My thoughts on the AF100 after 1.5 days

With CCD it doesn't do the rolling bars. What you might see is a minor color shift, like as if it was auto-white-balancing. With CMOS, you get the rolling bars.
 
Well honestly, we avoid ballasted lights, but, it is something I have looked for in our shots. Almost everything I have shot over the last year with the 7D has been at 1/50. I've not seen any flickering, and have specifically looked. Even under flouro lights in interior shots from one of the buildings we shot at. I was looking for banding too and neither I nor the other editor saw any of this.

Not that your advice isn't good, but I like to get the most of the exposure as much as I can. I am a 'every little bit counts' :)

Pertaining to the shutter settings, I will check it again tonight, but I wasn't seeing the operation in this way. I'll test it again tonight and report. (between FILM CAM and VIDEO CAM) What I saw was that VIDEO CAM had more slower shutter speeds still represented in fractions than FILM CAM which had a smaller number (nothing below 1/24) and both modes could set a degrees setting if on syncro only. You have to set the shutter speed to syncro, then hit the select button above it, then it lets you set a degree amount.
 
Barry, so if you're using Syncro Scan mode, what are the safe degrees to use? 180 degrees would be equal to 1/48, right? So what would we use safely?
 
grimepoch said:
I was looking for banding too and neither I nor the other editor saw any of this.
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Play the footage in fast forward and it'll make the bands a lot easier to see. And, not all light sources do it. An easy way to tell is to pop the shutter up to 1/250. If you see banding in 1/250, it's going to be banding in 1/48. If you see no banding in 1/250, you're safe to use any shutter speed.

Pertaining to the shutter settings, I will check it again tonight, but I wasn't seeing the operation in this way. I'll test it again tonight and report. (between FILM CAM and VIDEO CAM) What I saw was that VIDEO CAM had more slower shutter speeds still represented in fractions than FILM CAM which had a smaller number (nothing below 1/24) and both modes could set a degrees setting if on syncro only. You have to set the shutter speed to syncro, then hit the select button above it, then it lets you set a degree amount.
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There are more slow shutter speeds available in VIDEO CAM mode, yes.

Okay, just do this -- put the cam in FILM CAM mode. Use the shutter wheel to choose the speed between the slowest and fastest speeds; it'll be 180.0d if you haven't changed it. Then go in the scene file menu and change to VIDEO CAM. Look at your shutter speed. It'll now be 1/48.0.
 
Mike@AF said:
Barry, so if you're using Syncro Scan mode, what are the safe degrees to use? 180 degrees would be equal to 1/48, right? So what would we use safely?
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Only those that result in 1/120, 1/60, 1/40, 1/30, or 1/24. Anything else = banding. Although, as said before, the closer the shutter speed is to a safe shutter speed, the less banding you'll see.
 
Okay, funny you should post this as I was just going through the settings and now see the syncro settings change to fractional in video mode. That is some fine tuning I will say when scrolling the wheel in fractional mode :)

It's funny because I really wish I could set it as a hybrid. I think in terms of ISO for gain, but then I think in terms of fractional representation for shutter speeds. I guess they should have added "DSLR MODE" :P For people like me. I also went back to the HVX200 and yes, this is the same method of operation.

What I hadn't realized is that when it says shutter off, that is then the off setting which is NOT 48 but 50 for 24P. If that makes sense :)

Well, I can live with the shutter speeds, as I think it makes better sense to be safe on the shutter than not. However, I am still standing firm on the ISO settings. I'd actually like to swap the frame rate off the back dial and put ISO there instead. I VERY RARELY switch framerate, but I very often change ISO.
 
Grim, my friend -- leave the old DSLR thinking behind you, and embrace the video side. Jump in with both feet, instead of trying to make a video camera work the way you're used to with a DSLR. :thumbsup:

In film, you know how often we change the ISO? Never. Heck, you'd have to unload a magazine and reload it with a different film stock just to change the ISO!

In video, do you know how often we change the ISO? Rarely ever. Set it on 200 and forget it. If you have to change it to higher, we video guys get nervous and start asking for more lights instead. Changing the ISO frequently? That's... bizarre. :) It's like when in VIDEO CAM mode, ask the video shooters here how frequently they reach for the gain switch. Video guys know that "gain = grain", and gain is a last resort after all else has been explored. The first thing we do is change the ND filter to the most-clear we can get. Next is to open up the iris. Then, if we still need light, a small opening up of the shutter (if, presumably, it's safe to do so) so going to 1/40th or 1/30th or even 1/24th. And if we STILL need more light after that, then we'll consider the gain. Motion shooters are very used to the idea of, well, if you want to call it this, it's "shutter priority" mode. Know how to change the shutter speed on most film cameras? You can't. I've owned dozens, and I think only one has ever had a variable shutter angle. Most film cameras have a fixed shutter speed*, and the way you control exposure is by the iris, or by adding an external ND filter. If you're still hosed, then you can try changing to a slower film stock, but in film you really don't want to go mixing various speeds of film stock because the grain pattern is so very different, so you try to avoid that where you can. So it's odd to me to hear you saying that you make your decisions by choosing the aperture first and changing everything else to support that aperture; that's totally backwards from how all the motion shooters I know normally work. In motion (whether film or video) the shutter speed is basically considered fixed, and the ISO is basically fixed as much as we can, and the only things that change are the iris, and the presence (or lack thereof) of ND filters... and if you really want to pick your iris, that's when you use your lighting to change the exposure. If I want a particular shot at f/2.8 for some reason, then I use lights to get the scene to where f/2.8 is the proper exposure. The shutter speed stays fixed at 1/60th and the ISO stays at 200 (unless I just don't have that much light; then I might go to 400).

*yes modern film cameras frequently have adjustable shutter angles, but I'm talking about the good old days from 1917 up to, say, about 1985 or so...
 
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Hey Barry

I owned and ran a motion picture film lab for 6 years and we used to change the ISO for DPs frequently.

Some time by design and sometimes because they made an error!.

We used to push and pull the process.

But I agree with your post absolutely.

ps. paragraphs would be nice Barry.
 
Well let me say this, just because we didn't have these simple freedoms before doesn't mean we shouldn't use them now! :P But in seriousness, it comes down to noise, and what I want to happen with that noise.

I don't ever like to shoot below the native resolution of the sensor because we just start clipping the dynamic range. For this problem (like outdoors) or trying to use a really fast lens in a bright situation, absolutely, I like to use an ND filter. I used the FaderND all the time and completely agree.

However, one thing I don't want to do is drop to a higher gain in a huge step and then have to open up the lens a lot or put an ND filter on the front of it. Given the large steps that I have to choose for both ISO setting and ND setting, it means if I want to keep my iris consistent, I have to take that hit.

My biggest problem is Let's say I am at ISO800 and I want to lighten it up a bit, and that is my medium gain setting. I am shooting deep focus so I've got the lens stopped down, say for something I am going to do a lot of VFX work on. I don't want to go to 1600 as that is a huge jump. On my 7D, I can go to 1000 or 1250 inbetween. So my only option in this case if I want to keep the DoF I have going is to pop it up to 1600 then use an ND filter to bring it down, which then adds more noise than I'd like since I can't select a gain that would be almost perfect.

I'll just have to experiment with the IRIS settings and do some more tests to see if I can get the look I want and the freedom I want for lower noise. Having finer increments in gain to me is a VERY positive way of not having to decide between 3 gain settings and work up and down from them. This way, you can dial in less noise for darker scenes.

Sure, you can say add more light, but I'll be honest, I am glad we aren't shooting with the HVX anymore. It's not about not using lights, but it is nice to use lower wattage lights and have the freedom to use battery powered lights to do some really nice lighting design when you have a camera that is very sensitive and not overly noisy. I used the 7D up to 2000ISO on some shots, but mostly stayed at 1600 or below, and I used ALL the settings between 400 and 1600.

Time will tell :) We are shooting some pickup shots for our series soon, and we are shooting them on the AF100 instead of the 7D. Of course, we will be a little limited in what we can do till Birger starts shipping adapters! :) I have two full manual lenses. (50mm F1.8 Nikon and 85mm F1.4 Bower). Luckily, all the other lens work full open, and with the built in ND is not a huge problem.
 
So, the UPS truck brought my shiny new AF100 this afternoon, and in playing with it I've discovered something very odd. At any shutter speed from 1/250 and faster, if I set my frame rate to anything not a multiple of 24 or 30, I get those nasty rolling CMOS bands that are to be expected, as Barry describes, under certain ballasted lights at certain shutter speeds. The crazy thing is, the only lights I have on are normal, household tungsten incandescents! I don't even have CFLs on. Is this a normal CMOS artifact? Barry, does your AF100 do this?

If its related to 60 Hz AC somehow, why would 24 fps and 48 fps be clean? (And I thought that tungsten filaments running on AC aren't supposed to have time to cool down at all between cycles anyway?) I'm perplexed now...
 
I've looked at mine with EVERY shutter speed and I do not see this happening under tungsten bulbs. Now interesting, some of my electronic equipment had LEDs on them, and if I go further than 1/120 they blink A LOT. Must be how they are modulating them inside (since typically, an LED is run off of a DC voltage, but here, they must be multiplexing the LED readouts from a microcontroller and stepping through them really fast).
 
Mm-hmm. Glad to hear that, Grim, and also not, so glad. Sounds like I may have a defective unit...

Anyone else encounter this issue?
 
Do you see the banding in-camera or only on playback? If only on playback, is it during playback at normal speed or something else? I ask because when filming with the 7D I have issues with some of my HMI lights banding, but it is only visible during 2x playback.
 
Riddles everywhere on this forum about this camera. I wonder which one I'll run into with mine!
 
As Barry has been saying, a CMOS camera like the 7D or AF100 and magnetic ballasted HMIs are practically a recipe for rolling bands. However, I'm seeing this with normal tungsten lights.

However, I have to correct my previous post; 48 fps is not clean. It appears clean during recording, but the bands are visible upon playback. Also, now that Mr. Sun is back in the sky here in Minnesota, I've confirmed that this isn't a problem under natural illumination. All of which indicates an issue with 60 Hz line frequency, which is still really bizarre, since its somehow being conveyed through hot glowing tungsten filaments.

I haven't had time yet to fully charge a battery, so I wonder if not having the camera plugged into the wall would make a difference for me? Perhaps I should start a new thread...
 
Problem solved, I think. It appears the problem is the electricity in my house, not the camera!

I figured out that the rolling bands were actually present at regular 24P with a very fast shutter; they're just very subtle and move very slowly so they're hard to see. So I fired up my 7D, cranked up the shutter to 1/500, and lo and behold, subtle rolling CMOS nasty bands! I just had never noticed them before because I've never cranked the shutter that high under tungsten light in my house.

Out of curiousity, I fired up a 1K instead of a 100w household bulb, and the rolling bands were still present on both cameras, just a bit more subdued, likely due to the beefier filament. And no rolling whatsoever under a properly ballasted flourescent!

Will attempt to test out the camera at a different location with cleaner power to confirm....
 
Ljung said:
Problem solved, I think. It appears the problem is the electricity in my house, not the camera!

I figured out that the rolling bands were actually present at regular 24P with a very fast shutter; they're just very subtle and move very slowly so they're hard to see. So I fired up my 7D, cranked up the shutter to 1/500, and lo and behold, subtle rolling CMOS nasty bands! I just had never noticed them before because I've never cranked the shutter that high under tungsten light in my house.

Out of curiousity, I fired up a 1K instead of a 100w household bulb, and the rolling bands were still present on both cameras, just a bit more subdued, likely due to the beefier filament. And no rolling whatsoever under a properly ballasted flourescent!

Will attempt to test out the camera at a different location with cleaner power to confirm....
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Eli,

I wonder if it is some other kind of interference like wifi, microwaves, etc... Maybe it's time to sell.
 
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