Setting Auto ISO and then locking or AE + / - possible?
 

I'm doing a bunch of 'run and gun' with the 5D MkII (and 7D and 1D mkIV) a super zoom lens, which allows me to have a very wide range of focal lengths and get close to the action. However, the Super zoom lens I have, a Tamron 28-300, changes from 3.5-6.5 depending on the focal length (longer = smaller aperture).

So I've been using Auto ISO in full manual mode and shutter speed set to appropriate values for video to quickly get me to a fairly optimum exposure. It works pretty well, until something in the frame gets brighter or darker, then the ISO changes to get a good average.

What I'd really love to do, and haven't found a quick answer to, is to have the 5D set to Auto ISO, but then hit a button and 'lock' the ISO at that point. Then hit a + or - exposure to bump the ISO up or down if it's not quite right. Then hit another button to 'unlock' the ISO and have it go back into Auto ISO again and set what it thinks is proper.

Is this possible? Any advice is appreciated.

-Keith

I don't know if what you're wanting to do is possible. I think you can set iso on the fly, but that requires using the iso button and changing,which with practice you might be able to do effectively without looking.

I'm guessing you already know this, but the best option, when using a variable aperture, is to set the lens in manual mode to the higher F-stop and just going with that. So in your case F6.5. I know you lose a lot of light this way, but it will allow you to zoom without the aperture changing and keeping your exposure consistent.

Not to get nosy, but why on earth do you have so much invested in bodies and not good glass? I have that lens and it's good for for your bag and when you're out in sunlight, but it's not great glass and what you could have bought with not having a 1D mkIV.....not judging just wondering.

For run-n-gun stuff, there are plenty of options.

Here is one I use a lot:
Turn main power switch to "ON", set the camera dial to AV, point the lens at an evenly lit subject, press the *AE Lock button and then your exposure setting, aperture, frame speed, and ISO will remain locked on that first evenly lit setting. To adjust exposure slightly within that locked setting, simply move the power switch up one notch and then fine tune minus- & plus+ exposure values using your thumb on the main Control Dial.

Hi Christopher

Thanks for the reply. I'm aware of how the manual mode works and setting to stable fstop is what I do (if I want to), it's not that the fstop is creeping up or down, but the ISO is creeping up or down based on what it thinks is the average light of the scene. I want to be able to manually set the aperture and shutter "M", but have the auto iso work for me to balance the scene, but then be able to lock the AUTO ISO it move around with me and do some exposure compensation if I want with it.

I do have a lot of *very* expensive glass, as much or more than the bodies and I use this if I'm in a controlled situation. If you do run and gun, you can't switch out the lenses every few seconds and it's not practical to physically move in our out. Though you can get amazing images with primes and other good glass, for some type of video it's not as necessary, I've found. If I had a choice I'd use a prime or constant aperture zoom (I have many) but none has the 'throw' of the superzoom 3rd party lenses.

Keep the suggestions coming!

Thanks Tony. How do you get your shutter speed to be constant using that method?

When you press the exposure lock button, the speed value will appear on the rear screen, and will remain locked at that setting while you spin the rear dial to minus or plus values.

Ah I see Keith, I was confused as to why you brought up that lens in particular then.

I think you can really only do what others are suggesting. I love the idea of what you want to do, almost like there needs to be a dial for now the third manual control option that film never really had, variable ISO on the fly. I feel like when you adjust exposure this is what the camera is doing, changing the ISO one stop. I'm probably wrong, just a guess since I rarely use the +/- exposure adjustment.

These new cameras are so light sensitive, almost ISO agnostic and having Auto ISO means there should be another priority setting, like an Iv setting. I'll see if Tony's suggestion works. However please keep the suggestions coming!

If you set the camera dial to "M" and set ISO at a fixed setting, say 160 in decent daylight and to maintain quality, or at a higer fixed ISO value in dull light, you should be able to do plenty of off-the cuff stuff as long as light levels are fairly stable. Then just adjust aperture with rear dial or shutter with front dial while ISO remains constant.
Not as quick and easy as using the AV plus AE lock & rear dial method during constantly changing light levels, but OK during takes where light levels are not changing fast.

You can also use TV plus AE lock & rear dial method to have more control over the shutter, but the 5D tends to choose widest possible aperture for any given scene most of the time during TV, something I don't like because I prefer to have more control over the aperture settings.

No one has answered your question directly. The answer is "no" you cannot use AE Lock while in M mode using Auto ISO. M mode = no AE Lock. And yes, that sucks and was an oversight by Canon with the new firmware IMHO, but it is what it is. Also, if you shoot in shutter or aperture priority I personally believe you risk the repeated frames syndrome, but that is debatable. Bottom line is, just use M and manually set iso, it gets to be completely instinctual after a while, even in a run-n-gun context.

Yeah, been playing around with it and the lock just doesn't lock auto-ISO. That would have been awesome in M mode, and Auto ISO is on, just act like you're in a AV or TV mode and the * button turns the back dial into +/- ev.

Too bad the Canon's ISO setting can't be adjusted while recording. It's stop recording, click ISO, move some wheels, click ISO, click record. I was looking for some type of trick that somebody might have discovered, because I really actually like what Auto ISO does for me in very changeable focal lengths and hence, the exposure for the scene, as well as my variable aperture super zoom lens which doesn't help.

If anybody has other advice, please chime in.

Keith,

I assumed that you couldn't change ISO on the fly when you posted this, but I just got done playing around today testing out a new rig config and I was totally able to hit my ISO button and change the ISO while I was recording. It wasn't too difficult either. Hit the button, spin the front dial, all can be done by touch. If you have the bottom info showing on LCD, it will show the ISO changing as you do this. I just let it go without hitting ISO again when I set it to what I wanted and it was fine. My setup is balanced enough to be able to pull this off without much bouncing of the camera while hand-holding even.

Thanks Christopher, I'll check that out. I'm currently doing a lot of work on my 1D Mk IV so perhaps it's a bit different than my 5D as far as on the fly ISO.

Exactly. .