SOM Berthiot Cinor 20mm/1.5 on the G1

[petermcwerner]

SOM Berthiot Cinor 20mm/1.5 on the G1 compared to Vario Elmar R ASPH 21-35

View attachment 13692

Image circle of the SOM Berthiot Cinor 20mm/1.5 (white ceiling)


View attachment 13693

Uncropped image of SOM Berthiot


View attachment 13694

Cropped to eliminate all vignetting, corresponds to a 28mm lens


View attachment 13695

Leica Vario-Elmar-R ASPH 21-35mm/3.5-4 @ 28mm

Technical:
Covers full sensor : No
Vignetting : Yes
Smearing : No
Mechanical : No modification needed
Adapter : Rabenwolf c-mount->m4/3
Handling: Distance and aperture rings easy to reach and set

​

 

[milapse]

That's funny I was testing that lens yesterday too! Mine needs a little internal cleaning but it shows the same potential... A little curve or level adjustment and the detail flushes out of the images. I was also pleasantly surprised at the relatively large image circle of this lens.

 

[petermcwerner]

That's funny I was testing that lens yesterday too! Mine needs a little internal cleaning but it shows the same potential... A little curve or level adjustment and the detail flushes out of the images. I was also pleasantly surprised at the relatively large image circle of this lens.

Wouldn't it be better to have a 28mm lens that covers the full image circle? There are some good older non-M-mount 28mm/2.0 lenses available that do not smear nor vignette (Canon, Nikon) and do not cost a bomb.

View attachment 13701

Leitz Wetzlar Elmarit-R 28mm/2.8
​

 

[milapse]

Wouldn't it be better to have a 28mm lens that covers the full image circle? There are some good older non-M-mount 28mm/2.0 lenses available that do not smear nor vignette (Canon, Nikon) and do not cost a bomb.

A 28 on the G1 is closer to a 55 (35mm equiv.)?? To get the same FOV your back to 20 and under... Show me any lens between 10 - 20mm faster than F2 with >22mm IC for under $300.

 

[milapse]

Leica Vario-Elmar-R ASPH 21-35mm/3.5-4 @ 28mm

On a M8? correct? @28 this lens would be more like a 55 if you mated this lens to your G1... and I suspect when you say:

corresponds to a 28mm lens

You mean on the M8... Because if we are talking 35mm plate (the gold standard) the Berthiot 20 and your 28 on the M8 are closer to 38ish.

 

[petermcwerner]

A 28 on the G1 is closer to a 55 (35mm equiv.)?? To get the same FOV your back to 20 and under... Show me any lens between 10 - 20mm faster than F2 for .

If you crop away the vignetted part, the 20mm SOM has the same field of view as a 28mm lens (on the same G1). The example pictures with the Vario Elmar and the Elmarit on the G1 are there to prove the point. I also tried a 28mm/1.9 Ultron on the G1 but did not upload the picture because of severe smearing. All these lenses are full format 35mm lenses that can be used on the G1 with adapters.

Right now the wide angles I heard of of are the zoom Olympus 7-14 and 9-18 wide but they are not very fast. There are also some very expensive professional 35mm cine lenses like the 9.8mm/1.8 Kinoptik Tegea, the 18mm/1.8 Kinoptik and certainly some Zeiss, Schneider and other professional cine lenses that I do not know of and that are out of price.

The only lens I know under 20mm and below $300 that provides full coverage on the G1 is the 16mm/2.8 Zenitar. But then I do not know any c-mount lens under 20mm that after cropping the vignetted or uncovered area will provide the field of view of a 16mm or shorter lens. If you have access to one, please upload some examples (uncropped and cropped as I did) to show the REAL FOV (not the theoretical FOV that cannot be reached on the G1 due to insufficient coverage, smearing and/or vignetting) and post a comparative picture with the set lens covering the same FOV and the focal length it corresponds to.

 

[milapse]

If you crop away the vignetted part, the 20mm SOM has the same field of view as a 28mm lens (on the same G1).

Oh I get it now... point taken.

 

[ilovesonatas]

Hi Peter,
I'm from Hong Kong and is new in using the cine lens after I bought the G1 in September 2009. I am interest in your testing on the 20mm cinor, for a good fast wide angle for the G1, how about the 15mm f1.3? I know this not fully cover the sensor, but after crop, from some Japan users, it is okay. Have you had any experience on this? Or, except the 20mm cinor, are there any fast wide angle (cheap under $300) can be recommended. Thanks. Frankie

 

[petermcwerner]

Hi Frankie,

how about the 15mm f1.3? I know this not fully cover the sensor, but after crop, from some Japan users, it is okay. Have you had any experience on this?

No, I fear that shorter than 20mm the crop will be excessive. But I have had some good experience with the Russian 16mm/2.8 Zenitar. In is basically a fish-eye that covers the whole 24x36mm sensor. The central part that reaches the m4/3 sensor is nearly rectilinear and with software correction even the remaining distortion can be eliminated. For that I use Raw Therapee (free). You can see some examples on my website.

Or, except the 20mm cinor, are there any fast wide angle (cheap under $300) can be recommended.

Sorry, I do not know of any, prices for good and fast C-mount lenses have recently soared.

Cheers
Peter