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List of lens diagrams: triplets, planars & hybrid lenses
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PostPosted: Sat Mar 06, 2010 10:07 am    Post subject: Reply with quote

BTW, I found this link http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=001EOj reviewing many books on lens design. I read a few, and think this collection (and ratings) are adequate.


PostPosted: Sat Mar 06, 2010 10:17 am    Post subject: Reply with quote

Guliver: That is interesting. Prakticar 28/2.8 was always described as B-mount version of the Pentacon 29/2.8. But it can be wrong. E.g. prakticar 50/2.4 is often described as 5/4 lens, but mine seems to be 4/4 Confused

Could you identify, which lens element is "missing", or is the optical scheme completely different?


PostPosted: Mon Mar 08, 2010 10:55 pm    Post subject: Reply with quote

Ok, here is a very rough diagram of what I've got. Again, I have to mention, that my lens is M42x1 screw mount. Lens name (as written on body): Prakticar 2.8/28 PM Pentacon MC


Updated on 9.03.2010

Again, it is very rough sketch. First two lenses on the left side (right before the aperture) are the most uncertain.


Last edited by Guliver on Tue Mar 09, 2010 12:43 pm; edited 1 time in total


PostPosted: Tue Mar 09, 2010 8:55 am    Post subject: Reply with quote

That's quite atypical lens. I have never seen it. The lens diagram is also a bit uncommon - retrofocal lenses often have negative front elements. It could mean, that the lens is quite late optical design based on modern types of glass.

Does it state something like "made in ..."?


PostPosted: Tue Mar 09, 2010 12:33 pm    Post subject: Reply with quote

Oh, sorry! I drew it wrong - the front lens looks a little bit different. I've just replaced the existing diagram with more-or-less right one.
No, it does not state anything about manufacturer. It has serial number though...don't know if it is possible to check manufacturer through that information.


PostPosted: Thu Apr 08, 2010 9:58 am    Post subject: Reply with quote

Yesterday I cleaned my Elmarit 135. I didn't found optical diagram, so here is rough sketch. It's a Ernostar/Sonnar hybrid?


PostPosted: Wed May 12, 2010 10:58 pm    Post subject: Reply with quote

Yes it is. And quite similar to the Zeiss 135/2.8


PostPosted: Mon Jun 21, 2010 8:55 am    Post subject: Ricoh 500G Reply with quote

yesterday i open a broken ricoh 500g. I ever think that was a 4/4 tessar,
but when i open it the lens was a 4/2 and the lens scheme look like this:



i don't open the front and the rear group so i can't say if the group are cemented or not.

what do you think? still a tessar? or a dialyte?


PostPosted: Tue Aug 10, 2010 4:38 pm    Post subject: Re: Ricoh 500G Reply with quote

Latente wrote:
yesterday i open a broken ricoh 500g. I ever think that was a 4/4 tessar,
but when i open it the lens was a 4/2 and the lens scheme look like this:



i don't open the front and the rear group so i can't say if the group are cemented or not.

what do you think? still a tessar? or a dialyte?

MAJOR SPECIFICATIONS OF RICOH 500ME
Lens: 40 mm Color Rikenon f2.8 lens 3 groups. 4 elements

I guess it was a Tessar.


PostPosted: Thu Aug 12, 2010 11:47 am    Post subject: Re: Ricoh 500G Reply with quote

calvin83 wrote:

MAJOR SPECIFICATIONS OF RICOH 500ME
Lens: 40 mm Color Rikenon f2.8 lens 3 groups. 4 elements

I guess it was a Tessar.


maybe the 500ME the 500g have a 2/4 lens as show on my drawing.


PostPosted: Fri Apr 29, 2011 2:58 am    Post subject: Reply with quote

I just found some Leica lens diagram from this website :

http://www.rglewis.co.uk/LEICA/R/R_Lenses/R_Lens_Range.htm

From the 3 diagram that compiled by no-x on page #1 :

Summilux 80/1.4 = planar?

Summicron 90/2 looks like 5 element Takumar?

Summilux 50/1.4 = ultron?

Summicron 50/2 = planar Biotar?

CMIIW



PostPosted: Fri Apr 29, 2011 5:46 pm    Post subject: Reply with quote

Hi! Im looking for the lens diagram of Vivitar automatic tele converter 2x-8.
Im looking allover internet but with no success.
Maybe other 2x teleconverter use the same diagram.. if someone have other, please, could you post?
thank you!


PostPosted: Fri Apr 29, 2011 6:42 pm    Post subject: Reply with quote

Do you have the model number or name of the Vivitar 2x8 TC? Me, I've never heard of a Vivitar 8-element 2x TC. Seven, yes, but not eight.


PostPosted: Fri Apr 29, 2011 7:24 pm    Post subject: Reply with quote

Its a M42 teleconverter. Just have this entries on the lens.
There is: http://www.flickr.com/photos/8991613@N04/sets/72157626484913729/

I bought it cheap.
The lens has some fungus, and during cleaning i got confuse and lost the order and position of each element.

Thank you.


PostPosted: Mon May 09, 2011 10:14 pm    Post subject: Reply with quote

anyone?


PostPosted: Tue May 10, 2011 9:24 pm    Post subject: Reply with quote

no-X wrote:
That's quite atypical lens. I have never seen it. The lens diagram is also a bit uncommon - retrofocal lenses often have negative front elements. It could mean, that the lens is quite late optical design based on modern types of glass.

Does it state something like "made in ..."?


It is not so atypical, Nikon makes such wide angles lenses. Ai20/2.8S &
Ai24/2.8S for example. They say in the lens brochure, the first positive
element makes "wide angle" lens physically smaller. See>



This is for Ai AF Nikikor 20mm F2.8S, same as Manual Ai Nikkor 20/2.8S.
Ai24/2.8S has similar lens block diagram, so as AF 24/2.8S they are
optically same. And famous Flektogon 20/2.8 has a positive front element!!
And this Flektogon 20mm is much smaller than its brother Flektogon 25/4.

Btw, you have done a great work.


PostPosted: Tue May 10, 2011 11:03 pm    Post subject: Reply with quote

I was also very curious, so I disassembled my Prakticar 28/2.8 (plastic version).
(I have three Prakticar 28/2.8s, the other two are metallic construction.)

Optical block diagram looks like in RED.
(black one is Orestgor 29/2.8 )



The first element has very strong negative, aperture is between 3-rd and
4-th element, I am not quite sure about 2-nd and 3-rd element but they
form very strong positive power. Yes, the lens has 7 element and 7 group.

in short:


The second and third elements are much closer than this diagram indicates, I think.


PostPosted: Wed May 11, 2011 12:42 am    Post subject: Reply with quote

Guys, I've made the offer before, but I figure I should again since it's been so long ago. I have the Cooper books for both Nikon and Minolta system and the Canon F-1 book. Each of these books shows lens diagrams for all of the current lenses as of the date of their publication. In the case of the Nikon and Minolta books, these dates are probably sometime in the early 1970s (non AI Nikkors for example, and no MD Rokkors -- just MC), but the Canon books I have go to 1977 I believe, so they include all of the breechlock FD lenses.

So if you are interested in any of the lens formulas that were current during these time frames, let me know. I can scan them and post them here for your perusal.


PostPosted: Wed May 11, 2011 6:04 pm    Post subject: Reply with quote

cooltouch
Is there any 4 element teleconverter on this book?
Thank you.


PostPosted: Wed May 11, 2011 6:36 pm    Post subject: Reply with quote

Good question. I looked for teleconverters in both Joseph Cooper publications (Nikon and Minolta) and in the Canon F-1 Guide. In one of the Nikon books, Cooper discussed teleconverters at some length, and mentioned that Nikon did not make any. This was back in 1974, so pre-AI days. Coopers books on Minolta were copyrighted 1972, 73, and 76, and showed only MC lenses, and his book showed no teleconverters either. The Canon F-1 guide showed a 2x converter along with a few of its fluorite telephotos, and while the book showed the optical formulas for the teles, it did not for the 2x. Oh well. I tried.


PostPosted: Wed May 11, 2011 8:10 pm    Post subject: Reply with quote

cooltouch
thank you for the search!
I think that teleconverters are not much "well seen" from the manufacturers, just in case that it could be sold and make money.


PostPosted: Wed May 11, 2011 9:21 pm    Post subject: Reply with quote

Interestingly enough, I did a google search on the topic, looking at the "images" and found quite a few optical formulas for 7-element TCs, but none for 4-element TCs.


PostPosted: Thu May 12, 2011 2:48 am    Post subject: Reply with quote

cooltouch
I did the same, but with no success.
The modern canon 1.4x TC use 4 element, but I didnt saw any diagram, just some specs.
Id found some 5 elements TC but in this case reference isnt enough.
The vivitar series 1 also have one 4 element TC, but theres no more info about it.


PostPosted: Thu May 12, 2011 4:29 am    Post subject: Reply with quote

kelsonbueno wrote:
cooltouch
I did the same, but with no success.
The modern canon 1.4x TC use 4 element, but I didnt saw any diagram, just some specs.
Id found some 5 elements TC but in this case reference isnt enough.
The vivitar series 1 also have one 4 element TC, but theres no more info about it.

The canon 1.4x II use five elements four groups.
http://www.canon.com.hk/en/product/catalog/productItemDetails.do?categoryID=25&seriesID=10034&prrfnbr=349


PostPosted: Thu May 12, 2011 5:13 am    Post subject: Reply with quote

My mistake!
I found this nice info about tele converters!
http://www.pierretoscani.com/echo_focal_length.html#FocalLength07