The Panasonic G1HD | GH-1 Video Mode : A Real Video Mode

Daniel L. said:
More aliasing on wide angle shots may just have to do with the deeper focus. It's always there but with more of the frame sharp it's more common & noticeable.
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Ding! I think this is the case. On Bloom's shots, even a slight out-of-focus erases the aliasing. Its all over hard, sharp, high contrast edges in his medium and long shots.
 
so we can save money by buying cheaper less sharp lenses. Damn mine are all sharp.

Is downsampling what causes stairstepping on the D90? Where's Lee and Matt when you need them.
 
Yes. both the D90 and MKII cameras do not have enough processing power to downsample the 4k image to 1080p or 720p in realtime. Both cameras use line skipping in order to achieve recordable video. With the D90, there is a way to process the footage so that the stairstepping is gone. you can see this in the video in my signature. With the GH1, there is the added complexity of the footage being wrapped in a 60i container, much like the original DVX100 footage. In any case, this can be fairly easily fixed with post processing.
 
Edit.. Since plasmasmp has much more experience with the D90 probably should just go with the above post.
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squig said:
Is downsampling what causes stairstepping on the D90? Where's Lee and Matt when you need them.
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Someone please correct me if I am mistaking... It's not the same. On the D90 the stairstepping is problem with encoding.

The aliasing on the 5D Mark II and the GH1 it's already in the signal before it's encoded. Well, with the GH1 that's if our assumptions are true but sure sounds like it.

Could tell for sure if we had a sample original clip.
 
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One thing to keep in mind is Phil is shooting with a PAL GH1, so pulldown/deinterlacing should not be contributing to the stairstepping effect. His camera is essentially outputting 25p.
 
Also, Kholi/Hunter/Phil -

The camera has a feature called "Extra Optical Zoom"
http://panasonic.net/avc/lumix/systemcamera/gms/gh1/liveview.html

"The DMC-GH1 provides Extra Optical zooming, which increases the optical zoom power (recording at a resolution that is less than the maximum.). For example, when shooting in S-size (3-megapixel) with a 4:3 aspect ratio, the Extra Optical Zoom function can "cut out" an image area at the Live MOS sensor's center equivalent to 3-megapixel (of the total 12.1 mega effective pixels)."

It would be interesting to see if this works with video, because if it was using only the middle of the sensor, you would get almost 1:1 pixels/output. It would also allow you to use 16mm lenses that crop or vignette too much using the full sensor.
 
Kholi said:
Where do I find it again and does it work with FCP? Thanks a lot!
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Kholi,

Wow the posts on this thing just keep coming. If I step away for several hours it's like 20 pages longer. LOL.

Looks like you've already found the Cineform trial but just to share a bit about the workflow I find useful. There is both a PC and Mac version of the Neo Scene software. However, I've found the PC version to be a bit more useful. So I have dual boot with bootcamp on my macbook pro and I use the PC version to get the files into Cineform codec and then jump over the mac software to edit them in FCP. That isn't quite as relevent for the file transfer workflow for cameras like the D90 and GH1 but when working with tape based HDV import it will import the footage and perform the pulldown at the same time. I also find the PC version to be a bit faster when encoding and I do much of my After Effects or CGI work on the PC so the .avi wrapper files work well for that.

If you are planning to primarily work in FCP on the Mac then the Mac version of Neo Scene may be the best choice because the Cineform files that it creates are in a Quicktime .mov wrapper. The pc version of Neo Scene creates files with a .avi wrapper which can add an extra step if you are porting over to fcp. If you swap out the .avi wrapper for .mov then it's a pretty fast batch process but it still adds an extra step.

I just realized that this might sound a bit complicated. It's not really and just depends on your exact workflow to determine the best version to use. You can email me if you have any further questions. Cheers.

email me at my username at gmail dot com :)
 
squig said:
Is downsampling what causes stairstepping on the D90?
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That should be exactly right, if by "down sampling" you mean skipping lines. But another reason why it's so bad on the D90, I think, is because the line-skipping algorithm is a bit irregular. I believe that's how the stair-stepping fix works, by smoothing out the irregularity.

Think about it this way: No digital image can have perfectly smooth diagonal and curved lines, because digital images are made of pixels, and pixels are square (or rectangular). There are two ways of making lines appear smooth:
1) Anti-aliasing, whereby adjacent pixels of lighter color are used
2) Higher image resolution, so that when the image is viewed from the same distance, the blockiness/jaggedness is less apparent.

High resolution imaging systems, like DSLRs use both. When you skip lines, the anti-aliasing doesn't work as well because it wasn't designed for the lower resolution, and the lower resolution makes the jagged edges more visible as the image is blown up or viewed from a closer distance.

On top of that, then there's the irregularity of the line-skipping pattern. Imagine a smooth, diagonal line. Slice it up into as many horizontal slices as you can imagine. Now remove every third or fourth slice, and close the gaps between the slices. You should be able to see, with you're mind's eye, that there's an awkward stair-step pattern that was created. That's because you have chunks of smooth diagonal line that are jammed against other chunks that appear to be horizontally offset by a small amount. Like so:

*****
******
*******
*********
**********
***********

Now imagine skipping two slices at a time:

****
*******
**********
*************

Not as awkward, right? You don't get that weird hump. So the line-skipping pattern is an important factor. But I also seem to remember that a particularly annoying irregularity was that the pattern was not always consistent.

If the GH1 is line-skipping, which it almost certainly is, then it's doing a better job than the D90. It probably uses a better, more consistent pattern.
 
squig said:
it's the same model GH1 for PAL and NTSC territories. You can select 24p or 25p
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I wouldn't be too sure about this not until you have one in your hands at the very least! Has anyone got the Japan model recording at 25 / 50fps? It's up on the AU site now 24 30 and 60 modes are not listed.
 
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Kholi said:
That's what I'm trying to figure out.

If a 50mm Canon is the same as the 50mm point on the Kit Lens.

If that's true, then doesn't that make the Tokina 11-16, a DX Format Lens, an 11mm on the GH-1 with 11mm FOV. I really could just solve this in one stroke if I had my damned adapters already. Ugh.
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Yes, you've got it exactly! It will give you the same FOV if the Panny lens were to make it to 11mm. You can preview what 14-16mm looks like with the Panny lens. Don't feel bad if you don't immediately get this, it does take some time to wrap ones head around it as it's not immediately intuitive.

Here's and example- if you had a 11mm Nikon lens, which has 135mm format imaging target, and the 11mm Tokina lens which has a APC format imaging target, the FOV is identical as long as you are using both lenses on the same imaging format and both lenses have imaging targets that cover the format.

You may be using a higher % of the projected imaging target on the Tokina but the FOV will be 100% identical. If you change your imaging format (APC, 135..etc) then your FOV changes, the lens does not. A search on google will undoubtedly reveal some websites that explain the concept in great detail.

Bottom line- if you have the Panasonic (Leica) kit lens, and decided "I really like the FOV I get at 18mm on the Panasonic" and then you put ANY compatible 18mm lens on the camera (either mounted directly) or through a non-relay adapter- you'll get EXACTLY the same FOV, regardless of the manufacturer.

I.

Illya Friedman
Hot Rod Cameras
 
if i remmber correctly, if yo uuse the kitlens, (18-55mm dx) thats basically 28-85mm on a fullframe lens

and now thats what i was asking before.. whats the crop factor of DX lenses if used on a 4/3 sensor if full frame is 2x
 
The crop factor between DX (Nikon's APS-C) and Four Thirds is about 1.25x. It's shown in the table on divide's thread "equivalent lens" thread.
 
I need help

I need help

Please someone tie me up :Drogar-Kriz(DBG):, I'm about to buy that D5000 but it seems that the gh1 is meant for better things...

I know this is not a help group like AA but hey... ever had that feeling I'm going through right now?

(Btw, joined a year ago and this is my very first post).

Cheers!
________________________________
http://vimeo.com/channels/moviemusic
 
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Don't buy the D5000. It has all of the same problems as the D90, which is nowhere near the GH1, plus it's a lesser camera than the D90. The only advantage that I can see is the articulating LCD. So don't buy it, unless that's all that you can afford. Even then, don't buy it; save up more money over the next month. I don't think that anyone here can argue that the D90/D5000 is significantly superior to the GH1 in any way other than price and current availability.
 
True... I hadn't thought of that... Silly me, forgetting something so obvious. Thanks. But still, he/she wouldn't be posting here if the decision didn't hinge on the camera's video capabilities, methinks.
 
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