Lens Information in EXIF data

stevebrot · 07-22-2019, 08:18 AM

Originally posted by RobG

It's mentioned in at least one of the reviews:

I guess I got this one wrong.

A little Google work indicates that the problem is well-known in Pentax circles, has been for several years, and may be limited to Pentax (reports properly for Sony in one review). Strangely, the correct value is captured in the makernotes, but not recorded in the standard EXIF if the value is below 10mm. There is even a program to rewrite the EXIF posted here on PF.

Sigma 8-16mm modifier program - PentaxForums.com

-- or --

A discussion on the ExifTool site including a script suggested by Phil Harvey for ExifTool (he is the author):

Workaround for Sigma 8-16mm requested

Steve

RobG · 07-22-2019, 05:15 PM

Originally posted by stevebrot

I guess I got this one wrong.

A little Google work indicates that the problem is well-known in Pentax circles, has been for several years, and may be limited to Pentax (reports properly for Sony in one review). Strangely, the correct value is captured in the makernotes, but not recorded in the standard EXIF if the value is below 10mm.

Thanks Steve. So my reason for mentioning it in this thread is because it seems to be a Pentax camera firmware issue in terms of not reporting the focal length - unless it's a bug in the Pentax version of the Sigma lens itself.

stevebrot · 07-22-2019, 07:47 PM

Originally posted by RobG

it seems to be a Pentax camera firmware issue in terms of not reporting the focal length - unless it's a bug in the Pentax version of the Sigma lens itself.

There is something strange in how the firmware handles the information such that it stores the value in the makernotes, but not in the standard EXIF in the same manner as longer focal lengths.

Steve

RobG · 07-22-2019, 09:45 PM

Originally posted by stevebrot

There is something strange in how the firmware handles the information such that it stores the value in the makernotes, but not in the standard EXIF in the same manner as longer focal lengths.

Sounds like a bug to me.

Mercifulfate · 10-14-2019, 05:20 AM

I generally use a pencil because most of my lenses are manual. I do not do a lot of lens changing so its really not much of an issue.

RobG · 10-14-2019, 06:46 PM

Originally posted by Mercifulfate

I generally use a pencil because most of my lenses are manual. I do not do a lot of lens changing so its really not much of an issue.

If you're using manual lenses, then you'll need to set the focal length when you mount the lens. This won't work for the Sigma 8-16.

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07-22-2019, 08:18 AM	#16
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by RobG It's mentioned in at least one of the reviews: I guess I got this one wrong. A little Google work indicates that the problem is well-known in Pentax circles, has been for several years, and may be limited to Pentax (reports properly for Sony in one review). Strangely, the correct value is captured in the makernotes, but not recorded in the standard EXIF if the value is below 10mm. There is even a program to rewrite the EXIF posted here on PF. Sigma 8-16mm modifier program - PentaxForums.com -- or -- A discussion on the ExifTool site including a script suggested by Phil Harvey for ExifTool (he is the author): Workaround for Sigma 8-16mm requested Steve

07-22-2019, 05:15 PM	#17
RobG Otis Memorial Pentaxian Join Date: Dec 2009 Location: Canberra Photos: Gallery \| Albums Posts: 8,905	Originally posted by stevebrot I guess I got this one wrong. A little Google work indicates that the problem is well-known in Pentax circles, has been for several years, and may be limited to Pentax (reports properly for Sony in one review). Strangely, the correct value is captured in the makernotes, but not recorded in the standard EXIF if the value is below 10mm. Thanks Steve. So my reason for mentioning it in this thread is because it seems to be a Pentax camera firmware issue in terms of not reporting the focal length - unless it's a bug in the Pentax version of the Sigma lens itself.

07-22-2019, 07:47 PM	#18
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by RobG it seems to be a Pentax camera firmware issue in terms of not reporting the focal length - unless it's a bug in the Pentax version of the Sigma lens itself. There is something strange in how the firmware handles the information such that it stores the value in the makernotes, but not in the standard EXIF in the same manner as longer focal lengths. Steve

07-22-2019, 09:45 PM	#19
RobG Otis Memorial Pentaxian Join Date: Dec 2009 Location: Canberra Photos: Gallery \| Albums Posts: 8,905	Originally posted by stevebrot There is something strange in how the firmware handles the information such that it stores the value in the makernotes, but not in the standard EXIF in the same manner as longer focal lengths. Sounds like a bug to me.

10-14-2019, 05:20 AM	#20
Mercifulfate Forum Member Join Date: Mar 2018 Posts: 92	I generally use a pencil because most of my lenses are manual. I do not do a lot of lens changing so its really not much of an issue.

10-14-2019, 06:46 PM	#21
RobG Otis Memorial Pentaxian Join Date: Dec 2009 Location: Canberra Photos: Gallery \| Albums Posts: 8,905	Originally posted by Mercifulfate I generally use a pencil because most of my lenses are manual. I do not do a lot of lens changing so its really not much of an issue. If you're using manual lenses, then you'll need to set the focal length when you mount the lens. This won't work for the Sigma 8-16.