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500mm Mirror Lenses
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PostPosted: Tue Aug 06, 2019 8:54 pm    Post subject: Reply with quote

well here's some initial results from the spiratone minitel-m, straight from the camera .. finding it to be definitely less sharp than the sigma or yashica, but better than the rexatar and quantaray, and was able to get decent results with just using focus peaking (focus magnifier didn't improve the situation much) .. might put this lens in the bag in situations that size and weight matter.


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PostPosted: Wed Aug 07, 2019 12:17 am    Post subject: Reply with quote

Yep. I think that any Tamron collection should include either the 55B or 55BB.


PostPosted: Wed Aug 07, 2019 12:31 am    Post subject: Reply with quote

55B and 55BB have different optics. Any preference?


PostPosted: Wed Aug 07, 2019 10:09 am    Post subject: Reply with quote

visualopsins wrote:
55B and 55BB have different optics. Any preference?

I didn't notice the optics were different.
I can't answer as I have only the 55B and can't make a comparison.

The change in optical diagram seems to have the goal of increasing close focus quality.

55B : http://adaptall-2.com/lenses/55B.html
55BB : http://adaptall-2.com/lenses/55BB.html
"The major optical design change is the switch to a constant thickness meniscus main mirror in order to reduce close focusing spherical aberration. The change in the main mirror design also necessitated changes for the two smallest lenses located within the middle of the optical design."


I'm interested in the answer and comparison. Smile


PostPosted: Wed Aug 07, 2019 11:16 am    Post subject: Reply with quote

Remember our member Mo? She was very active for a few years, but it's been a few years now since the last time she posted anything. Anyway, she had a 55B and she posted a lot of images she took with it. After examining many of her images, I came to the conclusion that any difference there was between the two optics was very minor. Adaptall-2.com's comments on the 55BB theorize that, because of the different optical constructions, the 55B may have an advantage at telephoto distances,whereas the 55BB may have the advantage with close focusing. But I can honestly state that, from the many images that Mo posted here -- many of which were close focus -- I just couldn't see a significant difference. I'm not saying differences don't exist, they must because of the two different optical constructions. But are they significant? I'm not so sure on that one.


PostPosted: Wed Aug 07, 2019 11:19 am    Post subject: Reply with quote

cooltouch wrote:
Remember our member Mo? She was very active for a few years, but it's been a few years now since the last time she posted anything. Anyway, she had a 55B and she posted a lot of images she took with it. After examining many of her images, I came to the conclusion that any difference there was between the two optics was very minor. Adaptall-2.com's comments on the 55BB theorize that, because of the different optical constructions, the 55B may have an advantage at telephoto distances,whereas the 55BB may have the advantage with close focusing. But I can honestly state that, from the many images that Mo posted here -- many of which were close focus -- I just couldn't see a significant difference. I'm not saying differences don't exist, they must because of the two different optical constructions. But are they significant? I'm not so sure on that one.


I have the 55B and actually did quite a few closeups and still quite happy with it! Also ddi some comparisons upfront and saw no significa,t differences, too...

https://www.flickr.com/photos/kds315/albums/72157706177592215


PostPosted: Mon Aug 19, 2019 2:43 pm    Post subject: Reply with quote

Wasting my time here...

Last edited by Blazer0ne on Tue Aug 20, 2019 1:38 pm; edited 1 time in total


PostPosted: Mon Aug 19, 2019 5:29 pm    Post subject: Reply with quote

kds315* wrote:
cooltouch wrote:
Remember our member Mo? She was very active for a few years, but it's been a few years now since the last time she posted anything. Anyway, she had a 55B and she posted a lot of images she took with it. After examining many of her images, I came to the conclusion that any difference there was between the two optics was very minor. Adaptall-2.com's comments on the 55BB theorize that, because of the different optical constructions, the 55B may have an advantage at telephoto distances,whereas the 55BB may have the advantage with close focusing. But I can honestly state that, from the many images that Mo posted here -- many of which were close focus -- I just couldn't see a significant difference. I'm not saying differences don't exist, they must because of the two different optical constructions. But are they significant? I'm not so sure on that one.


I have the 55B and actually did quite a few closeups and still quite happy with it! Also ddi some comparisons upfront and saw no significa,t differences, too...

https://www.flickr.com/photos/kds315/albums/72157706177592215


That's the 350mm. Here's the 55B https://www.flickr.com/photos/kds315/albums/72157705807167585

Camera used is unknown, aps-c or ff. What were the insignificant differences? Smile

Is there a link to the comparisons with 55BB, please? Thanks.


PostPosted: Tue Aug 20, 2019 12:07 am    Post subject: Reply with quote

I did an internet search, to see if I could find a 'versus' between the 55B and 55BB that anyone has done, and published the results. Couldn't find any. But I did find loads of example photos taken with each lens, especially on flickr.com. So my advice would be to just check out the photos shot by each lens and decide for yourself. I think you'll conclude that there just really isn't that much difference between the two optics.


PostPosted: Tue Aug 20, 2019 9:07 pm    Post subject: Reply with quote

Right.

Found these:

http://allphotolenses.com/lenses/item/c_1092.html



http://lens-club.ru/lenses/item/c_1093.html



55B & 55BB respectively.

Please notice the "extra" flat element is a filter which doesn't need to be in optical path; both 55b & 55bb share the same number of elements.

Adaptall-2.com's often copied "The major optical design change is the switch to a constant thickness meniscus main mirror in order to reduce close focusing spherical aberration. The change in the main mirror design also necessitated changes for the two smallest lenses located within the middle of the optical design." leads to comparing close-focus CA to see mirror change effects, and long-distance iq to compare formula recalculation.


Last edited by visualopsins on Tue Aug 20, 2019 9:37 pm; edited 1 time in total


PostPosted: Tue Aug 20, 2019 9:30 pm    Post subject: Reply with quote

Here at mflenses on http://forum.mflenses.com/tamron-sp-55bb-500mm-mirror-lens-in-macro-mode-t61751.html is this comparison chart results of distance tests from several 500mm mirrors

http://translate.googleusercontent.com/translate_c?act=url&depth=1&hl=zh-TW&ie=UTF8&nv=1&prev=_t&rurl=translate.google.com&sl=zh-CN&sp=nmt4&tl=en&u=http://blog.dcview.com/article.php%3Fa%3DBjtTNw1qBjdWNQ%253D%253D&xid=17259,15700022,15700186,15700190,15700256,15700259,15700262,15700265&usg=ALkJrhjlckYVWQHED7UDS2TS40fygvP20g

Unfortunately no 55b. Sad



PostPosted: Fri Aug 23, 2019 5:27 pm    Post subject: Paragon 500/8 at the airshow Reply with quote

My paragon 500/8 mirror lens got to play at the airshow today
(Perhaps somewhat cheating as it's mounted via a Techart pro, but it's still a manual lens)

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The only processing done has been the usual contrast boost, cloning out the dust rings & resize.
This leaves the vignetting clear for you to access though it would have been less obvious without the contrast...


PostPosted: Fri Aug 23, 2019 7:13 pm    Post subject: Reply with quote

Awesome capture DConvert!

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PostPosted: Fri Aug 23, 2019 7:59 pm    Post subject: Reply with quote

visualopsins wrote:
Awesome capture DConvert!

Like 1 Like 1


Thanks, I've shot a whole load of junk as well today! Thank You Dog


PostPosted: Fri Aug 23, 2019 10:15 pm    Post subject: Reply with quote

Hey DConvert, what camera did you use for that shot?


PostPosted: Fri Aug 23, 2019 11:23 pm    Post subject: Reply with quote

cooltouch wrote:
Hey DConvert, what camera did you use for that shot?


It was my Sony A7ii (full spectrum converted but with a clip in UV/IR cut filter, which might slightly adjust the white balance from stock)