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08-11-2010, 08:43 AM   #1
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Carl Zeiss Jena DDR Flektogon M42 2.8/20mm and K-x

Hi bought a Carl Zeiss Jena DDR Flektogon 2.8/20mm M42 and K-x yesterday and am disappointed.
I don't know if the lens is broken or not compatible with the K-x.
I got the M42 adapter from a Pentax store it's from the HOYA corporation Japan.

The problem is when I screw the lens all the way in the focus will be somewhat infinite on short ranges. Between 1 -5 meters everything is pretty sharp but nut really. So I can run video and don't need to focus and it looks somewhat fine but not brilliant.

When I want to focus anything like 19cm or 25 centimeter it's impossible. Turning the on the sharpness does not change anything.

When I loosen the lens from the adapter about 2 complete turns I can focus 19 cm and focusing seems to work.

When then taking pictures with an aperture of 2.8 only the center is sharp the edges become very blurry.
At aperture 8 everything seems to look fine.

Any suggestions?

Here are some crops and shots made with the lens unscrewed.

Aperture 2.8
ISO 200


Aperture 8
ISO 200


Aperture 8
ISO 200


Aperture 2.8
ISO 200


Aperture 2.8
ISO 200


08-11-2010, 11:06 AM   #2
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Do you know what the minimum focusing distance for this lens is? I suspect you may be slightly too close since I think its minimum is supposed to 19cm but I have heard that it may be close to 2x that. I can see some changes in the dof in your samples. I don't think your K-x has a green button but it has a way to do the equivalent for metering with these old lenses.

Edit: Have you tried focusing to infinity?

Last edited by Blue; 08-11-2010 at 11:14 AM.
08-11-2010, 11:35 AM   #3
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Thanks for the reply.
The minimum distance should be 0.19 meters or 0.6feet.
I don't know.
When I turn the lens out of the adapter, till it's sharp at 0.19 meters, the focusing seams to work on the short distances. I however could not test this on infinity.
But I have the feeling that it is going off after 1.3meters or so. Then I can get more sharpens by turning the lens back in.
08-11-2010, 09:14 PM   #4
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Just came back from the dealer.
Something with the focusing is lose. He had a repair guy coming who confirmed that.
So first I got my money back.
Secondly, the repair guy is confident he can fix that.
Tomorrow I can buy the lens in fixed condition if I want to.

Question
Can this be fixed easily to last for long or is there a chance that they'll do some quick fix.
Should I deal him down? And how much? 30% 40% 50 or even more?
Thanks

08-22-2010, 08:23 AM   #5
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I got the lens fixed the next day.
No discount though. I think the repair guy did a great job.
The focusing values on the lens however seem to be off.
The closes focusing distance is somewhat 10cm not 19.5cm and infinity is a little before what is indicated to be infinity.
Here are some pictures taken so far.


Handheld Exposure Time: 1/12 sec.
ISO Speed Rating: 400



Handheld Exposure Time: 1/15 sec.
ISO Speed Rating: 400


On tripod
I guess F8 or higher
ISO 200
08-22-2010, 08:51 AM   #6
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Too bad, I liked the way it was before.
08-22-2010, 09:21 AM   #7
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QuoteOriginally posted by hangu Quote
Too bad, I liked the way it was before.
How do you figure that? It wasn't usable for those images before.
08-22-2010, 09:26 AM   #8
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Sure it couldn't go beyond 15 feet but it had a great rendering quality to it. You can see the texture on the green apple, so it was sharp, just in a very small area. You'd certainly get a few good portraits with that effect. Now it's just like any other wide angle lens.

08-22-2010, 09:40 AM   #9
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I am glad it's fixed.
But now I am thinking that my kit lens is rubbish.
So many missed shots with it and with the Zeiss lens hardly ever.
I shot like 300 pictures with it now and only a handful are unusable. Compare to the kit lens 18-55mm almost half of them are not good.
08-22-2010, 09:42 AM   #10
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QuoteOriginally posted by hangu Quote
Sure it couldn't go beyond 15 feet but it had a great rendering quality to it. You can see the texture on the green apple, so it was sharp, just in a very small area. You'd certainly get a few good portraits with that effect. Now it's just like any other wide angle lens.
We will have to agree to disagree there. The apple shots are anything but sharp, and the other test shots of magazines were just that.
08-22-2010, 09:44 AM   #11
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QuoteOriginally posted by davidvandoren Quote
I am glad it's fixed.
But now I am thinking that my kit lens is rubbish.
So many missed shots with it and with the Zeiss lens hardly ever.
I shot like 300 pictures with it now and only a handful are unusable. Compare to the kit lens 18-55mm almost half of them are not good.

Its really not surprising that it will outperform the Kit lens at 20mm!
08-22-2010, 10:44 AM   #12
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QuoteOriginally posted by Blue Quote
We will have to agree to disagree there. The apple shots are anything but sharp, and the other test shots of magazines were just that.
Check out the green apple's texture on the second apples photo. I think it's fairly sharp to have nailed the subtle texture of the apple. The thin depth of field at that close distance makes the rest of the apples seem blurry, perhaps?

I've had a few lenses that had misaligned helicoids. It threw off the focusing distance by a bit, which meant I couldn't focus further than 5-10 feet but the misalignment certainly did not affect the lens sharpness. After all, the group of elements are still the same distance apart relative to each other, the only difference is the distance between the sensor and the elements.

QuoteOriginally posted by Blue Quote
Its really not surprising that it will outperform the Kit lens at 20mm!
I'm not entirely sure the Flektogon 20mm is that much better. It certainly isn't worth the $300+ asking price that people are throwing around lately (in terms of sharpness). My guess is that its name (CZJ) and m42 mount is the prime reason why it's selling like hot cakes. There are quite a few other ~20mm MF lenses (Tamron 17mm, Vivitar 19mm, MIR 20mm, Cosina 20mm) that are just as sharp/sharper yet sell for a third to a half of its price.

Not a terribly scientific test of course:
jr-worldwi.de: Photography: Technic

Most MF lenses will exceed the kit lens in resolution but once you get below 24mm, it gets a bit iffy.
08-22-2010, 11:28 AM   #13
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QuoteOriginally posted by hangu Quote
Check out the green apple's texture on the second apples photo. I think it's fairly sharp to have nailed the subtle texture of the apple. The thin depth of field at that close distance makes the rest of the apples seem blurry, perhaps?

I've had a few lenses that had misaligned helicoids. It threw off the focusing distance by a bit, which meant I couldn't focus further than 5-10 feet but the misalignment certainly did not affect the lens sharpness. After all, the group of elements are still the same distance apart relative to each other, the only difference is the distance between the sensor and the elements.
That's just it, there isn't any texture showing on either variety of apple. Each of those varieties have a texture unique to them and this isn't showing that. I wasn't discussing the DOF so that isn't pertinent. If you are wanting a water color looking nondescript apple, that's another story.


QuoteOriginally posted by hangu Quote
I'm not entirely sure the Flektogon 20mm is that much better. It certainly isn't worth the $300+ asking price that people are throwing around lately (in terms of sharpness). My guess is that its name (CZJ) and m42 mount is the prime reason why it's selling like hot cakes. There are quite a few other ~20mm MF lenses (Tamron 17mm, Vivitar 19mm, MIR 20mm, Cosina 20mm) that are just as sharp/sharper yet sell for a third to a half of its price.

Not a terribly scientific test of course:
jr-worldwi.de: Photography: Technic

Most MF lenses will exceed the kit lens in resolution but once you get below 24mm, it gets a bit iffy.
What part about by statement about it outperforming the kit lens did you not understand? The part about it outperforming the kit lens or the part about it outperforming the kit lens? Furthermore, there are more things to performance than just sharpness. I didn't say jack about the Tammy 17 which is good but far from the best. I didn't mention the Vivitar which they didn't make anyway and I certainly didn't get into the Mir 20 which can have higher sample variability compared to German and top Japanese lenses. That said, I personally like the f4 zebra Flek better.

Just to clarify, my comment was about this Flek and the kit lens. Period.
08-22-2010, 12:42 PM   #14
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QuoteOriginally posted by Blue Quote
That's just it, there isn't any texture showing on either variety of apple. Each of those varieties have a texture unique to them and this isn't showing that. I wasn't discussing the DOF so that isn't pertinent. If you are wanting a water color looking nondescript apple, that's another story.

What part about by statement about it outperforming the kit lens did you not understand? The part about it outperforming the kit lens or the part about it outperforming the kit lens? Furthermore, there are more things to performance than just sharpness. I didn't say jack about the Tammy 17 which is good but far from the best. I didn't mention the Vivitar which they didn't make anyway and I certainly didn't get into the Mir 20 which can have higher sample variability compared to German and top Japanese lenses. That said, I personally like the f4 zebra Flek better.

Just to clarify, my comment was about this Flek and the kit lens. Period.
No need to get snarky here. I'm not looking for a fight with you. I think people just automatically assume that the Flektogon 20mm f2.8 is much sharper than the kit lens because of its CZJ name and that anything is better than a kit lens. I listed the details of the other lenses as an argument to show just how overrated the CZJ lens is in terms of price. Yes, there is more to performance than sharpness but that's what this thread is focusing on here. We're not discussing flare resistance, distortion control and contrast here, are we?

My point is that I find it very surprising that the Flektogon f2.8 is that much better than the kit lens according to the OP. Most old MF lenses wider than 24mm usually do not perform much better than modern day kit lenses in terms of sharpness.

I'm not seeing any sharpness problems with my Canon kit lens wide open at 18mm f3.5, which is considered inferior to the Pentax kit lens:
All available sizes | Untitled | Flickr - Photo Sharing!
All available sizes | Untitled | Flickr - Photo Sharing!

I seriously doubt the Flektogon will give me markedly sharper results than that. My guess is that the OP's abysmal record with the kit lens is caused by either user error or possibly back/front focusing. It's pretty damn hard to get more usable photos than an AF kit lens when starting out on a MF lens. None of the photos the OP has posted are beyond the capabilities of a kit lens. You can probably mix it in with the kit lens thread and no one would notice.

Oh and the texture:


I also doubt the lens got any sharper after the helicoid realignment. It just means the OP can now focus beyond 5 meters and to infinity.
08-22-2010, 12:57 PM   #15
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QuoteOriginally posted by hangu Quote
No need to get snarky here. I'm not looking for a fight with you. I think people just automatically assume that the Flektogon 20mm f2.8 is much sharper than the kit lens because of its CZJ name and that anything is better than a kit lens. I listed the details of the other lenses as an argument to show just how overrated the CZJ lens is in terms of price. Yes, there is more to performance than sharpness but that's what this thread is focusing on here. We're not discussing flare resistance, distortion control and contrast here, are we?

My point is that I find it very surprising that the Flektogon f2.8 is that much better than the kit lens according to the OP. Most old MF lenses wider than 24mm usually do not perform much better than modern day kit lenses in terms of sharpness.

I'm not seeing any sharpness problems with my Canon kit lens wide open at 18mm f3.5, which is considered inferior to the Pentax kit lens:
All available sizes | Untitled | Flickr - Photo Sharing!
All available sizes | Untitled | Flickr - Photo Sharing!

I seriously doubt the Flektogon will give me markedly sharper results than that. My guess is that the OP's abysmal record with the kit lens is caused by either user error or possibly back/front focusing. It's pretty damn hard to get more usable photos than an AF kit lens when starting out on a MF lens. None of the photos the OP has posted are beyond the capabilities of a kit lens. You can probably mix it in with the kit lens thread and no one would notice.

Oh and the texture:


I also doubt the lens got any sharper after the helicoid realignment. It just means the OP can now focus beyond 5 meters and to infinity.
Again, I was restricting my comments to the L kit lens and the Flek. You don't know much about pomology if you think that shows realistic texture of a Granny Smith or Gala apple. If the kit lens was all that damn good at 20mm, I wouldn't have the DA 21mm ltd. I have news for you, my copy of the DA 17-70 can't beat the DA 21mm at 21mm either. Furthermore, the kit lens doesn't get down to f2.8. Overall the II version and WR version of the kit lens is a good lens, but it has its limitations. I don't give a flip about a Canon kit lens.

I wasn't being snarky. However, you busted this guys chops for having the focus on a fine lens repaired. Your argument that the repair would make it less sharp is ludicrous. If you can't handle the heat, stay out of the kitchen.

Edit: Take a look at the pressure gauge taken with a copy of the 2.8 Flek on a Canon dSLR.

http://www.flickr.com/photos/buze/198366112/

Last edited by Blue; 08-22-2010 at 01:08 PM.
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