Focal length

julie32 · May 30, 2008

Morning.....

Where is it that I can tell what my focal length was on a certain shot? I have a canon, and I usually shoot with the info on the screen (histogram, file size, speed, iso and so forth......) but nowhere that I'm seeing does it say the focal length.

Thanks for your help.

Alfred D. · May 30, 2008

Hi Julie,

every photo file contains a little sub file – the 'EXIF data' – that lists all the values pertaining to that photo. Dozens of values. The focal length used is one of them. Many photo editing apps can make the EXIF data visible. If yours can't: there are also dedicated little EXIF 'viewers' you can download from the internet.

Example of EXIF data (bold face mine):

Make: NIKON CORPORATION
Model: NIKON D200
Orientation of image: 1
X resolution: 300.0 ppi (pixel per inch)
Y resolution: 300.0 ppi (pixel per inch)
Resolution unit: inch
Software: Ver.2.00
File date and time: 2008:04:12 18:02:29
Unknown tag (318): 0.3
Unknown tag (319): 0.6
Unknown tag (529): 0.3
Y and C positioning: co-sited
-- Exif IFD --:
Exposure time: 1/40 s
F number: 5.0
Exposure program: Normal program
ISO speed rating: 100
Exif version: 0221
Date and time of original data generation: 2008:04:12 18:02:29
Date and time of digital data generation: 2008:04:12 18:02:29
Meaning of each component: reserved
Image compression mode: 4.0
Exposure bias: 0.0
Maximum lens aperture: 4.7 APEX = F5.1
Metering mode: CenterWeightedAverage
Light source: unknown
Flash: Flash did not fire.
Lens focal length: 80.0 mm
Manufacturer notes: 26938 bytes
User comments: 44 bytes
Date and time subseconds: 31
Date and time original subseconds: 31
Date and time digitized subseconds: 31
Supported Flashpix version: 0100
Color Space: Uncalibrated
Valid image width in pixel: 3872
Valid image height in pixel: 2592
-- Interoperability IFD --:
Interoperability Index: R03
Interoperability Version: 0100
-- End of Interoperability IFD, EXIF IFD continues:
Sensing method: One-chip color area sensor
File source: DSC
Scene type: A directly photographed image
CFA pattern:
Custom image processing: Normal process
Exposure method: Auto exposure
White balance: Auto white balance
Digital zoom ratio: 1.0
Focal length in 35 mm film: 120 mm
Scene capture type: Standard
Gain control: None
Contrast: Normal
Saturation: High saturation
Sharpness: Hard
Subject distance range: unknown
Unknown tag (42240): 2.2
-- Main IFD continues --:
-- GPS IFD --:
-- Thumbnail IFD --:
Compression scheme: JPEG
X resolution: 300.0 ppi (pixel per inch)
Y resolution: 300.0 ppi (pixel per inch)
Resolution unit: inch
Offset to JPEG SOI: 28104
Bytes of JPEG data: 9403
Y and C positioning: co-sited
--- Nikon undocumented tags ---:
Nikon Makernote Version: 48, 50... (4 values)
ISO Speed Used: {0,100}
Colour Mode: COLOR
Quality: FINE
White Balance: AUTO
Sharpening: MED.H
Focus Mode: AF-C
Flash Setting: NORMAL
Auto Flash Mode:
White Balance Bias Value: 0
White Balance Coefficients: {1.8,1.7,1.0,1.0}
Unknown (13): 0, 1... (4 values)
Unknown (14): 0, 1... (4 values)
Unknown (17): 2366
Flash Compensation: 0, 1... (4 values)
ISO Speed requested: {0,100}
Photo corners: {0,0,3872,2592}
Unknown (23): 0, 1... (4 values)
Flash Bracket Compensation Applied: 0, 1... (4 values)
AE Bracket Compensation Applied: 0.0
Unknown (27): {0,3904,2616,3904,2616,0,0}
Unknown (28): 0, 1... (3 values)
Unknown (29):
Unknown (30): 2
Unknown (32): 0
Tone Compensation (Contrast): NORMAL
Lens Type: Nikon G series Lens
Lens Min/Max Focal Length, Max Aperture: {18.0,200.0,3.5,5.6}
Flash Used: 0
Auto Focus Area: 0, 0... (4 values)
Bracketing & Shooting Mode: 1
Unknown (138): 1
Unknown (139): 64, 1... (4 values)
Colour Mode: MODE3
Lighting Type: COLORED
Unknown (145): 0, 0... (784 values)
Hue Adjustment: 0
Noise Reduction: OFF
Unknown (151): 0, 0... (608 values)
Unknown (152): 0, 0... (31 values)
Unknown (154): {6.0,6.0}
Unknown (162): 3428029
Unknown (163): 0
Unknown (165): 3561
Unknown (166): 2
Total Number of Shutter Releases for Camera: 3563
Unknown (168): 0, 0... (20 values)
Image optimisation: VIVID
Saturation: ENHANCED
Unknown (176): 0, 0... (16 values)
Unknown (177): 0

Have fun!

Big Mike · May 30, 2008

Open the image with EOS Utility, Digital Photo Pro, Photoshop etc. The focal length will be in the EXIF data.

julie32 · May 30, 2008

I'm sorry I didn't specify, I mean on the camera at the time of the shot like the other data I can see..... Sorry.

Big Mike · May 30, 2008

If it's not on the info/histogram screen...then I'm not sure that you could find the exact focal length of shots that you have taken.

patrickt · May 30, 2008

My zooms have a scale on them that will tell me, approximately, the focal length I'm shooting. I don't have any reason to use the scale but it's there. My priority is to frame the shot the way I want and not the focal length.

Primes don't have the scale because they are always the same focal length.

julie32 · May 30, 2008

ok thanks for the fast replies. I'll just find it once the photo is on my computer instead of just on the LCD. Thanks again guys.

JimmyO · May 30, 2008

When going through the pics you've taken you should be able to set it that for each shot it shows the exif infront of the shot, sorry, i dont know how to do this with canon cameras.

mrodgers · May 30, 2008

I have a superzoom (Fuji S5700) and my problem with focal length listed in the exif is, it is always listed at 63 mm at my longest. My camera is 38-380 mm at the 35 mm equivalent.

I'm looking at one of my photos on photobucket and the details there state "Focal Length: 10.9mm (35mm equivalent: 264mm). I don't get this with any of my photo software or with the exif viewer in Firefox. Flickr also states the low focal length as well.

I don't know what the 10.9 mm is relating to in my example above. That is zoomed out probably longer than 3/4 of my zoom, but exif in software only states it as 10.9. I think at my widest angle it states 6.3.