... Shocked


PostPosted: Sat Dec 29, 2012 4:51 pm    Post subject: Carl Zeiss DISTAGON 3,5/15mm Reply with quote
The DistagonT* 3,5/15mm was originally designed for the famous CONTAREX SLR by the genius optical designer Dr. Erhard Glatzel. Lateron improved, the 15mm glass was available for the Contax RTS, Rolleiflex SL35E/SL2000/3000, and was also manufactured for Leica, as Leica-R Super-Elmarit 3,5/15mm!

Due to an collabration between PENTAX and ZEISS in the optical eye wear glass business, the optical design of the 15mm was also manufactured by PENTAX as SMC 3,5/15mm! But the Pentax 15mm has unfortunately not reached the optical quality of the original Zeiss glass, Made in Oberkochen!

I do use the Distagon T* 3,5/15mm with adaptor very successfully on my Canon 5DMkII, and I definately will never sell it!

Best


PostPosted: Sat Dec 29, 2012 5:17 pm    Post subject: Reply with quote
Congratulations - wonderful lens!


PostPosted: Sat Dec 29, 2012 8:33 pm    Post subject: Reply with quote
Based on size, I agree its not the same optical design as the Pentax. Do you know the groups/elements of the Zeiss?


PostPosted: Sat Dec 29, 2012 8:44 pm    Post subject: Reply with quote
About the minimum focusing distance, a possible explanation could be (pure speculation here, as I don't have any factual evidence support)
the absence in the Pentax model of the floating element whose purpose it's to optimize performance at close-up distances.
If the floating element was absent in the Pentax model (replaced by a non moving one), the designers may have decided to limit the focusing range to a distance of 30cms, which would be safe.

In any case, even if this type of home-made tests is subject to many variables and needs to be taken cautiously, this first comparison is quite embarassing for the Pentax lens.
The quality difference between the two lenses is visible at naked eye.


PostPosted: Sat Dec 29, 2012 9:12 pm    Post subject: Reply with quote
Orio wrote:
About the minimum focusing distance, a possible explanation could be (pure speculation here, as I don't have any factual evidence support)
the absence in the Pentax model of the floating element whose purpose it's to optimize performance at close-up distances.
If the floating element was absent in the Pentax model (replaced by a non moving one), the designers may have decided to limit the focusing range to a distance of 30cms, which would be safe.

In any case, even if this type of home-made tests is subject to many variables and needs to be taken cautiously, this first comparison is quite embarassing for the Pentax lens.
The quality difference between the two lenses is visible at naked eye.

Well if the Pentax lens is earlier, smaller, and less expensive, its no surprise that its not as good a performer, is it?


PostPosted: Sat Dec 29, 2012 9:40 pm    Post subject: Reply with quote
hifisapi wrote:

Well if the Pentax lens is earlier, smaller, and less expensive, its no surprise that its not as good a performer, is it?


The Takumar lens is (at least initially) the original Glatzel's model. It is shorter in lenght and smaller in size by Asahi's choice.
Glatzel made two versions of the lens: the first one with the aspherical element, and a second one with a spherical element + the addition of another element for the required correction.
The reason is that Zeiss asked Glatzel to make a spherical version of the lens because building the aspherical element with the technology of the time was too expensive.
Asahi instead opted for the aspherical version, and they started the production of the aspherical version,
but they soon stopped it because (as Zeiss already guessed) it was too difficult and expensive.
So they switched to a spherical version, too. But they had to re-calculate it themselves, because in the meantime,
the collaboration between Zeiss and Asahi was ended, and Glatzel was not more available to Asahi.

Please learn everything about it here:
http://www.marcocavina.com/articoli_fotografici/15mm_Zeiss_Pentax/00_pag.htm

I don't know if Propellor's lens is the original Glatzel's aspherical or the Asahi-redesigned spherical version.
It certainly is no "previous" lens because no previous 3.5/15 existed.


PostPosted: Sat Dec 29, 2012 10:09 pm    Post subject: Reply with quote
Is the smc Pentax lens shown in the comparison photos the aspherical or non-aspherical version? Pentax made it both ways in that lens. The M42 versions were all aspherical and the PKA version were all non-aspherical.


PostPosted: Sun Dec 30, 2012 7:03 am    Post subject: Reply with quote
There appears to be a aspherical K version, with a distance scale of 7 4 2 1.5...

http://www.bdimitrov.de/kmp/lenses/primes/ultra-wide/K15f3.5-i.html

The 3 pentax versions are all lighter than the contax one (550-600g vs 875g), so indeed it looks like they are not identical. Interesting.

Now we need someone to look at the Takumar and also the Hollywood. Smile


PostPosted: Sun Dec 30, 2012 8:18 am    Post subject: Zeiss Distagon T* 3,5/15mm Reply with quote
hifisapi wrote:
Based on size, I agree its not the same optical design as the Pentax. Do you know the groups/elements of the Zeiss?


The 15mm Distagon exists of 13 elements in 12 groups, with one floating element to compensate the close distance of 0,16m! Its not only the number of elements in a lens, it must also be assembled properly with high precise mechanical parts. Both parts together are making an almost perfect lens! The original price was listed with almost 5,000 € for this lens!


PostPosted: Mon Dec 31, 2012 3:16 pm    Post subject: Reply with quote
TrueLoveOne wrote:
What a fantastic piece of glass! Congrats with that one! I was curious and checked ebay.... Shocked

Nice glass indeed. I did not pay Ebay price btw....

Quote:
In any case, even if this type of home-made tests is subject to many variables and needs to be taken cautiously, this first comparison is quite embarassing for the Pentax lens.
The quality difference between the two lenses is visible at naked eye.

Embarassing may be a bit harsh. The Pentax is still a great lens. The size is much more convenient that the Distagon is. My arm muscles will testify to that...

Quote:
I don't know if Propellor's lens is the original Glatzel's aspherical or the Asahi-redesigned spherical version.
It certainly is no "previous" lens because no previous 3.5/15 existed.

Mine is the spherical in PK mount.

There seems to be some sort on consensus that both lenses are family, but they are not identical twins.
I wonder what the Leica 15mm looks like. Would that one be the same as the Distagon?


PostPosted: Mon Dec 31, 2012 3:31 pm    Post subject: Reply with quote
Some pics taken with the Distagon:
Most are F8, some wide open as mentioned.


1, Wide Open


2


3


4


5


6


7


8, Wide Open


9


10


11, F8


12, Wide open


PostPosted: Mon Dec 31, 2012 3:40 pm    Post subject: Reply with quote
and some more.


1


2


3


4


5, Wide open


6, Wide open


7


8


9


10


11


12, Wide open


PostPosted: Mon Dec 31, 2012 4:57 pm    Post subject: Reply with quote
Congrats to your new jeweler!


PostPosted: Mon Dec 31, 2012 6:30 pm    Post subject: Distagon 3,5/15mm Reply with quote
Unfortunately, we all have to live with it, the better is always the good enemy! The new Distagon T*2,8/15mm ZE, ZF.2 is even better than the "old" 3,5/15mm Distagon! I am using my Distagon 3,5/15mm mostly with f/5.6, and that's the best f/stop anyway, for all of these 15mm SWA glasses SWC PENTAX 15mm or ZEISS T* 15mm! Wink


PostPosted: Mon Dec 31, 2012 6:46 pm    Post subject: Distagon 3,5/15mm Reply with quote
The Leica R Super Elmar 3,5/15mm look very similar to the Zeiss 3,5/15mm glass.


PostPosted: Tue Jan 01, 2013 10:51 am    Post subject: Re: Distagon 3,5/15mm Reply with quote
OPAL wrote:
Unfortunately, we all have to live with it, the better is always the good enemy! The new Distagon T*2,8/15mm ZE, ZF.2 is even better than the "old" 3,5/15mm Distagon!


It would better be, after 40 years! Otherwise it would have meant that Zeiss did not improve in half a century. Wink
But obviously, a 2.8/15 today is the norm - at the time, a rectilinear 3.5/15 with the kind of control that Distagon has was something close to a revolution.
Only 1161 copies have ever been made of the Distagon 3.5/15 (of which 105 in Rolleiflex SL bayonet mount, not useable on Canon DSLRs). Some have been irreparably damaged over the years.
For it's rarity, and for the place and importance it has in the history of photographic optics, the lens is a museum piece already.


PostPosted: Tue Jan 01, 2013 11:01 am    Post subject: Re: Distagon 3,5/15mm Reply with quote
Orio wrote:
OPAL wrote:
Unfortunately, we all have to live with it, the better is always the good enemy! The new Distagon T*2,8/15mm ZE, ZF.2 is even better than the "old" 3,5/15mm Distagon!


It would better be, after 40 years! Otherwise it would have meant that Zeiss did not improve in half a century. Wink
But obviously, a 2.8/15 today is the norm - at the time, a rectilinear 3.5/15 with the kind of control that Distagon has was something close to a revolution.
Only 1161 copies have been made of the Distagon 3.5/15 (of which 105 in Rolleiflex SL bayonet not useable on Canon DSLRs). Some have been irreparably damaged over the years.
For it's rarity, and for the importance it had in the history of photographical optics, the lens is a museum piece already.



Sorry, but for an "museum piece", my 15mm Distagon works still very fine and active on my Canon 5DMkII, with excellent results! Guenther Grasse stated once "the progress is an snail", and that counts especially for optical designs! Wink


PostPosted: Tue Jan 01, 2013 4:50 pm    Post subject: Re: Distagon 3,5/15mm Reply with quote
OPAL wrote:

Sorry, but for an "museum piece", my 15mm Distagon works still very fine and active on my Canon 5DMkII


I never said it doesn't!
I have it too and also use it on the 5D MkII
My comment about it being a museum piece was only meant to be positive: it's a glass so rare and so important in the history of photographic optics, that it's something more worthy than the typical serial factory lens.


PostPosted: Tue Jan 01, 2013 6:02 pm    Post subject: Re: Distagon 3,5/15mm Reply with quote
Orio wrote:
OPAL wrote:

Sorry, but for an "museum piece", my 15mm Distagon works still very fine and active on my Canon 5DMkII


I never said it doesn't!
I have it too and also use it on the 5D MkII
My comment about it being a museum piece was only meant to be positive: it's a glass so rare and so important in the history of photographic optics, that it's something more worthy than the typical serial factory lens.



Never mind! Have you shortend the mirror on your 5DII to use the Distahon 15mm?


PostPosted: Thu Jan 03, 2013 4:32 pm    Post subject: Re: Distagon 3,5/15mm Reply with quote
Orio wrote:

For it's rarity, and for the place and importance it has in the history of photographic optics, the lens is a museum piece already.


It does feel like I am allowed to keep watch over this beautiful work of art for the time being. I will use it, but will be extremely careful with it.

This is the first Contax lens btw that hangs up my mirror. I am not going to change anything on the lens like shortening the fin. I did get a nice Leitax mount for it. I want to be sure that the lens stays on the camera...... Wink
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