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Biotar - T or not to T, that is the question.
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PostPosted: Sat Feb 21, 2009 5:10 pm    Post subject: Reply with quote
no-X wrote:
I can't check, it's dark evening - zero reflections for now, I'll try tomorrow Smile


Thanks, No-X

It's a very important date, of course.

If you can, don't forget it, please.

Regards, Rino.


PostPosted: Sat Feb 21, 2009 5:30 pm    Post subject: Reply with quote
Now ckecked two Tessars

1.M42 Tessar (CZJ) 1/1600 F2.8

2.Prakticar(CZJ) 1/1600 F2.8

3.M42 Tessar 1/5000 F2.8

4.Prakticar 1/5000 F2.8


The first two are identical (to me), the last two Prakticar Tessar has darker at shaded area.
That itself does not me MC is better, M42 one might have more internal reflections from
barrel design or something else. They are optically identical lenses except coating.


PostPosted: Sat Feb 21, 2009 6:25 pm    Post subject: Reply with quote
Hi again, Koji Smile

I agree with you in which in the two first, there are no differences.

In the second group, I see the M42 darkest in the more illuminated zones of the scene. It is showy, since being SC that part would have to be seen clearer since the internal reflections would have to clarify and not to darken the image in the more illuminated zone , or show more clear the rest of the image because the flare effects (it doesn't ocurr) , or subexpose the overall image because came more light to the meter (it doesn't ocurr)

I can infer from these clearly that, or the Prakticar is MC and it does not have the smaller influence - what justifies the lack of MC in the tessars designs; or they are both lenses SC.

Regards, RINO.


PostPosted: Mon Feb 23, 2009 10:35 am    Post subject: Reply with quote
estudleon wrote:
no-X wrote:
I can't check, it's dark evening - zero reflections for now, I'll try tomorrow Smile


Thanks, No-X

It's a very important date, of course.

If you can, don't forget it, please.

Regards, Rino.

There are many color nuances, so it's not easy to generalize, but for my Sigma SD14 the best is this one (checked under light-bulb): Front: Big yellow (maybe orange) reflection, mix of smaller reflections purple/yellow. Rear: big eyellow(/orange) reflection, 3 small purple reflections (different tints) close to each other and a mix of other reflections.

Other example (for comparision): Front: Big violet reflection, mix of different color reflections. Rear: Big purple reflection, 3 small reflectsion (indigo, cyan, orange) close to each other and a mix of other reflections.

The first one is better for me, because Sigma uses purple MC layers for IR filter, so when the rear element reflects mostly orange light, which is not reflected by the IR filter, than it simply works.

As for the second example - if the rear lens part reflects purple light, like the IR filter, than the picture becomes less contrasty and there are halos around contrasty areas.

But that's only for Sigma. The best way for other brands would be to check color, which is reflected by the sensor and use lens, which reflects opposite color to suppress the reflections.

as for the two examples, here is a comparision - it's overcast, real difference is visible only under direct skylight, but you can see, that the second sample has light halo around the trunk:

f/1.8 (the two examples I described)



Here is another example: the biggest difference I was able to record for two different MC Pancolars:

f/1.8 (the left one is not described here, but the right one is the 1st example)



PostPosted: Mon Feb 23, 2009 11:55 am    Post subject: Reply with quote
Thank you, very much.

What difference between the examples !!

Very informative, very usefull.

Rino.


PostPosted: Mon Mar 09, 2009 1:20 pm    Post subject: Reply with quote
CCCP Jupiters:



ZOMZ Jupiter-3 Π 50/1.5 M39 (1957) | KMZ Jupiter-8 Π 50/2 M39 (1955) | ZA Jupiter-8 50/2 Y/C (1970) | KMZ Jupiter-8 50/2 M39 (1977)


PostPosted: Mon Mar 09, 2009 2:18 pm    Post subject: Reply with quote
Nice examples. Very informative.

Very nice windows too.

Thanks. Rino.


PostPosted: Mon Mar 09, 2009 2:35 pm    Post subject: Reply with quote
I understand, that the coating changed in time, but I can't get, why each factory developed different coating. That had to be more expensive, than to reuse once developed method from other factory...


PostPosted: Mon Mar 09, 2009 3:10 pm    Post subject: Reply with quote
no-X wrote:
I understand, that the coating changed in time, but I can't get, why each factory developed different coating. That had to be more expensive, than to reuse once developed method from other factory...


Yes and it is almost impossible to know the reasons.
I believe that those changes must to the necessity to compete with others brands, to the different characteristics from color of more used films, to the fashions (to create it or to stay in it), reduction in price of costs, etc.
I consider that one is a complex decision that looked for the best adaptation of the lens to the changing necessities of the market for a greater economic yield.
We have the example of CZJ MC Pancolar 1.8/50 often changed of treatment benefitting the transmission of different colors, whereas Meyer in its Pentacon Multicoated 1.8/50 maintained always the same treatment. It is to say that all the brands did not see the necessity of such change, which makes still more complex the decision to change.

Rino.


PostPosted: Mon Mar 09, 2009 3:16 pm    Post subject: Reply with quote
Anyway, I'm really looking forward to try the Jupiter-3 50/1.5. It arrived today and I'm curious how it will perform as a close-up lens Smile


PostPosted: Thu Apr 02, 2009 3:54 pm    Post subject: Reply with quote
koji wrote:
Now ckecked two Tessars

1.M42 Tessar (CZJ) 1/1600 F2.8

2.Prakticar(CZJ) 1/1600 F2.8

3.M42 Tessar 1/5000 F2.8

4.Prakticar 1/5000 F2.8


The first two are identical (to me), the last two Prakticar Tessar has darker at shaded area.
That itself does not me MC is better, M42 one might have more internal reflections from
barrel design or something else. They are optically identical lenses except coating.


It seems to me that the M42 copy performs much better Exclamation


PostPosted: Thu Apr 02, 2009 4:14 pm    Post subject: Reply with quote
Why do you think? I think the PB version has definetely more contrast.


PostPosted: Thu Apr 02, 2009 4:57 pm    Post subject: Reply with quote
no-X wrote:
Why do you think? I think the PB version has definetely more contrast.


Agree.


PostPosted: Thu Apr 02, 2009 5:05 pm    Post subject: Reply with quote
After analized carefully both images, I think that not as much contrast differences (yes, it exists, but C/Y a very, very bit more contrast). The more difference that I found it was a greenish tonality in the CZJ lens (CZJ tendency), that opaque the image, making that it seems contrasted less, although in fact it is, but in this way the sensation is increased.

On the other hand, I think that there is a tint purple in the C/Y (it seems to be a tendency of some lenses of the brand) that, mainly by the color purple of some of the points on the left of the window and in compare with the greenish image of the CZJ, favor the sensation of greater contrast.

Equal I see a difference of color in the sky, that responds to the greenish tint of the CZJ.

On the building of the bottom, without windows, the tint greenish in the CZJ and purple in the C/Y notice.
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