7D Built-In Exposure and Focus Aids for Video?
 

Just starting out with the 7D. It's nice to have a superlative SLR, I like the ergonomics and the potential.

I'm having a hard time knowing how my video is being exposed. With my camcorders there are all kinds of ways, zebras, histograms, warnings, peaking. I haven't fully explored the camera, but it seems there aren't a lot of these in video mode.

I thought I'd shortcut my own investigation a bit and ask: Does anybody have hints on how to make sure I'm not blowing out highlights or crushing blacks and if I'm in focus? Don't worry about suggesting the obvious. Maybe we can call this thread "7D Video Exposure and Focus for Dummies"

Thanks all.

One thing for sure is don't go by the metering bar, it will help keep you close but it is not 100%, and could be way off if you are shooting a white dress or a scene that has dominant dark or white, I stop using that after too many bad exposure shots, what I found best is that I use the Zacuto viewfinder to focus but also for exposured, make sure that your edit monitor is properly calibrated and hook up your camera hdmi out to it and point your camera to a scene that has highlight and shadow and adjust the lcd brightness with the Zfinder until it is as close as your edit monitor and your eyes as possible, after I've done that, I rely strictly on the Zfinder/lcd, if the scene is not right in the Zfinder then it is not right, comparing the brightness in the zfinder with my eyes and adjust until it is as close as possible, and I say about 90% of my shots are properly exposed, the other 10% I kind a knew that it might not be right but could not adjust during the shoot and just left it there, easily fix in post since it is pretty close already.

Khoi, thanks for the hints.

What I'm struck with initially is, wow, that's a pretty 'manual' way to achieve correct exposure, relying on the built-in LCD. Also, I'm not actually sure what you mean by the 'metering bar.'

Keep the hints coming!

Call me old fashioned, but try using a incident lightmeter and spot meter?

It is the bar to the right of the F stop reading on the bottom, + or - 3, or when you pressed your shutter release halfway down it activated it, when the bar is at the center it is properly exposed according the what type of metering you are using, for video there is only 1 and that is evaluative and it is not accurate on certain scene.
Jim, I'm a wedding videographer, don't have time to get a reading from a meter, sometimes you want to catch a hug or a kiss or lightning could change at the ceremony after or before the bride walking down the aisle, we can't run out there and stick a meter on their face, but if you are not shooting event, there is a histogram for playback and so you could shoot a scene and then play back and reshoot if it is not right, but we wedding videographer have to get it right the first time, you can't tell them to repeat the vows for you cuz your exposure is not right. (-:

As far as exposure goes the metering bar in the live view will get you close then you can adjust with your eyes and a meter if you know how to use one. For focus the best thing to do is take the kit lens off and sell it. Then go buy some lenses that are parfocal (like the new Tamron 17-50 f2.8 and pretty much all Canon L glass) and set the focus just like you would a video camera. Zoom into your subject set your focus zoom out to the frame you want. The lack of ability to back focus was killing me.

There are a few ways to judge focus and exposure accurately before you roll; you can take a still and evaluate the histogram, and you can magnify the focus to make sure your subject is sharp. Obviously if your conditions change once you start rolling, exposure may be compromised and as if often the case with video, the subject may start moving!

A good solution to both is to use a good outboard monitor that has a false color exposure mode, and you will be able to judge focus that much easier. Obviously this represents an additional cash outlay but for me it is the only way to work with these DSLR's.

Using a traditional light meter with a DSLR is in my opinion pretty dicey, particularly when you are working in low light levels. The sensitivity of these cameras is such that a face metered virtually off the bottom of the meter at .7 can look pretty nice even when exposed at 2.8. The only times I use my meters on digital shoots any more is to pre-light a set.

Jerry, is the Canon 28-135 IS not Parfocal? I kind of like the lens but maybe not suited for manual focus -zoom in focus zoom out to frame video as you say. Have you personally noticed the Tamron is better for this?

Charles, one thing I have thought about but not yet experimented with is to establish some type of good exposure using the 7D's live still-mode (non-video) aids, such as histogram, highlight alert (akin to zebras I guess), then flipping the still/video switch over to video. I'm just wondering what results I might achieve, for example, will the equivalent ISO, aperture, and shutter that I've set in still mode apply exactly to video mode?

For example, in still mode, I establish settings to be good (no blown highlights or crushed blacks showing in histogram or zebras) to f2.8 and 1/60th and ISO 100.

I then flip the switch over to video mode, with these settings, will I get predictable results?

Thanks everybody for the great info.

No it is not. The only Canon lenses that I know of that are Parfocal, are the L series lenses. The Tamron works very well for this at about half the cost of the Canons.

My 17-55 IS 2.8 is parfocal.
Keith, you can do that but for me just way too long.

Keith,
I don't know if you know this, forgive me if this seems very basic to you. But, on the kit lens after you focus, if you change your zoom at all the lens is out of focus again. On the lower end lenses I guess Canon figured (and everyone else) that everyone would use auto focus. Eliminating the need for the Parfocal lenses.

Jerry, no answer is too basic in this thread, as I said, 'for dummies.' I haven't had time to put the Canon kit lens through it's paces regarding 'parfocalness' but I believe you. I just got my new Tamron 2.8 17-50 VR IS lens, are you using that one and how do you like it?

Just remember that the settings will only hold in M mode and not in any of the other modes.

Is the non VC version of that Tamron lens parfocal?

One thing I don't get about the 7d is why there's no need/ability to backfocus. What's the deal on that? And if we can't backfocus, why should we trust focusing at tele then zooming out for appropriate framing? Focus will be off right?

Depends on the lens just like your typical pro video camera. With the right lens you can back focus. With the kit lens just like most handy cams there is no back focus... You are dependent on auto focus. It's not the camera it's the lens that is on the camera.

What I find works is to turn on the histogram function for still pictures, which shows the histogram with the still image review (I have upped playback time to 4 seconds). I just click a picture before starting a video to look at the histogram. I also turn on the function that makes overexposed areas blink on the still-picture review screen, which is somewhat similar to zebra.

I find that if I use the 7D LiveView as a monitor (without the histogram function above), it tends to overexpose slightly, so I typically close it down a little more than the display would suggest to get the exposure I like. I'd like to get a zebra function on this thing!

Hi Roger

What's the advantage of taking a picture and using playback as opposed to just being in still mode, hitting the 'info' button until you see the histogram, and then switching over to the video mode and taking the video?

There's a way to back focus the 7d?

I don't know of any photo lenses that allow for back focusing. You have to remember, these aren't video lenses where you would normally need to back focus at all to pull off a push in or pull. And, of course, there would be no back focus on the body. It's the lens that has a back focus.

Keith,

I'm able to get a histogram in movie mode with a single button press (shutter), which is very fast. I don't have to press play or switch back an forth from still to movie or anything. After the shutter button is pressed in movie mode the camera "reviews" the still image taken with histogram automatically, if you have selected it to display histogram during review in menu options. I have it set up so that after any still picture is taken in any mode, the display shows the picture on the left, histogram on the right for 4 seconds before reverting back to whatever capture mode I started in. Also if something starts to happen on the scene I can just press the "start" button and the camera instantly aborts the image review and starts capturing video. I find this the most nimble way to get exposure feedback on the camera in its current configuration but I'd prefer to have Zebra or the histogram live on the LCD at all times.

As I read you response I took out my camera, put it in still mode, and pressed "info" several times but a histogram never appeared without taking a picture. I'd like to use that feature for stills if I can figure out how to get it hold on the histogram. Time to go back to the manual!

Parfocal lenses stay in focus all the way through the zoom range of the lens.

Roger, you have to have the Exposure simulation On (Camera setting screen 4, 4th item)for the histogram to be available after pressing the "Info" button.)

Thanks for the explanation. It sounds like a good mode. I had to fiddle with it to get the histogram to show up. Just like the live mode, you have to hit the info button a few times to get the right information set to display during the review period. Once it's set, it's sticky. I was trying for a while and nothing ever showed up until I re-read the manual.

However, though it's useful, and I'll have to use it real world situations, I think I prefer to check out the histogram in still mode first, in live mode and adjust the histogram for proper exposure real time, using ISO, aperture, shutter speed, and Fader ND, then switch over to movie mode once I'm satisfied. I chose the RGB histogram, as I like to see the relative levels of each color to see if I'm too hot or dark on a particular color. It's a histogram mode I wish my Sony EX1 camcorder had (it's just total brightness histogram). With your method I'd have to make a change, take a picture, make another change, take a picture, which could be time consuming. With my method I can make changes real time, then flip over.

Your mode, though, does have usefulness I think it would good if I'm in video mode and I just want to do a quick sanity check. Thanks for the hint! Keep them coming!

Keith,

Let's keep building on these ideas. I can see a use for both. I'm going to try using the RGB Histogram, which I have no experience using. It sounds very useful though.

Thanks for your explanation.

I find the histogram only useful to tell you if you are either clipping your blacks or whites, but not a real useful exposure tool. It for example won't tell you if you subject is correctly exposed at key. Also, in a low key scene it's close to useless because it will tell you most of the scene is dark, because it is and you will be probably clipping some blacks anyways. So I don't find much use for it besides black and white clip check. If you expose a scene to get a good reading in the histogram the scene will be boring and flat.

For white clipping is really easy. Just use highlight alert ON.


Yes, I don't find focusing on the 7D hard at all. I just use the focus magnification function in the camera. It works great. I don't get when people complain about the lack of focus assist. You don't really need it.

Yes, this is true. But I find it useful to set my key. If I set the ISO to 320 or 640 and the lens to 2.8 and I get a 2.8 reading for my key on my meter set to the same ISO I normally get skins at 60 IRE which seems to be a good range for the 7D. Also like using a meter for setting contrast ratios.

I don't really use histograms much myself either, but I wouldn't agree that getting a "good reading" in the histogram will result in a boring or flat image. This may be true if you are working with a predominantly dark scene for instance, you wouldn't want to drive the values up to the middle arbitrarily, but if the frame contains a full range of values it will return a full-looking histogram without resulting in a flat image. Shifting exposure will result in the histogram moving right and left; adjusting contrast or dynamic range would appear to squeeze or unsqueeze the histogram towards the center.

Focus magnification is only useful when the subject or camera is not moving, before the shot. If either happens (as things tend to when shooting motion pictures!), most will be pulling focus by eye and as I said earlier, on longer lenses and open apertures, this is not easy even for seasoned veterans.

This is exactly the method I've started using on my 7D as well. Pretty reliable.

Sure. But you can't really use it to expose your scene. As in it will not tell if your actor is too dark or not, it will not tell you if the wall behind the subject is exposed as you would like it to be for the mood etc. It's not really an exposure tool in my opinion. Rather a very rough guide that will tell you if you are clipping your dynamic range. Besides that I don't see any use for a histogram. If all I had on set was a histogram to expose, and no monitor, no waveform and no meter, I don't know how I could expose correctly. Now if all I have is a light meter, I can expose close enough without looking at the LCD or at the histogram or even waveform.

Not sure I follow here. Could you elaborate?

Oh yes, definitely. I was just talking about setting the focus rather than pulling focus. For setting the focus on the 7D I don't miss the EX1's focus assist at all. Now pulling focus you do have to pull by feel or by eye as you can't trust distance marks on still lenses.

What method/tools are you using to set exposure?

The histogram is one of the most useful tools on a digital camera. I use it shooting stills, on the EX1 and on RED.

I'm amazed that so few people understand it, let alone use it.

Here's a useful tutorial that I often recommend:

Understanding Histograms

Of course the histogram is just one tool. On stills I also use the TTL spot meter, on a video camera I use it in combination with a zebra pattern, false color is another useful tool found on some cameras and monitors.

Quoted: "you have to have the Exposure simulation On (Camera setting screen 4, 4th item)for the histogram to be available after pressing the "Info" button.)"

I would love to find out how to get this histogram setting in 7D working, but my 4th selection on that 4th page says "Sound Recording" and "Exposure Simulation" (as per the manual) is greyed out on the only screen I can find it on which is the MY MENU SETTINGS screen.

I'm missing something, but I can't figure out what it is. The Exposure Simulation doesn't show up where the manual says it should be in any mode dial setting. I know I'm going to feel foolish when I do figure it out, but any shortcut hints would be appreciated.

Are you in Still Mode or Video mode? I think you need to be in Still Mode, in Video mode it seems the menus change, some things like bracketing and histogram aren't available. The histogram is available only in Still Mode or in Playback mode.

BINGO! You now have a film camera (but the reels are disguised inside that CF card. Shoot it like film, and you'll be fine.

Well yes, there you are. The setting is there in still mode and enabled. Doesn't help much for video (I wish that term would disappear as video to me means 'interlaced' as in video and 'progressive' means motion digital in my book) mode though does it? I guess everyone who's suggested reverting to a light meter may have the best points in terms of accurate exposure readings and settings since we can't see a live histogram or a live HD picture to judge exposure and focus by. I'll trust my ancient but experienced eyeballs for focus but exposure is a different horse as it varies from camera to camera settings.

Back to the future.

I would make one caveat to that statement. Shoot it like REVERSAL film.

Agreed Bruce. Treat it like KodaChrome 64. You have to tease the goodness out of it, but it's like dancing with a gorgeous woman... get it wrong and you'll be disappointed. Get it right and you'll have every eye in the room...

Excuse me.
For those of us who've never made films from chemicals ;-) could you please explain the significance of these comments about reversal film?

I believe it's film for when you are walking backwards with your camera. : )

Reversal film has a very short exposure latitude. Meaning, you better nail your exposure or you'll be in trouble.

Negative film is very forgiving, you can mess up your exposure and with good post no one would ever know. This also means you can achieve a lot of creative effects when shooting on negative due to it's increased exposure latitude.

Like reversal film the H264 codec lacks exposure latitude and isn't great for grading in post. This is one of the reasons why so many of us are interested in RED, because it shoots RAW and allows far greater freedom in post.