Exposure Compensation Question

[DanK]

Why is that unique? On every DSLR I have seen, you can leave ISO set at one value. I often leave mine at a single value.


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[george013]

I have a Nikon Df, which granted is a fairly unique box as it is meant to emulate a film camera in its behaviour.
If I set the ISO to locked then it remains so. It makes sense for a couple of reasons:
1. Film cameras had the ISO locked for the whole film (unless you went for push processing, but that's a whole different story).
2. In manual one wants to control the exposure, usually by adjusting aperture and shutter, having the ISO keep changing on its own would be defeating the purpose.

It looks like a contradiction. I always wondered why and can't see any reason why auto iso is not disabled when shooting in M. I personal don't use auto iso.

George

[Manfred M]

It looks like a contradiction. I always wondered why and can't see any reason why auto iso is not disabled when shooting in M. I personal don't use auto iso.

George

George - a bit of a misreading on your part, I suspect. Auto-ISO can be enabled or disabled when shooting in manual mode on Nikon cameras. I use it in disabled mode all the time when shooting panoramas because I want no variation in exposure from frame to frame. I have not shot manual on auto-ISO yet, but suspect that I'm going to try it in the future. There are definitely times where I want a specific shutter speed and specific aperture for depth of field reasons; auto-ISO might be a solution in that type of shooting situation, if the light levels vary.

I usually do not use auto-ISO, but have done so on occasion when shooting is situations where there is a significant variation in light levels, for instance when shooting at events.

[rpcrowe]

I'd suggest something even simpler. It is a way for the photographer to correct for the assumptions built into the camera's metering system when the shooting conditions fool the meter into selecting an inappropriate exposure. Shooting at night, into the sky or on a snowy day are typical examples of where this happens.

Right on Manfred...
When shooting night cityscapes, I will bracket my exposures by three stops AND add a minus one stop exposure compensation.
This will result in 3-bracketed images... One as the camera reads, one at -1 stop b;ow the meter reading and one at -2 stops below the meter reading.
I can just about guarantee that in almost all cases, you will get at least one perfect exposure from that combination because, as Manfred mentioned, you need to "fool" the camera's meter not to expose for the overwhelming dark of the night.
If you don't "fool" the camera, you will likely result in one or both of the following problems...
A shot in which the night is not dark but rather a muddy gray...
A shot in which any light sources are quite overexposed...

BTW: I just tested my Canon 6D2 on manual exposure with AUTO ISO. I can add + or - EC...

[george013]

George - a bit of a misreading on your part, I suspect. Auto-ISO can be enabled or disabled when shooting in manual mode on Nikon cameras. I use it in disabled mode all the time when shooting panoramas because I want no variation in exposure from frame to frame. I have not shot manual on auto-ISO yet, but suspect that I'm going to try it in the future. There are definitely times where I want a specific shutter speed and specific aperture for depth of field reasons; auto-ISO might be a solution in that type of shooting situation, if the light levels vary.

I usually do not use auto-ISO, but have done so on occasion when shooting is situations where there is a significant variation in light levels, for instance when shooting at events.

No misreading on my part. Manual and auto iso is a contradiction. The question is why Nikon and probably other brands do enable that. Of course I know I can enable or disable it.

George

[rpcrowe]

George,
IMO, manual + ISO is not really a contradiction. It is a viable way to shoot when you want to keep the aperture and shutter speed constant and especially when the light is changing. I will often use that combination when shooting sports. I will want to keep the shutter speed very high in order to stop action and the aperture wide open to isolate the players/athletes.

[george013]

George,
IMO, manual + ISO is not really a contradiction. It is a viable way to shoot when you want to keep the aperture and shutter speed constant and especially when the light is changing. I will often use that combination when shooting sports. I will want to keep the shutter speed very high in order to stop action and the aperture wide open to isolate the players/athletes.

Still manual and auto is a contradiction to me.
But your example is a good one of how to make use of it. Thanks. I'll remember that.

George

[pschlute]

i am with George on this one. Manual mode to me means manual everything. On my camera , Pentax K-1 I cannot select auto ISO in M mode. There is however a separate exposure mode called TAv, which replicates Manual + Auto ISO. I don't use this much but it is useful when shooting action with a longer lens in order to select high shutter speed and desired aperture and let the camera choose the ISO. The high/low limits of the auto ISO can be changed too. This is really the only mode I use auto ISO at all.

[DanK]

No misreading on my part. Manual and auto iso is a contradiction. The question is why Nikon and probably other brands do enable that.

No more a contradiction than using manual mode with autofocus. "Manual mode" generally means manual control of shutter speed and aperture, nothing more.

I also rarely use auto ISO, but I do sometimes find it useful, particularly with manual mode. For example, a while back, I was asked to take photos of a play. The stage lighting was both dim an highly variable, and of course, I could not add lighting. I set a shutter speed to freeze motion and the aperture I needed for sufficient DOF (I was shooting at an angle to the stage), and therefore I needed to vary ISO to cope with the varied lighting. There wasn't time to do it manually--I had to try to capture moments as they happened--so I used auto ISO.

[Manfred M]

Manual mode to me means manual everything.

When I want to "go manual" on my camera, not only do I have to ensure that I am shooting with manual exposure (auto-ISO turned off), I also need to disable autofocus (when shooting a pano or when bracketing, I don't want the camera to re-focus between shots) and disable image stabilization as this will lead to minor, pixel level shifts when shooting on a sturdy tripod. I also cover the viewfinder to ensure that there are no light leaks from the viewfinder; when taking long exposure shots.

So "Manual" refers to exposure only. Some of the other automated camera functions remain "on". My biggest issue isn't disabling them, but rather remembered to turn them all back on.

[george013]

When I want to "go manual" on my camera, not only do I have to ensure that I am shooting with manual exposure (auto-ISO turned off), I also need to disable autofocus (when shooting a pano or when bracketing, I don't want the camera to re-focus between shots) and disable image stabilization as this will lead to minor, pixel level shifts when shooting on a sturdy tripod.

So "Manual" refers to exposure only. Some of the other automated camera functions remain "on". My biggest issue isn't disabling them, but rather remembered to turn them all back on.

Yep. We're talking of the M on the exposure mode button. Not the M on the lens or focus switch.

George

[Tronhard]

It IS interesting the different interpretations of the term "manual'

OK.. MY definition of Full Manual is that one manually sets all three exposure parameters. That doubtless comes from my film days when one has one ISO set for the film.

When I shoot normally I have my ISO set at a specific value, so that is normal for me. When I use Av or Tv I am usually allowing only one exposure parameter to be modified.

While I respect Manfred's approach to using manual focus I usually leave the AF on - but I use spot focus and locking - I suspect my eyesight up close is not that good!

[rpcrowe]

I "TRY" to remember to set all of my shooting parameters back after I have been using some unusual settings. However, I do occasionally have a "senior moment" and, at least at the moment I pick up my camera, shoot with the unusual settings and wonder why my exposure is so messed up or why the camera isn't autofocusing like it should Of course, I probably have the camera on EC or the lens on manual focus

[Tronhard]

Well at least you have a working camera - I have (thankfully on very rare occasions and some time ago) gone out without batteries or card!

[Manfred M]

No misreading on my part. Manual and auto iso is a contradiction.

From a pure semantics standpoint I tend to agree with you; "Manual" suggests completely manual control over the camera exposure functions.

Photography is not about semantics, but rather about having the functionality that gives the photographers the tools that they need to get the job done. From a functionality standpoint, it makes sense for Nikon (and other camera manufacturers) to incorporate auto-ISO as an option on all exposure modes.

If the tool works, works I don't really care what it is called. Nikon's VR (Vibration Reduction) is not a great name as the tool reduces the impact of camera movement. Exposure Compensation (EC) is another term I don't particularly like. What we are really doing is over-riding the exposure that the camera has calculated for us, so in my world I prefer to call it automatic exposure over-ride.

[Tronhard]

From a pure semantics standpoint I tend to agree with you; "Manual" suggests completely manual control over the camera exposure functions.

Photography is not about semantics...

Manfred I think semantics are important in any communication. If a variation in the definition of a term, feature or process is accepted it immediately opens the door to misinterpretation. I am not undermining your preference for using your own variation of manual, much as I hope you don't take exception to mine, but we need to have clear definitions of what we are discussing or there will be unnecessary debates. Many terms such as "IS" and "VR" are branded identities for manufacturers' versions of similar technologies, so they are essentially trademarks.

I absolutely agree that camera makers should strive to give photographers all the functionality they seek - it's a commercial imperative to sell gear. That said it is important that they use a common language for things that are not brand specific.

[pschlute]

MY definition of Full Manual is that one manually sets all three exposure parameters. That doubtless comes from my film days when one has one ISO set for the film.

Yes. If my post did not make it clear I was refering to manual control over exposure only.

I too come from the film era and perhaps that colours my expectations. On my camera I cannot use auto ISO in Manual exposure mode (which I am happy with), but can use exposure compensation which to me seems totally pointless.

[rpcrowe]

As a matter of semantics, what would you call it when camera has the mode dial set at Manual (M) and the ISO set at auto. I would call it "Manual with auto ISO"

I guess that you could call it "Automatic ISO selected by the camera with f/stop and shutter speed determined by the user and set into the camera an immovable combination".

That accurately describes it but, is quite a mouthful

All kidding aside; as an old film guy, I first revolted at Auto ISO until I began using it and realized how useful it can be! Just like I revolted at auto focus; thinking I can do a better job manually than the camera could do. I found out that I couldn't

[Dave Humphries]

My apologies to the OP for taking this off topic, but he seems to have already acknowledged the previous replies above had answered his query.

Ok, bear with me; I know this might just tip some 'over the edge'

If film cameras had never existed and manufacturers were to design a digital camera from scratch, what we might have is a mode dial with:
Auto for fully Automatic Exposure (camera uses aperture and shutter speed and ISO to achieve metered exposure)
S (or Tv) for Shutter Priority (camera uses aperture and ISO to achieve metered exposure)
A (or Av) for Aperture Priority (camera uses shutter speed and ISO to achieve metered exposure)
I (or Iv) for ISO Priority (camera uses aperture and shutter speed to achieve metered exposure)
SI (or SIv) for Shutter+ISO Priority (camera uses only aperture to achieve metered exposure)
AI (or AIv) for Aperture+ISO Priority (camera uses only shutter speed to achieve metered exposure)
SA (or SAv) for Shutter+Aperture Priority (camera uses only ISO to achieve metered exposure)
plus
M for Manual, aka "Full Manual".

Now this appeals to the part of my brain that likes unambiguous access to all the options in a very logical manner - but not everyone likes truth tables

However film cameras did come first (and they can't do auto ISO), so we were 'used to' cameras with P, S, A and M modes only.
So for legacy reasons, the mode dial remained the same and Auto-ISO was 'buried' in the menus.
Now that does have some advantages;

• there's not much practical value in an "I" semi Auto mode where we fix ISO and let shutter speed and aperture vary randomly to achieve the metered exposure
• turning Auto-ISO off and on in menu allows a less cluttered mode dial, at the expense of some confusion in people's minds when they first encounter it, or change cameras, plus even more confusion when we discuss it in forums

What happened to "P" mode?
Well that's a good question; P mode is Auto, with the ability to 'trade' shutter speed vs aperture, but now we might want to include ISO as well.
Probably the best option would be an LCD touch screen table with three columns, much like those in Trev's post #19, where we can finger drag or prod to select the value(s) we want and the other 'lit up' column values automatically change to obtain the same metered exposure.
Now there's an idea; has anyone done that I wonder?

Cheers,
Dave

[Dave Humphries]

Hi Trev,

I have a Nikon Df, which granted is a fairly unique box as it is meant to emulate a film camera in its behaviour.
If I set the ISO to locked then it remains so. It makes sense for a couple of reasons:
1. Film cameras had the ISO locked for the whole film (unless you went for push processing, but that's a whole different story).
2. In manual one wants to control the exposure, usually by adjusting aperture and shutter, having the ISO keep changing on its own would be defeating the purpose.

I agree, but I'm not sure the bit of my post you quoted is even talking about why, in Manual, you don't want ISO to change.

Touched on above, in various places, by various esteemed members, was the difference in behaviour of EC between Canon and Nikon in "Manual" Mode.

IIRC (and I'm pretty sure I do) with Nikon, even in Manual mode with Auto-ISO DISengaged, changing EC will bias the meter, which in turn will (for a given scene) 'encourage' you to turn whatever knobs are necessary to effect the exposure change you want.

The whole post is about the behaviour difference between Canon and Nikon cameras when, in M mode and with Auto-ISO off.

Please try it on your Df and let us know;

1. Keep the camera pointed at a static scene with constant illumination
2. Adjust the exposure controls until the meter is centred (i.e. as if displaying 'correct' exposure)
3. Does changing EC cause the meter point/needle to move?

I think it will, because it's a Nikon, but I'd be happy to learn if I'm mistaken.

Cheers,
Dave