Something strange going on with auto iso

[Deejaybeephoto]

Advertisement (gone after registration)

I’ve been using my M10 mode in aperture priority, auto-iso mode recently for street work.  My standard set up is f8, with 3m focus - set and forget - and adjust with exposure compensation for varying lighting conditions.

I understand how auto-iso should work in aperture priority mode, with the camera adjusting speed/iso within limits specified to give the correct metered exposure. However , I’ve only just noticed that the exif data in Lightroom indicates that the aperture is varying as well (according to the data that is)!!  
 

Clearly this is not the case as it’s a manual lens and the aperture is physically set.  I’ve never had this on my previous cameras or on my current Ricoh GR 3x which behaves as it should. Any ideas or suggestions will be gratefully received. The lens is a Voigtlander (new).  Could it be something to do with the communication between the camera and the lens? I’m really at a loss. 
 

Thanks

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[tim]

Hi Deejaybeephoto,

probably your camera is working as it should, at least as per my understanding of your post.

As long as you are not accidentally changing the aperture on your lens it will remain to be f8. But your M10 has no means to get that information but has to guess it using several parameters. The f-stop value you see in our RAW converter or editing software is just an 'guesstimate' and may be off by a stop or two. Simply stop looking at this piece of non-information the software provides to you.

Your Ricoh however 'knows the aperture you or it choses via its electronics. It is designed as a full digital camera system from the start, whereas your M10 is conceptually an analogue camera with an added sensor and digital signal processing. And that is great, since you can make use of all those (or at least most) brilliant lenses that have been produced since 1954 for the Leica M mount and with adapter even older ones.

So you are not losing anything ... embrace the freedom that the M concepts provides to you.

Cheers,

tim

[UliWer]

vor 2 Stunden schrieb Deejaybeephoto:

I’ve only just noticed that the exif data in Lightroom indicates that the aperture is varying as well (according to the data that is)!!  

The information about the aperture you get in Lightroom does not say anything about the actual aperture you used! There is no physical or electronic connection between the lens and an M camera which is able to indicate the aperture the lens is set to. The camera only guesses which aperture you used. Therefore different apertures in Lightroom do not say anything about a change of apertures.

That‘s the reason why the M10 originally did not show any information about the aperture in the EXIF.  As users protested and wanted „their aperture“ back - even if it was wrong - it was reinstated by Firmware update.

 

Edited February 12, 2024 by UliWer

[Deejaybeephoto]

6 hours ago, tim said:

Hi Deejaybeephoto,

probably your camera is working as it should, at least as per my understanding of your post.

As long as you are not accidentally changing the aperture on your lens it will remain to be f8. But your M10 has no means to get that information but has to guess it using several parameters. The f-stop value you see in our RAW converter or editing software is just an 'guesstimate' and may be off by a stop or two. Simply stop looking at this piece of non-information the software provides to you.

Your Ricoh however 'knows the aperture you or it choses via its electronics. It is designed as a full digital camera system from the start, whereas your M10 is conceptually an analogue camera with an added sensor and digital signal processing. And that is great, since you can make use of all those (or at least most) brilliant lenses that have been produced since 1954 for the Leica M mount and with adapter even older ones.

So you are not losing anything ... embrace the freedom that the M concepts provides to you.

Cheers,

tim

Thank you Tim for your explanation. I understand what you’re saying and I get it!  The camera is basically a manual or aperture priority camera only which is what I am forgetting as you point out. I grew up with film cameras and so should have perhaps thought this through. So, whilst the exposure compensation is making adjustments to the speed/ iso, this is shown by the data as theoretically equivalent to a variance in the aperture reading (although of course the aperture remains fixed).  Again many thanks. 

[Deejaybeephoto]

5 hours ago, UliWer said:

The information about the aperture you get in Lightroom does not say anything about the actual aperture you used! There is no physical or electronic connection between the lens and an M camera which is able to indicate the aperture the lens is set to. The camera only guesses which aperture you used. Therefore different apertures in Lightroom do not say anything about a change of apertures.

That‘s the reason why the M10 originally did not show any information about the aperture in the EXIF.  As users protested and wanted „their aperture“ back - even if it was wrong - it was reinstated by Firmware update.

 

 

That’s great information.  I didn’t know any of this history, although I did search the forum beforehand. Thank you for pointing this out!  I’ve been around a few years 😩 and was brought up on manual film cameras -I guess I’ve got a bit lazy as the years have progressed (and been tempted with the latest digital gadgetry)!  However, after the first purchase (at long last) of a used Leica last year, I’m really enjoying the challenges it sometimes brings.  At least it’s cured my (non-Leica)/GAS!  Thanks again  

 

 

 

 

 

 

 

 

 

Edited February 12, 2024 by Deejaybeephoto

[Stevejack]

6 hours ago, Deejaybeephoto said:

 

That’s great information.  I didn’t know any of this history, although I did search the forum beforehand. Thank you for pointing this out!  I’ve been around a few years 😩 and was brought up on manual film cameras -I guess I’ve got a bit lazy as the years have progressed (and been tempted with the latest digital gadgetry)!  However, after the first purchase (at long last) of a used Leica last year, I’m really enjoying the challenges it sometimes brings.  At least it’s cured my (non-Leica)/GAS!  Thanks again  

 

 

 

 

 

 

 

 

 

It's an easy mistake to make - sometimes I still look at the aperture displayed in lightroom and wonder what the hell I was doing before remembering it's just an estimated number. I wish it just displayed XX or something, I don't think an estimated number holds any value at all. 

[Deejaybeephoto]

Advertisement (gone after registration)

13 hours ago, Stevejack said:

It's an easy mistake to make - sometimes I still look at the aperture displayed in lightroom and wonder what the hell I was doing before remembering it's just an estimated number. I wish it just displayed XX or something, I don't think an estimated number holds any value at all. 

I quite agree. 

[adan]

16 hours ago, Stevejack said:

It's an easy mistake to make - sometimes I still look at the aperture displayed in lightroom and wonder what the hell I was doing before remembering it's just an estimated number. I wish it just displayed XX or something, I don't think an estimated number holds any value at all. 

Believe me, Leica has tried both ways. And just can't win.

Someone complains, regardless of whether the "aperture" in EXIF is shown approximately - or as "XX".

Been going on ever since the M8.

The original M10 firmware showed "---" in EXIF, for the aperture in use - and Leica got slagged for that.

So they restored the "visible" estimated aperture value in later firmware versions.

Ultimately it comes down to "the majority rules."

.............

BTW the main function of the estimated aperture has nothing to do with "users."

It is to adjust the amount of correction the camera applies for "sensor-induced" vignetting - because an optical formula's vignetting changes with aperture used.

So the digital Ms' firmware needs to know if the aperture was "f/2.4-ish" or "f/6.8-ish" or "f/11-ish."

[Deejaybeephoto]

2 hours ago, adan said:

Believe me, Leica has tried both ways. And just can't win.

Someone complains, regardless of whether the "aperture" in EXIF is shown approximately - or as "XX".

Been going on ever since the M8.

The original M10 firmware showed "---" in EXIF, for the aperture in use - and Leica got slagged for that.

So they restored the "visible" estimated aperture value in later firmware versions.

Ultimately it comes down to "the majority rules."

.............

BTW the main function of the estimated aperture has nothing to do with "users."

It is to adjust the amount of correction the camera applies for "sensor-induced" vignetting - because an optical formula's vignetting changes with aperture used.

So the digital Ms' firmware needs to know if the aperture was "f/2.4-ish" or "f/6.8-ish" or "f/11-ish."

Thanks for the explanation and history.