HV20 Gain?
 

Hi,

Is there a way to control the gain on a HV20 like you can on the XH-A1? If not when does the gain kick in or is there a way to tell if wain is on?

Also what is the best wide angel lens for the HV20, preferably wider than 0.7.

Thanks in advance,

Simon

1. Some links that have helped/taught me:

http://www.dvinfo.net/media/canon/hv...urecontrol.mov (great video tutorial).

http://www.dvxuser.com/jason/hv20/

2. Do a search for the many discussions on this, but the Canon WD-H43 0.7x appears to net out as the best option (I own it; I'm happy).

I seem to be missing something. With exposure locked and a miniSD card in place, if I press down the Photo button, I get a blinking red camera icon that says "OFF" and no display of shutter and aperture.

What am I doing wrong?

You probably have still image recording off in the video menu. Hit function button, toggle down to next to last item on the list of option, then toggle right to the level of image you want. It should now work.

That was it. Thanks, Chris!

There is a workaround, but it is complicated by built-in ND filters. These filters are undocumented but it appears that the camera has them. They are automatic. On a simpler camera like the Elura, one can lock the shutter speed, then lock exposure, check aperture, then increase exposure, then check aperture value again. If it increased then you are ok, if it didn't then it means that the gain kicked in.

With the HV20 you cannot be 100% sure because instead of turning gain on the camera might just remove one of the ND filters, reporting the same aperture value.

On the other hand, it SEEMS that the ND filters are used in f/4.0 - f/5.6 range only, so when you get to wider apertures the filter does not come into play anymore and the exposure is adjusted by gain only. YMMV ;-)

What i do is this:

Put the camera in Cinemode or Shutter Priority mode. (For shooting in 1/48th)

Point the camera at a light bright enough to make the aperture drop to around 4.4 (or something close to it, don't have the camera on hand so i can't check what the ideal number is). Half press photo button with sd card in and photo option on to check the aperture.

Once you get the light at the correct brightness to achieve 4.4/8 lock the exposure. (press in joystick, click down, click up, press again) Now you can move the camera way from the light and start knocking the exposure up or down to correctly expose the image if you can. You should be able to go all the way up or down without gain kicking in at all.

Reason is, at 4.8, the most the exposure slider will let you go is 11 clicks (i believe) and that happens to be 1.8, it's lowest aperture. If you were to set it at 3 for example and lock it. And starting opening the aperture, once you got past 1.8 it would start adding gain.

So it's really as simple as that. Point at light, lock at 4.8, open back up to 1.8 (if need be) and shoot.

Hope this helps

Why do you lock the aperture pointing at the light, if you are going to shoot in different conditions? I still cannot get the point of this technique. If you are going to shoot in low light, why not locking the exposure in low light? Going all way up to increase exposure locked on the light produces the same effect as simply locking exposure in the low light conditions and going couple of ticks up or down. The only difference is where you start from on the exposure scale. By locking exposure in different conditions than shooting conditions you limit yourself to at most 11 steps of exposure adjustment, which may not be enough for particular shooting conditions. Why are you doing this? No one so far gave me a sensible reason for this approach.

The purpose of pointing the camera at a light is this:

When you lock the exposure, it sets it at a RELATIVE "0". So - the purpose is to find a point that when you lock the exposure, no matter what you do to it from that point on will NOT introduce GAIN.

If you lock it in a low light situation the HV20 will probably turn up some amount of grain - since there is no way of telling how much gain there actually is at any given time, you have to MAKE SURE there isn't any gain being added by pointing the camera at a light.

Chances are, if you're pointing directly into a light of some kind, no gain is being added. You also know there is no gain being added because it's closing the aperture, there would be absolutely no reason to add gain if the conditions are bright enought to be turning down the aperture.

So, what i've found is, if you lock the exposure at 4.8, you can go ALL the way up and all the way down on the exposure dial, without EVER introducing gain. The shutter is locked (in Tv or (mostly) Cinemode) and now you're basically just controlling the aperture directly.

It is a pretty confusing concept at first, it took me a while myself to understand it. There is a tutorial floating around somewhere explaining this method, however he just says simply to "point it at a light", but never goes into how bright it needs to be. So if you point it into a light that is TOO bright, you'll end up locking the exposure at f5.6 or something, and ou won't be able to open the aperture up all the way, because the RELATIVE "0" mark at that point is 5.6.

I hope i'm making some sense. The bottom line is, is to start at a point where the exposure locking/sliding system basically turns into your aperture control without ever having to worry about gain.

Let me know if this helps at all...

Left out two things:

1 - you have to be zoomed out fully for this to work.

2 - try locking the exposure in a "lower light" situation, and try to lock it at around 2.8 or something. Then start opening up the aperture. Go up one notch on the slider, lock it again and press the photo button, and see what the aperture is at. Do that JUST until you get to 1.8. Then, now you know if you're going any further BEYOND 1.8 in the OPEN direction (to the right) every click is adding GAIN to simulate the aperture opening more.

Dale, your second posting completely crosses out what you wrote in the message above it. My question was: why using some sort of constant light to set the exposure. In your first post you answered: to set the "0" of the exposure scale at the same known aperture/gain level despite actual shooting conditions. Well, this is not the answer what I was looking for, I was looking for an answer to a question WHY do you want you "0" of exposure scale to be at the same position? You said this technique ensures that no gain is introduced when you go all the way up the scale. Well, this is some reasonable explanation, but then again, if you can check your current aperture and shutter speed at any time, why limiting yourself to specific constraints?

I might think of a reason. Say, instead of trying to find the best camera settings for current lightning conditions you can look at the scale and see that you are on the "+" edge of your ideal constant-shutter-speed-no-gain scale and you should add more light to the scene. This approach allows controlling the scene lightning based on camera limitations instead of controlling gain based on scene lightning. But this particuar reason has NEVER been mentioned in any thread related to the HV20's exposure settings, neither on this site nor on the other sites. I am not a movie pro, camcorders is just my new hobby, I suppose this is how pros work, they adjust lightning to equipment they have. I guess this is something every movie greenhorn should know. I didn't think of this before. Would be nice if you confirm that this is a reason (or THE reason) for a "fixed EV scale".

In your second message you are saying basically what I am saying: lock exposure, then increase it and check aperture. As long as aperture increases, there is room for the iris to open and gain is not introduced. If the aperture stops increasing while you increase exposure, this means that gain kicked in. Thank you, thank you, this is exactly my point. Which brings us again to the original question: why would you set "0" to an absolute position instead of locking exposure for specific shooting conditions and then checking current exposure?

One more thing. The HV20, like most consumer camcorders, has the lens with variable speed, it is f/1.8 at the wide setting and f/3.0 when fully zoomed in. This means, that you can lock exposure at full wide, then increase exposure, and you would not have gain. Then you zoom in, the iris closes, what happens to gain then? I have not tested this, but I suppose that camera will compensate by adding gain. which means, that exposure should be locked and tested not only for current lightning conditions, but for current zoom setting as well. I will test it today. I don't have my own HV20 yet, but my friend has. I am getting by with a simple Elura 100.

Michael,

I i'll try to answer your question the best that i can, forgive me if i didn't quite extract the correct questions from your post.

The point of having a controlled light source to lock the exposure with is only so you can easily set the exposure at the ideal 4.2 (don't know the exact number off hand) every time. This way you assure, no matter what the lighting conditions and no matter how far or low you jack up or down the exposure, you will not introduce gain. That is all. The real B of it all is when the HV20 shuts off or if you knock the dial by accident, you have to reset everything, having a controlled light source to calibrate the exposure at 4.2 just makes things easier.

Now the purpose of not locking it based on your specific shooting conditions is that if you specific lighting conditions are too dim, you might be locking the exposure with GAIN already being induced. Because the camera doesn't tell you how much gain it's adding, pointing at a plenty bright light is the only way to ensure it won't add gain. You just never know. By pointing at a specific light, you guarantee there is no gain when you lock the exposure. That is the difference.

I hope i'm making sense...

As for the zooming thing, i really don't know that answer to that question. I always thought it wouldn't add gain, but have never really confirmed that. Would be interested to learn your findings.

Thanks

Dale

What is the point of shooting with no gain, but with blacked out image? You either will need to jack up exposure (read: gain), or add more light. Which brings me back to an assertion in my previous message, which you haven't confirmed: instead of adjusting camera for a scene the proper workflow is to adjust scene lightning for camera's capabilities.

Are you saying that the idea is to always stay within the "ideal exposure range", centered around f/4.someting. If there is not enough light, add light. If there is too much light, add an ND filter. Is this so?

In this case this technique is starting making sense to me.

OK, i see where the miscommunication is now.

Yes, the whole reason for the controlled light thing is to guarantee no gain will be induced. Gain sucks, and i avoid it at all costs.

If you're at 1.8 with no gain and the image is too dark you have two choices:

Add Light
Add Gain

Light is always the better option for me. But it totally depends on what's practical for your situation.

THe last thing you said is exactly right. Too much light, (which would be rare) add nd filter or something, too little light (shooting 1.8) add light. This is just to ensure no gain will be added. Gain sucks.

I've been shooting a lot of interior night scenes lately and have found that it's just better to up the gain a couple notches if you can't adjust lighting. Slight noise is better if it means maintaining a dynamic range for post color correction. It's better than no noise and losing your range. Also, I think audiences are used to seeing some noise(within reason) in low light situations, something the human eye adds iteslf anyways.

Just keep in mind that gain is not always bad. It has to be considered, along with the alternatives, in light of the artistic intent of the shooter, expectations of the client, and field conditions.

The noise and image grain that are often associated with the use of gain may be just want you need for a "reality" look, and in many situations a noisy image is better than none.

I totally agree. A good slant on a much misunderstood part of video production. Grain is not necessarily something we aim for but it is not always totally bad. Now that I'm shooting video myself, and in many cases, done in low light conditions, I have become aware of many instances of grain in professionally shot productions of movies and videos. I believe a lot of video production of night scenes are really shot during the day and adjusted to look like night in order to avoid grain. If you are truly protraying reality, grain is part of that. This has led me to believe that grain can occur even with $100,000 cameras if the lighting conditions are not there to support a no gain situation. If sometime in the future, our consumer camcorders have the ability to shoot in the woods at night with no lights and no grain, do you think that grain will be gone forever from video production? Does an artist always attempt to paint a portrait that is exactly the same as a good photograph. As technology creeps ahead and Hollywood is able to do away with actors and create a movie completely void of real people, will we be satisfied as an audience. I think not.

I agree with you all in saying that grain is not ALWAYS bad... however, grain in video is like echo in audio (well maybe not completely) it's easy to add in post, but really hard to take way. It's always better to start with the cleanest source possible and then add what you need later.

NOW - this TOTALLY depends on what you're doing. Shooting a live event vs shooting for a feature film for instance are COMPLETELY Different things. Of course for the live event your audience is going to prefer seeing an image rather than not seeing any grain.

So, the technique i'm describing in my previous posts is just to guarantee you don't have gain/grain for those who don't want any. Use at your own discretion.

Also note- that even when i'm shooting with no gain, if you really look at the image, it's not a PERFECTLY clean image. Nothing is, just like i said it's nicer to start off clean (just like audio) and add what you need.

Another factor to keep in mind is that gain in the camcorder is typically applied to the analog signal read off the sensor before a/d conversion and compression. Adding gain in post can introduce different image artifacts and possible visible banding in the image. It goes back to which image look best meets your needs.

To me grain is ALWAYS bad. I see nothing artistic in grain, adding noise is not art. Grain is just defects in the film. The only reason for grain and speckles is for movie-within-a-movie situation, when it is necessary to show an "old" movie. I do not accept a whole movie made with grain and speckles to emulate an old movie, this is just a cheap effect.

Another thing is that random grain doesn't compress well, which is why a complex scene with grain may look blocky because there is not enough bandwidth both for real image and for grain.

A good noise filter does wonders to your footage...trust me....

http://www.neatvideo.com/

Michael I've seen plenty of big budget movies with suprisingly a lot,,and I mean LOTS of noise. People like to say film noise is different from video noise...that's hogwash...at least to my eyes. One recent movie that comes to mind is "Transformers"...lots of noise in the dark scenes. it did not take away from the movie however.

I understand your questions above...I agree with you...I ask myself in most cases why bother fighting it.....I have been recently shooting in dark situations and accept the grain that comes in...sometimes shots look good with the added grain... Also...when I fight it with the cellphone trick......in most cases (not all) it comes out too dark....then what....i dial the gain up in post and ....there is the noise that was hidden in the dark scene. But that is what noise filters are for.... The one I posted above....it\s amazing... I am used to using noise filters and they all suck....but this one "Neat Video".. is great. Your end product looks like it was shot with a cam that has high end ISO. Unlike other filters..it does not take away ANY of the "fine" detail in your shots. You have to see it to believe it.

The thing for me is...I let the cam focus the best it can in dark lit situations...allow some 9not a great deal0 of gain (which undoubtedly will add grain)...apply the filter in post...and no one would be the wiser. I am almost convinced a lot of high end cams do this internally to their footage...because that is what the end results look like after I apply it to my videos.

A lot of folks who shot and printed Tri-X might disagree with you, as might Geroges Seurat. In any case, art is in large part a matter of individual taste.

Oh....and the other movie was "Bridge to Tarabitha"....noise all over the place (it shocked me....but only because I was looking for it).....but....great movie (ok....I have a six year old)....

I guess gain is a necessary evil in some situation and I don't mind as much if I can get some range back with it, and because you have ways to suppress it in the post to some degree. I guess the bigger problem is the shot to shot consistency. Adjusting gain and exposure in a predictable way is essential but difficult with HV20, and locking to a light source to have a consistent starting point is very helpful. Didn't know about 4.8 as 0 guarantees no gain whatsoever. Thanks for the good info Dale.

Neat Video really works wonders. Best $45 I ever spent.

holy smokes that neat video seems like a very empowering tool. If those sample pics on its website are for real, then it's definitely something that will allow us to up our exposure.

You don't know the half of it.....Suen is right...it would be the best $45 you'd spend.

I have the Hv10. When I use the spotlight in the scene menu, there’s now gain kicking in!

I'm a firm believer in post as well, and it's something i forgot to mention in my earlier posts.

If youre at max aperture and the image is still too dark, and adding lights isn't an option or even just impractical, relying on some post techniques is always an option.

I was actually going to bring up the transformers example myself. I noticed that too, especially in the scene where they're in the NSA (or whatever) headquarters... crazy.

But i'm sure that for some reason was a choice (michael bay has done weirder things).

There is actually a plugin you can get for photoshop as well called "noise ninja" that does an extremely good job at de-noising shots. If it makes sense to do it frame by frame (batch) for your project.

Any who - you at least know how to control the gain for those who want to...

As has been supported here in this thread, gain grain, is definitely not a sign of a low budget production or consumer video.

I just meant by my statements, that we needn't or shouldn't necesarily throw away all of our grain clips if they are pertinent to the overall video. I'll certainly be purchasing the "Neat Video" and seeing how it will aid some of my video scenes.

I'll have to go watch my copy of Transformers in HD DVD again. I guess I was caught up in the movie and didn't pay that much attention to the grain. Looked very good in High Def by the way. I've watched it on an 8 foot screen at home, projected from my Optoma HD70.