GH2 official discussion thread

Resolution is very good :-)
I need to see more footage to talk about aliasing.
RIght now I don't see any big signs of it. But later careful tests will show all details.
 
Last edited:
Vitaliy Kiselev said:
Looked at 1:1 mode footage.
Pretty good. Definitely usable for any task.
So, start looking for fast and sharp lenses :-)

P.S. Guys, remember to donate to get GH2 body for our hack project. Only less than $200 left.
Btw thanks to all who donated already!
Click to expand...

Thanks for the update. I already have a ton of c-mount lenses lined up. Is there any moire or aliasing with that mode at all or is it totally clean? Also can you tell from the footage you have if it will be usable with longer lenses that don't have IS? Does the magnification affect the stabilization as much as if you used a lens with the equivalent focal length?
 
mpgxsvcd said:
Thanks for the update. I already have a ton of c-mount lenses lined up. Is there any moire or aliasing with that mode at all or is it totally clean? Also can you tell from the footage you have if it will be usable with longer lenses that don't have IS? Does the magnification affect the stabilization as much as if you used a lens with the equivalent focal length?
Click to expand...

All footage that I have are not extremely good for aliasing tests. But I don't see any up to this time.
And beware of bad cheap tripods or handheld usage if using long lenses with 1:1 mode.
 
svecher said:
If I understand correctly, what's usually referred to by video-style "stepless" aperture is lens's ability to change aperture in very small increments. To test it, you would need to be in one of the modes where camera is free to change aperture, like shutter priority mode. Point the camera at a darker part of the scene, set aperture parameters, then slowly point it at a light source. If lens is "non-stepless", there will be noticeable jumps (steps) in brightness levels as the camera adjusts aperture in 1 EV or 1/2 EV increments (however lens is designed). A stepless lens will adjust aperture (iris) smoothly.
Click to expand...

You are right, to those who aren't understanding the concept of a 'stepless' aperture, this is not a marketing gimmick and it is not in any way the same as a 'constant' aperture (which is where you have a fixed aperture across the entire zoom range).

The stepless aperture refers to the ability of the lens to change aperture in very small increments, which avoids any horrible obvious clicking from one aperture to the next - so when in video mode, the lens does not have to jump from say f/5 to f/4 in one jump, it can move smoothly between the two.

There used to be a very good video showing just how horrible a lens that does not feature a stepless aperture can be - using a Canon camera and the kit lens, but I've been unable to find it - the closest I could find is this, which still highlights how horrible it is if your lens has to change aperture in clear steps.

http://www.youtube.com/watch?v=3W6P-QFwYjU&feature=related

For those that have a 550D or similar with the kit lens, try filming from a dark to light area, allowing the aperture to change as you do so, you will find it is not pleasant.

You can also simulate this with an old manual lens on a GH1 - as you film, rotate the aperture ring on your lens and observe how it changes in large, obvious steps.

The 14-140 *does* feature a stepless aperture and changes in smooth increments, which is much more pleasant to look at.
 
I'm not so sure, in CMM I find as you zoom you get exposure bumps and in std PASM less so but am sure it bumps exposure? Maybe my lens is faulty?
 
Adventsam said:
I'm not so sure, in CMM I find as you zoom you get exposure bumps and in std PASM less so but am sure it bumps exposure? Maybe my lens is faulty?
Click to expand...

That's interesting, as certain focal lengths only support certain aperture sizes on the 14-140, I think what you are seeing is normal - i.e. by zooming you are forcing it to jump from one aperture to another - this is where a lens with constant aperture would be good.

But you should be seeing clear steps in normal use - have a look at the video at the bottom of this dpreview article - it clearly demonstrates the smooth way in which the aperture is changed going from dark to bright - if yours isn't doing this then there is probably somethign wrong (if you were to do this on a non stepless lens you would see a lot of flickery jumps as the lens changes aperture to suit the new lighting conditions!)

http://www.dpreview.com/reviews/panasonicdmcgh1/page19.asp
 
Last edited:
OK, yes it does do that, at crossed purposes, I was thinking as you zoom it might be stepless too, guess thats not possible?
 
Adventsam said:
OK, yes it does do that, at crossed purposes, I was thinking as you zoom it might be stepless too, guess thats not possible?
Click to expand...

I believe this would be possible, but you would need a zoom lens that is capable of all aperture settings at every focal length as well as having stepless aperture change ability.
 
Last edited:
That was funny, I needed a good laugh today. Maybe you could sell the idea to a European broadcaster? As long as they don't want it reshot in 25p your fine!
 
Vitaliy Kiselev said:
All footage that I have are not extremely good for aliasing tests. But I don't see any up to this time.
And beware of bad cheap tripods or handheld usage if using long lenses with 1:1 mode.
Click to expand...

IF you somehow would manage to hack the GH2 do you think you would be able to add 50/60p @ 1080? Since that is what the sensor outputs.
 
mpgxsvcd said:
Thanks for the update. I already have a ton of c-mount lenses lined up. Is there any moire or aliasing with that mode at all or is it totally clean? Also can you tell from the footage you have if it will be usable with longer lenses that don't have IS? Does the magnification affect the stabilization as much as if you used a lens with the equivalent focal length?
Click to expand...

c- mount is tricky ther is a problem, they need a shorter distans then 43 micro standard gives, at AF 100 it don´t fit
check it out... before you make to big hopes
Sorry to tell
Yours
 
Last edited:
You must log in or register to reply here.
Back
Top