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PENTACON 50/1.8 M42 with NEX-5 problem
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PostPosted: Wed Dec 07, 2011 1:19 pm    Post subject: PENTACON 50/1.8 M42 with NEX-5 problem Reply with quote

Hi, i'm a newbie in MFlenses and digital cameras.
I have a Pentacon 50/1.8 mounted with a M42 on a NEX-5 and i have few problems.
First, my focus works only between 0,40 and 1 (half of maximum focus)
Second, the picture looks like a zoomed picture (200%).

Question: is the problem the distance between the sensor and the lens that is not the native distance, or i need to fix something in the lens?
Thanks for your answers.
Alex


PostPosted: Wed Dec 07, 2011 1:51 pm    Post subject: Reply with quote

Hello and welcome Alex.

It sounds like an issue with the distance between the mount faces of the lens and the camera. With an M42 lens on the NEX this should be about 27mm. Are you using a proper M42>NEX adapter?

Or do you mean the focus dial on the lens is jamming? Is this OK when the lens isn't mounted on the camera?


PostPosted: Wed Dec 07, 2011 1:54 pm    Post subject: Reply with quote

Alex,

Welcome on board.

The Pentacon lens you own is build for Full Frame cameras(36x24mm). Your Nex-5 uses a crop sensor (APC-C,23x15mm) . So your lens is not a 50mm after you attach it but actually more or less like a 50x1.5=75mm since your sensor is 1.5x focal length crop.

That's why it looks like it zoomed when you shoot with it;)

Give a little more detail about your focus problem...

Unless your adapter is so wrong that you actually hit the sensor when you try to focus pass the 1m


PostPosted: Wed Dec 07, 2011 2:09 pm    Post subject: Reply with quote

Firstly, Thank you for your welcoming and sorry for my poor english Wink

Well, i understand the distance problem between old lenses and gigital sensors, but i tought that the M42 adapter (Leinox label) could fix that problem Sad
and my zoom diference is near 300%

Also for the focus problem, the focus ring works only between 0,40 and 1. But from 1 to ∞ (infinity) the ring doesnt turn. it stops at 1.
Is this a lens problem? did the focus distance have an influance with this problem? is there something i can fix in the camera options?

A lot of questions Confused thanks for your answers guys Razz
Alex


PostPosted: Wed Dec 07, 2011 2:22 pm    Post subject: Reply with quote

As Peter remarked, does your lens focus pass >1m when it's not attached to either your adapter and camera ?


PostPosted: Wed Dec 07, 2011 2:26 pm    Post subject: Reply with quote

If you are using an adapter like this there should be no problems like you describe.
http://tinyurl.com/cmbwjtj

It sounds like there is a big problem with the lens and there is nothing you can do with the camera that will cure it. Can you post some pictures of it?


PostPosted: Wed Dec 07, 2011 2:26 pm    Post subject: Reply with quote

Keysersoze27 wrote:
Alex,

Unless your adapter is so wrong that you actually hit the sensor when you try to focus pass the 1m


Actually (if i do understand your answer), the back lens dont hit the sensor because M42 adapter is very long.
I wonder if the problem is not coming from the lens itself. because it was hard to turn the ring, and i found some sand in the top of lens thread, while cleaning it with the edge of paper.
Thanks. Alex.


PostPosted: Wed Dec 07, 2011 2:28 pm    Post subject: Reply with quote

If the lens focus ring won't turn to infinity then the lens has a fault.

Pentacon 1.8/50 works great on NEX-3 for me:



PostPosted: Wed Dec 07, 2011 2:34 pm    Post subject: Reply with quote

peterqd wrote:
If you are using an adapter like this there should be no problems like you describe.
http://tinyurl.com/cmbwjtj


Yes, thats the right adaptor from Leinox. i'll send you the picture of both camera, ring & lens.
Cheers. Smile
Alex


PostPosted: Wed Dec 07, 2011 2:35 pm    Post subject: Reply with quote

iangreenhalgh1 wrote:
If the lens focus ring won't turn to infinity then the lens has a fault.

Pentacon 1.8/50 works great on NEX-3 for me:



Yes i know, i have the same kind of picture, but shoot at a distance of 1 m from the subject Laughing
That said, your photo is beautiful! Wink
Cheers.
Alex


Last edited by zedgraphics on Wed Dec 07, 2011 2:51 pm; edited 2 times in total


PostPosted: Wed Dec 07, 2011 2:46 pm    Post subject: Reply with quote

peterqd wrote:
Can you post some pictures of it?


Here's a ugly picture of my camera set taken from my iPhone Shocked
(you can see also the focus ring turned to maximum thread)



PostPosted: Wed Dec 07, 2011 2:57 pm    Post subject: Reply with quote

At 1m the front of the lens should be more protruding than yours!!!

like this :



Someone has wrongly repaired and reassembled the lens Wink


PostPosted: Wed Dec 07, 2011 3:20 pm    Post subject: Reply with quote

Keysersoze27 wrote:

Someone has wrongly repaired and reassembled the lens Wink


Yes, i think so. Can i fix-it myself? i have Fairy fingers and i am very patient Smile if you see repair instructions somewhere, let me know.
Thanks again, Alex


PostPosted: Wed Dec 07, 2011 4:02 pm    Post subject: Reply with quote

zedgraphics wrote:
Keysersoze27 wrote:

Someone has wrongly repaired and reassembled the lens Wink


Yes, i think so. Can i fix-it myself? i have Fairy fingers and i am very patient Smile if you see repair instructions somewhere, let me know.
Thanks again, Alex

The two parts of the focussing helicoil have a multi-start thread and it sounds very much as though it has been wrongly threaded. You'll need to take it apart again and find the correct thread. This sounds easy but.... Smile Much patience is needed.
There could be other things wrong too, if someone has reassembled it that poorly.
http://gabriel.mp3-tech.org/blog/index.php?entry=entry080827-180800


PostPosted: Wed Dec 07, 2011 4:51 pm    Post subject: Reply with quote

peterqd wrote:
zedgraphics wrote:
Keysersoze27 wrote:

Someone has wrongly repaired and reassembled the lens Wink


Yes, i think so. Can i fix-it myself? i have Fairy fingers and i am very patient Smile if you see repair instructions somewhere, let me know.
Thanks again, Alex

The two parts of the focussing helicoil have a multi-start thread and it sounds very much as though it has been wrongly threaded. You'll need to take it apart again and find the correct thread. This sounds easy but.... Smile Much patience is needed.
There could be other things wrong too, if someone has reassembled it that poorly.

Thank you for your help, i'm going to try to fix the focus Very Happy


PostPosted: Wed Dec 07, 2011 7:05 pm    Post subject: Reply with quote

It is only a very confident man that will admit to "Fairy fingers". Laughing


PostPosted: Thu Dec 08, 2011 12:48 am    Post subject: Reply with quote

That's what I thought too : )

Un aveu trs intressant, I should say.


PostPosted: Thu Dec 08, 2011 9:48 am    Post subject: Reply with quote

since I was little I love dismantle and assemble little precious things and my mother gave me this little nickname Shocked
But i'm not going to fix this lens because i dont have the patience that i had when i was a kid...

The alternative is that i can change my broken Pentacon 50/1.8 (which can be repaired) with a 50/1.7 Pancolar for 20 bucks more.

What is the fastest lens with a better contrast between those two?
thanks again Wink
Alex


PostPosted: Thu Dec 08, 2011 9:55 am    Post subject: Reply with quote

This is a fabulous deal! The Pancolar is on a different quality level to the Pentacon altogether - the best 50mm CZJ ever produced. Just make sure the blades are working freely, they can often become sticky and need cleaning.


PostPosted: Thu Dec 08, 2011 10:16 am    Post subject: Reply with quote

peterqd wrote:
This is a fabulous deal! The Pancolar is on a different quality level to the Pentacon altogether - the best 50mm CZJ ever produced. Just make sure the blades are working freely, they can often become sticky and need cleaning.

Thanks for your advice peter Wink
An other question linked with CZ 50mm lenses, is Planar T* better than Pancolar lens?
Cheers. Alex


PostPosted: Thu Dec 08, 2011 10:38 am    Post subject: Reply with quote

I've never used any Zeiss west lenses myself so I can't compare directly. Orio has hundreds of them though, and he states in this thread that the Pancolar is sharper. The build quality of the Planars is probably better, the CZJ lenses are more variable, and I would expect the Planars have better wide-open performance. The Pancolar needs to be stopped down to 4 or 5.6 to make it shine.

When I bought my first Praktica in 1969, the Pancolar was the most expensive kit lens option. I got the cheapest (Domiplan) and I've regretted it ever since! Smile

Here's a gallery of pictures taken with the zebra version. The coating was improved on later models which makes it a little more contrasty. Which version is yours?
http://www.mflenses.com/gallery/v/german/zeiss/pancolar/pnacolar_50mm_f1_8_zebra/?


PostPosted: Thu Dec 08, 2011 11:16 am    Post subject: Reply with quote

peterqd wrote:
I've never used any Zeiss west lenses myself so I can't compare directly. Orio has hundreds of them though, and he states in this thread that the Pancolar is sharper. The build quality of the Planars is probably better, the CZJ lenses are more variable, and I would expect the Planars have better wide-open performance. The Pancolar needs to be stopped down to 4 or 5.6 to make it shine.

When I bought my first Praktica in 1969, the Pancolar was the most expensive kit lens option. I got the cheapest (Domiplan) and I've regretted it ever since! Smile

Here's a gallery of pictures taken with the zebra version. The coating was improved on later models which makes it a little more contrasty. Which version is yours?


Thanks for your interest to my questions and your links Peter Wink
My (future) Pancolar is a 1,8/50 MC i think so (i dont no if it is an AUTO version) but i think its a newer version than the zebra. Do you know this version?