Automatic Aperture Selection: Simplifying Depth of Field Estimation for Family Photoshoots

[shealtieljkwak]

TL;DR
Is there a camera that can automatically choose the optimal aperture? To avoid having to estimate the depth of field while shooting?

“Challenge”
Setting the correct exposure that matches the scene and prioritizing clean/sharp photos for family photoshoot where subject(s) can be non-static.

Gear & Approach

1. Sony A7R3
2. Aperture mode
3. ISO AUTO Min. SS is set to at least a double than the lens focal length
4. Auto ISO

Bad Results
Too wide aperture causing out of focus subject(s) or too narrow aperture causing too noisy photos (higher ISO).
Unlike shutter-speed, where it is easy and fast to choose the correct one, aperture mandates complex DoF formulas and has no ideal rule of thumb.

Desired Camera
Cameras can be expected to be sophisticated enough to get a single input – focus area.
Then it calculates the rest based not just on lighting but DoF (and as a bonus, subject “static-ness”)
I would imagine every photographer does these strictly mechanical calculations and estimations before every shot. Seems like technology is there to make life easier.

1. Automatic and prioritizing low ISO.
2. Prioritize slowest shutter speed to avoid blurriness
3. Choose widest aperture based on chosen focus area and DoF

Notes
I hope I understand aperture, shutter speed and program modes correctly and did not miss that the described issue can be resolved by any of the existing modes.

 

[Phil V]

I hope I understand aperture, shutter speed and program modes correctly and did not miss that the described issue can be resolved by any of the existing modes.

Kinda - but I think not quite.

Shutter speed - you’re desiring as being ‘as low as you can but to avoid subject movement’, same thing but I’d say ‘high enough to avoid subject movement’. It looks like semantics but my description guarantees it’s high enough, your description sounds like you’re gambling around it being enough.

ISO - please don’t fall for the bull that it should be ‘as low as possible’. If you need 1/250 (regular moving people) and f5.6 (reasonable DoF) then the ISO will be whatever it is. You can’t control that, it’s dictated by the amount of light available. A bit of noise is preferable to an unsharp image.

Now let’s talk about DoF. Focus is a plane, you can’t focus on more than one subject, anything else within DoF is only ‘acceptably sharp’ it’s not ‘in focus’. You have to decide who is the ‘subject’ and the other family members will be not in focus, your composition leads you to this decision, but it’s generally a kid or the mum. Also helps if your grouping means they’re not millions of miles apart.


So - camera settings:
As I said I generally have auto ISO with a min shutter speed of 1/250
Aperture priority at F5.6 or f8 for groups, or a good lens wide open for individuals.
Eye focus - or if your camera doesn’t, then you should choose the subject and focus on the nearest eye.

It’s fairly straightforward; and for me pretty much automated cos I have pre-made the important decisions before lifting the camera to my eye. The rest of the decisions are made by the camera but it’s just maths and there’s no point me worrying about them.

 

[AndrewFlannigan]

If you explain why you are asking this question, we might be able to supply an appropriate answer.

In general, for maximum depth of field, switch to aperture mode, select the biggest number (e.g. f22) and press the button to take the picture,

 

[swanseamale47]

If your using the widest aperture, depending on the lens use you might have a very shallow depth of field.
Theres several factors affecting depth of field, distance from subject, focal length and aperture can all affect the result. As Phil says sharp is better than noisy, and a Sony really should be pretty decent at quite high iso from what I've seen. At the sort of iso you'd be using for a normal portrait session I cant see it being an issue.

 

[ecoleman]

To answer you question as to whether or not a camera can set the optimal aperture depending on your subject, the answer is no. The camera has no idea what your subject is.

Based on your desired camera it sounds like you want a phone or a cheap DSLR and stick it in AUTO although that can still only guess the best exposure.

The whole point of a decent camera where you can use Av, Tv or M mode is so that you make those decisions.

 

[Faldrax]

....
I would imagine every photographer does these strictly mechanical calculations and estimations before every shot. Seems like technology is there to make life easier.
......

In practice I suspect the majority do the same as me - and use an aperture based on experience of having taken similar shots before, or if it's a setup I'm not sure of, and have the time, I've a simple app on my phone that tells me the DOF for a given aperture, focal length and subject distance (or I'll take a few at different apertures and see which I prefer, since with digital it costs nothing other than a few moments to take the multiple shots).

Technically a camera could have a DOF mode, where you selected DOF and it auto calculated Aperture based on focal length and subject distance, but as far as I am aware it's not something that has been done.

 

[Phil V]

Actually Fuji have a ‘DoF’ display in the viewfinder, where based on your subject distance, the chosen Aperture creates a range on the VF which is similar to the window on a lens in the old days but easier to use.

 

[Deleted member 95743]

 

[Faldrax]

Actually Fuji have a ‘DoF’ display in the viewfinder, where based on your subject distance, the chosen Aperture creates a range on the VF which is similar to the window on a lens in the old days but easier to use.

That sounds like a neat little option to have.

 

[swanseamale47]

I've tried A-dep a few times, never worked for me, always got way better results stopping down to a suitable F stop and focusing a third of the way in.

 

[Phil V]

I've tried A-dep a few times, never worked for me, always got way better results stopping down to a suitable F stop and focusing a third of the way in.

ADep is awful, takes longer to set up than necessary and you have no control of what you actually want to focus on.

 

[Craikeybaby]

Actually Fuji have a ‘DoF’ display in the viewfinder, where based on your subject distance, the chosen Aperture creates a range on the VF which is similar to the window on a lens in the old days but easier to use.

I use that loads, I didn't realise it was a Fuji-specific thing, I thought it was all mirrorless cameras.

Whilst Googling it, I also learned about the "depth of field preview" function, which I've now set up. I've only been shooting Fuji for 5 years...

 

[wiltw]

I've tried A-dep a few times, never worked for me, always got way better results stopping down to a suitable F stop and focusing a third of the way in.

The issue may well be that the DOF Circle of Confusion value used by almost all lens/camera manufacturers is too large and assumes the viewer's vision is really pretty bad (not 20/20 US stamdard that optometrists strive to achieve for their patients!). So whan the average viewer looks at the print, the brain detects 'not in focus'.

 

[Plain Nev]

Lots of cameras will offer you the optimum depth of field insofar as the automatic metering determines it. That's not to say it's desirable, or the one you want. And you certainly don't want the slowest shutter speed where motion is concerned. As a general rule of thumb if it's moving shutter speed is what you need to worry about. If it's still then it's the aperture. Those are the two determinations you should make when approaching a subject. ISO can help, in as much as they can determine shutter speed. But if you've got it set to auto you don't really need to worry about it.

To be honest you sound like a beginner who is over thinking this stuff. Tell us where you're coming from with this.

 

[ecoleman]

Lots of cameras will offer you the optimum depth of field insofar as the automatic metering determines it. That's not to say it's desirable, or the one you want. And you certainly don't want the slowest shutter speed where motion is concerned. As a general rule of thumb if it's moving shutter speed is what you need to worry about. If it's still then it's the aperture. Those are the two determinations you should make when approaching a subject. ISO can help, in as much as they can determine shutter speed. But if you've got it set to auto you don't really need to worry about it.

To be honest you sound like a beginner who is over thinking this stuff. Tell us where you're coming from with this.

What does anything you have just written have to do with depth of field?

 

[lindsay]

Another thread started by a single-post fire and forget merchant by the look of it, and we always jump in with helpful suggestions and discussions, never to see them return. Kind of leaves you a bit jaded after a while. Thanks go to you guys who have been so positive and helpful above,

 

[Plain Nev]

What does anything you have just written have to do with depth of field?

Not a lot. I was talking b*****ks mostly. I was trying to say that the cameras automatic setting for an optimum aperture won't always work out like that. Although, I did wander and it got lost in translation.

 

[wiltw]

Back when all lenses were single FL, the DOF scale marks on the lens could give hint about DOF zone depth...(see photo below)

In this photo the lens is focused at 7' and if the chosen aperture was f/16, things would be in focus in the range 5' - 12' (although many photographers knew better and used the f/8 marks for better estimation of f/16 DOF)
But with the common use of zoom lenses today, most lack the DOF marks. While this does not address your desire for a tool, it does make you aware that one existed in the past (before zooms with reasonable performance and price became commonplace)