Help needed ;( with my GH1 and C-Mounts.

[Comatose79]

Hey guys, I was wondering if I can get some input, as I am new to the Micro 4/3 world and about to punch a hole on my wall.

As a filmmaker, I love my new camera- no doubt. I've owned almost every popular camera in the indie filmmaking world and my new GH1 seems like it's exactly what I've been looking for, for years.

As a photographer as well, I have a few lenses that I used often with my EOS, which I will now use with my GH1..
Sigma 10-20mm 3.5-4.5 (EOS>m3/4 adapter)
Pentax 50mm f1.4 SMC (w/ Pentax>EOS>m3/4 adapter)
Pentax 28mm f2.8 (w/ Pentax>EOS>m3/4 adapter)

Now, I completely understand the crop factor situation and everything that comes with these lenses mentioned above... (ie: my super dope wide angle 10-20mm isn't so super and dope with m3/4 sensors.) Wide, but not as wide as I'm used to, and would like it to be.

I am looking into the c-mount world but am reading so many different stories, regarding thread size and adapters like this 37/39mm diameter jazz, image turnout against the sensor (vignetting, color aberration, barrel distortion, etc). Some people seem to have some really great turnouts with these lenses, and some apparently don't. I just want to get a lens that I can pop right onto a c-mount>m3/4 adapter without worrying about modding.

Being that I have severe ADD and can't make up my mind on which lens(es) to use, (really..) I was hoping one of you shooters could give me some direct understanding with c-mount lenses and maybe suggestions to guide me toward the lens I am looking for... I read that infamous c-mount spreadsheet guide. Overwhelming. 😱

Naturally, like many, if not all of you, I'm a fan of bokeh, which I pretty much have situated with my 50mm Pentax and am fine with. What I'm really out for now is a lens that will give me true and exact 10mm, 20mm, 30mm, etc focal length, minus the vignetting and crop issue and most of all FAST- c-mount or not. Is all this even possible with c-mount lenses or even digital photography alone, outside of the full sensor universe? (I come from film photography). I am reading stories left and right that a lot of people don't go below 25mm to avoid vignetting, etc with the c-mount lenses.

I guess what I'm really asking here, is which wide angle 'c' lens seems to be the most successful over all, zoom or prime? What are you guys using? (Brand, focal length, aperature).

Also, are there any users here who use the movie mode with c's? What's it like focusing with these little guys? I could imagine it being weird, but at the same time, easier focusing motion being that the lens has such a small diameter.

Thanks so much. I know you probably answered these questions a million times. I apologize. 🙁

 

[laptoprob]

So you are looking for the Holy Grail? ;-)
Most of the C-mounts will give some vignetting and swirly bokeh on the outer edges.
On another forum I found some useful threads: getdpi.

 

[Abbazz]

I guess what I'm really asking here, is which wide angle 'c' lens seems to be the most successful over all, zoom or prime? What are you guys using? (Brand, focal length, aperature).

I use a few lenses in C-mount. Usually, I am not very found of wide angle lenses (those with a focal length shorter than 20mm), because of the heavy vignetting. Among the "normal" lenses, my favorite is the Cooke Kinic 1" F/1.5. It -- just -- covers the 4/3rds format, with some vignetting but no black corners. The lens is very sharp in the center of the field, even wide open, but the image gets quite fuzzy away from the center, even when the lens is stopped down. The "swirly" bokeh is also not everyone's taste. But I think this lens gives an unique look to pictures:

The Cooke Kinic also has the advantage of screwing on my C-mount adapter without requiring any machining. Beware of ultra-fast lenses, because their large diameter will often require some machining before they can fit on a standard C-mount to Micro 4/3rds adapter.

Here's a nice spreadsheet listing a few C-mount lenses and summarizing compatibility issues when they are used on Micro 4/3rds cameras:

http://spreadsheets.google.com/pub?key=p9kkgjwEQQQ-HJwvNDobeEw

Cheers!

Abbazz

 

[Comatose79]

Thanks bro! Yep, the holy grail is exactly what I'm looking for I guess!! getdpi?

 

[Comatose79]

I use a few lenses in C-mount. Usually, I am not very found of wide angle lenses (those with a focal length shorter than 20mm), because of the heavy vignetting. Among the "normal" lenses, my favorite is the Cooke Kinic 1" F/1.5.

I actually saw these pics previously. Great shots! I like the swirling bokeh here.. Yea, that spreadsheet confuses me. Haha!

 

[Dwig]

...
Here's a nice spreadsheet listing a few C-mount lenses and summarizing compatibility issues when they are used on Micro 4/3rds cameras:...

The chart was prepared for the G-1 and is valid as is for the G-1, GF-1, and Oly E-P1. GH-1 users need to understand that their 16:9 format is different from the other m4/3 models.

16:9 on the GH-1 requires the same 21mm image coverage as 4:3 due to the special multi-format sensor used in the GH-1. The other models simply crop the 16:9 out of the 4:3 image area.

 

[squirrel$$$bandit]

BTW, I'm surprised your Sigma 10-20 doesn't work well. It's an SLR lens and is not retrofocal...I would expect there isn't much smearing.

 

[justins7]

I just recently got the GF1. The Pentax CCTV 25mm 1.4 lens, which can still be found used under $100, is quite good. Although it is not wide, it is fast and tiny and fun. With the adapter I bought from "jinfinance" on ebay it screws in too much, but I remedied this by simply using some gaffer's tape and checking that infinity focus is indeed infinity and no further. This lens is ridiculously decent (minimal vignetting and not much weirdness) for the price. The main drawback is the handling, since it's so tiny.

Video has been great with this lens, and you can readily focus as you're moving around, keeping it wide open.

Otherwise, the wides I bought won't fit this "jinfinance" adapter, so I bought another one from ebay seller "hawks_factory" which is apparently better. (still waiting.)

There is a TON of information at www.getdpi.com
It seems like at a certain point you just have to order some of these lenses and see for yourself what kind of infinity focus problems there are.

I don't think there are any wide "holy grail" lenses out there, as anything smaller than 25mm will vignette. But look out for CCTV lenses, like Cosmicar and Pentax, as those are cheap enough that you can play around without risking too much.

 

[isorgb]

Hello Comatose79,
I still use two C-mount lenses on G1 16:9 aspect ratio. I know that GH1 is different on this mode. Sensor is "wider".
If you would like to take pictures with quality like from your Pentax lenses on 35mm camera, you may be disappointed.
Look theese sample. First is from Carl Zeiss Tevidon 25mm f1.4 and second from Canon TV-16 13mm f1.5. Both samples are not crop, so you can see the real action.
Canon has strong black vignette, Tevidon is much more better. Unfortunatelly theese lenses have "glow" which I don't like.

But, I think for video C-mount lenses are "the best" today. Inexpensive wide plans with quite shallow depth. Filmmakers should be satisfied ;-) Like Happy Hour at your favourite restaurant ;-)))

Tevidon 25/1.4:

Canon 13/1.5:

 

[Mephiloco]

In case you weren't aware, Schneider still produces some really nice primes in C-Mount. They produce EXCELLENT images, although they're a little pricey. I received a pair of 8mm/1.4's and 12mm/1.4's this past weekend. I'm not entirely sure the cost, but think they were around the $1k area each.

 

[squirrel$$$bandit]

Wasn't there some talk around here a couple years back about a digital camera someone had designed to take C-mount lenses? I believe he had a prototype working...and a few nice-looking renderings. m4/3 kind of rendered that pointless, but I wonder if it ever came close to happening.