Bob's Tests & Comments on the HMC40

BobDiaz

BobDiaz

The Professor
Think of this thread as my open blog about working with my HMC40 camera. With any equipment, I like to run it through its paces and see how it works. I freely admit to the fact that I'll get into areas that are a matter of opinion. Fell free to agree or disagree with my comments.

Initial Overview:

The perfect video camera does NOT exist, there's always going to be some trade-off in cameras. To me, the Panasonic AG-HMC40 is the video camera for those with Caviar and Champagne wishes, but have a Peanut Butter & Jelly Budget. Yes, if one is willing to dump a lot more money, there are more expensive video cameras out there what will do better than the HMC40, BUT at the $2,000 price range no other camera comes close to the HMC40 in terms of flexibility and features. (In Bob's opinion.)

The level of control of the settings is great; yet at the same time, everything seems so logical as far as getting to the adjustments. OK, I had one minor stupidly, I was looking for the menu setting to turn on OIS (Optical Image Stabilization) and I couldn't find it!!! OIS is not a menu item, it's a button, but that was stupid on my part... I just need to get used to the camera a bit more.


First Tests:

It has been said on this forum that the HMC40 is NOT the best choice for low level lighting. True, but that does not mean that indoor shooting or night shots are out of the question. There are 2 ways to deal with lower light levels: (1) Increase Gain. (2) Reduce the shutter speed.

In this test I went to a busy street corner at night and tried 1/60, 1/30, & 1/15 of a second shutter speeds. For each speed, I tried +12dB, +18dB, and +24dB gain. You can see the results I posted on VIMEO and if you have a VIMEO account, you can download the source video.


http://vimeo.com/8732993

No question that at 720/60p, 1/60 of a second is great when there's enough light, but at night, it may not be the best choice.

Using 1/30 of a second helps and is equal to +6dB of gain compared to 1/60. Fast movement still seems to flow even at 1/30 of a second. This speed may be the best choice for shutter speed when the light is reduced.

Using 1/15 of a second is equal to +12dB of gain compared to 1/60, but is a mixed blessing. On one hand it helps with the lower lighting level without producing the noise pattern. However, with fast moving objects, if you look closely, you can spot a strobe like effect. A whip pan can produce 7 --> 9 repeat images on florescent, LED, and neon lights. (This is due to the 60 Hz power.) With slower moving objects, the movement seems normal. If the lighting was really bad, I'd consider using 1/15 of a second, but this is a risky choice. While it will help, it could result in other problems (strobe & motion blur).

As for gain, +12dB does have some noise, but it doesn't seem too bad to me. Going to +18dB increases the noise level and subject to how much you are willing to accept, may or may not be an option. Pushing the camera to +24dB gain is an act of desperation. Well, maybe not that bad, but the noise level seems excessive.


On minor issue I had with the manual iris was that the little iris wheel was just a bit too sensitive for me. I'd try to set the gain for +xx dB and miss it by +/- 1. By using the menu, I could select that the focus ring could be used for the iris setting. A switch on the side of the HMC40 allows me to select Focus OR (Zoom/Iris). With the large wheel, setting the iris quickly was easy.

I did to some additional tests at slower shutter speeds, but this is not posted on VIMEO. At 1/8 of a second and lower you can spot every frame as it appears and the strobe effect is VERY strong. However, in shooting my neighbor's house in very poor lighting, 1/8, 1/4, and 1/2 of a second do allow the HMC40 to capture the image. Maybe this isn't practical for regular video, but could be useful for time lapse video.


Bob Diaz
 
Great test Bob. I've waiting for something like that for awhile. It seems the low light isn't as bad as some test make it out to be. The gain looks fairly clean. I've been using FX7's and from what I've seen they look worse at 9db than the HMC40 at 18.
Great video and keep them coming!!
 
BobDiaz said:
As for gain, +12dB does have some noise, but it doesn't seem too bad to me...

Bob Diaz
Click to expand...

After you've done some more playing around with the camera, you'll find that in some shooting situations 12dB of gain is all but unnoticeable. I'm really impressed by that. There's just no reasonably possible way to shoot at 12dB gain, with an XH-A1, and not notice the resulting noise (makes you want to check your radiation badge!).
 
I'm more curious about how many solicitations you received standing out on that street corner?

Seriously. Could I ask for a favor? could you show the zoom in action? I'd like to see how well it covers ground and how the stabilization works along side with it.
 
Unfortunately, the zoom speed on the HMC40 can't be fixed. I like being able to lock zoom speed to a smooth crawl. Zip-zooms especially, and unsteady zooming speeds too, are just a fantastic way to obtain very amateurish, crappy footage.
 
The zoom can be set to run at one constant speed, but the speed is a middle of the ground speed. You can use the W/T buttons on the LCD to use the zoom at one static speed. Unfortunately you can't choose which speed that is.

You can assign zoom to the lens ring and move the ring very slowly, or you can just barely press on the zoom rocker, to get the slowest speed it's capable of.
 
An option for fixed-speed smooth crawl zoom should be something akin to a mandatory feature on any camcorder costing more than $25 (and really shouldn't be just an option for newbies - should have to log 10000 hours before using zoom that moves even a bit faster than an elderly snail heavily medicated with Xanax). :thumbsup:
 
I should have added that the settings of the camera were all factory default. I made no attempt to reduce the noise by playing with the Detail Coring.



Bob Diaz
 
The HMC40 can shoot dang respectable images straight out of the box, simply setting the basics (shutter, WB, aperture/gain). Even auto focus works better than I expected. I suppose 1/4" imaging chips do help there.
 
I wanted to see how far off from the correct exposure I could be and still get a reasonably good image. As far as tests go, this was a simple one. All I needed to do was set the shutter to 1/2000 of a second and change the iris. The iris was opened in 1/2 stop steps. In retrospect, I should have just selected 1/500 of a second to help move the correct exposure point higher in the iris range.

You can watch or download the video from VIMEO:

http://vimeo.com/8752442

Depending on your personal tastes, the correct exposure was either F2.8 or F2.4 or maybe it was a step in between the two settings. Either one is close to ideal. Now in watching the video, I'd say that being off by 1/2 a stop is very minor. Yes, there's a slight difference in brightness, but nothing that can't be fixed in post. One could even be off by 1 full stop and there appears to be more than enough room to fix it. I don't think that 1.5 stops of over exposure can be fixed in post, but maybe 1.5 stops under exposure might be fixable.

The camera seems to show some forgiveness to over exposure and under exposure. It's best to get the exposure correct, but the good news is that there is some working room for errors.


As far as the audio for this clip, I used the BeachTek DXA-4S XLR adapter and a hand held dynamic mike. I don't have a deluxe sound system on my HDTV, just regular speakers, but this adapter seems to produce reasonably good sound. Other tests with the Azden SGM-2X shotgun mike also sound good. The BeachTek is temporary until I can save up to get the Panasonic XLR Adapter....


I'm still learning the fine details about the camera, but already I can see that it's a VERY powerful camera for the money...


Bob Diaz
 
Thanks Chris.

I haven't done a lot of testing today, but did manage to do a quick resolution chart at 720/30p... OK, I know a camera that gets 800 --> 900+ lines of resolution in 1080p mode isn't going to have a problem in 720p mode. True, but it's one of those things engineers do ...

Resolution_720p.png


Now the odd thing was that I was so careful in lining up the chart on the viewfinder, BUT looking at the final image it was slightly cropped from what I shot. ODD...

(1) I screwed up on the alignment.

(2) The viewfinder shows slightly more than what's recorded.

I think it's the first possibility, but I'll check this out later on. As for the numbers, one has to take whatever number you see and multiply it times 0.95 to get the correct resolution.

Also, it's impossible to get above the vertical resolution as the final result. You just can't resolve more lines than you have pixels and in truth, it's always slightly less than the number of pixels.

The bottom line is that even if you use a more expensive 2/3" camera to run this test, you should get about the same resolution, because the limit is not the camera but the number of pixels.

There are other parameters than resolution, but it's nice to see that the HMC40 is at the very top in 720p mode.


Tomorrow I hope to be at Wilson Park in Torrance; we have some little (1/8 the size of the real thing) trains that people ride on (open form 12 noon to 3 PM). If you live near Torrance, California, stop by for a free ride... Here's an older SD video:

http://vimeo.com/1933489


Bob Diaz
 
OK, so after the first part of my testing, it was time to do some real world video. So I went to the train rides at Wilson Park and shot some video of the "little" trains.

I just finished watching the video, the HMC40 >>> ROCKS <<<<!!! Maybe that's not the best technical way to express it, but the colors are rich, the contrast is outstanding, and the audio is SO CLEAN!!! Credit for the clean audio should also go to the AZDEN SGM-2X shotgun mic.

Someone had set up an audio system in the station playing background music. Great for the people waiting for a ride, but bad for me trying to get just the train audio. Well, by positioning my mic where the null of the mic was the music from the speakers playing the music, I can't hear the background music, but the train and station sound are so clear.

I didn't have a whole lot of time to shoot the video, so I had to rush getting my shots. Still, the images look great and this is just factory default. OK, I did put a polarizing filter on the camera, but didn't always adjust it for the best look.

I wish I could edit the video right now and post it, BUT I do have to be somewhere else tonight. So, the finished video will have to wait...


Bob Diaz
 
Nice Bob... I'm sure you'll play with the settings to get a more "film" look.. It's so sharp it looks kinda like video. I guess that is a good thing, but maybe with some tweaks it could look more like clear film.

Oh, the trains look like fun!
 
I don't understand getting obsessed with trying to imitate film. I shoot video with absolutely no apologies whatsoever. Video is not film. It has advantages and disadvantages. One of the big advantages video can offer is the ability to capture far more fluid, realistically smooth, motion.

Personally, the only reasons I ever shoot 24p are if that's the only progressive framerate a camera is capable of (like the HV20), or for the bandwidth advantages (slightly better image compression quality or for putting on the web where bandwidth is still a very serious consideration). Aside from that, I look at 24p as pretty lame really (especially compared to 60p!).
 
In terms of temporal resolution, higher FPS (Frames Per Second) is always better. For those who have an HMC40 to play with, try this:

Shoot cars moving left to right (or right to left) in the image. Shoot this at 720/60p and 720/24p with 1/1,000 of a second shutter speed for both frame rates.

With the 60p footage, the movement of the cars seems OK, but at 24p, the movement seems strobe like and odd.

Robert shoots 720/60p because the increased frame rate gives the most natural flow of movement in the video.

Now if you think you might be shooting a video that could be transferred to movie film, shooting 1080/24p makes a lot of sense. It makes the transfer a lot easier. However, one must be careful with the shutter speed when shooting 24p. In general, 1/48 of a second is about ideal. Shorter times produce too much of a strobe like effect and longer times (like 1/24 of a second) produce too much blur.



Bob Diaz
 
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