Is using Aperture priority bad?

[IainD]

I have been using aperture priority for years. Often I get back to the computer and see a blurred image and think Oh no, my Z9 missed focus! Then I notice the shutter speed was 1/60 or 1/30, and I think, ahh. not a problem with the Z9 then. I am changing to manual with auto iso, I think

 

[abc123brian]

I have been using aperture priority for years. Often I get back to the computer and see a blurred image and think Oh no, my Z9 missed focus! Then I notice the shutter speed was 1/60 or 1/30, and I think, ahh. not a problem with the Z9 then. I am changing to manual with auto iso, I think

It’s easy to want to use aperture priority for wildlife because it’s the easiest variable to know where you want it, usually wide open. The main issue with using aperture priority for wildlife is that the shutter speed is the usually the more important variable to change. In your case you needed a faster shutter speed. Many try to overcome this by using a minimum shutter speed and auto iso but if the subject goes from not moving to moving or vice versa you’re still stuck at the same shutter speed which could be too low causing motion blur or too high causing the iso to be higher than desired adding noise to the image. Using shutter priority makes more sense so you have more control over the variable of more concern. However, it is really just as easy to go to manual and auto iso. It gives you the most control and flexibility in an automatic exposure mode and it’s really quick and easy to go to full manual to lock in an exposure when desired.

 

[bleirer]

I find I start with manual and auto ISO but often once I get an idea what the light is doing choose the ISO myself. Either temporarily with EC or just switching to full manual. A few test shots with blinkies to place the brightest objects high in the histogram, then concentrate on the art.

Cameras are different, but I find it convenient to have shutter under the top wheel, aperture under the top-back wheel, and ISO or EC under the lower-back wheel. All 3 where I can find them without taking my eye from the viewfinder. If some camera models makes it difficult to get to EC or ISO that might make different modes more convenient.

 

[Geoff_G]

It boils down to this....Setting exposure is a 3 way deal consisting of SS, Aperture and ISO

Full Manual exposure control: User sets all three - SS, Aperture and ISO

​

Automatic exposure modes: User sets 2 out of 3 and the camera sets the other one.

• Aperture Priority: User sets Aperture and ISO, Camera decides SS​

• Shutter Priority: User sets SS and ISO and camera decides Aperture​

• Auto Iso Manual: User sets Aperture and SS, camera decides ISO​

​

Aperture and SS settings affect images whereas ISO has little effect (other than changing ISO noise levels). Ergo, if an auto exposure mode is to be used why not let the camera decide the "least important" (within reason) variable - ISO.

Question for the Nikon Manual - Auto ISO crowd....did you diddle with the ISO Sensitivity setting for Minimum Shutter speed Auto setting (Choosing faster of slower)?

 

[Geoff_G]

I find I start with manual and auto ISO but often once I get an idea what the light is doing choose the ISO myself. Either temporarily with EC or just switching to full manual. A few test shots with blinkies to place the brightest objects high in the histogram, then concentrate on the art.

Cameras are different, but I find it convenient to have shutter under the top wheel, aperture under the top-back wheel, and ISO or EC under the lower-back wheel. All 3 where I can find them without taking my eye from the viewfinder. If some camera models makes it difficult to get to EC or ISO that might make different modes more convenient.

I have flipped the command dials for SS and Aperture....much easier for me to change SS that way. So far I have EC assigned to the lens control ring which I'm liking...

 

[DRwyoming]

Question for the Nikon Manual - Auto ISO crowd....did you diddle with the ISO Sensitivity setting for Minimum Shutter speed Auto setting (Choosing faster of slower)?

I can't speak for other brands, but with Nikon when shooting Manual Exposure with Auto ISO the minimum shutter speed setting in the ISO menu is ignored so it doesn't matter what you set for that field. That setting applies to Aperture Priority and Program modes but doesn't come into play when shooting Manual with Auto ISO.

 

[fcotterill]

Exposure is the amount of light hitting the sensor.

Correct me if I’m wrong, but exposure depends on three things, not just two: Shutter Speed, Aperture and Luminance. (See Wikipedia.)

Thus, if the scene’s lighting (luminance) changes, for the same shutter and aperture settings, the amount of the light on the sensor changes and so the exposure changes,

ISO invariance means that the sensor sensitivity does not change with a change in ISO. The proportionality between the number of photons (exposure) hitting the sensor and the electrical charge generated remains invariant with the ISO setting. ISO is just a setting of the amplifier gain which makes it easier to see the signal. So, as the available light goes down, the amplifier gain (ISO) is turned up so we can see the smaller signal coming out of the sensor.

With less signal, the overall signal to noise ratio (SNR) is reduced. The SNR will change proportionally with the number of stops the light changes. Less signal means more noises images.

In Manual with Auto ISO, aperture and shutter speed are fixed in return for a trade off in SNR as determined by the camera.

Ain’t no free lunch.

Thanks for your succinct summary. I avoided mention of Luminance, as this thread is not discussing using flash, or other light sources, to change the luminance

I was also trying to avoid going deeper into the subject of "Sensor Innards". After all, the topics of Exposure, and ISO Invariance etc fuel a cottage industry of articles and forum debates (!)

Personally, I dod believe to understand the basic concepts of how a sensor works. This nerdy video does a fair job

One has to be critical of the www material. Photography Life, for example, has a large section of articles on Concepts and 'How To...' by different authors, but at least one is still hung up on the exposure-triangle idea, which can lead to misleading ideas: e.g. that increasing ISO increases luminance

ISO Invariance Explained

In this article, we will explore ISO invariance in detail and how you can use it to your advantage in your photography

photographylife.com

Learning to Shoot in Manual Mode

photographylife.com

Everything You Need to Know About Aperture Priority Mode

Aperture priority mode is a great way to control the look of your photos. In this article, we look into this mode in detail and explain how it works.

photographylife.com

 

[Geoff_G]

I can't speak for other brands, but with Nikon when shooting Manual Exposure with Auto ISO the minimum shutter speed setting in the ISO menu is ignored so it doesn't matter what you set for that field. That setting applies to Aperture Priority and Program modes but doesn't come into play when shooting Manual with Auto ISO.

Thanks, that makes perfect sense - I was 99% there but wanted to verify.

 

[bleirer]

It boils down to this....Setting exposure is a 3 way deal consisting of SS, Aperture and ISO

Full Manual exposure control: User sets all three - SS, Aperture and ISO

​

Automatic exposure modes: User sets 2 out of 3 and the camera sets the other one.

• Aperture Priority: User sets Aperture and ISO, Camera decides SS​

• Shutter Priority: User sets SS and ISO and camera decides Aperture​

• Auto Iso Manual: User sets Aperture and SS, camera decides ISO​

​

Aperture and SS settings affect images whereas ISO has little effect (other than changing ISO noise levels). Ergo, if an auto exposure mode is to be used why not let the camera decide the "least important" (within reason) variable - ISO.

Question for the Nikon Manual - Auto ISO crowd....did you diddle with the ISO Sensitivity setting for Minimum Shutter speed Auto setting (Choosing faster of slower)?

Just to add on, auto iso is also available in aperture priority and shutter priority mode.

 

[Geoff_G]

Just to add on, auto iso is also available in aperture priority and shutter priority mode.

Yeppers, good point! I should have added those case to my list...

 

[bleirer]

If I'm walking in the woods with an expert birder, and we both have normal hearing. How does he hear the song of a certain bird in the distance but I don't? By one definition he is more sensitive to birdsong than I am, yet we both have equal results on a hearing test.

Same idea with ISO. Light hitting a photosite/pixel dislodges electrons. The number dislodged doesn't depend on ISO, so in that sense ISO doesn't affect how sensitive the pixel is. But the camera system as a whole turns those electrons into a single raw number. That number gets bigger with higher iso settings. So in that sense, like my birder friend, we could say the ISO affects the sensitivity of the camera system to light. We certainly can force a pixel to blow out irretrievably with too high ISO. So in that sense one can be forgiven for including ISO at least in the photographic triangle if not the exposure triangle.

 

[JoPoV]

The Nikon exposure engine is surprisingly smart when it comes to compensating for scenes, though.

How is it smart ?
When you compensate 1EV, does it does something more than compensate 1EV ?

Some folks I've read try to spot meter the brightest object, then add 3 stops to that result to "place" the bright at the right side of the histogram. Too complicated when blinkies do the work for me.

Does blinkys give information from raw signal or from demosaiced raw signal modified by some in camera curve setting ?

I use manual w/ Auto ISO when the light is constant on the subject and background

What is the benefit of auto iso if light is constant on subject and background ?
Manual would not do the job ? (Unless you mean subject can change, which I understand).

 

[ARClark]

The problem with spot metering mode is always being able to place the spot on your subject. AND I am always confused if "the spot" is the spot under the focus point OR a central spot. I assume it is the spot being used for AF -- see extracts below.

I note that photographers of HUMANS receive the benefit of Matrix Metering with Face Detection -- and Nikon makes this clear that the faces have to be HUMAN -- Dear Nikon how about applying this to ANY Subject recognised by Subject Detection AF.

Wouldn't that be a great feature -- well it may already work that way -- but on has to dig for it -- and if the subject is small or unevenly lit 4mm may be unhelpful /need EC correction.

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The problem with spot metering mode is always being able to place the spot on your subject. AND I am always confused if "the spot" is the spot under the focus point OR a central spot. I assume it is the spot being used for AF -- see extracts below.

I note that photographers of HUMANS receive the benefit of Matrix Metering with Face Detection -- and Nikon makes this clear that the faces have to be HUMAN -- Dear Nikon how about applying this to ANY Subject recognised by Subject Detection AF.

Wouldn't that be a great feature -- well it may already work that way -- but on has to dig for it -- and if the subject is small or unevenly lit 4mm may be unhelpful /need EC correction.

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FYI, with my Z9, I’ve found spot metering in conjunction with 3D AF and subject detection handy in shooting perched birds in mixed light. With subject detection, the focus zeros in on the head/eye, and the spot meter reads exposure off the focus box. In manual with auto ISO, the camera then sets exposure for the eye or the head. The one other thing I’ve needed to adjust is the exposure compensation by -0.7 to -1.3 to avoid over exposure. The amount is dependent on the darkness of the birds eye and head. For example, a Carolina chickadee with black eyes and head needs greater compensation than a goldfinch or bluebird.

Bottom line, though, spot metering in auto ISO with subject detection will set exposure off of the subject in focus, wherever it is in the frame.

 

[bleirer]

How is it smart ?
When you compensate 1EV, does it does something more than compensate 1EV ?



Does blinkys give information from raw signal or from demosaiced raw signal modified by some in camera curve setting ?



What is the benefit of auto iso if light is constant on subject and background ?
Manual would not do the job ? (Unless you mean subject can change, which I understand).

The blinkies like the histogram depends on a jpeg-like input. So it is affected by camera settings. I once took a deep dive into my particular camera using a particular picture control looking at the files in Rawdigger. I raised exposure in 1/3 stop jumps and found the highest non blinkie value, then increased until Rawdigger said a channel was maxed out. So based on that I feel safe adding 2/3 stop to my highest non-blinkie exposure. You could probably do something similar in lightroom, finding the highest non-blinkie exposure then seeing how far to push before it was unrecoverable. In actual practice I've learned to rapidly judge a test shot for acceptable results.

 

[JoPoV]

The blinkies like the histogram depends on a jpeg-like input. So it is affected by camera settings. I once took a deep dive into my particular camera using a particular picture control looking at the files in Rawdigger. I raised exposure in 1/3 stop jumps and found the highest non blinkie value, then increased until Rawdigger said a channel was maxed out. So based on that I feel safe adding 2/3 stop to my highest non-blinkie exposure. You could probably do something similar in lightroom, finding the highest non-blinkie exposure then seeing how far to push before it was unrecoverable. In actual practice I've learned to rapidly judge a test shot for acceptable results.

Ok, you use it as starting point and know how to compensate to estimate raw need. I understand.

 

[bleirer]

How is it smart ?
When you compensate 1EV, does it does something more than compensate 1EV ?



Does blinkys give information from raw signal or from demosaiced raw signal modified by some in camera curve setting ?



What is the benefit of auto iso if light is constant on subject and background ?
Manual would not do the job ? (Unless you mean subject can change, which I understand).

The EC of -1 would be an exposure 1 stop less than whatever the camera decided. But what the camera decides using the evaluative/matrix metering is sophisticated, using the confirmed focus point and based on a database of many scenes with various exposure scenarios. Spot metering as far as I know is "dumb."

 

[Maljo]

Aperture Priority for landscapes with manual ISO, Manual for action with Auto ISO, to achieve higher shutter speeds.

 

[JoPoV]

The EC of -1 would be an exposure 1 stop less than whatever the camera decided. But what the camera decides using the evaluative/matrix metering is sophisticated, using the confirmed focus point and based on a database of many scenes with various exposure scenarios. Spot metering as far as I know is "dumb."

Ok, "compensate" was used for talking about matrix mettering, not exposure compensation. This confused me.

 

[NorthernFocus]

To me the most amazing thing about the topic of exposure is that it generates so much thought/discussion. I can understand it when shooting film. Or for pros shooting sports etc where they need to shoot jpeg and send them straight to market. But for capturing RAW format wildlife images on a modern sensor all that's needed is to keep it between the ditches(highlights/shadows) in the field and do the rest in post. Getting a "proper" exposure is at the bottom of my list of things to worry about when I'm in the field. I guess old habits die hard.

 

[JoPoV]

To me the most amazing thing about the topic of exposure is that it generates so much thought/discussion. I can understand it when shooting film. Or for pros shooting sports etc where they need to shoot jpeg and send them straight to market. But for capturing RAW format wildlife images on a modern sensor all that's needed is to keep it between the ditches(highlights/shadows) in the field and do the rest in post. Getting a "proper" exposure is at the bottom of my list of things to worry about when I'm in the field. I guess old habits die hard.

It's anyway interresting to see how other people use their gear and why. It can lead to some new ideas of setting gear.
But seing this, I stick with my habit : Manual when light does not change and manual + auto iso when light is changing, when it's about shoting birds.

 

[bleirer]

The problem with spot metering mode is always being able to place the spot on your subject. AND I am always confused if "the spot" is the spot under the focus point OR a central spot. I assume it is the spot being used for AF -- see extracts below.


FYI, with my Z9, I’ve found spot metering in conjunction with 3D AF and subject detection handy in shooting perched birds in mixed light. With subject detection, the focus zeros in on the head/eye, and the spot meter reads exposure off the focus box. In manual with auto ISO, the camera then sets exposure for the eye or the head. The one other thing I’ve needed to adjust is the exposure compensation by -0.7 to -1.3 to avoid over exposure. The amount is dependent on the darkness of the birds eye and head. For example, a Carolina chickadee with black eyes and head needs greater compensation than a goldfinch or bluebird.

Bottom line, though, spot metering in auto ISO with subject detection will set exposure off of the subject in focus, wherever it is in the frame.

That depends on the camera so worth checking. I know Canon always spot meters from the center and only do considers the focus point in evaluative (matrix) metering. Does Nikon have a setting where you can choose?

 

[eaj101]

How is it smart ?
When you compensate 1EV, does it does something more than compensate 1EV ?

The matrix metering is actually somewhat subject-aware. For example, it changes the exposure based on the amount if sky in the scene, determining whether to expose for the sky or the foreground based on the amount of sky. It can to some extent recognize specular highlights or unusually light elements such as snow. I couldn't give you the details, but Nikon says there are more than 30000 scenes used by the algorithm to determine what the 'right' exposure is. It's a lot more accurate for a given scene than center-weighted or averaging. Doesn't mean you'll like it, though. I tend to always underexpose from the 'textbook' because I prefer it.

 

[JoPoV]

The matrix metering is actually somewhat subject-aware. For example, it changes the exposure based on the amount if sky in the scene, determining whether to expose for the sky or the foreground based on the amount of sky. It can to some extent recognize specular highlights or unusually light elements such as snow. I couldn't give you the details, but Nikon says there are more than 30000 scenes used by the algorithm to determine what the 'right' exposure is. It's a lot more accurate for a given scene than center-weighted or averaging. Doesn't mean you'll like it, though. I tend to always underexpose from the 'textbook' because I prefer it.

I thought compensate was refering to exposure compensation. Not matrix metering. I misinterpreted this.

 

[bleirer]

Ok, "compensate" was used for talking about matrix mettering, not exposure compensation. This confused me.

I think the way it was used the poster meant that the system wasn't just indicating an exposure based on an average of the scene but has ways to compensate for something like a back-lit scene or a bright subject with a dark background. So in a sense the system is doing its own internal exposure compensation, adding or subtracting from what a straight average would give.

 

[Replytoken]

But what the camera decides using the evaluative/matrix metering is sophisticated, using the confirmed focus point and based on a database of many scenes with various exposure scenarios. Spot metering as far as I know is "dumb."

It is sophisticated, but also a bit of a "black box" as you do not know what the camera has decided upon in its analysis since it is not shared with you other than the decision. Granted, spot metering has become more advanced, and complex, since it can now be tied to the focus point, but the idea was that with spot metering, the user should at least be aware of what they were metering off of, rather than being told by the camera. In reality today, both are probably less than ideal for removing variables and just providing simple data to the user.

--Ken