Sony NEX 5N with Mamiya Sekor-C 150mm f4 lens

After testing the Mamiya Sekor-C 45mm f2.8 on my Sony NEX, it was time to test the 150mm f4. A great portrait lens for the Mamiya 645 medium format camera (90mm equivalent in 35mm format) which becomes a 225mm telephoto lens on the NEX. Due to the longer focal length, this lens is much harder to use than the 45mm. Narrower depth of field in combination with manual focus is not an easy task, and despite the focus peaking system or the LCD manual zoom, I was taking images at a much slower pace.

Image quality is great when you manage to nail focus and exposure, and since I don’t own a e-mount telephoto for my NEX, this lens is really very useful for the times that I need the long her focal length. At f4 it creates a creamy bokeh which I like very much.

I have also tried to shoot action with this lens, flying birds to be exact. The problem was that due to the narrow DoF and lack of autofocus, I had to use f11 and f16 apertures. Since I was shooting at a fast shutter speed the ISO went up, so the images were not as clear as I would like to. I think the e-mount 55-210 zoom from Sony with the auto focus and stabilizer functions is far more suitable for this kind of photography.


The image above shot at f16 also reminded me that I must clean my sensor !!!

In conclusion, the 150mm f4 is a great addition as telephoto lens for my NEX system, and I will sure use it at the future. Enjoy the rest of the images.


(C)2012 Konstaninos Besios. All Rights Reserved.

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3 Responses to Sony NEX 5N with Mamiya Sekor-C 150mm f4 lens

  1. Gabriela says:

    Hello, nice pictures and interesting reading but could you possibly explain me the counting behind that Mamiya Sekor-C 150mm “… becomes a 225mm telephoto lens on the NEX”? Do I miss something? I agree that 150mm is 90mm in full frame, but if Nex has crop factor 1,5 compared to full frame then 90 x 1,5 = 135mm. It seems you multiplied 1,5 x 150mm instead.

    • kbesios says:

      Hi, by reading again what I wrote, I saw that I didn’t correctly defined the different crop calculations. So, to be precise: on the Mamiya 645 this lens is a 90mm, on a full frame 35mm camera its a 150mm , and on the NEX is a 225mm. A 150mm lens is 150mm, regardless of the format it was designed for. It is the sensor size that changes the equation. Thank you for your observation, it is clear that I also got confused when performing the calculations !

  2. Gabriela says:

    Thanks for explanations. The confusing fact for me was that the 645lens is marked ‘150mm’ but it is 35mm camera 90mm lens equivalent. http://www.kenrockwell.com/pentax/645/35mm-equivalent.htm. Then I went on and mistakently multiplied the 90mm instead of dividing it by 1,5. So the a 60mm lens made for a APSC camera is an equivalent of a 90mm lens/FF camera.
    It was hard to understand for me until I found a chart on http://www.pentaxforums.com/forums/members/77-ole/albums/596-illustrations/picture3139.jpg , forgot all about the mms and used angle of view comparison.Thanks and good light!

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