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What's wrong with my Carl Zeiss Flektogon 35mm 2.4 (M42)
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PostPosted: Mon Dec 01, 2014 10:05 pm    Post subject: What's wrong with my Carl Zeiss Flektogon 35mm 2.4 (M42) Reply with quote

Hello Friends,

I am hoping that someone can shed some light on my Carl Zeiss flektogon 35mm f2.4 in M42 mount (auto or manual), no electronics.

Having looked around the web, most of these lenses appear to be F22 to 2.4, mine however is F16 to 2.4.

The other thing I have checked and rechecked is that at the closest focus, the end of the lens it 60mm (6cm) away from the object, again this seems to vary.

Serial number starts with 99***** and has red MC lettering.



Thank you for you assistance & I look forward to learning, hopefully good news Smile


PostPosted: Mon Dec 01, 2014 10:16 pm    Post subject: Reply with quote

Mine has the same engraving but is serial number 2881, red MC, f22 TO f2.4, close focus 0.2 Meters is engraved on the lens. Is the 60mm (6cm) a distance you have actually measured, or is it what is engraved on your lens ? I think the crop factor affects the closest focus distance.


PostPosted: Mon Dec 01, 2014 10:32 pm    Post subject: Reply with quote

The focus distances markings are measured from the image plane (sensor or film), not from the front of the lens.

Last edited by themoleman342 on Mon Dec 01, 2014 10:44 pm; edited 2 times in total


PostPosted: Mon Dec 01, 2014 10:37 pm    Post subject: A close up Reply with quote

Llyody, Thank you for the reply.

0.19 is engraved on the lens, but it turns past this (halfway between 0.19 & ft/m engraving) I have physically measured it at being 60mm.

I am using a Pentax K-3.

The other thing is it is engraved 16 to 2.4 on the aperture ring and the bit just above, it also has a red line with a dot on top to the right on the big line and just before the 4 (forgive my description but it is late although that is no excuse for incorrectly naming this parts).

On the picture below you can hopefully see the close focus position & the ir marking



PostPosted: Mon Dec 01, 2014 10:43 pm    Post subject: Oops Reply with quote

themoleman342 wrote:
The focus distances markings are measured from the image plane (sensor or film), not from the front of the lens.


themoleman342, thank you, I knew it had been a long day, I should have been so stupid. I will be looking at around 0.15 - 0.16 but will do a proper measure tomorrow, I guess that is within the justifiable range.


PostPosted: Mon Dec 01, 2014 10:53 pm    Post subject: Reply with quote

yes, Moleman is absolutely right - the measurement is to the film plane that is marked on every camera I can think of. And it isn't affected by crop factor.

The red line with a dot is the focus mark for infra red, used when the lens is on a film camera with infra red film.


PostPosted: Tue Dec 02, 2014 11:34 am    Post subject: Reply with quote

Just checked my example (s/n 1083####) and I can see a few points of difference between it and the example posted (s/n 99#####)..
  • Engraved aperture markings - mine runs from f/22-f/2,4 - the 99## example runs f/16-f/2.4.
  • The depth of field scales reflect the difference in the engraved aperture range.
  • The aperture ring on mine is continuously knurled around it's entire circumference with the markings engraved forward of the knurling, whereas on the 99# example the knurling breaks for the engraving.
  • The focus ring on my example has five rows of knurled diamonds whereas the 99# example has seven rows.
  • The lens barrel on my example narrows in diameter for the filter ring (49mm) whereas the lens barrel on the 99# example maintains a constant diameter (what's the filter diameter?)
  • The engraved focus distance scale starts at 0,2ft and 0,7m on my example, whereas on the 99# example it starts at 0,65ft and 0.2m
  • The engraved focus distance ends at 10ft and 3m (last engraved marks before infinity) whereas on the #99 example the last engraved distances are 12ft and 4m.

What I can't make out is whether or not the 99# example has the A/M switch? (mine does)

Has anyone documented all the known variants of this lens? I can find threads and conversations where one or two differences between lenses are mentioned (read or white MC, "Jena" or "aus Jena", auto/electric, etc.) but nowhere where all the differences are listed together. I imagine most of the differences are cosmetic.


PostPosted: Tue Dec 02, 2014 11:44 am    Post subject: Reply with quote

Looking at more lenses online, the 5-row and 7-row focus ring examples have a completely different lens barrel.

The 7-row examples have a continuous diameter lens barrel (at least from the front of the lens back to back beyond the focus ring) and a thicker focus ring.

The 5-row examples have a thinner focus ring and a wider lens barrel that narrows forward of the front element (to the depth of the filter ring).

Edit:
You can see the differences here..
https://www.flickr.com/groups/eos-manual-lenses/discuss/72157625794266951/


PostPosted: Tue Dec 02, 2014 2:48 pm    Post subject: Reply with quote

GeorgeSalt wrote:
Just checked my example (s/n 1083####) and I can see a few points of difference between it and the example posted (s/n 99#####)..
  • Engraved aperture markings - mine runs from f/22-f/2,4 - the 99## example runs f/16-f/2.4.
  • The depth of field scales reflect the difference in the engraved aperture range.
  • The aperture ring on mine is continuously knurled around it's entire circumference with the markings engraved forward of the knurling, whereas on the 99# example the knurling breaks for the engraving.
  • The focus ring on my example has five rows of knurled diamonds whereas the 99# example has seven rows.
  • The lens barrel on my example narrows in diameter for the filter ring (49mm) whereas the lens barrel on the 99# example maintains a constant diameter (what's the filter diameter?)
  • The engraved focus distance scale starts at 0,2ft and 0,7m on my example, whereas on the 99# example it starts at 0,65ft and 0.2m
  • The engraved focus distance ends at 10ft and 3m (last engraved marks before infinity) whereas on the #99 example the last engraved distances are 12ft and 4m.

What I can't make out is whether or not the 99# example has the A/M switch? (mine does)

Has anyone documented all the known variants of this lens? I can find threads and conversations where one or two differences between lenses are mentioned (read or white MC, "Jena" or "aus Jena", auto/electric, etc.) but nowhere where all the differences are listed together. I imagine most of the differences are cosmetic.


GeorgeSalt,

Thank you for that great bit of comparison,

Yes, mine does have an A/M switch & I will check the filter diameter later.

I only posted originally because I could only find details on the F22 - 2.4 model, I could not find any mention of a F16 - 2.4.

With regards to the shape of the barrel, I can only find pictures of this lens where the barrel narrows, however looking at some pictures of the CZ Distagon this does at some point seem to have the same barrel shape as my version of the Flektogon (see picture taken from the web below).



Would CZ have used parts from the Distagon to maintain production as they were bringing in the changes to the look of the lens.


PostPosted: Tue Dec 02, 2014 3:59 pm    Post subject: Reply with quote

I've seen others online with the straight barrel, but not enough to confirm my suspicion that 7-digit serial number lenses have the straight barrel and 8-digit have the stepped barrel (although that's the pattern I'm seeing).

At least two references give the filter thread on the straight barrel as 49mm - same as the stepped barrel. I suspect the stepped lens barrel will have a greater outside diameter than the straight barrel behind the step.

If this post is true..

http://forum.mflenses.com/carl-zeiss-jena-lenses-issue-date-by-serial-number-t6865.html

.. then the earlier lenses are the straight barrel and the later lenses are the stepped barrel. Which would suggest the design was moving away from the style of the Distagon.

Maybe the wider lens barrel is to incorporate the changed iris assembly for the f/22 design?


PostPosted: Tue Dec 02, 2014 4:19 pm    Post subject: Reply with quote

Mine has got a very low serial number - 2881 - can it be dated by that?

Pictures for comparison to other Flek's.




PostPosted: Tue Dec 02, 2014 4:34 pm    Post subject: Reply with quote

Lloydy, that is a low serial number, that doesn't appear to correspond to the link posted above.

Just doing a scan of the auction site, there is one like mine on it Click here to see on Ebay although this one does not have the red IR line and the dot, it just has the dot." target="_blank">Click here to see on Ebay


PostPosted: Tue Dec 02, 2014 5:16 pm    Post subject: Reply with quote

That seems to fit the pattern, the 4-digit and 5-digit serial numbers are described elsewhere as being more recent than the 8-digit serial numbers after CZJ changed the numbering system c.1975.


PostPosted: Tue Dec 02, 2014 5:54 pm    Post subject: Reply with quote

GeorgeSalt wrote:

At least two references give the filter thread on the straight barrel as 49mm - same as the stepped barrel. I suspect the stepped lens barrel will have a greater outside diameter than the straight barrel behind the step.

Maybe the wider lens barrel is to incorporate the changed iris assembly for the f/22 design?


Just in from work and I can confirm that on my version the filter thread is 49mm.

Only purchased it on Sunday from the local car boot, so can't wait to try it out in the daylight on Saturday. I'm very interested in it's close focus mode. So far tests in room lighting look very promising.

Thank you all for the replies, it certainly has been very interesting to find all this information out.


PostPosted: Tue Dec 02, 2014 9:47 pm    Post subject: Reply with quote

zelda_n64 wrote:
Would CZ have used parts from the Distagon to maintain production as they were bringing in the changes to the look of the lens.


Nope, CZ and CZJ are two different companies at this point.


PostPosted: Tue Dec 02, 2014 10:31 pm    Post subject: Reply with quote

I keep forgetting that this is the lens where CZ were copying the original optical formula of CZJ.

My guess is that the original Flektogon 35/2.4 design is the f/16 version with the straight barrel. It runs with minor variations but basically unchanged to the mid-1970s. Then something triggers a redesign. The aperture is replaced with a unit that can close down to f/22, but this (or another design change at the same time) requires the diameter of the lens barrel to be increased. This triggers a wholesale redesign of the entire body - if the two versions of this lens share much more than just the optical formula, filter/front ring and the back-end/mount I'd be very surprised. The thickened lens barrel gets a step-down at the front to aesthetically match the retained 49mm filter ring.

Maybe there was a supply issue with the original iris unit, or maybe the original tooling was just getting worn.

Of course, if anyone has a f/16 version with the stepped lens barrel that would sink this theory.

Do any other CZJ lenses show such a marked step-change in body design between variations?


PostPosted: Wed Dec 03, 2014 9:15 am    Post subject: Reply with quote

ManualFocus-G wrote:
zelda_n64 wrote:
Would CZ have used parts from the Distagon to maintain production as they were bringing in the changes to the look of the lens.


Nope, CZ and CZJ are two different companies at this point.


ManualFocus-G, I did realise this when I posted, but there is a very striking similarity in the design of these lenses at that particular point.

What I cannot understand though, is looking at my copy with S/N starting 99 (7 digit) I have the red dot and a red line for the IR marking, looking at the ebay one (link posted previously) with S/N starting 98 (7 digit) just has the dot, same as the ones with the 8 digit serial number.

Would they have implemented that small change for a short time?


PostPosted: Wed Dec 03, 2014 9:44 am    Post subject: Reply with quote

zelda_n64 wrote:
ManualFocus-G wrote:
zelda_n64 wrote:
Would CZ have used parts from the Distagon to maintain production as they were bringing in the changes to the look of the lens.


Nope, CZ and CZJ are two different companies at this point.


ManualFocus-G, I did realise this when I posted, but there is a very striking similarity in the design of these lenses at that particular point.

What I cannot understand though, is looking at my copy with S/N starting 99 (7 digit) I have the red dot and a red line for the IR marking, looking at the ebay one (link posted previously) with S/N starting 98 (7 digit) just has the dot, same as the ones with the 8 digit serial number.

Would they have implemented that small change for a short time?


There could have been a couple of different aperture rings available to fit - I think I'm right in saying that CZJ would have been making these in batches rather than continuously. Very easy to make slight adjustments to the engraving on the aperture ring between batches.