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Very early Helios 44 blue type coatings color rendition
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PostPosted: Thu Jul 22, 2021 7:12 am    Post subject: Very early Helios 44 blue type coatings color rendition Reply with quote
I wonder if anybody has had any experience in comparing the color rendition of the earliest helios-44 lenses, the ones with a coating showing a markedly strong blue reflection, to the later models.

I own a late Helios-44 (totally similar in color rendition to a run of the mill early 44-2 with green markings) and one 44-m4 and one 44-m-7.

I don't see a world of diference between the first two and the latter ones.

I wonder if it would be worthwile to buy a start type or a 13 blades early 44 with blue coatings, and this only from the point of view of having some different palette.

(As a side note, In terms of sharpness I didn't notice any significant difference between the early 44/44-2 and the latter 44-m-4 and 44-m-7: all of them are pristine, there is not any trace of defects in these lenses and mechanics are sound, so I assume them to be still in a factory spoecs condition. And they perform equally well in terms of swirly bokeh)


PostPosted: Thu Jul 22, 2021 10:53 am    Post subject: Reply with quote
I honestly don't think you can read too much into the colour of the coatings, the thickness of the coating can effect the colour that's reflected,
https://en.m.wikipedia.org/wiki/Thin-film_interference
Quote:
Thin-film interference explains the multiple colors seen in light reflected from soap bubbles and oil films on water. It is also the mechanism behind the action of antireflection coatings used on glasses and camera lenses.

When the thickness of the film is an odd multiple of one quarter-wavelength of the light on it, the reflected waves from both surfaces interfere to cancel each other. Since the wave cannot be reflected, it is completely transmitted instead. When the thickness is a multiple of a half-wavelength of the light, the two reflected waves reinforce each other, increasing the reflection and reducing the transmission.


https://en.m.wikipedia.org/wiki/Optical_coating
Quote:
By careful choice of the exact composition, thickness, and number of these layers, it is possible to tailor the reflectivity and transmitivity of the coating to produce almost any desired characteristic. Reflection coefficients of surfaces can be reduced to less than 0.2%, producing an antireflection (AR) coating.


https://en.m.wikipedia.org/wiki/Anti-reflective_coating
Quote:
Index-matching
The simplest form of anti-reflective coating was discovered by Lord Rayleigh in 1886. The optical glass available at the time tended to develop a tarnish on its surface with age, due to chemical reactions with the environment. Rayleigh tested some old, slightly tarnished pieces of glass, and found to his surprise that they transmitted more light than new, clean pieces. The tarnish replaces the air-glass interface with two interfaces: an air-tarnish interface and a tarnish-glass interface. Because the tarnish has a refractive index between those of glass and air, each of these interfaces exhibits less reflection than the air-glass interface did. In fact, the total of the two reflections is less than that of the "naked" air-glass interface, as can be calculated from the Fresnel equations.


Quote:
The exact nature of the coating determines the appearance of the coated optic; common AR coatings on eyeglasses and photographic lenses often look somewhat bluish (since they reflect slightly more blue light than other visible wavelengths), though green and pink-tinged coatings are also used.


PostPosted: Thu Jul 22, 2021 10:55 am    Post subject: Reply with quote
I don't like the early one SN starts with 000 in strong blue coating. The later copies with pale blue coating is better for my taste.


PostPosted: Thu Jul 22, 2021 11:30 am    Post subject: Reply with quote
Attila said sometimes, that the 44 aluminium version was sharper with better contrast.

In the oldest thread (near 2009/2011) you can find a lot of information


PostPosted: Thu Jul 22, 2021 12:24 pm    Post subject: Reply with quote
papasito wrote:
Attila said sometimes, that the 44 aluminium version was sharper with better contrast.

In the oldest thread (near 2009/2011) you can find a lot of information


That's good to know. I can compare directly my four copies to a very good copy of the biotar 58mm (2nd version) which shows no signs of fungus or scratches on the lenses, being spotless: all of them are as sharp as the Biotar, and equally capable of a great bokeh.

From what you say finding an early alu lens could be nonetheless a good idea, at this point a thirten blades could be worth the effort .

As for color rendition I see from the wikipedia article that it might not be affected by diferent coatings, likely because in all versions the glass being used is likely the same (given the results in terms of sharpness and image quality I doubt that the formula had been really changed, as claimed by some people over the net).
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