Thursday, July 16, 2020

Range Finder System

ZM 28/2.8 Biogon T*

The Compact Wide Angle     ZM 2.8/28 Biogon T*




28mm is a focal length that I like very much. I used a lot of 28mm with my Praktica PB system. When I switch to Rolleiflex QBM only Zeiss 25/2.8 Distagon was available. Now my Contax SLR I use the 28/2.8 Distagon, which performs very well to my expectation.


Rollei 35RF, UC100, f4 1/125. 29 Mar 2008 


The ZM 28/2.8 Biogon seems underrated, especially when comparing its MTF against the very popular and probably the highest resolution Zeiss ZM 25/2.8. On paper the ZM 28 Biogon MTF is comparable to the C/Y 28/2.8 Distagon, not very much superior other than the better distortion control. I own the 21/2.8 ZM Biogon, which has a very similar MTF to the 25/2.8 ZM Biogon. Comparing the photos taken by the ZM 21/2.8 and the 28/2.8, I am fully satisfied with the performance of the ZM 28. Perspective distortion is still tricky despite it is not as wide as the 21mm. Corner performance is very good and overall a lens very comfortable to use. It is a compact lens and can be used confidently wide open at f2.8. Bokeh at f2.8 is typical of Zeiss and is nice. I normally use the 28/2.8 ZM Biogon with the entire viewfinder of Rollei 35RF viewfinder. Sometimes I use it with the old Zeiss Ikon 436 exernal finder with very odd frame lines for 30mm, 40mm and 75mm, and with close distance parallax correction. One main consideration of me getting the 28mm over the 25mm is the possibility to frame without external finder. 



After many months of using the lens, I do get very satisfying photos from this lens. Despite a seemingly unimpressive MTFs, I would say for my practical purposes up to 8x12 prints, this lens is good enough, and in fact it is very good.


Jurong Point   17 Dec 2012

Rollei 35RF, Portra 400




Jurong Point Singapore - 35RF - Portra 400 - 17 Dec 2011




35RF - f2.8 1/60 - UC100 - 4 Jun 2009



China Town Singapore



Causeway Point Shopping Centre Singapore - 35RF - f2.8 1/15 hand held - VC160 - 14 Aug 2010



35RF - f5.6 1/500 - VC160 - 13 Feb 2010



Johor Bahru Pork Rib Soup - 35RF - Portra 400 - 11 Dec 2012



Pulau Ubin - 35RF - f8 1/2000 - Portra 400 - 27 Oct 2012



Red Dot Museum Singapore



ZM 21/2.8 Biogon T*

The ZM Super Wide Angle Artist      2.8/21 Biogon T*




This was the first ZM lens that I was eyeing when Zeiss was releasing its first badge of ranger finder lenses for Leica mount. While my first range finder lens was the HFT 40mm Sonnar that came with the Rollei 35RF, I had long been hoping to photograph with range finder super wide angle lens, believing that they should be superior in performance than the SLR counter parts, especially better corrected for distortion.


Resort World Sentosa S.E.A. Aquarium, Rollei 35RF Portra 400 10 Dec 2012



Resort World Sentosa South East Asia Aquarium - 35RF - Portra 400 - 10 Dec 2012



So when the 21 Biogon first arrived at the Singapore agent I quickly went down and bought a silver version of the lens. I am using it with the Voigtlander finder which I bought earlier on anticipating I will be getting this lens.


Melaka, Rollei 35RF Portra 400, 15 Dec 2011

Although the 21/2.8 ZM Biogon is better corrected in distortion than the C/Y or QBM 18/4 Distagons, it is still not easy to compose with human face at the corners of the photo. Nevertheless, it is much more confident to use in terms of distortion compared to the 18/4 SLR Distagon. Light falls off seems better than the 18/4 with aperture wide opens, but does not improve as much like the Distagon design when stops down.



I have tried a few times shooting at f2.8 and I am quite satisfied with its performance wide open. Now Zeiss offers 2 choices of 21mm, one at f2.8 and one at f4.5. I will stick to this f2.8 version but the 21/4.5 C Biogon is very attractive for its compact size and the near perfect distortion. 



35RF - f2.8 1/60 ZM 21/2.8 Biogon T* - VC160 - 16 Aug 2010


35RF - f2.8 1/60 - UC100 - 23 Mar 2008


   Patah Gelang Malaysia - 35RF - f2.8 1/60 - VC160 - 20 June 2010




ZM 50/2 Planar T*

The natural perspective: ZM 50mm f2 Planar T*






I had been thinking about the 50f2 for quite a while. The main reason was with the 40mm Sonnar that I am using and the range finder disengagement at 0.8m, I found for some of the composition taking kids I am not close enough. A good solution will be to use the 50mm as a shot tele, though in the title above it is suppose to be a natural view point like human eye. Also the 40mm depth of field sometimes is too much and the 50mm narrower depth of field will be more ideal. <p">  <p">Then came the announcement of the 50/1.5 Sonnar that is so tempting. Firstly it is the Sonnar design, which is different from the many Planar that I have been using on my Rolleiflex and Contax SLR systems. Then it is the compactness for the high speed. However, the f1.5 Sonnar can only close focus to 0.9m. I know that I wanted something closer, though may not be significant in practical sense. Then I realised there is this focus shift character of the Sonnar, especially at f1.5, but many Sonnar lovers had found the shift insignificant for most practical purposes. Then one day I managed to find a good deal for a used 50f2 at a price quite comfortable to me, so in the end I have this wonderful 50f2 Planar with me. <p">







Cosina did a good job. All the ZM lenses I owned so far I am very please with the workmanship and feel: the 21/2.8 Biogon, the 28/2.8 Biogon, the 35/2 Biogon, and this 50f2 Planar. Comparing with the made in Germany 15/2.8 Distagon, I do not see or feel a significant difference in terms of product quality, but the Germans ZM have better focusing smoothness. The chrome ZM lenses match nicely with my 35RF. 

I am very happy with the 50f2 in its practical performance. So far I used it confidently at f2 and f2.8 at close distance. When I need more ‘space’ in the composition I will go for the 40mm. If I want a tighter feeling I will use the 50f2. For situation requires f1.4, I would still prefer using my Contax Aria or RTS III SLRs.





I have using this lens and taking photos at close to wide open aperture. I am very happy with the results, both with the picture quality and the focusing accuracy at close distance. At 8R enlargements I can hardly see any flaws at the corners.


Sembawang MRT station Singapore, f2.8 1/125 50/2 ZM Planar T*, 1 April 2007

Rollei 35RF, UC100 



I like the above photo very much. There is a high key effect due to the strong back lighting. It was not my original intention to create this effect though. The new series of ZM lenses are all very flare resistance. You hardly get any softening effect or flare when shooting directly into strong light.




f2.8 1/125 15 March 2007



f2.8 1/60 10 Mar 2007 

Rollei 35RF, 50f2 ZM Planar T*, Kodak UC100 


f4 1/125 50f2 ZM Planar T*

Rollei 35RF UC100 10 Feb 2008










35RF - f2.8/4 1/125 - UC100 - 16 Feb 2008






The Legend Reborn - 40/2.8 HFT Sonnar

Reborn of a Legend: Zeiss HFT 40mm Sonnar 

The 40mm Sonnar on a Rollei 35RF. On the right is the very popular Rollei 35 S.


I bought a Rolei 35RF range finder camera that came with a 40mm f2.8 Sonnar lens in Rollei’s very beautiful HFT multi-coating. This lens is kind of sentimental to me, as I had used the once very popular all mechanical Rollei 35S. The 40mm Sonnar now in M-mount is very likely the same as the 40mm Sonnar used on the numerous Rollei 35S, maybe with some design improvements. From various information the optical layout is identical.  








 Lens optical layout from a Rollei Classic brochure. 


Lens optical  layout and performance curves from a Rollei 35RF brochure. 



Very small and compact, but by no mean light weight for its size. Filter size is 39mm. For me I use the lens with a 39mm UV filter, then fitted on the original silver hood, and then fitted on a 39-46mm Heliopan step up ring made of solid thick metal as a hood extension. Overall the package is still quite compact in size. The lens construction and design is very different from the rest of my ZM lenses. Aperture settings are in half stops. There is a focusing tab. The lens is originally in Leica M39 thread mount, supplied with a M-bayonet adaptor when purchased. Mounting of the lens on the body is not as easy as the ZM lenses which has a blue protruding dot for easy locating of the lens mounting position. The lens is made in Germany. The focusing ring and aperture ring have more damping than the made by Cosina ZM lenses. 





Character of the lens seems different from the old Sonnar on the Rollei 35S. But I might be wrong as I have not been using both the new and old design side by side, and I do not have the intention to do so. One thing I dislike about the 35S is that it is difficult to take sharp pictures at close distance at big aperture. I am not good at judging distance less than 2m. 



To school, Rollei 35RF, 40/2.8 HFT Sonnar, Kodak VC160



The 40mm Sonnar does exhibit some loss of sharpness at large aperture at the corners and there is apparent pespective distortion at the edge of the photo especially with human faces. I guess this is the compromise for designing the lens to be compact. Sonnar concept allows a compact design but suffers addition distortion. 




Fushan Park Singapore, Rollei 35RF, 40/2.8 HFT Sonnar, f4 1/250, Kodak VC160.


Alpha 7R - f5.6 1/250-1/500 - ISO 100 - 7 Dec 2013


 Size comparison:   ZM 35/2, ZM 28/2.8, HFT 40/2.8.



Overall, a cute little lens, and I like it very much.





The Wide Angle Super Star

The Wide Angle Superstar: Zeiss ZM 15 f2.8 Distagon T*  2.8/15



As Zeiss called it, the 15/2.8 Distagon T* is the wide angle superstar of the ZM series of lenses. The price is crazy, and I am crazy enough to get one after a very very long wait for the lens. As usual there were quite some delays in the launching of this superwide, and there were further delays for it to reach Singapore, where I stayed. Getting impatient, I managed to find one in the eBay and taking risks getting from a German seller that I was not familiar with. The deal was a complete package with the 15/2.8 lens, lens pouch, 72mm centre filter and the very expensive 15mm finder. In the end I got a fair deal considering the purchase price, UPS shipping and the tax.






  Zeiss ZM 2.8/15 T*

First glance of the 15mm Distagon actually did not impress me very much. As least the lens does not look that expensive. The old Rolleiflex or Contax SLR 15/3.5 Distagon looks much more impressive with the very protruding front element. For the case of the ZM Distagon, the front element recesses well into the build-in hood and therefore allows a 72mm filter to be used with the lens. It is actually remarkable that the lens can take a filter and therefore a centre filter can be attached for critical light falls off situation or a protective UV filter can be used.

According to Zeiss special glass materials were used and floating element design was implemented. Physically turning the focusing ring I cannot see any movement of the front nor the back element, and therefore was wondering whether the floating elements were resite within the lens. Handling is comfortable as I have been using heavy SLR lenses for many years. The original 15mm finder has bright frame lines but not much space is there outside the frame lines. Finder is very bright, barrel distortion at the edges as usual. Exposure reduction for the centre filter is 1.5 thus you do not loose too much light when it is used.

The focusing and aperture rings have more damping then the made by Cosina ZM lenses. 

By looking at the MTF curves I was surprised that the top curve seemed to be slightly better in the centre at f2.8 than that at f5.6, a characteristic that I have not seen before in other designs.


Distortion was a bit disappointing. I was expecting the distortion to be improved over the Contax 15/3.5 Distagon but by looking at the distortion curve worst distortion was about 3.75%, only slightly better than the 4% in the 15/3.5. I guessed probably Zeiss wanted to cater for the space in front of the negative for proper TTL metering.







Light falls off was quite prominent, and apparently Zeiss purposely designed the light falls off in such a way that it would not improve drastically with stopping down. As a result you get consistent light falls off characteristics for different aperture setting and thus the supplied centre filter can be used with consistent results. The 15/3.5 lens light falls off improve with stopping down.






Ideally this lens is best used for architecture or scenery photography. Below is an example of me taking interior under hand held condition with the lens aperture wide open:

Voigtlander R4M, Kodak UC400, 15/2.8 D ZM T*, f2.8 1/30, without centre filter, 11 April 2009


I had also taken some photos with the lens outdoor under very good sunlight. When I first saw the distortion curve of the lens I was sort of disappointing at the distortion of 3.75%, which was only slightly better than the old 15/3.5 Distagon of about 4%. So far in practice the distortion did not give me any visible problem yet.


  Rollei 35RF, Kodak VC160, 15/2.8 D ZM T*, without centre filter, 14 April 2006

I do hope I have sometime to play with this lens. Anyway I have learnt that super wide angle photography is not straight forward. It is not easy to get a good composition, especially if there are objects in the foreground. Also I have yet to get use to range finder photography where I need to visualise what the lens see through the external finder which I think is not an easy task. Also perspective distortion especially with human face near the edge of the composition is not possible to visualise as in the SLR.   



  Voigtlander R4M, Portra 400, 15/2.8 ZM T*, without centre filter, 7 July 2013, Buddha Tooth Relic Temple and Museum,  f4 1/2, Manfrotto 190B/410gear, 7 June 2013.


Sultan Mosque Singapore - 35RF - f4 1/125 - with centre filter - UC100 - 11 Oct 2007 


35RF - f2.8 1/60 - no centre filter - UC100 - 9 Aug 2009 


Changi Airport Terminal 1 - 35RF - f4 1/8 - no centre filter - VC160 - Manfrotto table tripod - 20 Mar 2010


35RF - f5.6 1/15 - focus at 2m - no centre filter - table tripod - VC160 - 16 Jan 2010


Seletar East Camp, old Junior Flying Club - f4 1/60 - with centre filter - focus at infinity - UC100 - 6 Sept 2008








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