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CZ Ultron 50 f/1,8 M42
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PostPosted: Wed Jun 11, 2014 2:20 pm    Post subject: CZ Ultron 50 f/1,8 M42 Reply with quote

Hello everybody,

I was thinking on buying a CZ Ultron 50 f/1,8 in M42 mount to use on my K 10D , but recently have learned that such lens has no A/M switch as my SMC Tak´s 50 f/1,4 and 35 f/3,5 have Therefore have a lot of doubts about the possibility of the camera to take right measurements whether in Av or M mode. If the lens hasn´t the A/M switch , is wide open all the time when attached on the camera ? How is possible to take correct measurements with such a lens ?

I have seen the stunning pictures of kuuan with such Ultron 50 ( https://www.flickr.com/photos/kuuan/4840291911/) and are wonderful . All the gallery is really impressive .

Thanks in advance for your answer
Kind regards


PostPosted: Wed Jun 11, 2014 3:00 pm    Post subject: Reply with quote

Usually, a drop of super glue will keep the pin pressed. There are flanged adapter adapter but the quality not be as good as the Pentax one.

BTW, this lens is pretty expensive especially in M42 mount. Have you ever consider the excellent Voigtlander Color-Ultron 50mm F1.8 M42? It is much more easily to find and only cost 1/4 to 1/5 of the CZ Ultron 50.


PostPosted: Wed Jun 11, 2014 3:03 pm    Post subject: Reply with quote

With a M42 lens you are going to use real aperture to measure the exposure and shoot.
If you camera has no switch A/M on your lens, you have to check that the adapter that you buy, pushes the pin which closes the aperture. Most of them do it.

Keep in mind that there will be no transmission of informations from the lens to the body.
Keep in mind that closing the aperture will make the image in your viewfinder darker.


PostPosted: Wed Jun 11, 2014 3:08 pm    Post subject: Reply with quote

calvin83 wrote:
Usually, a drop of super glue will keep the pin pressed. There are flanged adapter adapter but the quality not be as good as the Pentax one.

BTW, this lens is pretty expensive especially in M42 mount. Have you ever consider the excellent Voigtlander Color-Ultron 50mm F1.8 M42? It is much more easily to find and only cost 1/4 to 1/5 of the CZ Ultron 50.


The Ultron Voigtlaender 50 1.8 should be the same as the Rollei Planar 50 1.8.
I think that the Zeiss Ikon Ultron ( for Zeiss Ikon cameras not for Rollei cameras) is not the same lens.


PostPosted: Wed Jun 11, 2014 3:11 pm    Post subject: Reply with quote

memetph wrote:
calvin83 wrote:
Usually, a drop of super glue will keep the pin pressed. There are flanged adapter adapter but the quality not be as good as the Pentax one.

BTW, this lens is pretty expensive especially in M42 mount. Have you ever consider the excellent Voigtlander Color-Ultron 50mm F1.8 M42? It is much more easily to find and only cost 1/4 to 1/5 of the CZ Ultron 50.


The Ultron Voigtlaender 50 1.8 should be the same as the Rollei Planar 50 1.8.
I think that the Zeiss Ikon Ultron ( for Zeiss Ikon cameras not for Rollei cameras) is not the same lens.

I am not saying it is the same lens but suggesting an alternative.


PostPosted: Wed Jun 11, 2014 3:29 pm    Post subject: Reply with quote

There are for sure many good 50mm 1.8 lenses.


PostPosted: Wed Jun 11, 2014 5:04 pm    Post subject: Reply with quote

calvin83 wrote:
Usually, a drop of super glue will keep the pin pressed. There are flanged adapter adapter but the quality not be as good as the Pentax one...


which is about the same as I had given you as answer to your same question via a comment to one of my photos at flickr. Do you understand it?: There is a pin sticking out from the rear of the lens, once this is pressed the aperture will close / open on moving the aperture ring. That pin can be kept in pressed position by a drop of glue or by using a M42 > K mount adapter that has an inner flange that keeps the pin pressed. There are cheap ones and at least one of high quality, also very expensive but I am not sure if that one is sold outside Japan.


PostPosted: Wed Jun 11, 2014 10:53 pm    Post subject: Reply with quote

Thank a lot to Calvin 83, memetph and kuuan for your answers and kind suggestions. I´ve got a M42 - K adapter which is the original from Asahi Pentax , and use with my Tak 50 and 35 on the K10D. Is it perhaps the same that you mentioned ?

The other possibility is to switch to the Voigtländer Ultron 50 , wich is not the same lens as the CZ Ultron , but of course is cheaper. But I was really impressed with the results and the sharpness obtained wide open with the Zeiss lens. A comment in Pentax Forum even compares with five of the best Pentax 50 and apparently " it blows them all away ".

Thank you very much


PostPosted: Thu Jun 12, 2014 9:32 am    Post subject: Reply with quote

jopenmx wrote:
Thank a lot to Calvin 83, memetph and kuuan for your answers and kind suggestions. I´ve got a M42 - K adapter which is the original from Asahi Pentax , and use with my Tak 50 and 35 on the K10D. Is it perhaps the same that you mentioned ?

The other possibility is to switch to the Voigtländer Ultron 50 , wich is not the same lens as the CZ Ultron , but of course is cheaper. But I was really impressed with the results and the sharpness obtained wide open with the Zeiss lens. A comment in Pentax Forum even compares with five of the best Pentax 50 and apparently " it blows them all away ".

Thank you very much


the CZJ Ultron is said to achieve amazing resolution, in this regard the 'blowing away', which calls for elaboration to be meaningful, might be justified. As a cheaper alternative to mention also the humble 55mm Takumars, they are said to have a very similar 'original Ultron' lens design, from my personal experience I'd particularily recommend the early f2/55mm Auto Takumar for it's amazing color rendition


PostPosted: Thu Jun 12, 2014 12:02 pm    Post subject: Reply with quote

From the sample in this site(http://forum.mflenses.com/ultron-1-8-50-blur-test-sample-t35780.html), the resolution is good at wide open but the sharpness damped by spherical aberration. I think sharpness of many 50s is good enough for practice use(including the old little Auto-Yashinon 5cm f2). Bokeh, color or flare resistant are important factors too.


PostPosted: Thu Jun 12, 2014 12:23 pm    Post subject: Reply with quote

calvin83 wrote:
From the sample in this site(http://forum.mflenses.com/ultron-1-8-50-blur-test-sample-t35780.html), the resolution is good at wide open but the sharpness damped by spherical aberration. I think sharpness of many 50s is good enough for practice use(including the old little Auto-Yashinon 5cm f2). Bokeh, color or flare resistant are important factors too.


Calvin certainly you are very right!
but on the other hand, many other lenses having "good enough sharpness for practical use" can't be, for us old lens lovers, much of an argument against buying yet another one, right?
and that CZJ is quite special!


PostPosted: Thu Jun 12, 2014 3:04 pm    Post subject: Reply with quote

kuuan wrote:
calvin83 wrote:
From the sample in this site(http://forum.mflenses.com/ultron-1-8-50-blur-test-sample-t35780.html), the resolution is good at wide open but the sharpness damped by spherical aberration. I think sharpness of many 50s is good enough for practice use(including the old little Auto-Yashinon 5cm f2). Bokeh, color or flare resistant are important factors too.


Calvin certainly you are very right!
but on the other hand, many other lenses having "good enough sharpness for practical use" can't be, for us old lens lovers, much of an argument against buying yet another one, right?
and that CZJ is quite special!

There are lots of reasons buying more no matter the lens we have are "good enough sharpness for practical use". Some people want better build quality, some people want better sharpness, some people want nicer colors, some people want smooth bokeh and some want more flare etc. Interestingly, softness is one of the reason buying a Trioplan 2.8/100!

From the sample in the web, I will rate the Zeiss Ultron higher than other modern lenses I tried including the Rollei Planar 1.8/50, Contax Planar 1.7/50 and Contax G 45. I bought a copy last month in M42 mount and I can't wait to try it. Wink


PostPosted: Thu Jun 12, 2014 4:46 pm    Post subject: Reply with quote

hey congrats Calvin, great lens Wink


PostPosted: Thu Jun 12, 2014 5:06 pm    Post subject: CZ Ultron 50 Reply with quote

Calvin 83, kuuan many thanks for your comments. Certainly I have not " logical " reasons to buy the lens apart from my LBA and passion for the old lenses ( specially the 50¨s and 28 ¨s ) . Perhaps , once read the literature concerning the optical formula, the concave front element and its possible special features , I became more and more interested on it.

Also I think that after the years , my clear conclussion is that I would prefer the old manual lenses rather than the new ones , with only one exception , which is my FA 31 ltd.

Having already the SMC Takumar 50 f/1,4 and S-M-C Takumar 35 f/3,5 , why not the Auto Takumar 55 f/2 ? Never tested it but will keep in mind your advice.

Best regards


PostPosted: Thu Jun 12, 2014 7:06 pm    Post subject: Reply with quote

I have 4 Takumars 55mm . The best of them is my SMC 55/2. One reason is that it is the most recent and therefore in better condition.