Recording focus details??

[cheadle hulme]

Right bear with me.

New Nikon D3100 for Christmas, new Tamron zoom lens too.

I'm amazed at the pictures I can get with auto and pre-set modes. I'm also amazed at the data the camera records with each image - aperature, focal length, shutter speed, ISO etc. I am unable to find the focus settings however; I assumed that in auto-focus mode, with the camera in charge, it would record what the focus was? Sorry, I don't know how to express focus measures.

The reason for asking is the zoom lens at 300mm doesn't focus very quickly. I want to take pictures of aircraft landing from a set point. The aircraft will always be at a set point (give or take a few metres, allowing for wind and size of aircraft).

I thought if I managed to get a good shot with auto focus (using continuous servo mode) I could then use these settings manually. This would mean I could take pictures at 3 per second (with fixed focus) rather than with auto focus.

However, the camera doesn't tell me its auto focus settings? Or does it??

[Simpo Two]

cheadle hulme said:

I am unable to find the focus settings however; I assumed that in auto-focus mode, with the camera in charge, it would record what the focus was? Sorry, I don't know how to express focus measures.

Do you mean the distance to subject?

cheadle hulme said:

The reason for asking is the zoom lens at 300mm doesn't focus very quickly. I want to take pictures of aircraft landing from a set point. The aircraft will always be at a set point (give or take a few metres, allowing for wind and size of aircraft).

I thought if I managed to get a good shot with auto focus (using continuous servo mode) I could then use these settings manually. This would mean I could take pictures at 3 per second (with fixed focus) rather than with auto focus.

Gotcha. Well if your subject distance is the same and autofocus is hindering you, you can either use manual focus (can be tricky with a small viewfinder) or use autofocus to find the right point, then disengage it and try not to touch the focus ring! The important thing is to get the subject sharp. Whether it's 26 or 27 feet away isn't inmportant - and even if you knew it was 26 feet, you couldn't set it like that.

cheadle hulme said:

However, the camera doesn't tell me its auto focus settings? Or does it??

As far as I know this is not recorded, although the camera's metering system can (depending on the lens) use subject distance information to calculate flash exposure.

Edited by Simpo Two on Thursday 20th January 21:41

[cheadle hulme]

Simpo Two said:

Gotcha. Well if your subject distance is the same and autofocus is hindering you, you can either use manual focus (can be tricky with a small viewfinder) or use autofocus to find the right point, then disengage it and try not to touch the focus ring!

Thanks! Its exactly this. The autofocus finds the right settings; I wanted to record what those settings were so I could use them again (all the time actually).

[adamfogerty]

Simpo Two said:

cheadle hulme said:

I am unable to find the focus settings however; I assumed that in auto-focus mode, with the camera in charge, it would record what the focus was? Sorry, I don't know how to express focus measures.

Do you mean the distance to subject?

cheadle hulme said:

The reason for asking is the zoom lens at 300mm doesn't focus very quickly. I want to take pictures of aircraft landing from a set point. The aircraft will always be at a set point (give or take a few metres, allowing for wind and size of aircraft).

I thought if I managed to get a good shot with auto focus (using continuous servo mode) I could then use these settings manually. This would mean I could take pictures at 3 per second (with fixed focus) rather than with auto focus.

Gotcha. Well if your subject distance is the same and autofocus is hindering you, you can either use manual focus (can be tricky with a small viewfinder) or use autofocus to find the right point, then disengage it and try not to touch the focus ring! The important thing is to get the subject sharp. Whether it's 26 or 27 feet away isn't inmportant - and even if you knew it was 26 feet, you couldn't set it like that.

cheadle hulme said:

However, the camera doesn't tell me its auto focus settings? Or does it??

As far as I know this is not recorded, although the camera's metering system can (depending on the lens) use subject distance information to calculate flash exposure.

Edited by Simpo Two on Thursday 20th January 21:41

Depending on the manufacturer and specific lens, some do have distance scales marked on the lens barrel so you can actually do this.

[cheadle hulme]

adamfogerty said:

Simpo Two said:

cheadle hulme said:

I am unable to find the focus settings however; I assumed that in auto-focus mode, with the camera in charge, it would record what the focus was? Sorry, I don't know how to express focus measures.

Do you mean the distance to subject?

cheadle hulme said:

The reason for asking is the zoom lens at 300mm doesn't focus very quickly. I want to take pictures of aircraft landing from a set point. The aircraft will always be at a set point (give or take a few metres, allowing for wind and size of aircraft).

I thought if I managed to get a good shot with auto focus (using continuous servo mode) I could then use these settings manually. This would mean I could take pictures at 3 per second (with fixed focus) rather than with auto focus.

Gotcha. Well if your subject distance is the same and autofocus is hindering you, you can either use manual focus (can be tricky with a small viewfinder) or use autofocus to find the right point, then disengage it and try not to touch the focus ring! The important thing is to get the subject sharp. Whether it's 26 or 27 feet away isn't inmportant - and even if you knew it was 26 feet, you couldn't set it like that.

cheadle hulme said:

However, the camera doesn't tell me its auto focus settings? Or does it??

As far as I know this is not recorded, although the camera's metering system can (depending on the lens) use subject distance information to calculate flash exposure.

Edited by Simpo Two on Thursday 20th January 21:41

Depending on the manufacturer and specific lens, some do have distance scales marked on the lens barrel so you can actually do this.

Thanks, my lens does, but I'm at the limit of the focal length (300mm) so the markings are not much use.

[Simpo Two]

adamfogerty said:

Depending on the manufacturer and specific lens, some do have distance scales marked on the lens barrel so you can actually do this.

Well yes, most do - but then you either have to guess the distance, get a tape-measure or consult the EXIF data from the last shot taken in that situation.

This is why God invented AF

Main thing IMHO is to get the focus where it needs to be, and how you get there isn't important - each tog to himself!

[flat-planedCrank]

Can you use that AE-L/AF-L button to lock the focus in place and set the shutter not to trigger the af?

Sorry, don't know Nikon sets this up but its a pretty popular way of working - you split the af from the metering and shutter release.
For example, means that if you are shooting through a fence at circuit you don't have the af trying to grab the fence when you take each shot.

[adamfogerty]

cheadle hulme said:

Thanks, my lens does, but I'm at the limit of the focal length (300mm) so the markings are not much use.

The focal point and focal length markings are different. Admittedly a subtle difference, but a difference nonetheless.

The focal point markings might go as close as 1m and extend out to infinity, but your focal length markings will relate exactly to the zoom range of your lens - 100mm-300mm or whatever that might be.

I think you're referring to later, while I was talking about the former

Adam

Edited by adamfogerty on Thursday 20th January 22:52

[Simpo Two]

He may mean that as the subjects (aircraft landing) are so far away that the marking on the lens only go from (say) 30m to Infinity and there is no setting for 100m, 200m, etc. The amount of 'turn' required at those focal lengths is very small yet very critical due to the magnification.

I'd use AF for the first one, then switch to MF. Or buy an AF-S lens which will focus faster.

[RobDickinson]

Canon records which focus point(s) it thinks were used/in focus and also with USM lenses it records the distance to the focus point.

Dunno about nikon.

I dont think it records the autofocus mode tho.

[Ledaig]

The following lists the information which can be gained from Nikon exif data, this includes focus details:

Standard Information
Make: NIKON CORPORATION
Model: NIKON D3
Software: Capture NX 2.2.2 W
ImageSize: 2832x4256
ComponentsConfiguration: Y, Cb, Cr, -
CreateDate: 2008:11:27 15:10:28
ModifyDate: 2009:12:22 14:20:26
DateTimeOriginal: 2008:11:27 15:10:28
ExposureTime: 1/60"
Aperture: F4.5
MaxAperture: F2.8
DepthOfFocus: 2.53 m (0.60 - 3.13)
CircleOfConfusion: 0.030 mm
HyperfocalDistance: 1.45 m
ExposureProgram: Aperture-priority AE
ExposureBiasValue: 0
MeteringMode: Multi-segment
Flash: On, Return detected
ISO: 800
WhiteBalance: Auto
FocalLength: 14.0 mm
FocalLength35efl: 14.0 mm (35 mm equivalent: 14.0 mm)
SensingMethod: One-chip color area
SceneType: Directly photographed
ColorSpace: sRGB
NoiseReduction: Off
Contrast: Normal
Saturation: Normal
Sharpness: Normal
ShutterCount: 7106
LensSpec: 14-24mm f/2.8 G

GPS Information
GPSVersionID: 2.2.0.0

Other Information
AFAperture: 2.8
AFAreaMode: Single Area
AFInfo2Version: 0100
AFPointsUsed: C6
ActiveD-Lighting: Off
Artist:
AutoBracketRelease: Unknown (255)
AutoFocus: On
BitsPerSample: 8
BlueBalance: 1.175781
BlueMatrixColumn: 0.14305 0.06061 0.71399
Brightness: Normal
CFAPattern: [Red,Green][Green,Blue]
CMMFlags: Not Embedded, Independent
ColorBalance1: 2.046875 1.17578125 1 1
ColorComponents: 3
ColorSpaceData: RGB
Compression: JPEG (old-style)
ConnectionSpaceIlluminant: 0.9642 1 0.82491
Copyright
CropHiSpeed: Off (4288x2844 cropped to 4288x2844 at pixel 0,0)
CustomRendered: Normal
DateDisplayFormat: Y/M/D
DaylightSavings: No
DeviceAttributes: Reflective, Glossy, Positive, Color
DeviceManufacturer: none
DeviceModel
DigitalZoomRatio: 1
Directory: C:\Documents and Settings\stevmcge\My Documents\P Docs\Images\Lightning
DirectoryNumber: 100
EffectiveMaxAperture: 2.8
EncodingProcess: Baseline DCT, Huffman coding
ExifByteOrder: Little-endian (Intel, II)
ExifImageHeight: 4256
ExifImageWidth: 2832
ExifVersion: 0220
ExitPupilPosition: 85.3 mm
ExposureBracketValue: 0
ExposureDifference: -1.5
ExposureMode: Auto
ExternalFlashFirmware: 5.02 (SB-900)
ExternalFlashFlags: [0]
FNumber: 4.5
FOV: 103.5 deg (2.54 m)
FileInfoVersion: 0100
FileModifyDate: 2009:12:22 14:20:26+00:00
FileName: DSC_6934.jpg
FileNumber: 6934
FileSize: 7.6 MB
FileSource: Digital Camera
FileType: JPEG
FilterEffect: n/a
FlashCommanderMode: Off
FlashControlMode: iTTL-BL
FlashExposureComp: 0
FlashFocalLength: 17 mm
FlashGroupAControlMode: Off
FlashGroupAExposureComp: 0
FlashGroupBControlMode: Off
FlashGroupBExposureComp: 0
FlashGroupCControlMode: Off
FlashGroupCExposureComp: 0
FlashInfoVersion: 0103
FlashMode: Fired, External
FlashSetting: Normal
FlashType: Optional,Ttl
FlashpixVersion: 0100
FocalLengthIn35mmFormat: 14 mm
FocusDistance: 1.00 m
FocusMode: AF-S
FocusPosition: 0x31
GainControl: Low gain up
GreenMatrixColumn: 0.38507 0.71687 0.09706
HighISONoiseReduction: Off
HueAdjustment: None
IFD0_Offset: 9914
ISO2: 25
ISOExpansion: Off
ISOExpansion2: Off
ISOSetting: 800
ImageAuthentication: Off
ImageDataSize: 7913307
ImageHeight: 4256
ImageWidth: 2832
JFIFVersion: 1.02
Lens: 14-24mm f/2.8
LensDataVersion: 0203
LensFStops: 6.00
LensID: AF-S Zoom-Nikkor 14-24mm f/2.8G ED
LensIDNumber: 146
LensType: G
LightSource: Unknown
LightValue: 7.2
MCUVersion: 148
MakerNoteVersion: 2.10
MaxApertureAtMaxFocal: 2.8
MaxApertureAtMinFocal: 2.8
MaxApertureValue: 2.8
MaxFocalLength: 24.5 mm
MediaWhitePoint: 0.9505 1 1.0891
MinFocalLength: 14.1 mm
MultiExposureAutoGain: Off
MultiExposureMode: Off
MultiExposureShots: 0
MultiExposureVersion: 0100
NikonCaptureVersion: Capture NX 2.2.2 W
Orientation: Horizontal (normal)
PictureControlAdjust: Default Settings
PictureControlBase: Standard
PictureControlName: Standard
PictureControlQuickAdjust: Normal
PictureControlVersion: 0100
PreviewIFD_Offset: 9814
PreviewImageLength: 36688
PreviewImageStart: 13734
PrimaryPlatform: Apple Computer Inc.
ProfileCMMType: NKON
ProfileClass: Display Device Profile
ProfileConnectionSpace: XYZ
ProfileCopyright: Nikon Inc. & Nikon Corporation 2002
ProfileCreator
ProfileDateTime: 2002:10:25 13:32:16
ProfileDescription: Nikon sRGB 4.0.0.3001
ProfileFileSignature: acsp
ProfileID: 0
ProfileVersion: 2.2.0
ProgramShift: 0
Quality: Raw
RawImageCenter: 2143 1422
RedBalance: 2.046875
RedMatrixColumn: 0.43607 0.2225 0.01392
ReferenceBlackWhite: 0 255 0 255 0 255
RenderingIntent: Perceptual
ResolutionUnit: inches
RetouchHistory: None
ScaleFactor35efl: 1.0
SceneCaptureType: Standard
SerialNumber: 2039573
ShootingMode: Single-Frame
ShotInfoVersion: 0210
ShutterSpeed: 1/60
SubSecCreateDate: 2008:11:27 15:10:28.84
SubSecDateTimeOriginal: 2008:11:27 15:10:28.84
SubSecModifyDate: 2009:12:22 14:20:26.84
SubSecTime: 84
SubSecTimeDigitized: 84
SubSecTimeOriginal: 84
SubjectDistanceRange: Unknown
ThumbnailLength: 3696
ThumbnailOffset: 10038
Timezone: +00:00
ToningEffect: n/a
ToningSaturation: n/a
UserComment:
VRInfoVersion: 0100
VibrationReduction: Off
VignetteControl: Normal
WB_GRBGLevels: 256 524 301 256
WhiteBalanceFineTune: 0 0
XResolution: 300
YCbCrPositioning: Centered
YCbCrSubSampling: YCbCr4:4:4 (1 1)
YResolution: 300

[crmcatee]

I'm still not sure what you're trying to achieve.


You're only going to get the EXIF information after the shot so it's kind of useless if you're trying to set up the next shot. Especially with lots of variables such as where the aeroplane is going to land.


As has been said - I'd be focussing on something manually on or near where you think the planes going to land, a mark on the runway for instance. You can either do this using MF or use one of the focus points on the camera to select the point you wish. Keep the AI Servo on and don't push the shutter button or it will focus on something else.


Other than that I know my Canon can do it (sorry don't know about the Nikon) but if you look in the menu's you may find the ability to turn off the shutter button from both selecting the AF point, focussing and then taking the shot. I've set mine so that the shutter wakes up the camera and shows the focus point that I'm using and takes the picture. One of the buttons where my thumb is, actually focuses the camera on the focus point when I push it - allowing me to focus on a single point then reframe without having to worry that the camera is going to focus on another point when I touch the shutter.



On mine it's listed as Shutter Button AF-ON button (C. Fn IV number 1).

[Elderly]

Ledaig said:

The following lists the information which can be gained from Nikon exif data, this includes focus details:

Standard Information
Make: NIKON CORPORATION
Model: NIKON D3
Software: Capture NX 2.2.2 W
ImageSize: 2832x4256
ComponentsConfiguration: Y, Cb, Cr, -
CreateDate: 2008:11:27 15:10:28
ModifyDate: 2009:12:22 14:20:26
DateTimeOriginal: 2008:11:27 15:10:28
ExposureTime: 1/60"
Aperture: F4.5
MaxAperture: F2.8
DepthOfFocus: 2.53 m (0.60 - 3.13)
CircleOfConfusion: 0.030 mm
HyperfocalDistance: 1.45 m
ExposureProgram: Aperture-priority AE
ExposureBiasValue: 0
MeteringMode: Multi-segment
Flash: On, Return detected
ISO: 800
WhiteBalance: Auto
FocalLength: 14.0 mm
FocalLength35efl: 14.0 mm (35 mm equivalent: 14.0 mm)
SensingMethod: One-chip color area
SceneType: Directly photographed
ColorSpace: sRGB
NoiseReduction: Off
Contrast: Normal
Saturation: Normal
Sharpness: Normal
ShutterCount: 7106
LensSpec: 14-24mm f/2.8 G

GPS Information
GPSVersionID: 2.2.0.0

Other Information
AFAperture: 2.8
AFAreaMode: Single Area
AFInfo2Version: 0100
AFPointsUsed: C6
ActiveD-Lighting: Off
Artist:
AutoBracketRelease: Unknown (255)
AutoFocus: On
BitsPerSample: 8
BlueBalance: 1.175781
BlueMatrixColumn: 0.14305 0.06061 0.71399
Brightness: Normal
CFAPattern: [Red,Green][Green,Blue]
CMMFlags: Not Embedded, Independent
ColorBalance1: 2.046875 1.17578125 1 1
ColorComponents: 3
ColorSpaceData: RGB
Compression: JPEG (old-style)
ConnectionSpaceIlluminant: 0.9642 1 0.82491
Copyright
CropHiSpeed: Off (4288x2844 cropped to 4288x2844 at pixel 0,0)
CustomRendered: Normal
DateDisplayFormat: Y/M/D
DaylightSavings: No
DeviceAttributes: Reflective, Glossy, Positive, Color
DeviceManufacturer: none
DeviceModel
DigitalZoomRatio: 1
Directory: C:\Documents and Settings\stevmcge\My Documents\P Docs\Images\Lightning
DirectoryNumber: 100
EffectiveMaxAperture: 2.8
EncodingProcess: Baseline DCT, Huffman coding
ExifByteOrder: Little-endian (Intel, II)
ExifImageHeight: 4256
ExifImageWidth: 2832
ExifVersion: 0220
ExitPupilPosition: 85.3 mm
ExposureBracketValue: 0
ExposureDifference: -1.5
ExposureMode: Auto
ExternalFlashFirmware: 5.02 (SB-900)
ExternalFlashFlags: [0]
FNumber: 4.5
FOV: 103.5 deg (2.54 m)
FileInfoVersion: 0100
FileModifyDate: 2009:12:22 14:20:26+00:00
FileName: DSC_6934.jpg
FileNumber: 6934
FileSize: 7.6 MB
FileSource: Digital Camera
FileType: JPEG
FilterEffect: n/a
FlashCommanderMode: Off
FlashControlMode: iTTL-BL
FlashExposureComp: 0
FlashFocalLength: 17 mm
FlashGroupAControlMode: Off
FlashGroupAExposureComp: 0
FlashGroupBControlMode: Off
FlashGroupBExposureComp: 0
FlashGroupCControlMode: Off
FlashGroupCExposureComp: 0
FlashInfoVersion: 0103
FlashMode: Fired, External
FlashSetting: Normal
FlashType: Optional,Ttl
FlashpixVersion: 0100
FocalLengthIn35mmFormat: 14 mm
FocusDistance: 1.00 m
FocusMode: AF-S
FocusPosition: 0x31
GainControl: Low gain up
GreenMatrixColumn: 0.38507 0.71687 0.09706
HighISONoiseReduction: Off
HueAdjustment: None
IFD0_Offset: 9914
ISO2: 25
ISOExpansion: Off
ISOExpansion2: Off
ISOSetting: 800
ImageAuthentication: Off
ImageDataSize: 7913307
ImageHeight: 4256
ImageWidth: 2832
JFIFVersion: 1.02
Lens: 14-24mm f/2.8
LensDataVersion: 0203
LensFStops: 6.00
LensID: AF-S Zoom-Nikkor 14-24mm f/2.8G ED
LensIDNumber: 146
LensType: G
LightSource: Unknown
LightValue: 7.2
MCUVersion: 148
MakerNoteVersion: 2.10
MaxApertureAtMaxFocal: 2.8
MaxApertureAtMinFocal: 2.8
MaxApertureValue: 2.8
MaxFocalLength: 24.5 mm
MediaWhitePoint: 0.9505 1 1.0891
MinFocalLength: 14.1 mm
MultiExposureAutoGain: Off
MultiExposureMode: Off
MultiExposureShots: 0
MultiExposureVersion: 0100
NikonCaptureVersion: Capture NX 2.2.2 W
Orientation: Horizontal (normal)
PictureControlAdjust: Default Settings
PictureControlBase: Standard
PictureControlName: Standard
PictureControlQuickAdjust: Normal
PictureControlVersion: 0100
PreviewIFD_Offset: 9814
PreviewImageLength: 36688
PreviewImageStart: 13734
PrimaryPlatform: Apple Computer Inc.
ProfileCMMType: NKON
ProfileClass: Display Device Profile
ProfileConnectionSpace: XYZ
ProfileCopyright: Nikon Inc. & Nikon Corporation 2002
ProfileCreator
ProfileDateTime: 2002:10:25 13:32:16
ProfileDescription: Nikon sRGB 4.0.0.3001
ProfileFileSignature: acsp
ProfileID: 0
ProfileVersion: 2.2.0
ProgramShift: 0
Quality: Raw
RawImageCenter: 2143 1422
RedBalance: 2.046875
RedMatrixColumn: 0.43607 0.2225 0.01392
ReferenceBlackWhite: 0 255 0 255 0 255
RenderingIntent: Perceptual
ResolutionUnit: inches
RetouchHistory: None
ScaleFactor35efl: 1.0
SceneCaptureType: Standard
SerialNumber: 2039573
ShootingMode: Single-Frame
ShotInfoVersion: 0210
ShutterSpeed: 1/60
SubSecCreateDate: 2008:11:27 15:10:28.84
SubSecDateTimeOriginal: 2008:11:27 15:10:28.84
SubSecModifyDate: 2009:12:22 14:20:26.84
SubSecTime: 84
SubSecTimeDigitized: 84
SubSecTimeOriginal: 84
SubjectDistanceRange: Unknown
ThumbnailLength: 3696
ThumbnailOffset: 10038
Timezone: +00:00
ToningEffect: n/a
ToningSaturation: n/a
UserComment:
VRInfoVersion: 0100
VibrationReduction: Off
VignetteControl: Normal
WB_GRBGLevels: 256 524 301 256
WhiteBalanceFineTune: 0 0
XResolution: 300
YCbCrPositioning: Centered
YCbCrSubSampling: YCbCr4:4:4 (1 1)
YResolution: 300

Well that's just useless - where does it tell you in which position your 'little lever' for covering the eyepiece was ?

[Ledaig]

Elderly said:

Well that's just useless - where does it tell you in which position your 'little lever' for covering the eyepiece was ?

Ah...yes....well.....that's because either:

a) Nikon didn't want to upset people who don't have one
or
b) Realised that no one uses them anyway

[crmcatee]

Elderly said:

Well that's just useless - where does it tell you in which position your 'little lever' for covering the eyepiece was ?

That'll be the one that's listed.



EyeShutter :Open

Edited by crmcatee on Friday 21st January 11:53

[crmcatee]

You did look though didn't you

[dibbly dobbler]

crmcatee said:

You did look though didn't you

Yes - bd!

[Simpo Two]

Ledaig said:

DepthOfFocus: 2.53 m (0.60 - 3.13)
HyperfocalDistance: 1.45 m

Impressive - but that's a D3; do lower models record as much?



So the OP lines up on the airplane taking off, focuses by some method and takes the shot.

He then downloads the image to a laptop, analyses the EXIF data and possibly discovers that the aircraft was 291m away.

So what? Why this is important? If you can focus on the airplane once to get the data, you can either focus on it again for the next shot, or once focused, switch to manual focus and keep shooting without waiting for a slow AF system. There is no point in quantifying the distance (for anything other than passing amusement) because you can't do anything with it!

Edited by Simpo Two on Friday 21st January 13:16

[Diabolik]

Why don't you autofocus the point where the plane lands? Then flick the switch to manual focus and not touch it again

Edited by Diabolik on Friday 21st January 13:16

[Ledaig]

Simpo Two said:

Ledaig said:

DepthOfFocus: 2.53 m (0.60 - 3.13)
HyperfocalDistance: 1.45 m

Impressive - but that's a D3; do lower models record as much?

No idea - only have a D3 file available - but I would wouldn't be suprised if they did.

Simpo Two said:

So what? Why this is important?

In my opinion it's not - autofocus (AFC mode) and single point selction has never let me down for either aircraft or vehicles (and that's with a D70, D200 and D3).

Just giving the direct answer to the original question.



ETA -
Just checked a D200 file and you get the Hyperfocal distance

D70 - Dof and Hyperfocal,

Couple of compacts - Hyperfocal distance.

Edited by Ledaig on Friday 21st January 13:50

Edited by Ledaig on Friday 21st January 14:03