The Missing Program Mode

Started 6 months ago | Discussions thread
OP TacticDesigns Veteran Member • Posts: 6,204
Re: The Missing Program Mode

Gerry Winterbourne wrote:

TacticDesigns wrote:

Gerry Winterbourne wrote:

TacticDesigns wrote:

Ok. This is a bit off the wall . . . but a progression of an idea that I've had for a while . . .

I've read all though the thread (and some of the earlier ones you linked to). I think I can distil it down into something much simpler than you describe here and in some later posts. I think much of the reason your are getting suggestions that don't fit your bill stem from the fact that the way you are expressing your desire - in a very complicated way - is obscuring what it is you really want.


Gerry, thanks for the reply.

Reading through your post, I can see you completely understand what I want.

I think I obscure what I am saying because I am combining what I want with the "The Missing Program Mode" which is a more generic and programmable solution that can probably resolve other wants more so than my simple initial want. LOL.

I think this says concisely what you want (I've clipped it to its essentials from a reply to Wheatfield):


I don't want the camera metering.

All I want is that when the aperture changes (because I am using a variable aperture lens), that the ISO changes so that the end brightness of the JPG picture remains consistent across the set of pictures I take.

As I understand it what you want is to set your exposure parameters manually - all of them - so you can pre-determine output brightness. And that works fine as long as the lens can give the f-stop you want. The only problem comes when a variable aperture lens changes f-stop.

+1. Yup. For my initial want.

I've emphasised "lens" because that's the crucial point: in all the exposure modes it's the camera that determines the settings (with your input for some parameters, but ultimately it's the camera that controls things).

So all (!) that is needed is a new routine that looks at the aperture set by the camera (which includes you) and the aperture set by the lens. If they differ the routine overrides one of the other two parameters by adjusting by the opposite amount of f-number change. By saying "one of the other" I've gone beyond what you say: all you ask for is an increase in ISO.


There's no need to consider anything else: it doesn't matter why the lens has stopped down (so FL is irrelevant)

+1. For my specific application. Although it one potential caveat.*

- all that matters is that it has stopped down and by how much.


Say you are using a lens of f/2.8 to f/4. You set up f-stop at f/2.8 (short FL), ISO100 and whatever shutter speed you need. Then you zoom in and the lens stops down to f/4. All you need is

[(a) camera f-number?]

[(b) lens f-number?] [is (a) < (b)?]

[If yes, increase ISO by {(a)/(b)^2}].

Note that while it is the lens that sets the new f-number it's the camera that reads it, so we are comparing camera reading to camera setting.


That solution would work for me and my initial want.

I think I am obscuring this with trying to resolve potentially other problems as well.

For instance . . . what if you want the shutter speed to be set by the focal length to reduce handshake blur. So the "The Missing Program Mode" I describe can look at the focal length and set the shutter speed based on the focal length. And then fill in the settings for aperture and ISO as well. LOL.

I'm not sure but I believe some cameras already do this. In the Pentax P mode there is an option to prioritise fast shutter speed, which isn't quite the same but goes part way.

But Pentax P mode would then involve the meter again, wouldn't it?

And I want to avoid the meter.

If I was ok with meter, I could set my Nikon up to Aperture priority mode, and set the min. shutter speed to 1/500 sec and then do auto-ISO.

But when the bright lights start flashing behind the cheer athletes on stage, then the camera will underexpose my pictures. LOL.

Or . . . for instance, what if you decide at the wide end you want aperture to get set to f/4 to shoot group shots, but as you zoom out aperture goes to f/2.8 to isolate individual shots. This "might" actually make sense shooting a cheer routine with a single lens + camera. LOL.

I think this goes beyond what can reasonably be expected of any automatic system: it's expecting the camera to guess your aesthetic choices. Again, the Penta P mode has options for DOF control - deep or shallow. If you select the shallow option it will automatically open up if the lens allows it; as it happens, that would also give the widest available aperture - and hence fastest shutter speed - when zoomed in. But that is still only part of what you're asking.

Not for "The Missing Program Mode" LOL.

That would be . . .

[Line-001][Watch][Focal Length][28-75]
[Line-002][Link to][Aperture][Line-001][f/4-f/2.8]
[Line-003][Link to][ISO][Line-002][6400-3200]
[Line-004][Set to][Shutter Speed][1/500]


But this is opposite to how the lens naturally works when you zoom a variable aperture lens. If I shoot this with a constant aperture lens, the aperture stays the same throughout the range. What I am suggesting is . . . what if you could program the camera to change aperture to whatever you want? LOL.

How does it guess what you want?

Because you would program how your camera changes aperture based on focal length.


Several people have pointed to the Pentax TAv mode but it fails your requirement because it is a metering mode and you don't want metering. Yes, it deals with the lens changing its f-number; but it only does that in reference to the way the camera is metering in the first place. And, yes, you can alter the output brightness for a given scene by using +/-EC; but that's no help if you change your scene and the background has a range of brightness.



I want metering off.

And I want to affect ISO when aperture changes. Not shutter speed. I want shutter speed fixed at 1/500 to freeze motion blur in the athletes.

Thanks for the post.

Yes. You know what I am looking for!

For my individual need, the solution could be a lot simpler than what I have outlined in the "The Missing Program Mode".

But will any manufacturer change their cameras for one scenario for one photographer?

No. But if one photographer expresses a general (but as yet not publicised) desire the makers might take note. Especially if the programming is simple.


I might send an email directly to Nikon and Pentax.

I've sent emails before, but nothing happens.

But if a programming solution could resolve many photographers minute wants . . . maybe it would seem more worth while? LOL.

But there's the rub: the more potential needs it meets the more complex it gets; and the more the complexity the less chance of the makers bothering.


Yes. I would tend to agree. Unless someone is able to do it, and then those that want it could decide if they want to go ahead and learn the system to control their camera more finitely.

I was actually thinking of seeing if picking up an Olympus Air-01 m43 camera and trying out their programming interface might let me try this idea out and see if it worked.

Not the programming language, but just change ISO based on aperture. Or maybe even the reverse aperture range on a lens (narrow at the wide end / wide at the long end.)

But I'm not sure if Olympus is still supporting that SDK.

The other option is to look at CHDK again and see if there is anything there that is doing this, or if it can be programmed in Lua.

But that would be a summer project.

I have 2 weeks to design this year's yearbook! LOL.

Again! Thanks for the post.

Take care & Happy Shooting!

Take are & Happy Shooting!

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