Konica Hexanon Dual 21-35 f3.4-4 - collimation

[menos]

I have been lucky, to find one of those rare birds for sale on the weekend.
I sacrificed my Leica 50 Summilux ASPH, to buy the exotic Konica and am the happiest man on earth after shooting it for a night and a little ;-)

This lens is special, little is known about it on the net, but despite many uninformed comments about it's performance on diverse internet fora, there are a few very interesting reads and facts available (nicest read, I found is Dante Stella's older short article after testing it on the M8 on his website).

I am interested, to find the Erwin Puts review, mentioned on every internet forum as well, but the old link is dead, I am afraid.

Konica actually provided some very detailed technical information about the lens - including a fantastic high resolution PDF document, showing a detailed cut drawing of the mechanical construction of the lens.

Based on this drawing, some comments from users of this lens and my own findings on my first outing, I had to adjust the lens, to be used mainly on digital Leica bodies.

The upshot is, that this lens has been designed by Konica for best performance on film cameras with a certain amount of film movement towards the subject taken in account.

This is not desirable, when used on digital bodies and should be corrected for, or it will result in back focussing.

Excuse the crappy iPhone (old) pictures, but it was very early in the morning, and I didn't care, to do proper product shots, after having set and proofed three Leica rangefinder bodies and shot a test range trough all critical lenses (this must be the most boring task, one has to do from time to time, maintaining a rangefinder kit with several bodies and lenses).

The lens is a wonderful mechanical design marvel! Konica engineers seemed, to thought about every detail and improved so many design solutions upon Leica lenses, I am still euphoric and amazed by the little things within this lens!

Konica has designed this lens in foresight, to be easily accessible for servicing and very precise collimation of both focal lengths independently
(!!!).

So far, I only had to correct the master shim directly under the lens mount and enlarge it's thickness by just 0.03mm.
As I did not have correctly sized sheet metal material, I used a self adhesive 3M copper tape, designed for shielding electronics, which I applied directly to the chrome plated lens mount for easy removal or change afterwards without leaving track marks (this is an ever growing more expensive collectors lens after all).

Some photos (I have some before and after shots, made with the lens, which show DRAMATIC improvement of the finest detail, which is now recorded, as focus sits, where it should be).

Dont underestimate the importance of correct collimation even with such super wide, slow (f3.4) lenses - 0.03mm made all the impact, needed, to elevate this lens from so so to very sharp on the M9.

lens with lens mount removed - note, how Konica's engineers even improved upon Leica's "fall off - glue on" red dot mounting index mark! This spirit goes through the whole design of the lens!

BE CAREFUL with the screws - two of the six screws are shorter!

the opened rear end of the lens with it's rear group shifted to the 35mm setting (collapsed)

the original shims - the lens has been unopened before. the original shims are t=0.47mm

the lens mount with applied copper tape t=0.03mm

I will post some before and after shots, showing the impact on focussing.
I am really amazed by this wonderful lens - especially @ 21mm.
I always wanted, to find a nice Leica Super Angulon - this wish is not there anymore!

 

[magicianhisoka]

Would love to see sample images 🙂

 

[kanzlr]

reminds me of my 50/2 M-Hexanon adjustment...I also used copper tape and just sticked a 0.05mm sheet onto the focusing mechanism and it was spot on afterwards on the M8.

surprising that 0.03 did it for you, while I used 0.05 🙂

 

[Moriturii]

Is this just a digital, as compared to film, phenomena because obviously a sensor doesn't bulge out due to humidity.

 

[Sonnar Brian]

Thanks for posting this.

accurate positioning of short-focal length lenses is even more critical than longer lenses for the point of exact focus to be correct.

 

[brbo]

reminds me of my 50/2 M-Hexanon adjustment...I also used copper tape and just sticked a 0.05mm sheet onto the focusing mechanism and it was spot on afterwards on the M8.

surprising that 0.03 did it for you, while I used 0.05 🙂

I just got my m-hexanon 50/2 and it's backfocusing too. If I correct for the backfocus with focusing in front of the subject, this lens is very sharp! Hope I will manage to adjust it myself following the principle menos described. Maybe I will start with 0.05mm as that seemed to work for you.

 

[menos]

Would love to see sample images 🙂

Ok, here comes the first - I hope, this can be observed in the small web size - smoker - focus is on the man's face - sharpest plane of focus is actually well behind him (before correcting the main shim):

- focus is on the left Police officer's face, actual sharpest plane of focus well behind him (the man, who is sitting with his back against the building behind the Police officer is pretty detailed in the enlarged file - even @21mm f3.4, his face should be slightly blurred at these distances):

Basically most of the shots, I did the first night out with the Hexanon were back focussing on the test range @ ~20 − 80 cm, depending on focus distance.

Here is after correcting the shim (and reaffirming with a very, very slight adjustment to the M9's rangefinder):

focus is on the very small tree right in front of the center pillar of the fence - the tree is remarkably detailed and DOF reaches towards the pillars of the fence. The whole fence from outmost frame areas is astonishing detailed - I was almost shocked, when I saw the difference to the before detail (actually Tom Abrahamsson here on the forum hinted me to it, commenting, that this very lens should equal the performance of the Leica 21 f2.8 Elmarit ASPH, so something must have had been wrong, I figured ;-)

This was a drive by shot, taken from the back of a car, passing the bicycle rider.
It entirely confirmed spot on focus for me after the operation - christen sharp detail in the man's face and the center line of the bicycle - exactly, where I focussed.
Before the correction, this would have been all mushy:

Another drive by shot - I prefocussed on infinity and framed through the external finder, when passing the house in a vehicle - every window frame shows sharp detail, as it should:

When testing the lens now on the test range, it slightly front focusses @ 1m on my M9 (not more than −5mm though) and gains to almost perfect, spot on focus @ 3.5m.
I plan, to use the lens mostly @ 1.5 meter, shooting candid photographs and close up scenes and the odd urban landscape, focussed @ infinity.

I will shoot the lens for a while like this, but so far am pretty confident, it is spot on.

I might see another sample soon of the rare Hexanon Dual 21-35, as Andrew, a member here on the forum as well, has one too.
I am very curious, how it behaves, but would bet, it has the same calculated calibration, optimized for film, if not already corrected by the former owner of the lens.

I am pretty confident, that one or the other owner of this wonderful lens has never seen the full potential in fidelity, he or she could see ;-)

I plan, to share more photographs from the lens in the Konica rangefinder forum in this thread from Phil (flip) here:
http://www.rangefinderforum.com/forums/showthread.php?t=89757

Technical stuff, I will continue, to post in this thread here.

Btw - big thanks goes to Brian, who was never reluctant, to spread his knowledge and give a helping hand for curious people, like myself ;-)

 

[menos]

reminds me of my 50/2 M-Hexanon adjustment...I also used copper tape and just sticked a 0.05mm sheet onto the focusing mechanism and it was spot on afterwards on the M8.

surprising that 0.03 did it for you, while I used 0.05 🙂

In dry testing the lens on a range on a calibrated M9 body, the back focus was surprisingly high judged (from moiré pattern on my focus target, as precise plane of focus was difficult to judge) between +20cm and +80cm!

After adding the shim, the lens ever so slightly front focusses @ 1m by about −5mm and looks spot on at working distances of about 1.5m - 2m,

Shooting in the wild (only from a vehicle Today), focus is spot on ;-)

Is this just a digital, as compared to film, phenomena because obviously a sensor doesn't bulge out due to humidity.

The lens has been obviously designed with film bodies in mind (Hexar RF and Leica M mount cameras) for a market introduction in 2003.
Film does indeed bulge towards the subject, the most in the center, the least around the frame edges.

It is documented, that this very lens has extraordinary center sharpness (in older reviews and comments, still done with film cameras).

I can see very, very little sharpness falloff towards the frame edges horizontally - the lens is amazing sharp.
I have to shoot it more than a few days though.

What is really fascinating, is, how Konica designed this lens for very easy maintenance and precise independent adjustment - this is not the case with Leica lenses in this price class!
The Konica Hexanon Dual is a beauty for any mechanically interested! Just look at the technical drawings in the lens report - love this stuff!

Thanks for posting this.

accurate positioning of short-focal length lenses is even more critical than longer lenses for the point of exact focus to be correct.

Yes indeed Brian - I was surprised quite about the impact on the thin shim ;-)

I just got my m-hexanon 50/2 and it's backfocusing too. If I correct for the backfocus with focusing in front of the subject, this lens is very sharp! Hope I will manage to adjust it myself following the principle menos described. Maybe I will start with 0.05mm as that seemed to work for you.

I don't know the 50/2 Hexanon - proceed with care and prepare the right tools and environment - not, to get one of these nice lenses scratched up ;-)

Chances are good, that Konica optimized all fast Hexanon lenses with film bulge and the differently estimated mount to film distance in mind.

 

[Moriturii]

This is a good reason to buy an M9 isn't it, to test lens collimation >_<

 

[menos]

This is a good reason to buy an M9 isn't it, to test lens collimation >_<

I think, taking pictures with one is a better reason ;-)
You can use any film camera, to verify lenses, it is just less convenient.

 

[Phil_F_NM]

I've been looking for a Dual Hexanon for a few years under the $1800 mark but that will probably never happen again.
Until I get my hands on one of the very few in existence, I'll just have to live vicariously through others' gorgeous images made with it.
Arrgh.

Phil Forrest

 

[kbg32]

I own one of these. It is a fantastic lens. Mine works fine on both my M8 and M9. No focus issues whatsoever!

http://www.flickr.com/search/?w=99734516@N00&q=Konica+Dual&m=text

 

[menos]

Phil, I think, times, when one could get such lenses for a song are over.
The Hexanon Dual 21-35 sells now (if you can fine one complete and in nice condition) for the price of a new Leica 21 f3.4 Super Elmar :-(

Keith, that's interesting - I suppose, your sample has been adjusted already then or Konica had them produced with a much wider tolerance for calibration (with the possibility designed into the lens, to match it perfectly to any body or standard for very fine precision).