Monday, February 27, 2012

Birns & Sawyer (Tewe) Omnitar 200mm f3.2 -- First Look

Sometimes luck just happens and makes you happy.  Yesterday I was thinking about how to convert the Omnitar 200mm f3.2 that I bought the day before, so that I could use it either on Canon or NEX.  The M42 to Canon FD adapter on my desk was staring at me.  Instant brain fart!  I tried it on the Omnitar and what do you know?  The rear of the lens fits the M42 opening on the adpter perfectly.  In fact, it fits so snugly that I don't even need to glue it down to try it out.  I did have to saw off the tail tube, which would scratch the sensor of the NEX-5N if I didn't.  But, even with the tail section off, the rear still hits the mirror on the 1D III, but at least I can use it for the time being on the NEX-5N.

Sharp!  NEX-5N & Birns & Sawyer (Tewe) Omnitar 200mm f3.2 @ f3.2.

The lens now has an M42-FD adapter, and then a FD to NEX adapter.  Since it's not set in place with anything, the lens would rotate slightly if the focusing ring is turned too hard, making it awkward to use.  But that didn't stop me of course!  I walked around my work area at lunch time with camera/Omnitar 200mm 3.2 in hand and had some good walking exercise while taking pictures.

I was hoping the lens would be sharp to the edges, but it was just wishful thinking.  This, and the Omnitar 150mm f3, were made for 16mm movie cameras, and the NEX sensor is quite a bit larger than 16mm film.  This lens has very high resolution at the center and is very sharp wide open, but as I said, the edge is blurry.  Not as bad as the 150mm f3, but not sharp, at least wide open.  Another thing I was hoping for is that it would not vignette, but it does, though I think it's due to the small opening of the lens at the rear.  The vignette is worse at infinity than close focus.  As expected,  there is a lot of purple fringing at wider apertures, a problem with most old lenses.  But how does it render pictures?

Golden butterfly -- NEX-5N & Birns & Sawyer (Tewe) Omnitar 200mm f3.2 @ f3.2

Quite good actually, if you are not using it to shoot landscapes and hoping or razor sharp edges like the Distagon 21mm f2.8.  It does not have the modern lens look of the clinically sharp image, but its personally makes itself seen. Generally, images are pleasing to look at, but I also find it, and its bokeh to be slightly too harsh for a movie lens.  I am not sure I like the bokeh very much, but on the other hand, it's not objectionable.

Bokeh -- NEX-5N & Birns & Sawyer (Tewe) Omnitar 200mm f3.2 @ f3.2

Can't help but to bitch about the lack of built-in viewfinder of the 5N (I know an external one is available, but it's way too expensive).  Today was sunny and it was nearly impossible to see the LCD screen clearly.  The peaking level feature helps tremendously, but for critical focus, I still need to check image via magnified view, especially for longer lenses where depth of field is very shallow.  This makes me think about the Olympus E-M5 with its 5-axis sensor shift IS, coupled with an internal EVF, would probably makes long lenses much easier to use and end up with more keepers.

Wind Chime
Wind Chime -- NEX-5N & Birns & Sawyer (Tewe) Omnitar 200mm f3.2 @ f3.2


  1. Congrats! Lucky hand and clear head to find the adapter combination that just fit. But how could you know that lens was put in the right distance to the sensor (get infinity etc.)? Is that trial an error?

    1. It's trial & error, but pretty easy to setup with live-view. Basically I move the adapter back and forth until I get infinity focus, and then use spacers to fill the space between the adapter and the lens. Not 100% accurate, but I never go by the marking on the lens, so it doesn't really matter.

  2. Thanks for your reply. Ah yes ... thats seems to be pretty simple. This encourages me to no longer leave aside massive and respectable looking glass (with unknown bayonets) offered during my Munich flee market walks. Saw I got as well! By the way ... bokeh and sharpness are impressive. 200mm F3 shots that has a really special flair.

  3. Lovely framing of the menue with the bright background!

    On the EVF for 5N: Just get it and buy less Altglass :-)
    It is a help for MF and adds stability for long lenses.
    Heck, it makes the 5N almost feel like a good old SLR, and in
    some ways better (brightness compensation in finder, WYSIWIG)

    1. You are tempting me! Seriously, the EVF is the only thing that I want for the 5N.

  4. Hi,

    I bought a 200 Omnitar a few years back & never used it. Tonight I checked it on my NEX 5 & it had serious vignette which should not be w a long lens like that. It was a :"C" mount so I figure it was because of the little "C" hole causing the problem so I checked it out & saw there were 3 set screws holding the "C" mount onto the lens so I thought I'd remove it & voila! When I took it off, under it as an Arri S mount. So I got out my Arri S - m-43 adapter & put it on one of my Pana's & sure enough it covered the whole frame. I then checked how large it projected an in focus image circle & saw that it would cover at least a 6x6 cm frame! Any idea who made those lenses for Birns & Sawyer?

    Also I love your PIX! How much do you color correct & sharpen the images?

    1. The Birns & Sawyer 200mm f3.2 and 150mm f3 lenses were made by TEWE, as is in the title. The 200mm f3.2 lens actually says TEWE on it while the 150mm f3 does not. TEWE was a German company that specialized in telephoto cine lenses.

      I develop my pictures from RAW and usually there is no sharpening, as resizing already sharpens the pictures.