tu lis les exifs de ton dernier fichier, c'est le plus simple, il y a sinon des utilitaires comme shootnum etc...
En effet c'est noté dans les exif de la dernière photo dans la section "Shutter Count"exemple d'un fichier exif avec la valeur "Shutter Count: 22233":
ExifTool Version Number : 7.89
File Name : LV1_2055.NEF
Directory : .
File Size : 15 MB
File Modification Date/Time : 2010:07:03 19:28:06+02:00
File Type : NEF
MIME Type : image/x-raw
Exif Byte Order : Big-endian (Motorola, MM)
Make : NIKON CORPORATION
Camera Model Name : NIKON D3S
Orientation : Horizontal (normal)
Software : Ver.1.01
Modify Date : 2010:07:03 19:27:59
Artist : LUC VIATOUR
Jpg From Raw Start : 175488
Jpg From Raw Length : 1448177
Y Cb Cr Positioning : Co-sited
Subfile Type : Full-resolution Image
Image Width : 4288
Image Height : 2844
Bits Per Sample : 14
Compression : Nikon NEF Compressed
Photometric Interpretation : Color Filter Array
Strip Offsets : 1623680
Samples Per Pixel : 1
Rows Per Strip : 2844
Strip Byte Counts : 14580773
X Resolution : 300
Y Resolution : 300
Planar Configuration : Chunky
Resolution Unit : inches
CFA Repeat Pattern Dim : 2 2
CFA Pattern 2 : 0 1 1 2
Reference Black White : 0 255 0 255 0 255
Copyright : WWW.LUCNIX.BE
Exposure Time : 1/160
F Number : 2.8
Exposure Program : Aperture-priority AE
ISO : 8000
Create Date : 2010:07:03 19:27:59
Exposure Compensation : +1/3
Max Aperture Value : 2.8
Metering Mode : Multi-segment
Light Source : Unknown
Flash : No Flash
Focal Length : 200.0 mm
Maker Note Version : 2.10
Quality : Raw
White Balance : Auto
Focus Mode : AF-C
Flash Setting : Normal
Flash Type :
White Balance Fine Tune : 0 0
WB RB Levels : 1.3984375 1.73828125 1 1
Program Shift : 0
Exposure Difference : 0
Preview Image Start : 11580
Preview Image Length : 105918
ISO Setting : 200
Flash Exposure Bracket Value : 0.0
Exposure Bracket Value : 0
Crop Hi Speed : Off (4288x2844 cropped to 4288x2844 at pixel 0,0)
Serial Number : 2013283
Color Space : sRGB
VR Info Version : 0100
Vibration Reduction : On
Image Authentication : On
Active D-Lighting : Off
Picture Control Version : 0100
Picture Control Name : Standard
Picture Control Base : Standard
Picture Control Adjust : Full Control
Picture Control Quick Adjust : Normal
Brightness : Normal
Hue Adjustment : None
Filter Effect : n/a
Toning Effect : n/a
Toning Saturation : n/a
Timezone : +01:00
Daylight Savings : Yes
Date Display Format : D/M/Y
ISO Expansion : Off
ISO2 : 200
ISO Expansion 2 : Off
Vignette Control : Normal
Lens Type : G VR
Lens : 70-200mm f/2.8
Flash Mode : Did Not Fire
Shooting Mode : Continuous, Auto ISO
Auto Bracket Release : None
Contrast Curve : (Binary data 578 bytes, use -b option to extract)
Shot Info Version : 0218
NEF Compression : Lossless
Noise Reduction : Off
Linearization Table : (Binary data 46 bytes, use -b option to extract)
WB RGGB Levels : 0 0 256 358
Lens Data Version : 0204
Exit Pupil Position : 97.5 mm
AF Aperture : 2.8
Focus Position : 0x11
Focus Distance : 3.16 m
Lens ID Number : 162
Lens F Stops : 6.00
Min Focal Length : 71.3 mm
Max Focal Length : 201.6 mm
Max Aperture At Min Focal : 2.8
Max Aperture At Max Focal : 2.8
MCU Version : 164
Effective Max Aperture : 2.8
Raw Image Center : 2143 1422
Retouch History : None
Shutter Count : 22233
Flash Info Version : 0103
External Flash Firmware : n/a
External Flash Flags : (none)
Flash Commander Mode : Off
Flash Control Mode : Off
Flash Exposure Compensation : 0
Flash Group A Control Mode : Off
Flash Group B Control Mode : Off
Flash Group C Control Mode : Off
Flash Group A Exposure Comp : 0
Flash Group B Exposure Comp : 0
Flash Group C Exposure Comp : 0
Multi Exposure Version : 0100
Multi Exposure Mode : Off
Multi Exposure Shots : 0
Multi Exposure Auto Gain : Off
High ISO Noise Reduction : Off
AF Info 2 Version : 0100
AF Area Mode : Single Area
Auto Focus : On
Primary AF Point : Unknown (22)
AF Points Used : Unknown (00 00 20 00 00 00 00)
File Info Version : 0100
Directory Number : 106
File Number : 2055
User Comment :
Sub Sec Time : 47
Sub Sec Time Original : 47
Sub Sec Time Digitized : 47
Sensing Method : One-chip color area
File Source : Digital Camera
Scene Type : Directly photographed
Custom Rendered : Normal
Exposure Mode : Auto
Digital Zoom Ratio : 1
Focal Length In 35mm Format : 200 mm
Scene Capture Type : Standard
Gain Control : High gain up
Contrast : Normal
Saturation : Normal
Sharpness : Normal
Subject Distance Range : Unknown
GPS Version ID : 2.2.0.0
Date/Time Original : 2010:07:03 19:27:59
TIFF-EP Standard ID : 1 0 0 0
Aperture : 2.8
Blue Balance : 2.796875
CFA Pattern : [Red,Green][Green,Blue]
Image Size : 4288x2844
Jpg From Raw : (Binary data 1448177 bytes, use -b option to extract)
Lens ID : Unknown (A2 48 5C 80 24 24 A4 0E)
Lens : 70-200mm f/2.8 G VR
Preview Image : (Binary data 105918 bytes, use -b option to extract)
Red Balance : 0
Scale Factor To 35 mm Equivalent: 1.0
Shutter Speed : 1/160
Create Date : 2010:07:03 19:27:59.47
Date/Time Original : 2010:07:03 19:27:59.47
Modify Date : 2010:07:03 19:27:59.47
Circle Of Confusion : 0.030 mm
Depth Of Field : 0.04 m (3.14 - 3.18)
Field Of View : 9.6 deg (0.53 m)
Focal Length : 200.0 mm (35 mm equivalent: 200.0 mm)
Hyperfocal Distance : 475.46 m
Light Value : 4.0