Help Please! 14" Goerz Apochromat Artar will not focus

mkillmer · Aug 3, 2013

Help!
I bought a 14" Goerz Apochromat Artar off eBay,
Glass is clear, but it will not focus!
It looks like it is starting to focus on infinity at about 5", but my 8x10 will not go any smaller.
My guess is the glass was cleaned and assembled incorrectly - but I have tried variations and still no luck.
Any ideas?
Does anyone have a picture of the lens formula so that I can check to see if I am missing an element?

shutterfinger · Aug 3, 2013

http://www.cameraeccentric.com/html/info/goerz_3.html page 23.

LJH · Aug 3, 2013

What's it look like when you extend to 14" (or more)?

5" is way too short to render anything remotely close to being in focus.

mkillmer · Aug 3, 2013

LJH said:
What's it look like when you extend to 14" (or more)?

5" is way too short to render anything remotely close to being in focus.

Nothing at all abut blur at 14", extending out - still blurry - only less blurry when close in...

ic-racer · Aug 3, 2013

Does that lens cover 8x10 anyway? I'd send it back.

mkillmer · Aug 3, 2013

shutterfinger said:
http://www.cameraeccentric.com/html/info/goerz_3.html page 23.

Excellent link - thanks!
According to documentation, the lens should be:
Convex - concave - shutter - Concave Convex

() )( S )( ()

Instead the lens came

Convex - Shutter - Concave - Convex - Concave

() S )( () )(

easy to change as it screws apart.

Lens now focuses!!

Thanks again!!

E. von Hoegh · Aug 6, 2013

mkillmer said:
Excellent link - thanks!
According to documentation, the lens should be:
Convex - concave - shutter - Concave Convex

() )( S )( ()

Instead the lens came

Convex - Shutter - Concave - Convex - Concave

() S )( () )(

easy to change as it screws apart.

Lens now focuses!!

Thanks again!!

Send it back. It doesn't cover 8x10 sharply, and you don't know what else is screwed up - my guess is plenty.

LJH · Aug 6, 2013

E. von Hoegh said:
Send it back. It doesn't cover 8x10 sharply, and you don't know what else is screwed up - my guess is plenty.

mkillmer said:
"Lens now focuses!!"

Seems your guess was incorrect...

Dan Fromm · Aug 6, 2013

LJH said:
Seems your guess was incorrect...

Per Goerz, the 14 inch Artar covers 14 x 17 at 1:1, i.e., 7 x 8.5 at infinity. 7 x 8.5 seems smaller than 8 x 10.

Its hard to imagine how the lens was screwed together as the OP reported. Its unusual for individual elements' mounts to be threaded so that assembly as described by the OP reported is possible. I believe him, am puzzled.

The lens isn't fit for its intended purpose and its condition is unknown and suspect until proven otherwise. 16.5"/9.5 Artars aren't rare and will do what the OP needs. They can even be put in shutter..

Tom1956 · Aug 6, 2013

I'd have sent it back. Somebody's been fooling with it, Might be full of fake glass. Who knows what?

mkillmer · Aug 9, 2013

It was my first time to see such a modular lens...
The inner lenses are mounted in threaded lens holders. All of the lens groups seem to have matching threads, even the back lens, so I could rebuild the lens like this:
() )( )( S ()
or this
() S () )( )(
or this
() S )( )( ()
etc...

I think the seller was genuine, maybe made a mistake while cleaning.
For me here in Australia, cost of shipping makes returning a very expensive option, so I'll be keeping the lens.
If I was in the USA I probably would not.
It seems to cover 8x10 - I'll post a sample this weekend for anyone interested.
Thanks for your comments everyone.

mkillmer · Aug 9, 2013

Here's a quick paper neg I just took with the 14" apo artar...- the lens seems sharp and clear:
http://www.flickr.com/photos/9314116@N06/9473867254/sizes/k/in/photostream/

Dan Fromm · Aug 9, 2013

On my screen it looks very soft. Could be the scan, could be my screen.

And there's no detail discernable in the corners so assessing coverage is impossible.

And it is a closeup shot so even if there were detail in the corners assessing coverage at infinity is impossible.

dpurdy · Aug 9, 2013

The Goerz 14" Apo Artar must be very different from the lens I have which is a Goerz 14" Apochromatic Red Dot Artar. I use mine more than any other on my 8x10 and it has lots of coverage and is very sharp. I do mostly still life but I have taken it out and used it at infinite a few times.
Dennis

mkillmer · Aug 9, 2013

Hi dpurdy,
I'm interested to hear your comments... I haven't used the lens much -the picture above is the first time I really used it, so I don't want to draw conclusions about image quality yet.
I thought the red dot variations were coated, non red dot are non coated.
The lily picture is shot as a paper negative... Does it seem soft compared to your expectations?
Thanks,
Mark

mkillmer · Aug 10, 2013

8x10 coverage Test @f/32
http://www.flickr.com/photos/9314116@N06/9475125525/
Seems good, haven't tried movements yet.
Next I will try f/9.

Tom1956 · Aug 10, 2013

seems soft.

Dan Fromm · Aug 10, 2013

mkillmer said:
8x10 coverage Test @f/32
http://www.flickr.com/photos/9314116@N06/9475125525/
Seems good, haven't tried movements yet.
Next I will try f/9.

Another non-test.

Shoot a brick wall, and make sure that the film plane is parallel to the wall. That way you'll have detail in the corners. No detail in the corners, no information about coverage.

And to my eyes y'r non-test is soft all over. The lower right corner is especially soft. How's your eyesight?

mkillmer · Aug 10, 2013

A brick wall is a good suggestion, Dan.
Unfortunately the shutter on the goerz is not 100%.. No B or T mode. I'll have to work out a good way to find a wall the shoot it. Since I'm shooting paper at iso3, long exposures are difficult until I get the shutter fixed.

E. von Hoegh · Aug 10, 2013

According to Goerz' specifications, the shortest Artar which covers 8x10 sharply at infinity is the 16 1/2".

E. von Hoegh · Aug 10, 2013

dpurdy said:
The Goerz 14" Apo Artar must be very different from the lens I have which is a Goerz 14" Apochromatic Red Dot Artar. I use mine more than any other on my 8x10 and it has lots of coverage and is very sharp. I do mostly still life but I have taken it out and used it at infinite a few times.
Dennis

The Red Dot series is coated. This is the only difference.
Don't confuse "illuminate" with "cover sharply to the corners".

E. von Hoegh · Aug 10, 2013

mkillmer said:
It was my first time to see such a modular lens...
The inner lenses are mounted in threaded lens holders. All of the lens groups seem to have matching threads, even the back lens, so I could rebuild the lens like this:
() )( )( S ()
or this
() S () )( )(
or this
() S )( )( ()
etc...

I think the seller was genuine, maybe made a mistake while cleaning.
For me here in Australia, cost of shipping makes returning a very expensive option, so I'll be keeping the lens.
If I was in the USA I probably would not.
It seems to cover 8x10 - I'll post a sample this weekend for anyone interested.
Thanks for your comments everyone.

Those inner biconcave elements have different radius curves on each side. How do you know they're in the right way?
There should be pencil markings on the edges of each element, put on at the Goerz factory to show the proper orientation of the elements. Are they still there? Did you follow them (if you can decipher them) when you reassembled the lens?

mkillmer · Aug 10, 2013

E. von Hoegh said:
Those inner biconcave elements have different radius curves on each side. How do you know they're in the right way?

Great question - I did not realise they were different. The inner lens do not have any pencil marks, so I will label them myself and take 2 photos to compare. Should these be at infinity or is closer up ok? Infinity photos are problematic at the moment, so I would prefer a stobe illuminated target.

Jim Rice · Aug 10, 2013

An Artar should be an extremely sharp lens. It is my understanding that those factory mounted in shutter are corrected for more distant subjects than those mounted in barrel which are corrected for 1:1. If I'm not mistaken the difference is the distance between cells.

clayne · Aug 10, 2013

I see no reason to send the lens back and I doubt anything is massively wrong with it. You've got what, 4 major lens groups to worry about with only 2-3 real ways to screw it up? Seems like you could just exchange elements around until you have "sharp enough" images. Although not razor, the lily looked fine.

Help Please! 14" Goerz Apochromat Artar will not focus

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