GH2 THE ULTIMATE FAST WIDE SHARP and CHEAP LENS FOR GH2 !!!!!!!!

seb33 · Mar 9, 2011

... That's why I'm working with C-mount lens since a while. I don't care of very sharp modern lens, or small vignetting, I use to enjoy "lomo" and "super 8" style, far from the "video" look.... What is surprising for me is the availability of fast zoom in C-mount lens, up to 1:1.0 ! There is a lack of fast zoom in DSLR, the only fastest I know is the Zuiko 35-100 F2, but it costs 2540 €.

shaveblog · Mar 9, 2011

Good points all, Barry. Except I must disagree about what made the 20mm pancake such a hit. I don't believe it was size alone, or even predominantly. Yes, the ultra small size was a tantalizing selling point, as was the equivalent normal prime focal length. But I don't think it would've been nearly as well received had it been as slow as the 14mm pancake and the kit zooms. You -- well, I -- don't hear people raving about the 20mm's size, ever. We love it for its speed and its excellent IQ even wide open. Fortunately for us it's also small and lightweight, and quite affordable.

This may surprise you and others reading this, but I am not an optics expert. I don't know why a fast wide m43 lens has to be huge and heavy and expensive, when normal fast m43 lenses like the 20mm can be so utterly tiny and relatively cheap. I don't need an f.95 like the Nokton. F/1.7 would be fine, f1.4 would be sensational, f1.2 I'd wet myself. But I don't need f.95 just because Cosina's making one. I don't think I would ever shoot a lens like that wide open, and even in the hands of a shooter like Bloom that kind of DOF doesn't do anything for me. I like seeing things. Clarity is good. But a lens that's nicely sharp by f2 or faster would be a wonderful thing to have.

Even just taking the 20mm pancake and making it a bit wider would be great. If Panasonic can make it so small, good and cheap, I would think nudging the optics a bit wider to 16mm or 14mm and maintaining the same speed wouldn't require a severe jump to big/heavy/expensive. Unless the 20mm pancake is so pushing the envelope of the possible that it's some kind of bumblebee that shouldn't be able to be so fast, tiny and cheap but yet it is.

Something just doesn't compute here. I don't buy that Panasonic can easily make a tiny 20mm f1.7 lens for $330 but anything wider than that at the same speed or less needs to be big, bulky and cost $1,500. It's not something I lose sleep over, but I am interested in why Pana/Oly/et al seem to be offering every kind of lens for m43 except the one that everyone here seems to be lusting for, to the point where they'll go to great lengths to adapt obscure little CCTV lenses and custom-ground adapters and ETC just to get a taste of fast wide.

moxrox · Mar 10, 2011

Thx so much for the info, bought one for 15€ didnt think much in this moment due to the price. Someone offered 10x used lenses and within 30 min 5 were sold. Lets see how the used one looks like, what kind of modification did you use besides the Adapter ? You did write "see pictures below" about the rear barrel..dont see any pictures, what do I need here. Lets see if Iam lucky and the lens is in good condition.

seb33 · Mar 10, 2011

moxrox said:
Thx so much for the info, bought one for 15€ didnt think much in this moment due to the price. Someone offered 10x used lenses and within 30 min 5 were sold. Lets see how the used one looks like, what kind of modification did you use besides the Adapter ? You did write "see pictures below" about the rear barrel..dont see any pictures, what do I need here.

Here's the link of the flickr's pictures:
http://www.flickr.com/photos/43243778@N04/5507294907/
http://www.flickr.com/photos/43243778@N04/5507103527/

and a blog on modification (Mine was done by a professional) :
http://cjeastwd.blogspot.com/2009/06/adapting-lens-to-fit-mount.html

Can you send me the link of the ebay seller ? Thanks.

moxrox · Mar 10, 2011

Thx a lot, did send you the link.

seb33 · Mar 10, 2011

Thanks for the link, but due to legal regulation it's not working from France... Anyway I've got mine, hope you will enjoy yours !

PJF · Mar 10, 2011

Well done, Seb. Considering there is a variable ND filter in front and it's ETC, it looks nicely sharp and clear. If I had a GH2 I would grab one of these in a flash. In fact, I might get one anyway just in case I do get a GH2 (increasingly likely).

Nice to see your videos again; had some catching up to do on vimeo. I see the road is still dug up outside your apartment - it must be months!

seb33 · Mar 10, 2011

PJF said:
Nice to see your videos again; had some catching up to do on vimeo. I see the road is still dug up outside your apartment - it must be months!

LOL there's always work outside my building, when it's not the gas, it's water lead pipe replacement, when it's not lead pipe, it's pavement replacement... DAMN

moxrox · Mar 10, 2011

seb33 said:
Thanks for the link, but due to legal regulation it's not working from France... Anyway I've got mine, hope you will enjoy yours !

Well, I have to find a professional aswell who can fix this for me. I did read about this guy who did just file the lens, but Iam a bit aware about that since it has to do with the focus and the lens has to fit tight. It just has to to fit into the adapter, so maybe cnc milling could do the job ? Ah well...will ask around in some photo clubs or shops.

JackBayer · Mar 11, 2011

seb33 said:
the rear barrel has been limed to fit and go enough deeply in the C-mount adapter for infinity focus

Hi Seb,

am I wrong to assume that this special lens only requires to be modded? There are some other c-mount lenses out there with F1.4 at also 6mm focal length that say "fits standard c-mount".

Barry_Green · Mar 11, 2011

Fitting c-mount, and fitting an m43 c-mount adapter, are not the same thing. Lenses can fit flush on a c-mount camera, but not fit into the recessed mount of a c-mount adapter. M43 has a flange focal depth of about 20mm, and c-mount is 17.52mm. That means that the c-mount adapter has to actually be concave, it has to move the lens 2.48mm deeper into the body. So there's a recessed portion of the c-mount adapter that the lens has to fit into, in order to snugly mount at the appropriate distance. Most (if not all) c-mount movie lenses I've seen are built to do this. Few if any c-mount security/CCTV lenses are. Many/most of them have a rear diameter that's too big to fit into the recessed portion of the c-mount adapter. That's why people have to file them down, modifying the back of the lens to make it smaller so it'll fit within the recessed portion of the adapter.

Note: none of this is to be confused with "CS" mount, which is the same screw threads and same diameter, but is meant to have a 12.52mm flange back distance (IIRC). You can put c-mount lenses on a CS camera by using a 5mm spacer, but you cannot ever mount a CS-mount lens on a C-mount camera or adapter and expect to be able to focus.

seb33 · Mar 11, 2011

JackBayer said:
Hi Seb,

am I wrong to assume that this special lens only requires to be modded? There are some other c-mount lenses out there with F1.4 at also 6mm focal length that say "fits standard c-mount".

No, this is not sure. The 1.2 6mm Pentax is a standard c-mount too. The problem is that because of the maximum of the 41mm of the micro 4/3 mount inner circle, the C-mount adapter can't take all the C-mount, especially those which have large rear barrels.

S. Matthews · Mar 11, 2011

Not really cheap but kind of fast and wide.
http://www.amazon.com/Rokinon-FE14M-C-Ultra-Canon-Black/dp/B003VSGQPG

Apefos Adapter · Apr 21, 2011

joe1946 · Apr 21, 2011

S. Matthews said:
Not really cheap but kind of fast and wide.
http://www.amazon.com/Rokinon-FE14M-C-Ultra-Canon-Black/dp/B003VSGQPG

If you also use it with a Canon,Nikon, Pentax or Sony DSLR it would be great but just for a m4/3rds camera I think the 14-45 would be better since it is very sharp at 14mm F3.5 and has IS on Panasonic bodies.

moxrox · May 30, 2011

Finally I did modify the 6mm Pentax by myself and it fits with an 4/3 slim adapter and I can reach infinity. Its really a fun lens so far I can see, a bit softer than the other normal manual lenses I used before. But the possibilities with the wide of the lens is quiete cool. Thx a lot for the hint about this lens !

seb33 · May 30, 2011

moxrox said:
Finally I did modify the 6mm Pentax by myself and it fits with an 4/3 slim adapter and I can reach infinity. Its really a fun lens so far I can see, a bit softer than the other normal manual lenses I used before. But the possibilities with the wide of the lens is quiete cool. Thx a lot for the hint about this lens !

Great I'm glad that you manage to do it. Have fun !

moxrox · Jun 1, 2011

Thx, I think its really a fun lens.

Someone did make a video and compared the nokton 25mm with the Pentax 6mm.
http://vimeo.com/24439212

J Davis · Jun 1, 2011

can somebody post the height and width of the tele-mode windowed area in millimeters so we can calculate fov and dof?

1st edit:
don't forget dof changes with focal length. In the original video, i think both lenses were f1.2 and the fov was the same but the dof is not. This is more of an issue when not going wide tho. When going wide we want stuff in focus so the dof change is on our favour

2nd edit
Also aliasing and moire 'should' be reduced on a windowed sensor as there would be less down sampling
(or no downsampling if 1:1)

MatthewC · Jun 4, 2011

moxrox said:
Thx, I think its really a fun lens.

Someone did make a video and compared the nokton 25mm with the Pentax 6mm.
http://vimeo.com/24439212

Wicked video, really showed the differences. Lot of noise in the darker BG of the Pentax, but still a decent cheap find. Trying reading the back of the boxes, not soo good.

GH2 THE ULTIMATE FAST WIDE SHARP and CHEAP LENS FOR GH2 !!!!!!!!

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