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What's the difference between Contax MM and AE lenses?
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PostPosted: Fri Jun 03, 2011 11:11 pm    Post subject: Reply with quote
AhamB wrote:

Coatings are part of the optics and they do make a difference (in colour rendering and flare resistance).


They are all T*: yes or no?


PostPosted: Sat Jun 04, 2011 1:57 pm    Post subject: Reply with quote
Have you taken a look at the test from slrlensreview that I linked to?


PostPosted: Sat Jun 04, 2011 6:31 pm    Post subject: Reply with quote
you mean this, right?
Code:
.....Needless to say, flare handling in AE lens at least is not particularly impressive, with ghosting and glare visible throughout the aperture range. While I don't have similar shots done with an MM lens at the moment, the two copies I've had on my hands over the last two years have not showed such a heavy flare, which leads me to speculate that there might have been some minor changes in coating when Zeiss transitioned from AE to MM version. I will try to re-shoot the same situation with an MM copy in the future and report back in the review.....


I think that T* stands just for quality of coating - not that every lens has same coating (material, number of layers, thickness etc). each lens needs specific coating, so making it same on every lens wouldn´t make it better.. right?


PostPosted: Sun Jun 05, 2011 4:35 am    Post subject: Reply with quote
AhamB wrote:
Have you taken a look at the test from slrlensreview that I linked to?


Where's the link?

In any case, what colour you see on the front lens does not mean necessarily anything particular except that it's the last layer of the coating.

The purpose of multicoating as opposed to single coating is that multicoating uses several layers at different frequency to block the most possible reflections of the lens. Single coating instead choosed only one frequency (most typically the central ones, which makes so that most single coated lenses look blueish) and let both extremes go.

Since it is not thinkable that Zeiss Oberkochen omitted some layering in a T* lens, whatever colour you do not see on the outside of the front lens, must be present as underlayer.
Contax lenses (like modern Z lenses) were assemble to provide constant colour rendering. Professionals require that when they change lens, this does not create a shift in the colour tones. That was even more important in the Contax time, because those lenses were made for film, not for digital where small hue shifts are correctable easily.
So you can be sure that all Contax lenses have the same coating that ensures the same precise colour rendering with no shifts. It may only be that they changed the order of the layers at some point during production of the 85mm Sonnar.

In any case, I have all four types of the lens. I hate testing - I much prefer photographing - but I will sacrifice for science and test my copies - when I have time.


PostPosted: Fri Jul 21, 2017 4:50 pm    Post subject: Reply with quote
Dear Experts

Currently I am planing to purchase a second hand Sonnar 85 mm 2.8 lens. There is a possible item within my reach.
 
Carl Zeiss Sonnar 2,8/85 5283203 
Lens made in West Germany (back of the mount) 
QBM mount (?)
Aperture numbering white, also has an auto-manul switch. 

According to Zeiss support the lens was made in 1972 for Rollei. I need your help to determine whether it has a T* or HFT coating or not? The front of the lens does not show this. 
Also tried to contact Rollei customer service but they were not been able to provide help.

Thank you for your assist, 
 


PostPosted: Fri Jul 21, 2017 7:38 pm    Post subject: Reply with quote
According to the list here: http://www.klassik-cameras.de/Rollei_QBM_dt.html
the 85/2.8 lens wasn't available with HFT coating.
However, the coating of the non-HFT lenses isn't bad as well and if you use a sun shade any difference will hardly be visible.


PostPosted: Fri Jul 21, 2017 7:58 pm    Post subject: Reply with quote
tb_a wrote:
According to the list here: http://www.klassik-cameras.de/Rollei_QBM_dt.html
the 85/2.8 lens wasn't available with HFT coating.
However, the coating of the non-HFT lenses isn't bad as well and if you use a sun shade any difference will hardly be visible.


... unless there's a light source in the frame.


PostPosted: Sat Jul 22, 2017 7:57 am    Post subject: Reply with quote
visualopsins wrote:
tb_a wrote:
According to the list here: http://www.klassik-cameras.de/Rollei_QBM_dt.html
the 85/2.8 lens wasn't available with HFT coating.
However, the coating of the non-HFT lenses isn't bad as well and if you use a sun shade any difference will hardly be visible.


... unless there's a light source in the frame.


Information taken from the Rolleiclub:

quote:
Having HFT multi coating is only important when a small bright source of light strikes the front lens. In that case, the lens shows more of a grayish lens flare than the HFT version will do.
Keep in mind that the original Zeiss lenses with dual coating already were extremely good protected against flare, and according to some connoisseurs, the HFT coated lenses are believed to draw a little bit softer image.
Good advice: always use a shade
unquote.

At least they should know a little bit about HFT coatings. I never compared those lenses with and without HFT coating myself. My Voigtlaender twins of the Rollei Zeiss lenses seem to be non-HFT versions as well and I never noticed any flare troubles up to now.


PostPosted: Sat Jul 22, 2017 6:34 pm    Post subject: Reply with quote
The Sonnar 2.8/85 only has 6 air-glass surfaces so the exact coatings it has will make less of a difference than with more complex lenses.


PostPosted: Sat Jul 22, 2017 8:23 pm    Post subject: Reply with quote
tb_a wrote:
visualopsins wrote:
tb_a wrote:
According to the list here: http://www.klassik-cameras.de/Rollei_QBM_dt.html
the 85/2.8 lens wasn't available with HFT coating.
However, the coating of the non-HFT lenses isn't bad as well and if you use a sun shade any difference will hardly be visible.


... unless there's a light source in the frame.


Information taken from the Rolleiclub:

quote:
Having HFT multi coating is only important when a small bright source of light strikes the front lens. In that case, the lens shows more of a grayish lens flare than the HFT version will do.
Keep in mind that the original Zeiss lenses with dual coating already were extremely good protected against flare, and according to some connoisseurs, the HFT coated lenses are believed to draw a little bit softer image.
Good advice: always use a shade
unquote.
At least they should know a little bit about HFT coatings. I never compared those lenses with and without HFT coating myself. My Voigtlaender twins of the Rollei Zeiss lenses seem to be non-HFT versions as well and I never noticed any flare troubles up to now.


"the lens shows more of a grayish lens flare than the HFT version" vs "any difference will hardly be visible"


PostPosted: Sat Jul 22, 2017 10:40 pm    Post subject: Reply with quote
tb_a's info is wrong because the lens definitely was available in a HFT version:



Therefore 'it makes no practical difference' will be the more accurate statement.


PostPosted: Sat Jul 22, 2017 11:13 pm    Post subject: Reply with quote
Laugh 1 perfect!


PostPosted: Sun Jul 23, 2017 8:18 am    Post subject: Reply with quote
iangreenhalgh1 wrote:
tb_a's info is wrong because the lens definitely was available in a HFT version:


Well, there is obviously some contradictory information around. BTW, that's not my information but from the quoted site. Even my books don't show this information; i.e. that the 85/2.8 was available in both coating versions (obviously depending of the time of manufacturing).

I've found this additional information also from the Rolleiclub. Hopefully that clarifies it better:

"The German production of "Made by Rollei" lenses, and those made in Singapore, were all HFT lenses.

Except for the fact that multi coated lenses bear the HFT sign on the front lens mount HFT lenses can be easily identified because they glow red and/or dark green, as opposed to single or dual coated Zeiss lenses which have a golden and blue glow. A few Zeiss lenses have been sold with HFT coating not bearing the HFT sign on the lens."

It appears that not even the markings on the lenses have been always correct and only the color of the coating will tell the difference. Interestingly all of my Voigtlaender twins (my preferred version because of the M42 mount) have been produced in Singapore as well but whilst the Tessar shows more of a red glow the Planar/Ultron appears more bluish. Finally I wouldn't even trust that information, i.e. that all Singapore produced lenses are multi coated HFT lenses, any longer.

Fortunately I don't really care about the type of coating as long as it does what it is supposed to do. Wink

Last edited by tb_a on Sun Jul 23, 2017 3:41 pm; edited 1 time in total


PostPosted: Sun Jul 23, 2017 8:41 am    Post subject: Reply with quote
I'd rather go by what lenses are known to exist than any writings.


PostPosted: Sun Jul 23, 2017 10:24 pm    Post subject: Reply with quote
May somebody get lucky and get a Zeiss with HFC (not marked on lens, of course!) Laughing


PostPosted: Tue Jul 25, 2017 11:12 am    Post subject: Reply with quote
Thanks for everybody the info.
In the meantime I've received an answer from Paepke Fototechnik, Düsseldorf. The Rollei service stated that this lens - Carl Zeiss Sonnar 2,8/85 5283203 - made for Rollei SL 35 w/o HFT coating.

So I'm going for a T* CZ Sonnar.


PostPosted: Wed Sep 13, 2017 6:42 pm    Post subject: Reply with quote
So finally I skipped the sonnar and bought a planar mmg. Can't wait for the adapter...
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