I have GH1 for almost a year. Amazing camera! I'm just wondering how many of you shoot video with Auto ISO? I'm asking because when I do shoot with full manual I lost the ability to use Auto ISO and I hate constantly adjusting ISO settings. I've also noticed with full manual mode the video seems a lot darker with max ISO setting, but Auto ISO has much brighter picture.
Auto ISO
- Thread starter dojoman
- Start date
It's always struck me as odd that auto iso is not among the options in manual operation. You want a certain shutter speed and a certain aperture, but in real world conditions a very small movement of the camera or change within the scene is likely to result in over or under exposure, which auto iso might compensate for. As you can't vary the manual settings within a shot without causing noise or vibration, about the only option is deft use of a variable ND filter, being sure to keep your fingers out of the shot.
The sudden changes of exposure produced by using shutter priority rule that out as a method of dealing with changing light conditions too.
The sudden changes of exposure produced by using shutter priority rule that out as a method of dealing with changing light conditions too.
I don´t think that people are really wondering why here isn´t an auto setting in full manual but they just would like to see a "Manual Priority Mode" in which ISO varies while all other settings stay as set up. I sure would try it out if it existed.
I suppose since aperture priority exists and shutter priority exists, having some sort of auto ISO would be useful to some. But I can't imagine it being very pleasant while rolling video. ISO setting are calculated in 1/3 stops, so if lighting conditions change while rolling, chances are any "Auto ISO" would cause a noticeable "bumP" as it shifts from one ISO to another. And would you really want to ramp from say 100 ISO to 1600 ISO as you pan from the sky to a shady area? Not only would it look like a consumer camcorder on Full Auto (aka amateurish), but the image would go from clean to noisy. Again I'm not against it existing. In fact, I think this is what Canon and Nikon video modes have to control exposure. Would I use it? No.
Exactly, you either shoot auto and have the bumps and don't care about anything, or you shoot in full manual and you take care to not go from full light to dark. Movies are shot like that, if the camera goes to a completely different lighting, it either goes dark or the image washes out.
Film cannot change ISO and if you want to emulate that look you dont care about auto ISO.
Film cannot change ISO and if you want to emulate that look you dont care about auto ISO.
But not keep the shutter speed and aperture fixed but vary the ISO in any of those modes.
Like you see if shutter speed or aperture are allowed to vary. The ISO setting, being totally a matter of electronic processing, should be capable of being smoothed, I would have thought.
It doesn't have to be so radical a pan for problems to become evident with exposure. Modest ISO changes would, I'd guess, be less likely to cause visible image changes compared to aperture (and therefore DOF) changes.
I would have thought that pro equipment would allow for in-shot manual aperture variations to cope. Is it really the case that in pro movie making situations, all settings are fixed at the start of a shot and don't vary despite any unavoidable lighting changes? I appreciate it's best to avoid illumination variations during a shot but it must happen sometimes.
I know people seem to be jumping your case for wanting Auto ISO and well...they are jumping your case. It's not that it can't be done, and done smoothly. It can. It's just that the idea is a bit repugnant for people who want to see the GH1 as a professional moviemaking camera. Auto ISO reeks of a "consumer" option for the Average Joe's who want to point-and-shoot. To answer your question:
9 times out of 10, the cinematographer will use lighting or somehow control the variations in light amounts so that it fits within the dynamic range of the sensor/film. On rare occasions (i.e. Steadicam going from interior to a sunny exterior), they may do an aperture ramp. They try to keep it within a stop or so, otherwise it may look too noticeable. Does this affect depth-of-field? Yes it does. An ISO ramp in this instance seems like a viable solution if one were shooting with a digital cinema camera. But most cinematographers are going to prefer to solve the problem by adding more LIGHT, not by pumping up the gain and adding more NOISE, which is what an ISO boost does.
9 times out of 10, the cinematographer will use lighting or somehow control the variations in light amounts so that it fits within the dynamic range of the sensor/film. On rare occasions (i.e. Steadicam going from interior to a sunny exterior), they may do an aperture ramp. They try to keep it within a stop or so, otherwise it may look too noticeable. Does this affect depth-of-field? Yes it does. An ISO ramp in this instance seems like a viable solution if one were shooting with a digital cinema camera. But most cinematographers are going to prefer to solve the problem by adding more LIGHT, not by pumping up the gain and adding more NOISE, which is what an ISO boost does.
D90GH1_eric
Active member
By logic, you are right, but auto ISO can make the manual mode so much easier on the photographer. My Nikon cameras all allow auto-ISO in full manual mode, and it really speeds things up for you.
Back to the OP, I have seen several videos on Vimeo in which people use the iA mode and the results are surprisingly good. I have tried the A and P mode for video but I found the default auto-ISO is too conservative as the camera is reluctant to go beyond ISO 400. This creates a problem at low light because it creates too much shallow, which in turn intensifies the noise/banding problems.
Again, I can see the value of an "Auto ISO" function. And I know that Nikon and Canon have this, but as an option to "Full Manual"? Anything "Auto" in something called "Full Manual" seems like an oxymoron to me. The whole point of "Full Manual" is that everything is under MY control, not what the camera thinks is correct. If I'm going into Full Manual, it's because I know best what exposure I want, not the camera's best guess. If I know my image needs to be intentionally overexposed or underexposed, or if I know the camera's meter will be fooled by an unusually bright or dark subject, I don't want "Auto ISO" to try to adjust the image. To put that option in "Full Manual" makes no sense to me.
So if ever auto-ISO in full manual mode is provided, you won't be using it, thus retaining your control. It's all about options. There could even be a menu option to turn such a facility off altogether for those not liking even to be offered it.
Taking you literally, that's not the only point in full manual. It enables you to choose what shutter speed you want to smear or freeze motion, and it enables you to choose what aperture you want for depth of field effects. Unless you then want a deliberately under or over exposed image (which you might well, I agree) then the result of auto-ISO should be to save you the trouble of making the same selection as the camera would, and in the context of video to deal with any variation in the illumination of the scene during the shot.
In a sequence of video shots you might well want to use (say) 1/50 (PAL) and f5.6 for all of them, and let's say you want 'correct' exposure of all of them. So you got three options for those shots -
- light them to ensure illumination level between shots is the same, which may present practical difficulties especially out of doors
- use ND filters to control the light passing through the lens regardless of actual scene illumination, which can be require a fair amount of faffing about and perhaps picture quality issues
- use a different ISO setting for each shot to control the exposure.
If taking the third route, you're going to have variable noise between shots, so I'm not convinced that variable (auto) ISO within a shot (smoothly varied) is going to be such a bad thing in comparison.
Perhaps someone should devise an auto-varying ND filter, or devise one with a flange that can be easily rotated from behind the front glass.
PhilJackson
Active member
I'd rather a video shot go a bit dark or over exposed due to the natural situation than the camera get fooled by some passing car head lights or camera flash and think the sun is right next to me and black out everything.
If you want an extra option on the turn wheel for Auto Iso then that's cool but saying that full manual should be anything but full manual is sort of idiotic.
If you want an extra option on the turn wheel for Auto Iso then that's cool but saying that full manual should be anything but full manual is sort of idiotic.
D90GH1_eric
Active member
This is exactly how Nikon does it. In M-mode, I can choose to use auto-ISO or not. If you choose auto-ISO, you can still set a high ISO limit so the camera won't go over it. For the D90 that I have, which has very low noise all way to ISO1600, any variation in ISO below that does not really affect image quality. I thus think that the lack of auto-ISO for the GH1 is an oversight but not a feature.
pro or not pro, I think no one could really deny the addition of options if you had an optional auto iso in a manual mode. say you have to shoot a planned sequence and as an indie you don´t have the possibility to add huge numbers of lights throughout the scene because you´re on a budget.
when slight differences in your lighting could be compensated for by autochanging the iso (seemlessly) in between 100 to 400...that´s nothing else than an option-giver.
grain between 100 and 400 is neglectable, maybe even 800 if neccessary.
I do everything video in manual but if I think about it, I´d much more like to say "let´s try it on auto iso (limited to 400)" than something like "well, it´s too dark there, let´s add more lights. hm? we don´t have more lights? ok, then it will be dark in that spot..."
like all settings, it would be a tool, to be used in the right moment.
when slight differences in your lighting could be compensated for by autochanging the iso (seemlessly) in between 100 to 400...that´s nothing else than an option-giver.
grain between 100 and 400 is neglectable, maybe even 800 if neccessary.
I do everything video in manual but if I think about it, I´d much more like to say "let´s try it on auto iso (limited to 400)" than something like "well, it´s too dark there, let´s add more lights. hm? we don´t have more lights? ok, then it will be dark in that spot..."
like all settings, it would be a tool, to be used in the right moment.
PhilJackson
Active member
True options aren't bad, I guess it was poorly presented.
Martti Ekstrand
Veteran
Just use a Fader ND or Vari-ND in such a situation. Image quality (ISO), DOF (aperture) and motion blur (shutter) stays the same during the shot while exposure is still controlled.