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Here's the very first test of my "homebrew" 1.7 mm Periscope lens, with the optical elements installed in a 3-part aluminum tube with threaded joins:

https://youtu.be/8tTAG7qLysQ

For a description of the optics, go to:  https://www.magiclantern.fm/forum/index.php?topic=9741.msg242199#msg242199

Still some adjustments to be made to the tubes, improving focusing (now push-pull, will be threaded), reducing the vignetting, etc...

This was shot with an EOS M, at f8, 400 ISO, h264 with ML's 3x zoom.

Over 20 years ago I bought a Canon 13x zoom, 7.5 - 97.5 mm, f 1.4 at an auction held by a production house here in Helsinki, Finland. They let go all of their ENG cameras.

I paid only 20 euros ($22) for the lens, but found that even when adapted to the EOS M and using the 3x feature in ML to remove the vignetting, there was horrible aberrations; at f 1.4 it was totally unusable. To get any sharpness at all, I had to stop down to about f 11. How come it was usable by the previous owner?

Took me some years to stumble on the reason for it, when I finally found a technical paper explaining why it was so atrociously bad at full aperture:

"Offsets in back focal distances for television cameras with CCD sensors"

You can read the full paper here: https://tech.ebu.ch/docs/tech/tech3294.pdf

Well, this sleuthing told me that the lens was designed with these aberrations! In a 3-CCD camera, there is a block of color-separating prisms, splitting the light into red, green and blue components, each for a single black-and-white sensor.

Those prisms counteract the lens distortions, and provide a sharp image on the sensors.

So, I made a block of glass to fit inside the lens mount! That block consists of two binocular angle prisms glued together with optical UV-glue. By sliding the prisms' long sides along each other, I could adjust the thickness of the block between 30-36 mm, and the ends were absolutely parallel. Ideally, the block should have been 40 mm thick, but that much glass wouldn't have fit behind the lens, and in front of the camera shutter. I had to settle with 35 mm. Not perfect, but usable...

There still is some chromatic aberration that won't disappear when stopping down, and some spherical aberration (fuzzy halo around highlights) visible at apertures larger than f 4.

Here's an example, showing the wide zoom range, shot at f 4:

https://www.youtube.com/watch?v=MED-N2X5YEU

This certainly isn't perfect, edges are soft and "rainbowy", but for shooting concerts on a stage with spotlighted soloists, it's good enough...

Sorry if this already has been requested, but is there a way to keep the 3x movie crop in effect when camera is powered off and then on again, until actively changed by the user?

It always resets when I power off my EOS M1.

Maybe this has been discussed before, sorry for duplicating in that case, but I just did some experimenting with my EOS-M, and noted that the video crop mode uses only 1720 x 968 pixels of the sensor, not the full 1920x1080. (It's the same in other EOS cameras, too. AFAIK...)

Why use a smaller area and scale it up?

Wouldn't it even be less processor-intensive to use the unscaled 1920x1080, or is this impossible to implement for some reason ?

Header says it all, really:

"ML boot hangs on EOS-M with manual lens"

This happened even when I changed to the Canon 22mm lens. So, I waited until the orange light stopped blinking, then took out the battery.

FIX:
When I start with a non-ML card and the original Canon lens on the camera instead of a C-mount, everything appears normal again, except that 3x movie crop is still on, and size and quality icons are grayed out in photo mode - but can be changed in menus. 3x crop will only disappear when changing movie size; photo quality & size icons will then reappear.

Conclusion: Since I need ML only for 3x movie crop, I can set it with ML and 22mm lens, then change to non-ML card, and continue to have 3x crop. I must not change movie fps - if I do, I need to boot from an ML card and re-set 3x crop.

It appears (but I'm not sure) that the video produced in crop mode is scaled up from 1728 pixels wide to 1920 pixels wide, i.e. the end result isn't a pixel-by-pixel image.

Can anybody confirm this?


(I'm not talking RAW here, just ordinary, compressed .MOV video...)

I have adapted some C-mount lenses to the EOS-M, and thanks to ML, they cover the entire image area when using the 3x video crop!

This is a Canon TV Zoom, 12.5-75 mm f/1.8:



Here's a cute little 8mm CCTV lens on the EOS-M:



Without the crop, this is what it provides:



Here's a cropped video - note that any 8mm lens intended for the full C-frame would be a huge chunk of glass! But with this tiny lens, I can get a wide coverage in a very small package, thanks to the 3x crop!

The video is a bit soft, since it was shot with the f-stop almost wide open, and my follow-focus wasn't too precise... and, it's shaky, to boot! But that will have to do for a first test...

Hi!

I bought an EOS-M two weeks ago; a wonderful camera, a fantastic 22mm lens.

I've been searching this forum for hours, but can't seem to find basic instructions on how to install ML on my camera. (I use Mac OS X 10.6.8.)

Thus, I registered!

Could anyone kindly point me in the right direction; links to any relevant pages would be very welcome!

Greetings from Finland, where we finally have got some snow and cold weather !