Rubinar, MTO, and Tamron 500mm f8 lenses..

[ftngrave]

Hello, i'm an amateur just getting back into photography. I'm interested in the Rubinar, MTO 3M-5CA, and Tamron SP lenses, all 500mm f8.

My first question is what kind of focal length I can expect, if this can be practically illustrated. For instance, with these lenses, would it be possible to focus in close up on a person's face from across a street? Or rather, what distance away can the photographer be to obtain a close up of a person's face?

I'm leaning towards the Rubinar or MTO. I can't find any practical comparisons on the internet. I did find a comparison between the MTO 3M-5CA and the Rubinar f5.6 500mm, where the photographer felt they performed equally well (although the Rubinar had one f stop lower, he kept the MTO and sold the Rubinar as the Rubinar is heavier and bulkier). But there's apparently a 1.2kg weight and 1.6kg weight version of the Rubinar f8 500mm lens. Anyone know the difference or history of these two different weight lenses?

Here is information I found via Google Translate on Russia's wikipedia pages for Rubinar and MTO, although the translator's not perfect I imagine (I'll paste both links at the bottom of this post as the url addresses are quite long). LZOS in Russia make the Rubinar lenses, while the MTO lenses are made by LZOS and KMZ. Apparently the MTO lenses have been made since 2008, while the Rubinar lenses--"In 2009 continued to produce lenses." It seems like these lenses have been reissued since 2008 and 2009? Can someone maybe verify this? Both Russian lenses are available for purchase at LZOS.ru. I would think these catadioptric lenses were made long before that, and the Maksutov design was created as early as 1941. I'm thinking the 1.2kg and 1.6kg Rubinar lenses' difference is that one weight is the reissue, and the other weight is the original. I also wonder if LZOS have always made these lenses, and there was just a period when they didn't produce them, and as I've alluded perhaps they modified the reissues from the originals.

Also, the MTO lens is based on a Maksutov design, while the Rubinar lens is a modified scheme of a Maksutov-Cassegrain design with intra-focal field corrector. People on forums seem to say that the Rubinar lenses are an improved version of MTO lenses, but I cannot find anything to verify this. It seems that the Rubinar design might just be different. But if anyone understands the design schemes and their differences, or what a intra-focal field corrector is, perhaps we can shed some light on the Rubinar-MTO differences--basically whether the Rubinar is an improved design over the MTO, or just different.

So basically this post is an attempt to get to the heart of the matter on these Russian lenses. Also, for anyone to offer there opinions if they've personally used and compared the Rubinar, MTO, or Tamron lenses (all 500mm f8 of course). If anyone feels that the Tamron performed better than the Rubinar or MTO, please share.

I also understand that all three of these lenses are quite good, and I'm sure I'd be happy with any of them. But also thought this post could be of interest. Thanks!

Rubinar Russian wiki page: http://ru.wikipedia.org/wiki/%D0%A0%D1%83%D0%B1%D0%B8%D0%BD%D0%B0%D1%80

MTO Russian wiki page:
http://ru.wikipedia.org/wiki/%D0%9C%D0%A2%D0%9E_(%D0%BE%D0%B1%D1%8A%D0%B5%D0%BA%D1%82%D0%B8%D0%B2)

[have your browser or google translate the pages, as translated the urls are too long to post here]

[ftngrave]

Apparently there's also a Rubinar wikipedia page in english. It states that, "MTO (Russentonne) is a different related lens design, with a single Maksutov achromatic corrector. The Rubinar uses 2 milder such full aperture plates, being slightly shorter, lighter and ultimately better corrected, thanks to more decentering tolerance." The citation for this statement is at http://www.slrphoto.narod.ru/rubinars.htm. It explains the Rubinar lens design. Maybe someone can make sense out of it? So does this mean the Rubinar is indeed a better design over the MTO lenses?

[SXR_Mark]

It is my understanding that the Rubinars are improved optically over the MTO designs, but I have no personal experience of MTO mirror lenses to say. If you haven't already done so, you should read the section on mirror lenses on the commiecameras website

http://www.commiecameras.com/sov/35mmsinglelensreflexcameras/lenses/index.htm

I do have the Rubinar 500mm f8 and f5.6. The f5.6 is the sharpest mirror lens I have - better than my Tamron 55B and Zuiko 500mm f8. I made a post on this forum.

http://forum.mflenses.com/rubinar-500mm-f5-6-mirror-lens-tested-with-oly-om-d-e-m5-t54803,highlight,%2Brubinar.html

The 500mm f8 Rubinar has always disappointed me. When focusing with live view on my Olympus E3, it seems to resolve good detail in the test chart (better than Tamron and Zuiko). But the pictures have never had the same level of detail and are worse than Tamron and Zuiko. I could never find out why. But the potential is for the f8 also to be very sharp. One day I will try the F8 again with the E-M5.

With regard to close focusing, both the Rubinars and the Tamron will focus to a couple of meters. But my Tamron 55B is much better than my Rubinar f5.6 when it comes to close-focus performance. I haven't tested the close focus of the F8 Rubinar.

If I understand you correctly, you want to know how close a person would need to be for their face to fill the picture. This depends on the type of camera you are using (full frame, APS-C, 4/3) and the "crop factor". I use Olympus 4/3 gear with a 2x crop-factor, but even with that I would need much more than 500mm FL to get a person's face to fill the image from across a street. But I could certainly get a detailed picture of their face.

I am not sure how helpful it is to understand the optical details of the competing mirror lens designs. It is my opinion that mirror lenses are rather more sensitive to quality of the optics (especially the primary mirror) and alignment than refractor lenses. Therefore, it is possible to get a bad sample with very poor performance of a highly regarded type. I have had enough mirror lenses to know just how bad they can be. The best scheme in the world for correcting the aberrations of the primary mirror are worthless if the mirror is not accurately made.

AFAIK, all photographic catadioptric lenses are Cassegrains as this refers to the way the light exist through the centre of the main mirror. I suspect all the main types will use a spherical primary mirror as well. Therefore, the detail differences are in how the residual aberrations of the spherical primary are corrected. The Zuiko 500mm f8 uses just 5 elements in total (the Tamron 55B uses 7), but performs very well indeed.

In my opinion, a Tamron 55B or 55BB is a good lens to start with. They are plentiful and handle very well because they have a low-geared and smooth focus that makes fine adjustment easy. If you find the performance not to your liking, they are easy to sell. My experience is the Tamron is better than the Tokina 500mm f8 and much better than the Sigma 600mm f8.

Mark

[ftngrave]

The commiecameras web site was very informative, thank you.

The history of the MTO lenses spans from the MTO 500 f8.0 to the MTO 500 f8.5 to the 3M-5A f8.0 to the 3M-5CA f8.5. Only the first, the MTO 500 f8.0, was originally manufactured by KMZ (don't know release year) while production of this lens moved over to LZOS somewhere around 1970 (they also made 3 minor changes to the lens). From the MTO f8.5 onward, these lenses were produced by LZOS. So LZOS has always produced the MTO 3M-5CA and still does.

I've never been able to figure out the release year of the Rubinar lenses, but I think they've always been produced by LZOS.

I really wonder why you've had discrepancies with the 500mm f8 Rubinar. I don't understand how it could be better than your Tamron and Zuiko with test charts but be worse in actual use. Please let me know if and when you try this lens with your E-M5.

When you say, "Therefore, it is possible to get a bad sample with very poor performance of a highly regarded type." You're referring to the optical design type, right? I'm just making sure you're not saying a tamron 55b compared to another tamron 55b could be vastly different in performance, because of primary mirror differences when they were made. I'm sure that happens on rare occasion, but anyway I wanted to clarify your statement.

I think you're right, I should probably go with a Tamron. As they seem to be plentiful, I could probably get a good price on one if I'm patient. If money were no issue I'd love to just get the Rubinar f5.6 (I had read your post on it before).

This link: http://www.adaptall-2.org/lenses/55BB.html points out the differences in the 55b and 55bb. If their assumption is correct, that " It may turn out that the earlier version is slightly superior for long distance photography while the later version likely is somewhat superior for tele-macro work," than I should go with the earlier version as I care more about sharpness over long distance rather than short.

This link: http://birdshots.eu/index.php?cat=8&pageid=45&lang=1 is where Raymond Dam reviews and compares the Rubinar 5.6 and MTO 3M-5CA, and he ends up keeping the MTO due to less bulk and felt the lens performed as well as the Rubinar. It's pretty interesting considering the Rubinars are supposed to be an improvement over the MTOs and he's using the Rubinar with the 5.6 f/stop.

Perhaps it gets pretty subjective as all these lenses must be good.

Thanks a lot for your reply Mark! PM me if you ever find out more about your Rubinar 500mm f8.

[kds315*]

If you really want a good mirror lens, get a Zeiss Mirotar, there is no better...

[fuzzywuzzy]

[ftngrave]

Thanks fuzzywuzzy! Just what I was wondering.