Subject Distance in EXIF

[davegee]

Does anyone know how the subject distance can be determined in the EXIF of a RAW or JPEG file?

Is it possible?

I have tried right clicking on a file in Windows Explorer and going to Properties. Subject distance is an available parameter but is blank for my RAW and JPEG files.

My RAW converter does not list subject distance as an available parameter.

Any third party gizmos out there that might do this?

TIA,

DG

[PGA]

Dave,

Shouldn't your first check be: does my camera actually fill this field? That is something the maker should be able to tell you.

regards,

Peter

[Ken Cox]

Dave

will this help

http://www.dpreview....s/post/40091244

http://www.birdphotographers.net/forums/showthread.php/75235-Focal-Distance-in-EXIF-Data

ken

[cottage]

Does anyone know how the subject distance can be determined in the EXIF of a RAW or JPEG file?

Is it possible?

I have tried right clicking on a file in Windows Explorer and going to Properties. Subject distance is an available parameter but is blank for my RAW and JPEG files.

My RAW converter does not list subject distance as an available parameter.

Any third party gizmos out there that might do this?

TIA,

DG

Dave,

Cheap and dirty way is to use IrfanView. It provides Subject Distance in the EXIF data if it's available from your camera.

Bill

[davegee]

Hi Bill,

It might well be that the D600 does not supply the info.

DG

[cottage]

Hi Bill,

It might well be that the D600 does not supply the info.

DG

Dave,

I found this on the web concerning the D600.

"Exposure metering is determined through Nikon's Intelligent Scene Recognition System, which utilizes 3D Color Matrix Metering II. This metering system makes use of a 2016-pixel RGB sensor for evaluating the entire scene's brightness and contrast values, subject distance and colors in order to determine the exposure settings. The acquired data is then stored for comparative use to ensure consistency among different exposures in regard to white balance and overall exposure values. It also helps to improve i-TTL flash measurements and subject-tracking focus."

Whether or not the Nikon D600 then retains this info for later use.... I don't know. Sorry, Canon man! :-)

Bill

[davegee]

Hi Bill,

There are some discussions which Ken pointed out which suggest that this is one thing they don't retain.

The EXIF data section in NX2 is extensive and includes Subject Distance (Blank for my Camera / Lens) and tells me all that I need to know about Master and Remote Flashes, EV Compensations in a wireless multi flash setup setup but does not offer me Subject Distance which is important to me to analyse some High Speed Sync images.

EXIF Tool is highly recommended apparently.

DG

[cjdnzl]

My camera, a Canon 40D, does not seem to record subject distance in the exif data. I think it is because with a zoom lens, the lens setting for a given distance varies with the zoom setting, making it difficult for the camera to figure the distance.

My most-used lens is the Canon 17-85 mm lens, and I notice that the infinity mark in the window shifts with zoom setting. The mark is correct for the long end of the lens, but when the wide end is at infinity the focus scale indicates about the 10 metre mark, a linear distance on the scale of about 5 or 6 mm. I just tried focusing on a target about 5 metres away; at the wide end the scale indicated about 3 metres, while the long end indicated more like 5 or 6 metres.

So it appears that the camera cannot derive an accurate distance from the lens, so - no distance in the exif.

A point to consider: there are two types of variable focal length lenses, 'zoom' and 'varifocal'.

A true zoom lens is one in which the focus does not change with zooming. They are very expensive, and used mainly for professional movie cameras where the focus must be maintained while zooming.

Varifocal lenses change focus when zoomed, but for still cameras it isn't really a problem. What we call zoom lenses are in fact varifocal lenses, so the focus does shift when zooming, and I believe that is the reason your exif data doesn't show distance.

I believe that some lenses, like primes, do show distance, but I haven't seen that. I don't own any primes.

[davegee]

Hi Colin,

Thanks.

I only use primes for (outdoor) portraits in a wireless multi-flash setup with High Speed Sync - in the case that I am trying to analyse it was a Nikon 105 f2.8 VR. I also used my 50 f1.4 on the same session.

As I said to Bill, NX2 gives a VERY comprehensive list of EXIF info but does not include Subject Distance for any lens.

If I right click on a NEF File in Explorer and look at Properties there is an even more comprehensive list of EXIF parameters which includes Subject Distance which in my case is always blank.

It looks like you cannot access this for Nikons??

DG