MSZM-7K 5,6 / 300 (AOMZ) and comparison with MS Rubinar 4,5 / 300 (LZOS). Article by Rodion Eshmakov

Material according to MSZM-7K 5,6 / 300 specially for Radozhiva prepared Rodion Eshmakov (subscribe to Instagram!)

This MC ZM-7K is a little tired of life, but it will still work.

This MC ZM-7K is a little tired of life, but it will still work. increase.


In the USSR, mirrored lens objectives (ZLO) and telescopes of the Maksutov-Cassegrain system have been mass-produced since the 40s (a brief history of Maksutov's lenses is given in here), but only models with a focal length of 500 mm or more were available. Short throw telephoto lenses (e.g. MTO-350 / OB-107), apparently, did not leave the walls of institutes and design bureaus of enterprises. Possibly, short-focus EVA required more complex circuits for correcting aberrations and were obtained no cheaper than the lens lenses produced at that time. analogues at a lower aperture and comparable image quality. One way or another, at the end of the last century, together with the beginning of use Mangin mirrors lenses with a focal length of 300 mm appeared available to the consumer: these are MC Rubinar 300 / 4.5 Lytkarino optical glass plant and MSZM-7K 300 / 5.6 of the Azov OMZ (presented in this article). The name of the lens from AOMZ looks rather strange and requires an explanation. "MSZM" is nothing more than a solidly written MC (Multilayer Coating) ZM (Mirror-Meniscus) for some reason. And "7K" is, apparently, something from the Doom - like BFG9K https://ru.wikipedia.org/wiki/BFG9000, since the letter K denoted lenses designed for the Pentax K mount, but my copy has a threaded mount М42 ... In this article I will refer to the lens as MS ZM-7K.

Specifications:

Optical design - Maksutov-Cassegrain with a Mangin mirror and a two-lens field corrector (5 elements in 5 groups);
Focal length - 300 mm;
Relative aperture - F / 5.6, taking into account central shielding (estimated) - T / 6.9;
The diaphragm is constant;
The minimum focusing distance is 1.7 m;
Light filter thread - 67 mm;
Mount to the camera - М42 (there are variants with Pentax K mount);
Dimensions - 73x78 mm;
Weight - 0.47 kg;
Source

design Features

The design of the MS ZM-7K is similar to other Soviet EVILS, such as the MS ZM-5SA, distinguished by the presence of a rubberized focusing ring and a dark "plug" behind which the secondary Mangin mirror is hidden.

The appearance of the MS ZM-7K is nevertheless closer to modern EVIL than to the old Soviet MTO and ZM.

The appearance of the MS ZM-7K is nevertheless closer to modern EVIL than to the old Soviet MTO and ZM.

The dimensions of the MS ZM-7K are very modest - in size it is smaller than Rubinar 300 / 4.5, rather resembles a fast 85-ku.

MC ZM-7K is not much larger than Jupiter-9 85/2.

MS ZM-7K is not much more than Jupiter-9 85/2.

Comparison of the size and weight of the MS ZM-7K with the lens Carl Zeiss Sonnar 4 / 300 serves as an excellent justification for the use of a mirror-lens scheme.

David and Goliath: MS ZM-7K and Sonnar 4/300.

David and Goliath: MS ZM-7K and Sonnar 4/300.

Is there a big chance that the 4kg Sonnar 300/7 will often be used with a photocall? But a pound on the MS ZM-XNUMXK may be found.

Is there a big chance that the 4kg Sonnar 300/7 will often be used with a photocall? But a pound on the MS ZM-XNUMXK may be found.

The lens I got was by no means in perfect condition: there are no helicoid stoppers, there is damage to the optics (generally not critical), the case with pronounced traces of use. However, I did not have a great desire to return the stoppers, since without them the lens is able to focus at a distance of about 1 meter (and even the initial 1.7 m is better than most lens lenses!) And can be easily installed on Nikon cameras with a lensless adapter with a good reserve. The small size of the MS ZM-7K will make it easy to use on SLR cameras with a built-in flash.

Without the MDF stopper, it is theoretically possible to accidentally spin the lens into two parts, but in practice it will take a long time to twist. The paintwork looks scary.

Without the MDF stopper, it is theoretically possible to accidentally spin the lens into two parts, but in practice it will take a long time to twist. The paintwork looks scary.

The close-focus field corrector of this objective consists of 2 separate lenses, the attachment of which is connected with the attachment of the "carrot" hood, which is more cunning in comparison with the "Rubinars".

View of the lens from the shank side with the M42-EOS adapter fitted.

View of the lens from the shank side with the M42-EOS adapter fitted.

The objective lenses are multi-coated in green-violet shades - typical for Soviet / Russian optics of the late 80s - 90s. The serial number indicates that this lens was manufactured in 1993.

However, the presence of enlightenment does not help this lens in any way, because the factory quality of blackening the inner surfaces of the lens unit is completely disgusting (the effect is described below). All the insides of the lens must be carefully and matt blackened, no options. In this regard, the new LZOS Rubinars went much further - such hack was not noticed in them. This drawback, in essence, negates all the advantages of the MS ZM-7K as a finished product.

In addition to blackening, I loosened the fastening of the full-aperture meniscus corrector - it was overtightened, as is usually the case with Soviet EVIL.

Complaints also arise about the quality of the peeling paintwork. Although even such a well-worn lens looks good on Canon 5D, and on the old Zenit-12SD - as shown by Oleg Isaev (Instagram - cat.tangent) who helped me with the material for this article.

In general, despite a number of advantages, the performance of the lens gives rise to criticism. After the experience of handling the new Rubinars, the MS ZM-7K does not look attractive.

Optical properties. Comparison with MC Rubinar 4,5 / 300

I used MS ZM-7K both before blackening and loosening the meniscus attachment, and after. Before blackening, the lens completely disappointed me: the contrast of the image was very low, poor colors - the image could not be "stretched" even in the editor. Sharpness was also not impressive - even on a 12 megapixel full-frame matrix in the center, the lens frankly "washed out". This is definitely not attributable to the condition of the lens.

Below are photos on MS ZM-7K and full-frame Sony A7s before blackening.

Then I was able to compare MS ZM-7K with MS Rubinar 4,5 / 300, taking a panorama of the manufacturing plant from the balcony. Paradoxically, although the aperture value I estimated, taking into account the central shielding of the ZM-7K MC, turned out to be higher than that of Rubinar (~ 1: 6.9 versus 1: 7.4), to obtain frames of approximately equal illumination, it was necessary to add 1/3 of an ISO stop when shooting at MS ZM-7K. Apparently aperture MC ZM-7K "cuts" the hood - "carrot".

I was surprised by the striking superiority of the Rubinar in resolution and contrast over the MS ZM-7K. The Rubinar differs from the ZM-7K only in the full-aperture corrector split into two lenses, but it seems that this is the whole point. Another observation was the presence of noticeable chromatic aberrations (!) In MS ZM-7K, which I did not find in Rubinar lenses (I tested the 300 / 4.5 on an 18 Mp APS-C camera Canon 600D).

One of the advantages of the MS ZM-7K is the ability to work with medium-format matrices 44x33 and shift adapters on full-frame cameras without critical vignetting.

Below are paired images on MC ZM-7K and MC Rubinar 4.5 / 300 on Sony A7s, as well as cropped photos. A couple of vertical shots - shift panoramas (a little more detail - here).

After the blackening procedure and the weakening of the meniscus attachment, the contrast of the image formed by the MS ZM-7K significantly improved. Sharpness has also increased, which speaks of the importance of proper assembly of such lenses.

I found it interesting to use the lens in the macro range, where it provides a rather interesting picture with a characteristic bagel bokeh at an image quality acceptable for a 12 megapixel full-frame sensor. You can also shoot landscapes with this lens, but when used with a shift adapter, a strong curvature of the field appears outside the 36x24 mm frame. Rubinars, again, have the best correction.

Below are sample photos taken with the Sony A7s full-frame camera.

On cameras with a higher pixel density than the Sony A7s, the lens behaves unsatisfactorily. A rather strong chromatism appears (“You should have fought with evil, and not joined it! ..”), the sharpness is not enough due to spherical aberration.

Examples with Nikon D7100 (APS-C, 24 Mp), made by Oleg Isaev (Instagram: cat.tangent) - below.

conclusions

MC ZM-7K is certainly not the most common lens, but it could be considered as a more affordable alternative to the Rubinar 300 / 4.5, which is now estimated by the manufacturer in ~ 400 $... If only he were this alternative: unfortunately, both the optical quality and the workmanship do not reach the level of modern mirror-meniscus lenses. After revision, the lens is quite suitable for solving creative problems, but as a telephoto lens, the MS ZM-7K is bad.

You will find more reviews from readers of Radozhiva here... All Rodion reviews in one place here.

Add a comment: Rinatk

 

 

Comments: 22, on the topic: MSZM-7K 5,6 / 300 (AOMZ) and comparison with MS Rubinar 4,5 / 300 (LZOS). Article by Rodion Eshmakov

  • Sergei

    Was like this about 3 years ago. I literally managed to take test photos, I realized that I had sold everything pretty and quickly.
    Soon I bought a much more decent Tamron SP 350 mm f / 5.6 Adaptall-2 model 06B (also quite rare)

  • Sergei

    It is somewhat incorrect to compare a well-worn random shabby lens of 1993 with a new version of LZOS 2020 or 21 years old (besides, issued to the author for testing by the plant itself). Those. a priori, passed the secondary selection from the manufacturer itself.
    By the way, LZOS itself produced its own version of the ZM-90 in the early 7s. And it would be more interesting (and more correct) to compare it.

    • Rodion

      Sergey, you yourself are well aware that Rubinar 300 from the review is no less random, because at LZOS, believe me, no one will specially collect demo samples in a special way, especially for review on Radozhiv. There was no secondary selection, they gave what remained unsold at that time.
      It is also easy to guess that peeling paint does not affect the sharpness of the lens. And even small traces of rubbing in places do not have any effect, except for a psychological one.
      The ZM-7 version from LZOS is not even in the LZOS museum. As I have repeated to you many times - if something is more interesting to you, then send it, we will do what is more interesting. And more correct)

      • Sergei

        It is interesting that the resolution (according to TU) at infinity for both lenses is absolutely the same - 40/32 lines / mm.
        True, the AOMZ designer turned out to be more honest - they indicated in the passport a noticeable decrease in resolution during macro photography (which is not in the documents for EVIL from LZOS).
        I believe that Rubinar also has a similar phenomenon.

        • Rodion

          Any lens has a reduction in resolution when used at a scale that is not provided for by the scheme when calculating. Photo lenses are corrected “to infinity”.
          It is strange that you are interested in passport permission - this value is absolutely useless, since it is measured under conditions known to God - on incomprehensible photographic materials, at incomprehensible distances, etc. The practice of handling any (post) Soviet products suggests that the quality is affected most of all by the degree of sobriety of the assembler, and not by the capabilities of the circuit (see MTO-1000 in astronomy - the most striking example). "Resolution" is not used at all in the documentation for any other lens, normal manufacturers have been publishing MTF for a long time. At LZOS they are only just beginning to guess that the photographers of the ChKKh can also worry, they live there with “traditions” from the 50s.

  • Dim

    The new, absolutely not rare Nikon AF-P DX NIKKOR 70-300 with a store warranty costs about $ 230 and has a stub, excellent sharpness, autofocus, weighs less and has a zoom. Although the DX is physically longer and will not fit nicely on Canon, there will be no feeling of elitism and it is slightly darker than 5,6 vs 6,3. At the same time, it must be said that the prices for old lenses are completely inadequate, as well as for their "new versions".

  • Sergei

    Unfortunately, both lenses being compared are quite expensive. Rubinar - about $ 400, ZM-7K on the secondary housing from $ 200.
    At the same time, People's China on Aliexpress sells EVIL 300mm / 6,3 for a mirrorless crop from $ 90 (!!!). At the same time, the optical design of 7 lenses in 4 components (simpler than the analogous Samyang), but more complicated than the Russian EVIL.

    • Rodion

      Sergey, it would be much more interesting and correct if you made a comparison of a 300 mm lens from aliexpress and a Russian ruby ​​...

      • Sergei

        So it is just such a cheap new Chinese that it would be desirable for you to take as a "whipping boy".
        I have no doubt that the modern Rubinar will surely outplay him, but the question is - with what score?
        Today the ZM-7 is more of a collectible lens than a real player in the EVIL market.

        • Rodion

          I do not want to "take" a cheap Chinese, I am not interested in him. I have a full frame camera. There is no desire to bet on it at your own expense the darkest (F / 6.3) three hundred with a vignette. In addition, from a manufacturer with an extremely bad reputation (if not everywhere, then certainly in the field of the structure of EVIL for sure). As far as I know, detailed tests of the Samyang EVIL were carried out at LZOS, in particular, thermal breakdown tests, and it was after this that they gave the go-ahead for the launch of a series of rubies. Guess why)

        • Rodion

          In general, if the result of comparing the ZM-7 with the Rubinar-300 turned out to be the same, then it is reasonable to assume that the ZM-5SA will be much worse than the Rubinar 500/8. About XA in ZM lenses, here is another “fan” of domestic EVIL Dmitry (aka negodun) spoke out - apparently, not in vain, though.

          • Rinatk

            A colleague and I tested the ZM-7K a little a few years ago. It is possible that the early versions were slightly better than those released in 93. Only this file remained from the test, the lenses were 1.ZM-7K in 93, 2. MTO-350, 3.ZM-7K in 89 , 4. Tair-3 from the photosniper. The ZM-7K of the 89th was a little better than the 93rd, both were heavily losing to the MTO-350 in the center, the MTO edge was just awful. Unfortunately, the Rubinar-300 was not available for a full test at that time.

            • Rinatk

              the file is not added for some reason, apparently not destiny

  • Rinatk

    A colleague and I tested the ZM-7K a little a few years ago. It is possible that the early versions were slightly better than those released in 93. Only this file remained from the test, the lenses were 1.ZM-7K in 93, 2. MTO-350, 3.ZM-7K in 89 , 4. Tair-3 from the photosniper. The ZM-7K of the 89th was a little better than the 93rd, both were heavily losing to the MTO-350 in the center, the MTO edge was just awful. Unfortunately, the Rubinar-300 was not available for a full test at that time.

  • Rinatk

    the file is not added for some reason, apparently not destiny

  • Sergei

    Fresh testing (2020) of the Japanese Tokina SZX 400mm / 8.
    Very competent conclusions.
    https://www.christopheanagno.com/tokina-szx-400mm-f8-reflex-mf-lens-review/#

  • Alexander

    Not. I understand everything, lenses are a hobby of the author, LZOS produces what it can using technologies of the last century.
    But who is interested in this today?
    Pros, without autofocus ... hardly.
    For an amateur, well, perhaps a “dead nature”. birds, of course, you can, but calm.
    So this is a budget superzoom. yes in the bright sun. copes even better (example in the photo).
    Plus, it is not a fact that the autofocus indication will work, and the wedge focusing will not turn into a black circle in the middle of the screen due to the small opening.
    And in the second picture, the object is 1,5 km away from me, superzoom is shot, manual focusing through the branches.
    And lastly, a used Tamron 70-300 1: 4-5.6 autofocus cost me $ 20, and comparisons today, which is better, VAZ 2101 or 2103 ... what century are we in?

    • Vvs

      Tamron 70 - 300 for all its shitty sometimes gave pleasure

      • Alexander

        Yeah, budget for amateurs, like me, who are too lazy to tear the ass @ tsu from the chair.
        Jpeg close-up from the camera from 3 meters

  • Alexander

    A bird that did not break into the post above.

  • Vvs

    It would be interesting to compare with Samyangov's evil 500mm

  • Vvs

    It's nice that Rodion not only shoots, but also treats lenses.
    In the box lies dm 5a, 78 years old.
    I sincerely envy, because I could not treat him myself

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