Soligor 400 f/6.3 : Infinity adjustment?

SkedAddled · Expire: 2021-08-12

I own a Soligor 400mm f/6.3 prime lens, #17100644.
I believe it was manufactured by Tokina in the 1970s, as it has all the
visual and physical cues of my Soligor 75-260, which was recently
confirmed as a Tokina-made lens. The 400mm is a T4 mount, with a
M42 mount end installed.

I was attempting some shots of the moon tonight, and found that I am
unable to reach infinity focus with this lens. The split-circle image will
not align on my focusing screen, while other lenses do. I've tried using
all aperture settings, and am unable to capture a focused image.
The actual issue is that it does not quite reach infinity. I would be happy
if it even reached 'beyond' infinity, but it never gets to the infinity point
to begin with.

Can anyone offer ways to adjust proper infinity focus for this lens?
It's biggest hurdle is that closest focus apparently achieves at almost
25 feet, and I think this may be reason to believe I can not use any of
the "shortcut" methods as for shorter lenses.

The glass is unblemished, with the coatings flawless. The outer barrels are
also nearly like new, which is why I hesitate to dig into this lens without
first arming myself with some information.

Might this be caused by a too-thin M42 to EOS adapter?
I'd much rather add thickness to the adapter somehow, instead of dismantling
such a spiffy-looking lens.

All suggestions and advice will be appreciated.

marty · Joined: 09 Apr 2009 Posts: 767 Location: Italy

greg · Expire: 2012-12-03

I was under the assumption that the further away from the 'film plane' the lens is moved, the more 'macro' it becomes resulting in a further from infinity capability. That is what macro tubes and bellows accomplish. I'd think you would be looking to move the lens closer, rather than shimming further away.

marty · Joined: 09 Apr 2009 Posts: 767 Location: Italy

SkedAddled · Expire: 2021-08-12

I actually understood that a too-thick adapter might be a problem,
but I was also fishing for some other ideas.

So, on the front of 'other' ideas, how would I adjust this lens to focus
'beyond' infinity? I'd rather it focuses past infinity, at least slightly.

As it's my only good T4 mount, I think I'd rather calibrate my only other
T4 lens and this Soligor to it with a single M42 adapter. The other T4
I have is a Soligor 135mm, which is essentially a testbed lens for
mechanical disassembly/reassembly. I'd like to keep the one M42
to EOS adapter on the same T4 mount.

Any suggestions appreciated.

marty · Joined: 09 Apr 2009 Posts: 767 Location: Italy

I don't know the construction of this lens, but I think you have to gain access to focusing helicoid and see if you can make the rear element coming closer to the film/sensor plane. If you have an extra film body Mr. Rick Oleson has a good page on testing infinity focus :http://rick_oleson.tripod.com/index-123.html. I used his suggestion to check a couple of my lenses with good result.

Regards, Marty.

luisalegria · Expire: 2018-01-18

I don't think you need to worry about losing any significant degree of close-focus, as the likely adustment needed to achieve infinity will be very small and on the close end the loss will be trivial.

I have this lens, I may get some time to try disassembling it. Its probable, as mentioned by marty, that the helical travel can be adjusted to get the front elements to come in just a bit closer.

visualopsins · Expire: 2025-04-11

Try a T4-EOS adapter instead of T4-M42-EOS...

luisalegria · Expire: 2018-01-18

Is there a T4-EOS ? If so I'd really like a T4-PK

SkedAddled · Expire: 2021-08-12

visualopsins · Expire: 2025-04-11

SkedAddled · Expire: 2021-08-12

Old thread resurrection alert!!!! Shocked

Sorry to bring this up again, but I may have found a solution.
It's almost midnight for me, so actual testing will have to wait until daylight returns to my side of the world. Rolling Eyes

I was very hesitant to try much of anything about infinity focus for
my 400mm Soligor, but I was browsing through some other older threads
and came upon Martin's revelation for a small lens he has. This got me
thinking in more reasonable terms for my Tokina-made Soligor.
All in all, I just hated the idea of messing about with a lens in such fine
optical and cosmetic condition, and I delayed doing anything about it
for a long time. Until now.

Here's a picture to illustrate. Yes, I know it's crooked, and the white balance
leaves much to be desired, but that's what I get for having a computer
monitor as my best lighting solution for quick impromptu shots. Wink

Here we find three grub screws located adjacent to the flared housing for the
outer element, located on the knurled focusing barrel. These are indicated
by the red arrow. They are tiny screws, no more than 1.5mm in diameter,
as my 1 mm screwdriver fits, but my 2mm driver does not.

The larger grub screw, indicated by the green arrow, is much larger,
and there is only one. I suspect it is the main stop point of the focus
helicoid at both extremes of the barrel's travel. I tested a 2.5mm driver
in it, with room to spare, so it's likely to be 3mm or larger.

After a bit of trial and error experimentation, I managed to determine
that the three tiny grub screws not only secure the focus barrel's place
on the lens, as well as securing the front element assembly in place,
but also appears to allow adjustment for infinity focus, as I was able
to rotate the barrel further than the infinity stop before tightening them
all back down again.

However, to reiterate, I have not yet tested this for success, as I cannot
do so under cover of darkest night. But I am encouraged, and I will
report my findings as soon as I am able to do so.

cooltouch · Joined: 15 Jan 2009 Posts: 9097 Location: Houston, Texas

I think you're onto something. I was about to suggest that a previous owner may have disassembled the lens and not gotten the helical back together properly -- this can happen easily enough if one dismantles the lens without marking the helical's position.

But it sounds as if you may have run across an even easier solution.

SkedAddled · Expire: 2021-08-12

I would normally agree with you Michael, except for the fact that the clear
adhesive used to secure all the grub screws was fully intact before I took
a driver to anything. I don't believe this lens has ever been disassembled
or adjusted before.

I do hope I've landed on a solution, but only time and overcoming my
laziness will tell us anything. Embarassed

I'll be sure to pop in with an update if there's been any real change,
once I have an opportunity to put it to a test.

aliasant · Joined: 17 Feb 2010 Posts: 39 Location: Stockholm, Sweden

SkedAddled · Expire: 2021-08-12

Thanks for the information, aliasant.

I haven't yet put the lens through any testing, though it should be soon.
Life and death have gotten in my way, as of late...

SkedAddled · Expire: 2021-08-12

I am happy to report that my initial thoughts about infinity adjustment
were correct. I successfully adjusted both my 400mm and 75-260mm
zoom lens to infinity. Both are branded Soligor, both made by Tokina.
The adjustment was simple and quick.

A couple of notes about the procedure:
1) After loosening the three grub screws, hold the focusing barrel
against the infinity stop while turning the front assembly.
2) Be sure the focusing barrel is pushed against the front assembly
when retightening the grub screws.

I checked the procedure around 3 times per lens, just to be sure
of my adjustments. I've adjusted both to slightly 'past' infinity, just
to be sure I'll be able to properly focus.

Here's an example taken through the 75-260 today:

Scheimpflug · Expire: 2011-11-18

raulcosta · Joined: 24 Jun 2010 Posts: 16

Hi SkedAddled,
Sorry for this small and almost off-topic, but I've bought a Tele-Raynox 400mm F6.3 and my problem is that I can only focus from 8m to about 3m.
I believe that or I'm missing a glass on the bottom of the lens, or there is something very wrong with it.
The reason I'm writing here is to ask you to post a photo of the rear of the lens (I believe that both lens are almost identical) so I can see that part of the lens.

Thank you in advance,

Best regards,

Raul Costa

SkedAddled · Expire: 2021-08-12