C-mount lenses on the EOS-M

[Janke]

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...

[Danne]

Nice.
What, s the highest picture you can film in 3xmode on an eos m?

[ItsMeLenny]

What you've done was my suggestion to someone somewhere in terms of using low resolution raw modes.
Looks good. The lens is probably soft at wide apertures anyway, it would probably be best to stop it down regardless.

[Janke]

"The lens is probably soft at wide apertures anyway"

You are correct. Stop down a couple of clicks, and it's much better.


"What's the highest picture you can film in 3xmode on an eos m?"

What do you mean by "highest"? In pixels, Mbps, or meters, or feet?

[Danne]

aspect ratio, fps? Does it do 1920x1080 24fps zoomed in?

[gary2013]

aspect ratio, fps? Does it do 1920x1080 24fps zoomed in?

The M can't go above 1728 from hardware limitations writing to the memory card. It usually runs around 36Mbps. 1920 x1080 needs a cam with CF cards, like a 5dm3. The M can do 1270x720, 24 fps Crop Mode continuously.

[Danne]

Thanks, sounds good.

[Janke]

"The M can't go above 1728"

Eh? At least it looks like I'm getting full-HD 1920x1080 from mine... even at 1.5x bit rate.

Or are you talking about RAW?

[1%]

You oft forget that crop mode is possible, not just movie mode crop but FPS override + canon 5x zoom. Its just really inconvenient to enable due to lack of buttons + touch screen.

[AnthonyEngelken]

Doing the math, the M is really a 16mm shooter. Movie crop mode in 1920x1080 (h264) only requires 9.48mm sensor coverage, and standard 16 glass gives about 11mm.  Super 16 lenses cover about 14mm, which would be great if 2048 raw gave more than ~60 frames at a time. Just received my c-mount adapter in the mail, and the crappy little eBay Fujian 35mm is on its way from China now. Plan to get a PL adapter and rent some legacy 16mm glass for a weekend experiment soon. If I shoot anything fun and noteworthy, will be sure to share it.

[Janke]

Don't expect the Fujian to be stellar...

I have lots of CCTV lenses, none is tack sharp at full aperture, a lot of spherical aberration and some coma. Stop down to 5.6 or so, and they get good.

Having checked the size of the recorded image, it looks like even the 1920x1080 (h264) is scaled up from 1728x972 !

I wonder why it's not pixel-by-pixel 1920x1080 from the sensor, that would not require the scaling...

[gary2013]

"The M can't go above 1728"

Eh? At least it looks like I'm getting full-HD 1920x1080 from mine... even at 1.5x bit rate.

Or are you talking about RAW?

Raw.

[AnthonyEngelken]

Don't expect the Fujian to be stellar...

I have lots of CCTV lenses, none is tack sharp at full aperture, a lot of spherical aberration and some coma. Stop down to 5.6 or so, and they get good.

That's sort of what I expected, but I just ordered it for cheap test purposes. If I like the results, then I'll hunt around for some better glass to use. All the same, found some test videos of the Fujian and I kind of dig the dreamy barrel distortion. Not great of course for all applications, but fun for what it is.

[Janke]

Speaking of fun, this Canon 7.5 - 97.5mm f/1.4 ENG TV camera 13x Zoom was fun to adapt to the EOS-M, even though the quality is nothing to write home about:

PS: That shadow at lower left in mid-zoom is gone, now, had to rotate the lens 45° to get it to the bottom, outside the frame...

[Janke]

Warning: Do not boot the camera with a manual lens, it will (may?) hang!

[ItsMeLenny]

Warning: Do not boot the camera with a manual lens, it will (may?) hang!

I've never had a problem.

[Janke]

It hung up for me while switching on with a C-mount lens. Needed to take out battery and restart with a non-ML card.

[maxotics]

I kind of dig the dreamy barrel distortion. Not great of course for all applications, but fun for what it is.

I too, put on the Fujian onto my EOS-M on a lark and now I can't bear to take it off!

All these shots that don't say D600 were shot with the EOS-M and Fujian 35mm 1.7.   That's right, thousands of dollars worth of camera in the Nikon and I'm still reaching for this baby.  LOW LIGHT, no flash!

http://www.flickr.com/photos/maxotics/sets/72157639434130995/

Here's another shot.

http://www.flickr.com/photos/maxotics/12041902535/in/set-72157639946239006

And of course my Angry Toddler's video which I'll post again  It takes some getting used to the lens. It is truly an artistic tool.   If you focus too hard the lens can come screwing off.   Getting the camera to take properly exposed photos AND show on the screen takes some finesse (I usually use Aperture mode).  Did I say I LOVE this lens

[AnthonyEngelken]

Man, check out that wonky focal plane. Damn it's sexy.

[Janke]

Damn it's sexy.

Just ordered one for 20 euros...   

Is that video shot full frame, or 3x crop?

[maxotics]

Just ordered one for 20 euros...   

Is that video shot full frame, or 3x crop?

Best 20 euros you will have ever spent!  Make sure you get the effective 35mm 1.7,  I found the 25mm to have too much vignetting.

I shot the video in normal mode (no crop) with ML CBR set to 1.3, but I doubt that effected the quality much.  The irony is that I never meant to shoot this video with the EOS-M.  I had brought my 50D with 16GB card, to shoot RAW, and ran out of space in a few minutes!  (BTW, a corrupted frame at the end made the video useless--didn't feel like spending the time to fix).

The lighting was really nice, near sundown, cloudy, that surreal evenly lit feel.  So I only shot this with the EOS-M as a nothing else better to do. 

What's really nice about that focal plane you mentioned is it allow you to shoot multiple looks with one camera lens.  It helps the viewer not get tired of the same view, sort of poor man's way of making a multi-camera shoot  

Anyway, I look forward to what you shoot with the lens!  Photographers pay thousands of dollars to get wide aperture lenses for portraits on full-frames (like me) and yet this lens can give you virtually the same look.  You don't have to spend thousands of dollars to get a nice shallow DOF.

[Danne]

Cool video. Like the guitarist hendrixstyle playing. Cool band

[Janke]

Photographers pay thousands of dollars to get wide aperture lenses for portraits on full-frames

Not to make you green with envy, but I happen to own a Leica Thambar 90mm f/2.2 soft-focus portrait lens... one reason for buying the EOS-M was to use this lens!



Here's what it can do:



Here's a test shot with the Canon TV Zoom 12.5-75mm f/1.8, shot at f/5.6 - note that the "jell-o" is from warm, turbulent air; it was -15°C outside :

[maxotics]

Nice lens!  10 years ago I suspected these lenses might make a come-back but didn't bother to collect them when I saw them on old cameras at garage sales.  I had my chances

[a1ex]

This lens seems to be the perfect candidate for this: http://www.magiclantern.fm/forum/index.php?topic=8564.0

[Janke]

Thanks, a1ex, that was an interesting little video. Loved the math formula, it looked kinda cool!

I had my chances

They still abound on eBay.

[Oswald]

Here's my little test using 8-48mm f1.0  (it is fast) with 3x crop mode. Eos M is little beast! 

Iso 400 and shutter 1/50 almost all shot in f1.0

[AnthonyEngelken]

I too, put on the Fujian onto my EOS-M on a lark and now I can't bear to take it off!

Received my Fujian today, and I have a couple of questions for you. Seems the back focus needs a little adjustment to have accurate infinity, same case with yours? If I unscrew the lens a ways, I'm able to correct this, and I'm just wanting to make sure my adapter is built right. Also, I don't know what the GH1/NEX guys are talking about, but I have zero vignetting with this glass; seems to cover the whole sensor. Again, same case with you?

[Janke]

Haven't got mine yet.

But, don't fret about that infinity focus - there's quite a bit of tolerance in cheap CCTV lenses.

If you get infinity by unscrewing the lens, it means you will be able to shim it slightly, i.e a little ring of some suitable material between the lens and the adapter takes care of it.

OTOH, you will get infinity without any shim, but the scale on the lens will be off a bit. Happens with most CCTV lenses. You do focus via the finder, right? It may even be possible to correct the error, if the focus ring is movable - are there some very small screws along the rim? But don't mess with them if you're not sure what you're doing...

Much worse is not getting to infinity at all, then some lathe or mill work is needed to seat the lens further inwards.

[AnthonyEngelken]

If you get infinity by unscrewing the lens, it means you will be able to shim it slightly, i.e a little ring of some suitable material between the lens and the adapter takes care of it.

Good to know this isn't out of the ordinary, will probably hit up the hardware store tomorrow for some washers.

[Janke]

Remember that the C-mount has a 1/32" (almost exactly 0.8 mm) pitch; you can easily calculate the thickness of the shim from that, checking how many degrees you have to unscrew the lens to get infinity focus when the focus ring is on infinity...

I had to add a very thin shim to my 12.5-75mm zoom to get it to keep focus over the zoom range.

Focusing at telephoto, and zooming to wide, the focus shifted from infinity to 3 meters, and calculating with the lens formula 1/a + 1/b = 1/f  thus 1/x + 1/3000 = 1/12.5 gave me ∆f = 0.052 mm - so, two layers of scotch tape between lens and adapter was enough!

[AnthonyEngelken]

[removed]

[maxotics]

Received my Fujian today, and I have a couple of questions for you. Seems the back focus needs a little adjustment to have accurate infinity, same case with yours? If I unscrew the lens a ways, I'm able to correct this, and I'm just wanting to make sure my adapter is built right. Also, I don't know what the GH1/NEX guys are talking about, but I have zero vignetting with this glass; seems to cover the whole sensor. Again, same case with you?

I never use the lens to take a photo of anything at infinity   For me it's a shallow-depth of field bokeh monster.  I know you can calibrate it to focus properly at infinity, as the other posters say, but I never bothered. 

The benefit of this lens, to me, is it takes you away from the technology and back to primitive imaging--though with fantastic sharpness in the center (or where you're focused.). 

[AnthonyEngelken]

The benefit of this lens, to me, is it takes you away from the technology and back to primitive imaging--though with fantastic sharpness in the center (or where you're focused.).

Totally agree with this, but calibration never hurt anyone. Love the lens, by the way; beautiful shots so far.

[Janke]

Love the lens, by the way; beautiful shots so far.

Can't wait till I get mine... it was shipped 4 days ago...

[tupp]

Got my EOS-M with the Fujian 35mm f1.7!

The lens (and camera) is fantastic and fun, and it is amazing that it does not vignette on the ASP-C sensor (the lens is rated for a 2/3" sensor).

However, I am noticing an excessive "circular of flare" in the center of the frame, on the widest f-stops.  I know it is flare, because I can flag it with my hand.  This flare is so excessive, that, if a little bit of light hits my hand, the color of the "circle of flare" (on the side closest to my hand) changes to the color of my hand.

Anyone else notice the same phenomenon?

I think that the filter size of my Fujian is 35mm wide, so I will probably try a long lens hood.

[dfort]

The Fujian 35mm f1.7 lens is gaining quite a following. There's even a Flickr group for that lens: http://www.flickr.com/groups/2062341@N22/

I got the fever and ordered an EOS-M and the Fujian lens. One thing I'd like to do is to play around with the 3x zoom with 1280x720 raw video. I did some quick calculations and the 22.3 wide APS-C sensor in 3x crop comes out to 7.4mm which is between somewhere 2/3 inch and 1/2 inch video.

Of course there's lots of C-mount lenses out there but watch out--many of the shorter focal length lenses are for 1/2 inch or even 1/3 inch sensors. I looked up some film/video formats and here's what I found:

Format              Width
1 inch video     12.8mm
Super 16mm    12.5mm
Reg. 16mm      10.26mm
2/3 inch video    8.8mm
1/2 inch video    6.4mm
Super 8mm        5.79mm
1/3 inch video    4.8mm

As long as I'm throwing out a bunch of numbers, the EOS-M sensor is listed at 5,184 pixels wide. At 16:9 it should be using 2,916 vertical pixels. Scaling this down to 1280x720 to avoid "line skipping" I came up with a 4.05 crop factor so that means that there still must be some scaling/line skipping going on in 3x crop. However, the videos I've seen done at 3x and 1280x720 on Canon APS-C sensor cameras don't exhibit any aliasing or moire pattern issues. Can anyone explain why? (1% answered this question.)

(Note: I edited this post on March 3, 2014. I originally had the width and height of Super16mm transposed and was under the impression that the 3x crop mode on the EOS-M would turn it into a Super16mm camera--I was wrong.)

References:
http://www.lensrentals.com/blog/2012/01/sensor-size-matters-part-1
http://en.wikipedia.org/wiki/Image_sensor_format

[dfort]

1% elaborated on line skipping in 3x crop mode in another post: http://www.magiclantern.fm/forum/index.php?topic=10056.msg103983#msg103983

Back to C mount lenses. I had a little CCTV camera that used CS mount lenses. C mount lenses could be adapted to CS mount cameras but not the other way around. The threads are identical but there's a 5mm flange to focal plane difference. If your "C mount" lens doesn't focus to infinity it is probably a CS mount lens.

[AnthonyEngelken]

The lens (and camera) is fantastic and fun, and it is amazing that it does not vignette on the ASP-C sensor (the lens is rated for a 2/3" sensor).

Fujian was probably taking into account the barrel distortion while making the 2/3" claim.

Was under the impression that the 3x crop mode on the EOS-M would turn it into a Super16mm camera--I was wrong.

Not necessarily; in movie crop mode, Super 16 glass would be quite ideal for 2k raw sensor utilization (if the M could capture more than a second or two of 2k raw). Standard 16 glass on the other hand projects about the perfect circle for 1080p h264 capture in 2.7x crop mode. The M's sensor/pixel proportions don't seem terribly different from the Digital Bolex's.

I have a question for those in the know: Is it just me, or is the field of view much narrower on a c-mount 35mm than on an ef-mount 35mm? Rather, I was expecting my c-mount 35mm to have a similar field of view in crop mode as an ef-mount 35mm in full-sensor mode, but that doesn't seem to be the case. Instead, both the c-mount and the ef-mount lenses have about the same field of view in crop mode.

Maybe I need a cinema history lesson, but were much wider lenses used back in the day when 16mm was common? In effect, while 25mm is sort of a go-to wide for Super35 format today, did the go-to wide use to be 8mm or 12mm for Super16 format?

[dfort]

Is it just me, or is the field of view much narrower on a c-mount 35mm than on an ef-mount 35mm? Rather, I was expecting my c-mount 35mm to have a similar field of view in crop mode as an ef-mount 35mm in full-sensor mode, but that doesn't seem to be the case. Instead, both the c-mount and the ef-mount lenses have about the same field of view in crop mode.

Huh? Both the 35mm C-mount and the 35mm EF-mount lenses should have the same field of view. There are some variable that will might the field of view slightly different but they should be fairly close.

Remembering way back when I first picked up a 16mm camera the "normal" lens was a 25mm. For a 35mm "Academy Aperture" movie camera it was 50mm and for a 35mm full frame still camera it was also 50mm. On the EOS-M in crop mode I tried a 12mm lens and it seems a bit too long for me so I ordered an 8.5mm lens.

Here's a Wikipedia page that does a fairly good job at explaining how to determine a "normal" lens for still and motion picture film and digital formats: http://en.wikipedia.org/wiki/Normal_lens

I've never very "normal" in my choice of lenses or anything else for that matter.

I'm discovering that it is a challenge to find decent C-mount lenses wide enough make shooting with the EOS-M in 3x crop mode practical. If you have experimented with raw video on the EOS-M you'll discover that 1280x720, 3x crop, RAW and not MLV RAW (which means no audio), Global Draw off, and a few other tweaks are needed to get the camera to record more than a few seconds of raw video. Then there's the whole post production process that I won't get into on a post about lenses!

[AnthonyEngelken]

Captured some footage with a Computar 12.5-75mm f/1.2, shared to the forum here: http://magiclantern.fm/forum/index.php?topic=11456.0

[canoneer]

Just got a Fujian 35/1.7 from Hong Kong with EOs M adapter. But focus is only within a very limited distance and not anything further than 4-5 feet/ 1 ++ meter. I understand that should indicate a to large distance from lense to chip. But how....?

[tweak]

I think that means you need to shave some metal off your lens or adapter (or both). What adapter do you use?

What adapters is everyone here using?

[AnthonyEngelken]

Just got a Fujian 35/1.7 from Hong Kong with EOs M adapter. But focus is only within a very limited distance and not anything further than 4-5 feet/ 1 ++ meter. I understand that should indicate a to large distance from lense to chip. But how....?

Don't shave anything off the lens, the Fujian 35 needs a shim for most adapters (I discovered); a 1/16" rubber ring from your neighborhood hardware store should do the trick. You'll always be fiddling with tightening and loosening the threads to get proper infinity focus, but that's CCTV lenses for ya'. If this doesn't help and the flange distance is in fact too long, return your adapter and get a different one.

[LeicaFan]

I too, put on the Fujian onto my EOS-M on a lark and now I can't bear to take it off!

I can see why you like that Fujian C Lens

The dramatic difference between in focus & out of focus areas really makes for nice looking video.

[canoneer]

I returned the lens and got a replacement quickly - which work great.

[tweak]

I just modded the Fujinon 1.4/9mm C-mount to fit my EOS-M... what  lens! I used a Fotga adapter and had to dremel both lens and adapter to get a flush fit, now it focuses to infinity.

[QuickHitRecord]

Reviving an old thread. I recently came into a few C-mount lenses that I would like to try out, but I've been out of the ML loop for a bit. What is the state of EOS-M crop-mode shooting in 2019? Am I right in understanding that there are now two modes that allow pixel to pixel cropped recording? If so, what are the advantages of each? Thanks.

[dfort]

Am I right in understanding that there are now two modes that allow pixel to pixel cropped recording? If so, what are the advantages of each?

Not sure what you are understanding. There are a bunch of new resolutions available in the crop_rec module if you download Danne's bleeding edge builds. I'd suggest reading up on the latest developments on the Canon EOS M topic. Note that even though these new resolutions are in the crop_rec module some of them use the entire sensor area so if you are planning on using C-mount lenses check to see if your lens can cover the whole APS-C area.