Review: Carl Zeiss Jena 35mm 2.4 Flektogon

Introduction

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Carl Zeiss Jena Flektogon 35mm 2.4 with K&F II M42 adapter on Sony A7rII

The Flektogon 35mm 2.4 is a highly regarded lens from Carl Zeiss Jena in the former German Democratic Rebpulic. It is the predecessor to the Distagon design still used for many modern lenses. But does this oldie still have a place on today’s digital cameras? Let us find out in this review.

Sample Images

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4

Most of the sample images in this review can be found in full resolution here.

Version History

There is quite a bit of background information on the Flektogon series to be found here. The design principle of the Flektogon lenses is the same as what is today usually referred to as retrofocus design. Carl Zeiss Jena (Eastern Germany) and Angenieux were apparently the first to come up with such designs before it was adapted by Carl Zeiss Oberkochen (Western Germany) and named Distagon, a term which is still used today for Zeiss’ retrofocus lenses. There is an older version which only offers a maximum aperture of f/2.8 but I am looking at the faster f/2.4 version here which was apparently released in 1976.

Specifications

The Flektogon 2.4/35 reviewed here has the following specifications:

    • Diameter: 64 mm
    • Field of view: 63° (diagonally)
    • Length:  48.5 mm (at infinity without adapter)
    • Weight: 240g
    • Filter Diameter: 49 mm
    • Number of Aperture Blades: 6 (straight)
    • Elements/Groups: 6/6
    • Close Focusing Distance: 0.2 m
    • Maximum Magnification: 1:2.4
    • Mount: M42

This lens can only be bought used and prices start at $200/130€ on ebay.com/ebay.de (affiliate links).

Handling / Build Quality

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Carl Zeiss Jena Flektogon 35mm 2.4

This sample has quite a nice build quality. The focus ring has very nice resistance and travels ~280° from the minimum focus distance (0.2 m) to infinity. But as I am not sure about sample variation (rumors are that there is quite a bit) and this lens might have been serviced recently I cannot speak about CZJ lenses in general here.

The aperture ring has 1/2 stop click stops. It travels about 60° from f/2.4 to f/22. The click stops are a bit noisy, so this might not be your best choice if you are into video shooting.

The lens is made from a mix of metal and high quality plastics. All markings are painted and engraved.

Vignetting / Colorcast

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 vignette vignetting

The lens is rather small and wide open there is strong vignetting of roughly 2.2 EV, stopped down to f/2.8 vignetting improves to still rather strong 1.9 EV, at f/4.0 it is 1.4 EV and at f/8.0 still 1.0 EV. This is comparable to other small 35mm lenses at shared apertures.

I did see a very slight green color cast in the extreme corners on my A7rII.

Sharpness

infinity

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus

Good news is the lens barely has any focus shift issues. The center is a bit soft at f/2.4 and f/2.8 but improves significantly at f/4.0, same is true for the midframe.
The corners look best at f/11, but I would rather use f/8.0 because otherwise center and midframe suffer a bit due to diffraction.

close (0.20m), center


100% crops from center, A7rII

The performance at the minimum focus distance in the center is really astonishing. Even wide open there is nothing to complain about. There is also pretty much no focus shift, which is present on so many other fast 35mm lenses.

close (0.20m), midframe


100% crops from midframe, A7rII

Unfortunately already in the midframe performance ain’t that great anymore. There is lots of astigmatism and it takes stopping down to f/5.6 to get okay performance in the thirds of the frame. Still, f/2.4 in the center looks better than f/5.6 in the midframe.

Flare resistance

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/11

Flare resistance stopped down is quite good for such an old lens. While there is a loss of contrast, ghosting is not really an issue. Wide open the situation is quite different, at f/2.4 you can catch really bad artifacts across most of the frame. Luckily stopping down to f/2.8 already solves this issue.

Unlike many other lenses this one has barely any issues with the sun in one of the corners, so a hood won’t be of much use I guess.

Coma

As was to be expected coma performance wide open isn’t great but already quite good at f/4.0. Still I have seen much worse from older lenses like this and for web usage you could even use it for handheld wide open cityscape shooting during blue hour without completely ruining the shot.


100% crops from extreme corner, A7rII

Distortion

Whilst not as bad as the Voigtlander 35mm 1.4 Nokton E classic there is distinct barrel distortion which you will want to correct for shots with straight lines running near the borders. At least it is not wavy so you can correct it rather easily by plugging in +8 in Lightroom or Photoshop.

Bokeh

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4

Bokeh is a subjective matter, yet many people claim this lens has rather good rendering in that regard, so I will go a bit more into detail here.

In general I think the bokeh is not that bad, as the transition zone is comparably smooth for a 35mm lens. Yet you have to be a bit careful with the background, especially tree branches can show double edged structures and at certain distances the corners will be much less out of focus compared to center and midframe.

Many people like to use fast 35mm lenses for environmental portraits. With a maximum aperture of f/2.4 this works good for head shots and reasonably well for half body portraits. For full body shots on the other hand f/2.4 is not enough and the background will only show marginal blur.

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4

Cat’s eyes towards the corners are not that much pronounced, but outlining gets strongers:

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4

In real world shots this translates to more nervous bokeh in the corners, actually comparable to using wide angle rangefinder lenses on Sony cameras:

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4

You can also encounter slightly ninjastar-shaped highlights, but luckily only at f/2.8, so this can easily be avoided:

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.8 | 100% crop

I did a thorough comparison of four other 35mm lenses in my 35mm comparison and just lately reviewed the Voigtlander Nokton 35mm 1.4 FE Classic. I enjoy this Flektogon’s bokeh more than that of the Loxia 35mm 2.0 or the aforementioned 35mm 1.4 Classic but not as much as the Voigtlander 1.7/35’s or the ZM 1.4/35’s.

Sunstars

With 6 rather straight blades you don’t get overly great sunstars. Have a look at our Best lenses for Sunstars article if you want to know more about this.

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/16

Chromatic aberration

lateral


Sony A7rII | Carl Zeiss Jena Flektogon 35mm f/2.4 |  f/16 | 100% crop from border region

There are some lateral CA visible but as usual they can easily be corrected using e.g. Lightroom.

longitudinal

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3
Sony A7rII Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4 | 25% crop | minimum focus distance

In close up scenarios the longitudinal CA are corrected pretty well, it is actually hard to spot any color fringing at all.

In real world shots they are visible but rather unobstrusive as well, you really have to look for them:

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4 | 50% crop

Alternatives

Zeiss Loxia 35mm 2.0:
This lens based on an older rangefinder design. I think the Loxia’s Bokeh is actually worse and corner as well as coma performance at f/2.0 to f/2.8 isn’t great either. Still, almost no distortion and a really great landscape and architecture lens at f/8.0.
If you are looking for a compact manual 35mm lens with mainly stopped down shooting in mind I think this is the better choice, get a used one as new they are a bit too expensive.

Voigtlander Ultron 1.7/35:
A very good performer for a decent price. A modern lens which is a great performer and offers the smoothest bokeh of all small 35mm lenses. If you want to make the best of it on your Sony camera get an Optosigma 5m PCX filter.

Voigtlander Nokton 1.2/40 E:
This is the modern interpretation of very fast yet still decently compact wide angle lens. While it isn’t a perfect lens I think it is optically better in every regard.

Zeiss ZM 35mm 1.4 T* Distagon:
This is Zeiss’ most recent rangefinder lens and while there is so much to like it also suffers from midzone dip on the Sony cameras and as there is the Voigtlander Ultron 1.7/35 I find it hard to recommend.

Sony/Zeiss FE 35mm 2.8 ZA:
Worse minimum focus distance, worse vignetting, half a stop slower. Should be much better in terms of sharpness, flare resistance and coma correction.

Other 35 mm SLR legacy lenses:
We haven’t reviewed many of these. Most will have a worse minimum focus distance, but without a direct comparison it is hard to compare bokeh, flare resistance and across frame sharpness. You may want to have a look at our Canon FD 35 mm comparison nevertheless.

Conclusion

good

  • center sharpness 
  • across frame sharpness at f/8.0
  • contrast (starting f/4.0)
  • correction of longitudinal CA
  • bokeh (nothing distracting in the corners)
  • minimum focus distance
  • build quality
  • price
average

  • correction of lateral CA
  • flare resistance (f/2.8 and smaller)
  • vignetting
  • size/weight
not good

  • off center sharpness until f/4.0
  • flare resistance (f/2.4)
  • coma correction (until f/4.0)
  • bokeh (foliage or similar things in the corners)
  • sunstars
  • distortion

I have reviewed lenses with barely any flaws which I still didn’t really enjoy using. Shooting with this lens – despite it’s shortcomings – I actually did enjoy: build quality, handling and size are great, the minimum focus distance allows for interesting shots, bokeh is quite good (especially for an old 35mm lens, but look for foliage in the corners) and it is sufficiently sharp and contrasty stopped down.
So if you are looking for an interesting 35mm lens or something wider to complement your Jupiter-9 85mm 2.0 this one might be worth a look.

A remake of this lens I would rather welcome than the Voigtlander 35mm 1.4 Nokton E Classic. While you can argue both have character (uncorrected aberrations) this one has a character I like and that doesn’t really get in the way of producing nice images.

This lens can only be bought used and prices start at $200/130€ on ebay.com/ebay.de (affiliate links).

Sample Images

carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/8.0
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/8.0
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4
carl zeiss jena flektogon retrofocus m42 prakticar 35mm 2.4 review sony 42mp a7rii a7rm2 a7rm3 sharpness close focus
Sony A7rII | Carl Zeiss Jena Flektogon 35mm 2.4 | f/2.4

Most of the sample images in this review can be found in full resolution here.

Further Reading

The following two tabs change content below.
My name is Bastian and for many years I have been mostly shooting Nikon DSLRs. As of today I have made my transition from Nikon to Sony and I am mainly using small but capable manual lenses. My passion is landscape photography but I also like to delve into other subjects from time to time.

15 thoughts on “Review: Carl Zeiss Jena 35mm 2.4 Flektogon”

  1. Great review!

    One the thing to note regarding build quality. This lens seems to be very susceptible to decentering (if that’s the correct word, I don’t know). On my copy one side of the frame is significantly less sharp than the other and it’s very difficult to adjust without proper equipment (if I remember correctly the front element must be adjusted). Maybe I was just unlucky and got a rare bad copy but it really was bad and it was a pain to fix.

  2. Hi Bastian,
    interesting review. Too bad you weren’t able to compare to the CY Zeiss Distagon 2.8/35
    Should you be interested in that lens (or other CY Zeiss lenses) for review purposes, we could take advantage of the fact that we both seem to be from the Wiesbaden area.
    All the best

  3. Other CZJ review ideas 🙂

    135/3.5 Sonnar
    50 /1.8 Pancolar (regular 6 blade and the very sharp 8 blade zebra with tons of ThO2)

    and then the Stasi-lenses SO 3.1, 3.2, 3.3…

    Anyhow, I used to own a couple of copies of the 35/2.4 – one APS-C scope with 24MP it was quite nice indeed. Very easy to CLA too like most MC jenas. Nice build quality, though with a couple of plastic parts inside.

    Due to copy variation I’d buy a copy with some wear and tear in appearance – or a PB-mount version as they tend to be cheaper.

    About the review: the click noise etc. depends largely on wear&tear and CLA – also if I recall right, eliminating click stops should be easy.

  4. Hey Philip,
    in the comparison post you wrote about the A7 and the A7 II, at the end you said that you returned the A7 II you tested and you want to stick with the A7.
    As I’ve seen in recent posts from you, you’re now calling an A7 II your own.
    I’m now going for the step from the NEX Series to the Alpha Series and im not sure if I should choose the A7 or the A7 II.
    Can you write something about your switch from the A7 to the A7 II? Would be really helpful for me. 🙂
    Best regards, Sascha

    1. The short version is that my a7 developed a defect, so I didn’t trust it any more and had to replace it. Since the price difference had decreased and I had a bit more money available I decided not to buy a new a7 but go for the a7II. At them moment prices for the a7II are really down because people replace it with the a7III so unless money is really tight I would recommend to get the a7II which is without a question the better camera.

      1. Thanks a lot for your explanation!
        Do you think it makes sense to buy the A7 II used for around 850€ (without lenses) instead of spending 1200€ for a new one, or do you see any risks?
        Thanks again for your reply 🙂

  5. hi Bastian,

    enjoyed the review, as I am considering a 35/40mm manual lens fod some time now I must admit this Flektogon was on my radar, but as you I too read about sample variation of this lens whicb allway kinda turns me away from it… currently I am trying to find any usefull reviews of CV 2.4/35mm color skopar but not having much luck, do you perhaps have any information/opinion on the color skopar?

    Keep up the good work, it’s much appreciated… 🙂

    Cheers A.

  6. Great review :)!
    And you tested a good copy of the lens. There are many decentered copies out there. There are only a few people in the world now that can fix that.
    I have this lens from a long time and I quite like it. It is a very versatile tool.

Leave a Reply

Your email address will not be published. Required fields are marked *