topic Re: Av vs. Manual in EOS DSLR & Mirrorless Cameras

EOS Rebel T8i image differences in Av vs. Manual

stevet1 — Tue, 26 Nov 2024 14:06:48 GMT

I'll state right up front that I am puzzled.

I have noticed this before, but I don't understand why there is a difference.

If I take a shot in Aperture Priority Mode, and take the exact same picture in Manual Mode with the exact same settings, the Av shot looks more washed out or lighter, and the Manual shot looks fuller.

Here's an example. I drew a dark diagonal line at the bottom of the Manual exposure to differentiate between the two. Look at the brown field in the upper right quadrant.

The settings are irrelevant, but they were both shot at 1/100, f/7.1 and ISO at 100. They were taken through a window. so you have to take that into account, but both were. I've noticed the difference before, even outside in the open air.

Why is there a difference?

It makes me want to stick with Manual.

Steve Thomas

Re: Av vs. Manual

kvbarkley — Mon, 25 Nov 2024 16:44:32 GMT

What Camera?

Is the white balance the same in both?

How about the Picture Style?

Re: Av vs. Manual

p4pictures — Mon, 25 Nov 2024 17:05:55 GMT

On many cameras of recent generations - DSLR and mirrorless - when you select manual exposure mode the camera will also deactivate auto lighting optimiser too. This can be overridden, but not many people do so.

I just checked an EOS 7D Mark II (2014), EOS R10 and EOS R6 Mark II, if you find the Auto Lighting Optimiser on the red menu you will see that a check mark is present to disable ALO in manual and bulb modes. You can clear the check mark so that the ALO is done the same in Av and M.

Re: Av vs. Manual

stevet1 — Mon, 25 Nov 2024 17:20:36 GMT

kvbarkley,

Yes. All settings (Picture Style, White Balance, etc) remained the same.

The camera is a T8i.

Steve Thomas

Re: Av vs. Manual

stevet1 — Mon, 25 Nov 2024 17:22:21 GMT

Brian,

Auto Lighting Optimizer has been disabled in the Menu.

Steve Thomas

Re: Av vs. Manual

Peter — Mon, 25 Nov 2024 21:47:33 GMT

If you share two untouched JPEG files from the camera it would be easier to troubleshoot.

$ Exiftool -all yourfile1.JPEG > yourfile1.txt

$ Exiftool -all yourfile2.JPEG > yourfile2.txt

In Linux, use Diff to compare the difference.

$ diff yourfile1.txt yourfile2.txt > difference.txt

In Windows, use fc.

fc yourfile1.txt yourfile2.txt > difference.txt

Re: Av vs. Manual

jrhoffman75 — Mon, 25 Nov 2024 22:24:10 GMT

Same metering mode?

Re: Av vs. Manual

stevet1 — Tue, 26 Nov 2024 00:09:34 GMT

Peter,

Thanks. I'll have to look at the Exif data to see if what comes out of my camera is what I put in. There might be some slight variations. I'll have to take a couple of SOOC jpgs and look at the results.

Steve Thomas

Re: Av vs. Manual

p4pictures — Tue, 26 Nov 2024 00:21:59 GMT

Steve,

Is it disabled for both Av and M modes? On my cameras with default settings using AV, P, Tv then ALO is on and for M & bulb ALO is off.

Re: Av vs. Manual

stevet1 — Tue, 26 Nov 2024 00:53:49 GMT

Brian,

Thanks. Yes it is off in both modes.

I'm going to do what Peter suggested and look at the Exif data of a couple of SOOC jpgs. There may be a decimal point or two variation between what I put in and what comes out.

Steve

Re: Av vs. Manual

wq9nsc — Tue, 26 Nov 2024 01:15:35 GMT

I always shoot in manual with auto ISO but I wonder whether the auto mode always uses 1/2 or 1/3 stop increments regardless of where you have your preference set for manual choice. This could cause a slight difference if it is adjusting one of its automatic parameters in a finer or coarser step than you are choosing. The EXIF data should show the exact parameters used at capture for aperture, shutter speed, and ISO.

Rodger

Re: Av vs. Manual

stevet1 — Tue, 26 Nov 2024 03:07:04 GMT

Roger,

Thanks. I'm definitely going to examine to see if what comes out is the same as what I put in.

I think I'll also toy a little bit with a 1/3 stop of negative exposure compensation on my Av shots.

Steve Thomas

Re: Av vs. Manual

wq9nsc — Tue, 26 Nov 2024 03:17:53 GMT

Steve,

I look forward to your solution of this interesting mystery! 🙂

Rodger

Re: Av vs. Manual

p4pictures — Tue, 26 Nov 2024 08:55:21 GMT

Which picture style do you use? The default is AUTO, and that means the camera chooses between standard, portrait and landscape styles based on what it thinks the photo is. I would make sure you select a specific picture style, standard or fine detail are my preferences. Each of the three styles portrait, landscape and standard have different amounts of contrast and colour saturation, as well as colour rendering.

Re: EOS Rebel T8i image differences in Av vs. Manual

stevet1 — Thu, 28 Nov 2024 15:44:34 GMT

Here's another example:

img 1509 is on the left. Taken in Av at 1/20th. img 1510 is on the right. Taken in Manual. Also at 1/20th. I drew a circle on the Manual shot. Exif data reports 1/20th in both shots. Look at the tree on the left side, and the color of the jeep.

The Manual shot just looks a little fuller to me. The file size is 4/10th of a Mb larger than the Av shot.. Hmmm.

Steve Thomas

File Name IMG_1509.JPG

File Size 3.0MB

Camera Model Canon EOS Rebel T8i

Firmware Firmware Version 1.0.0

Shooting Date/Time 11/28/2024 9:43:33 AM

Owner's Name

Shooting Mode Aperture-Priority AE

Tv(Shutter Speed) 1/20

Av(Aperture Value) 7.1

Metering Mode Spot Metering

Exposure Compensation 0

ISO Speed 100

Auto ISO Speed OFF

Lens EF-S18-135mm f/3.5-5.6 IS USM

Focal Length 19.0mm

Image Size 5776x3836

Crop/aspect ratio 3:2

Image Quality Fine

Flash Off

FE lock OFF

White Balance Mode Color Temperature (5300K)

AF Mode AI Servo AF

AF area select mode Manual selection

Picture Style Standard

Sharpness:Strength 4

Sharpness:Fineness 2

Sharpness:Threshold 4

Contrast 0

Saturation 0

Color tone 0

Color Space sRGB

Long exposure noise reduction Auto

High ISO speed noise reduction Standard

Highlight tone priority Disable

Auto Lighting Optimizer Disable

Peripheral illumination correction Enable

Chromatic aberration correction Enable

Distortion correction Disable

Diffraction correction Enable

Digital Lens Optimizer Enable(Correction data not available)

Dust Delete Data No

Drive Mode Single shooting

Live View Shooting OFF

Camera Body No. 082031000350

Comment

File Name IMG_1510.JPG

File Size 3.4MB

Camera Model Canon EOS Rebel T8i

Firmware Firmware Version 1.0.0

Shooting Date/Time 11/28/2024 9:44:24 AM

Owner's Name

Shooting Mode Manual Exposure

Tv(Shutter Speed) 1/20

Av(Aperture Value) 7.1

Metering Mode Spot Metering

Exposure Compensation 0

ISO Speed 100

Auto ISO Speed OFF

Lens EF-S18-135mm f/3.5-5.6 IS USM

Focal Length 19.0mm

Image Size 5842x3743

Crop/aspect ratio 3:2

Image Quality Fine

Flash Off

FE lock OFF

White Balance Mode Color Temperature (5300K)

AF Mode AI Servo AF

AF area select mode Manual selection

Picture Style Standard

Sharpness:Strength 4

Sharpness:Fineness 2

Sharpness:Threshold 4

Contrast 0

Saturation 0

Color tone 0

Color Space sRGB

Long exposure noise reduction Auto

High ISO speed noise reduction Standard

Highlight tone priority Disable

Auto Lighting Optimizer Disable

Peripheral illumination correction Enable

Chromatic aberration correction Enable

Distortion correction Disable

Diffraction correction Enable

Digital Lens Optimizer Enable(Correction data not available)

Dust Delete Data No

Drive Mode Single shooting

Live View Shooting OFF

Camera Body No. 082031000350

Comment

Re: EOS Rebel T8i image differences in Av vs. Manual

jrhoffman75 — Thu, 28 Nov 2024 15:45:54 GMT

Somewhere in the process image aspect ratio is being modified.

Re: EOS Rebel T8i image differences in Av vs. Manual

jrhoffman75 — Thu, 28 Nov 2024 17:51:18 GMT

@stevet1 wrote:

I'll state right up front that I am puzzled.

I have noticed this before, but I don't understand why there is a difference.

If I take a shot in Aperture Priority Mode, and take the exact same picture in Manual Mode with the exact same settings, the Av shot looks more washed out or lighter, and the Manual shot looks fuller.

Here's an example. I drew a dark diagonal line at the bottom of the Manual exposure to differentiate between the two. Look at the brown field in the upper right quadrant.

The settings are irrelevant, but they were both shot at 1/100, f/7.1 and ISO at 100. They were taken through a window. so you have to take that into account, but both were. I've noticed the difference before, even outside in the open air.

Why is there a difference?

It makes me want to stick with Manual.

Steve Thomas

Putting on my engineer hat, here is a possible explanation:

1. Nature doesn't work in increments of light; it is continuous.

2. all devices have acceptable levels of accuracy.

3. Deleted.

4. The camera calculates exposure with the aperture wide open and "does the math" to select the appropriate settings.

5. The camera allows and reports settings in set increments, generally 1/3 stops.

6. In Av mode you are setting aperture and ISO. The camera needs to determine the appropriate shutter speed using the internal computer. Then it reports the closest programed value within the accuracy of the algorithm.

7. When you set Manual mode you are telling the camera to use set values of shutter speed, aperture and ISO. So when the internal computer analyzes the scene and tells you the exposure is correct by centering the needle on the meter there is an allowable tolerance. Since the hash marks are 1/3 stops the allowable tolerance would be maybe +/- 1/4 stop.

8. Perhaps that is why the images look slightly different.

In DPP I cropped the image you posted to create a left and right side image.

In Lightroom I increased the exposure of the right side image by .07 stops.

This is adjusted right compared to left.

This is right before/after exposure adjustment.

Re: EOS Rebel T8i image differences in Av vs. Manual

p4pictures — Thu, 28 Nov 2024 17:31:03 GMT

Hi John,

The anti flicker control on a DSLR works differently to a modern mirrorless camera. On the DSLR, the camera frame rate is adjusted in continuous shooting so that if flicker is detected the frames should be in-sync with the same part of the cycle of the lights to ensure consistent brightness and colour. Anti flicker is targeted to cope with lights powered from AC, so 50Hz 60Hz frequency.

Some of the newer mirrorless cameras have an additional High Speed Anti Flicker capability. This is designed to deal with the faster frequency that is sometimes used for LED lighting. With this function activated the camera fractionally adjusts the shutter speed. The EOS Rebel T8i does not have this capability.

Re: EOS Rebel T8i image differences in Av vs. Manual

stevet1 — Thu, 28 Nov 2024 18:25:06 GMT

John,

I cropped both freehand to remove an offending window sill on the left. I may have cropped the Manual shot a little more than the Av.

Steve