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07-22-2017, 12:55 PM - 4 Likes   #1
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Zeiss 25mm f/2 on Pentax K1

.
I just finished converting a Zeiss ZF Distagon 25mm f/2 lens from the Nikon F mount to the Pentax K mount. Below is a photo of this lens on my K1 camera.

I used the terrific Leitax F to K adapter mount with their "long screws". It fits nice and tight on my K1 and functions perfectly.

I've now successfully converted all Zeiss Classic lenses to the Pentax K mount with one exception - the Zeiss ZF 15mm f/2.8.

I'm just starting to shoot and get to know this lens. From initial testing, I have found that the far corners and edges are at their very best at f/16 (see McD's photo).

My next mission will be to see which wide aperture renders the best depth/3D-pop/bokeh.

[IMG][/IMG]


Last edited by Fenwoodian; 12-23-2017 at 12:12 PM.
07-22-2017, 01:25 PM   #2
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Looks great! Have you shot with the older f/2.8 version of that lens on the K1?
07-22-2017, 02:14 PM   #3
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Thanks for sharing this. Great to see the 25mm f2 on the K-1
07-22-2017, 02:18 PM   #4
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great 3-D pop - looks good

07-22-2017, 02:26 PM   #5
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QuoteOriginally posted by sibyrnes Quote
Looks great! Have you shot with the older f/2.8 version of that lens on the K1?

Yes, I just sold mine to help fund this purchase. The f/2 was about 2.5 times more expensive than the f/2.8 I just sold.

Comparing the two Zeiss 25mm lenses I'd say:

They both have nice Zeiss like colors and contrast. The f/2 is definitely much sharper. At f/2 and f/2.4 the f/2 has a very thin depth of field and nice bokeh!

The f/2 has a bit more distortion/field curvature - it takes the f/2 until f/11 to achieve decent corners; while the f/2.8 has good corners well before that. At wider apertures, the f/2 has better bokeh/depth/subject-isolation.

Last edited by Fenwoodian; 07-22-2017 at 02:59 PM.
07-22-2017, 02:39 PM - 1 Like   #6
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.
Here's a test shot on my K1 at f/2. I focused on the rhubarb leaf on the lower left of the image.

Very thin depth of field, and good sharpness when viewed at 100%, and I think it has a nice rendition of it's out of focus background (bokeh).

At f/2 there's noticeable vignetting. At f/2.8 there is less vignetting, but the background blur is not as nice as it is at f/2. For the best subject isolation with the best bokeh and minimal vignetting I believe that I'll be using this lens at the half click between f/2 and f/2.8 (f/2.4?).

[IMG][/IMG]

Last edited by Fenwoodian; 07-22-2017 at 03:01 PM.
07-22-2017, 02:50 PM   #7
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.
Also, I have not noticed any of the purple fringing that so many of the other Zeiss lenses exhibit at wide apertures.

Also, the internal components of this lens are more "Milvus like" than any of the other "Classic" Zeiss lenses are. This is the only "Classic" Zeiss lens that I have converted that has the same type of thin metal gaskets inside of it that all of the Zeiss Milvus lenses have.


Last edited by Fenwoodian; 07-22-2017 at 03:03 PM.
07-22-2017, 03:49 PM   #8
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Wasn't that lens made in ZK mount as well? Looks good though. Sharp, colorful and contrasty
07-22-2017, 04:27 PM   #9
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QuoteOriginally posted by Fenwoodian Quote
Here's a test shot on my K1 at f/2
QuoteOriginally posted by Fenwoodian Quote
At f/2 there's noticeable vignetting.
Seriously Dave, stop doing this, I can't afford you to make me want one of these. The shallow DoF at this focal length is awesome. Oh, like the 21 the vignetting adds to the look for me. Each to their own of course.

QuoteOriginally posted by Na Horuk Quote
Wasn't that lens made in ZK mount as well?
No, the 15/2.8, 25/2, 35/1.4 and 135/2 were released after ZK production ceased, or there abouts. The Leitax conversion is the best chance of enjoying any of these lenses on Pentax cameras.
07-22-2017, 06:25 PM   #10
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Very nice work. It would seem that the performance at f16 is consistent with the Zeiss design ethos for wide angles as evident in the 28/2 (best resolution achieved at f16 - beating anything else on the market). If you can convert the 15/2.8 then I will certainly consider this lens. Waiting with anticipation.
07-22-2017, 07:10 PM   #11
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QuoteOriginally posted by Wild Mark Quote
Very nice work. It would seem that the performance at f16 is consistent with the Zeiss design ethos for wide angles as evident in the 28/2 (best resolution achieved at f16 - beating anything else on the market). If you can convert the 15/2.8 then I will certainly consider this lens. Waiting with anticipation.
I can certainly have the ability/tools to convert the Zeiss 15/2.8 lens. But it will have to be someone else's 15/2.8 lens that I convert, because 15mm is far too wide for my tastes.

I can't help but wonder how these Zeiss lenses will compare from an IQ standpoint against the upcoming Pentax "Roadmap Primes". It would certainly be nice to see some side by side comparisions after the Pentax primes come out. While I've got a few Zeiss lenses, I have no intention of purchasing any of the new Pentax primes because I'm through with acquiring new lenses as I'm very happy with my current Zeiss kit (Z25/2, Z28/2, Z35/1.4, ZMilvus50/1.4, and ZMilvus85/1.4).

Last edited by Fenwoodian; 07-22-2017 at 07:21 PM.
07-22-2017, 08:23 PM   #12
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QuoteOriginally posted by Tas Quote
No, the 15/2.8, 25/2, 35/1.4 and 135/2 were released after ZK production ceased, or there abouts. The Leitax conversion is the best chance of enjoying any of these lenses on Pentax cameras.
Those lenses are all available in the native Pentax M42 mount:

ZEISS Large Image Format Lenses | Industrial Lenses

---------- Post added 07-22-17 at 10:29 PM ----------

QuoteOriginally posted by Fenwoodian Quote
The f/2 is definitely much sharper.
Zeiss rate both the 25/2 and 25/2.8 the same on their sharpness scale,
good for a 3.4 micron pixel size at 30% contrast.
07-22-2017, 09:07 PM   #13
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QuoteOriginally posted by lytrytyr Quote
Those lenses are all available in the native Pentax M42 mount:
Ah yes, I do keep forgetting about the Industrial M42 lenses. Do you know of anyone shooting these on Pentax?
07-22-2017, 10:16 PM   #14
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QuoteOriginally posted by lytrytyr Quote
Those lenses are all available in the native Pentax M42 mount:

ZEISS Large Image Format Lenses | Industrial Lenses

---------- Post added 07-22-17 at 10:29 PM ----------



Zeiss rate both the 25/2 and 25/2.8 the same on their sharpness scale,
good for a 3.4 micron pixel size at 30% contrast.
lytrytyr, from your statements above, I strongly suspect you don't own any of the modern Zeiss "Classic" lenses.

First, on my two Pentax K1 cameras, the Zeiss f/2 is noticeably sharper and more detailed than the Zeiss f/2.8 lens that I owned for years and used on the same "REAL WORLD" test subjects. Your response is typical of someone whose only experience with either of these lenses is a quick Google search and finds an obscure laboratory test to prove your point. I'll take real world results on the very camera that I shoot with any day over lab tests that were not done using a Pentax K1 camera.

Here's what the premiere independent lens tester (Roger Cicala) in the USA has to say about the sharpness of the Zeiss 25/2 lens: "In terms of pure resolution it’s superb, generating numbers in our testing similar to the legendary 21mm f/2.8. Sharper than the Nikon or Canon 24mm f/1.4 lenses when shot at f/2.0. Sharper than any 35mm, 50mm, or 85mm lens we stock at f/2.0. And that’s both in the center and overall (weighted average) sharpness. But there’s a bit of a catch: that’s for testing at middle distances (10 to 25 feet). But at infinity (where the MTF charts are made) it doesn’t seem quite as good (it’s still good, but not amazingly good)."

Second, I am certainly aware that Zeiss makes these lenses in the M42 mount. Zeiss ZF lens (Nikon Mount) in the Nikon mount are much more available on the used market than are the rarer Zeiss ZS (M42 mount) lenses.

For years I have watched Ebay auctions on Zeiss ZS (M42 mount) lenses. I have only found the following three versions Zeiss Classic lenses ever on sale on Ebay - 25/2.8, 35/2, and 50/1.4. The Zeiss 25mm f/2 lens that this thread is focused on has NEVER been available on Ebay to my knowledge in the ZS (M42 mount).

For the last few years, both Adorama and B&H have sold only two Zeiss ZS lenses - 25/2.8 and 35/2. Both of these lenses were also made by Zeiss in the Pentax K mount, so why would a K1 shooter ever want to buy one of these two Zeiss lenses in the M42 mount?

I have never seen a Zeiss 25/2 lens in M42 mount offered for sale by either a major retailer or on Ebay. That makes me doubt if any ZS mount 25/2 lenses were ever made by Zeiss. If you think I'm wrong - please show me where I might buy a Zeiss 25mm f/2 lens in M42 mount.


P.S. I have shot dozens of M42 lenses on my K1 cameras. I have used them on a variety of M42 - K adapters (including various genuine Pentax versions). The M42-K adapters I have owned are flimsy/weak compared with Leitax adapters. Further, Leitax adapters are stronger and better made than any of the dozens of Zeiss lens mounts I have held and examined. When it comes to choosing the tightest and most secure mount for my expensive (and often heavy) Zeiss lenses, I purposely choose Leitax mounts over both M42-K mounts AND Zeiss mounts.

Last edited by Fenwoodian; 07-22-2017 at 11:18 PM.
07-23-2017, 06:57 AM   #15
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QuoteOriginally posted by Tas Quote
Ah yes, I do keep forgetting about the Industrial M42 lenses. Do you know of anyone shooting these on Pentax?
I don't, although I did contemplate the new 15mm in M42.

QuoteOriginally posted by Fenwoodian Quote
lytrytyr, from your statements above, I strongly suspect you don't own any of the modern Zeiss "Classic" lenses.
My "statements above" are references to current Zeiss information.
But you are, of course, welcome to hold whatever suspicions you may feel the need to harbor.

QuoteOriginally posted by Fenwoodian Quote
First, on my two Pentax K1 cameras, the Zeiss f/2 is noticeably sharper and more detailed than the Zeiss f/2.8 lens that I owned for years and used on the same "REAL WORLD" test subjects.
...
Here's what the premiere independent lens tester (Roger Cicala) in the USA has to say about the sharpness of the Zeiss 25/2 lens: ... But at infinity (where the MTF charts are made) it doesn’t seem quite as good (it’s still good, but not amazingly good)."
If you know the ZK 25/2.8, you will be aware that it is designed to perform best at infinity.
I find that mine nicely complements my Pentax A 24/2.8, which is best at closer range.

QuoteOriginally posted by Fenwoodian Quote
Your response is typical of someone whose only experience with either of these lenses is a quick Google search and finds an obscure laboratory test to prove your point.
This comment seems a little out of touch with the spirit of our forum.
I have no idea what "obscure laboratory test" you might be referring to.
I have given you a link to a reputable manufacturer's specifications of their products.

QuoteOriginally posted by Fenwoodian Quote
Second, I am certainly aware that Zeiss makes these lenses in the M42 mount. Zeiss ZF lens (Nikon Mount) in the Nikon mount are much more available on the used market than are the rarer Zeiss ZS (M42 mount) lenses.
The M42 lenses that my link addresses are new lenses from the manufacturer.

---------- Post added 07-23-17 at 09:04 AM ----------

QuoteOriginally posted by Fenwoodian Quote
The M42-K adapters I have owned are flimsy/weak compared with Leitax adapters.
The Pentax adapter draws the lens in against the face of the bayonet. It is very solid.
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