ASTM E3235-21

Standard Practice for Latent Print Evidence Imaging Resolution

SIGNIFICANCE AND USE
5.1 The procedure described in this document is in accordance with current SWGFAST guidelines (6), as well as National Institute of Standards and Technology (NIST) standard (7), which specify 1000 pixels per inch (ppi) at 1:1 as the minimum scanning resolution for latent print evidence. This standard appears primarily to be historical and directed towards scanners, rather than cameras, though recent studies suggest that it is suitable for capturing Level 3 detail (8).  
5.2 While the 1000 ppi resolution standard permits the capture of level three detail in latent prints, it does not mean that any image recorded at a lower resolution would necessarily be of no value for comparison purposes. Such an image could have captured level two details sufficiently for comparison. However, there are some latent print impressions that are so degraded or contain such limited quantity of information that at least 1000 ppi resolution is required to conduct an accurate examination. Some automated fingerprint identification systems require 1000 ppi for submission purposes. The relationship between machine (optical) resolution and achievable resolution (sometimes called resolving power) can vary greatly by manufacturer (8).
SCOPE
1.1 This practice provides recommendations on the resolving power that enables recording of Level 3 details of latent print evidence that are suitable for comparison purposes using a digital camera, a flatbed scanner, or other image capture device. These recommendations take into consideration the minimum resolution requirements for utilizing the photographs for comparison.  
1.2 This practice describes procedures that can be used to verify the resolving power of such imaging systems and recommends equipment to be used.  
1.3 Certain commercial equipment, instruments, or materials are used in this document as representative examples to more clearly explain the procedures. Such use does not imply a recommendation or endorsement.  
1.4 This standard is intended for use by competent forensic science practitioners with the requisite formal education, discipline-specific training (see Practice E2917), and demonstrated proficiency to perform forensic casework.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2021
• ICS: 35.240.15 - Identification cards. Chip cards. Biometrics
• ICS: 37.040.99 - Other standards related to photography
• Technical Committee: E30 - Forensic Sciences
• Drafting Committee: E30.12 - Digital and Multimedia Evidence

Relations

• Refers: ASTM E1732-24 - Standard Terminology Relating to Forensic Science
• Effective Date: 01-Feb-2024
• Refers: ASTM E2917-24 - Standard Practice for Forensic Science Practitioner Training, Continuing Education, and Professional Development Programs
• Effective Date: 01-Feb-2024
• Refers: ASTM E2916-19 - Standard Terminology for Digital and Multimedia Evidence Examination
• Effective Date: 01-Mar-2019
• Refers: ASTM E2917-19 - Standard Practice for Forensic Science Practitioner Training, Continuing Education, and Professional Development Programs
• Effective Date: 15-Feb-2019
• Refers: ASTM E1732-19 - Standard Terminology Relating to Forensic Science
• Effective Date: 15-Jan-2019
• Refers: ASTM E1732-18b - Standard Terminology Relating to Forensic Science
• Effective Date: 01-Nov-2018
• Refers: ASTM E2916-18 - Standard Terminology for Digital and Multimedia Evidence Examination
• Effective Date: 01-Nov-2018
• Refers: ASTM E1732-18a - Standard Terminology Relating to Forensic Science
• Effective Date: 01-Jun-2018
• Refers: ASTM E1732-18 - Standard Terminology Relating to Forensic Science
• Effective Date: 15-May-2018
• Refers: ASTM E1732-17 - Standard Terminology Relating to Forensic Science
• Effective Date: 01-Sep-2017
• Refers: ASTM E2916-13 - Standard Terminology for Digital and Multimedia Evidence Examination
• Effective Date: 01-Jun-2013
• Refers: ASTM E1732-12 - Standard Terminology Relating to Forensic Science
• Effective Date: 15-Jun-2012
• Refers: ASTM E1732-11b - Standard Terminology Relating to Forensic Science
• Effective Date: 01-Oct-2011
• Refers: ASTM E1732-11a - Standard Terminology Relating to Forensic Science
• Effective Date: 01-Oct-2011
• Refers: ASTM E1732-11 - Standard Terminology Relating to Forensic Science
• Effective Date: 01-Jun-2011

Overview

ASTM E3235-21: Standard Practice for Latent Print Evidence Imaging Resolution provides comprehensive guidelines for forensic science practitioners on achieving suitable imaging resolution when capturing and documenting latent print evidence. Developed by ASTM International, and aligned with SWGFAST and National Institute of Standards and Technology (NIST) standards, this practice outlines minimum resolution requirements, recommended procedures, and verification methods for image capture devices used in latent print analysis.

The standard emphasizes the significance of using a minimum scanning or photographic resolution of 1000 pixels per inch (ppi) at a 1:1 scale, which is essential for recording Level 3 details in latent print evidence. This facilitates both manual and automated fingerprint identification processes and forms the foundation for effective comparison and analysis in forensic casework.

Key Topics

• Minimum Resolution Requirements: Recommends a minimum of 1000 ppi at 1:1 scale, based on current SWGFAST and NIST guidelines.
• Applicable Imaging Devices: Addresses the use of digital cameras, flatbed scanners, and other imaging systems, including specifications for suitable equipment.
• Resolving Power and Verification Procedures: Discusses methods to verify the resolving power of imaging devices, ensuring the capture of detailed print features.
• Forensic Practitioner Qualifications: Specifies the need for formal education, discipline-specific training, and demonstrated competence in forensic imaging, referencing ASTM E2917.
• File Format and Image Handling: Advises the use of lossless image formats (e.g., TIFF, RAW) to preserve image integrity. Lossy compression is discouraged due to potential loss of critical detail.
• Equipment Recommendations: Provides guidance on appropriate lenses, camera settings, lighting, and support equipment to minimize distortion and maximize resolution.

Applications

• Forensic Investigations: Ensures that latent print evidence is documented with sufficient detail to support reliable comparison and identification, including Level 3 detail necessary for court-admissible evidence.
• Automated Fingerprint Identification Systems (AFIS): Meets the minimum input requirements for many AFIS systems, supporting efficient search and matching of latent prints.
• Evidence Documentation: Enables the digital preservation of latent print evidence in formats that support both analysis and archival storage.
• Quality Assurance: Establishes repeatable verification protocols for imaging resolution, contributing to the reliability of forensic laboratories and compliance with accreditation standards.
• Training and Professional Development: Serves as a reference for building practitioner competence in digital evidence imaging, supplementing formal training programs.

Related Standards

• ASTM E2916: Terminology for Digital and Multimedia Evidence Examination – provides essential definitions referenced in E3235-21.
• ASTM E2917: Practice for Forensic Science Practitioner Training, Continuing Education, and Professional Development Programs – outlines training requirements for practitioners.
• ISO-16067-1: Standard for measuring the spatial resolution of reflection scanners, recommended for resolution verification.
• ISO/IEC 17020 and ISO/IEC 17025: International requirements for the operation of inspection bodies and calibration/testing laboratories, relevant for ensuring the traceability and quality of measurement equipment.
• SWGFAST Digital Imaging Guidelines: Offers contemporary best practices for digital imaging in friction ridge examination.
• NIST Special Publication 500-271: Details standards for finger print imaging used in automated systems.

---

Keywords: latent print imaging resolution, forensic photography, digital evidence, ASTM E3235-21, latent fingerprint comparison, flatbed scanner, digital camera, ppi, AFIS requirements, evidence documentation, resolving power

For additional guidance, refer to related ASTM and ISO standards, and ensure imaging systems are routinely tested and calibrated according to ASTM E3235-21 protocols for robust forensic evidence processing.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E3235 − 21 An American National Standard
Standard Practice for
Latent Print Evidence Imaging Resolution
This standard is issued under the fixed designation E3235; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E2916Terminology for Digital and Multimedia Evidence
Examination
1.1 This practice provides recommendations on the resolv-
E2917Practice for Forensic Science Practitioner Training,
ing power that enables recording of Level 3 details of latent
Continuing Education, and Professional Development
print evidence that are suitable for comparison purposes using
Programs
a digital camera, a flatbed scanner, or other image capture
2.2 Other Documents:
device. These recommendations take into consideration the
ISO-16067-1Reflective Scanner Test Chart
minimumresolutionrequirementsforutilizingthephotographs
ISO/IEC17020Conformityassessment—Requirementsfor
for comparison.
the operation of various types of bodies performing
1.2 This practice describes procedures that can be used to
inspection
verify the resolving power of such imaging systems and
ISO/IEC 17025 Testing and calibration laboratories
recommends equipment to be used.
T-90-N-CGUltra High Resolution Target
1.3 Certain commercial equipment, instruments, or materi-
als are used in this document as representative examples to
3. Terminology
more clearly explain the procedures. Such use does not imply
3.1 Definitions—Refer to Terminologies E1732 and E2916
a recommendation or endorsement.
for terms not defined in this practice.
1.4 This standard is intended for use by competent forensic
3.1.1 achievable resolution, resolving power, n—the mea-
science practitioners with the requisite formal education,
sure of imaging system’s practical limit to distinguish between
discipline-specific training (see Practice E2917), and demon-
separate adjacent elements, typically by imaging a known
strated proficiency to perform forensic casework.
reference standard. E2916
1.5 This standard does not purport to address all of the
3.1.2 bit depth, n—thenumberofbits(binarydigits)usedto
safety concerns, if any, associated with its use. It is the
specify the brightness or color range of each pixel in an image
responsibility of the user of this standard to establish appro-
sensor.
priate safety, health, and environmental practices and deter-
Photo Review Magazine Digital Imaging Glossary (1)
mine the applicability of regulatory limitations prior to use.
3.1.3 Dmax, n—an abbreviation for maximum density. The
1.6 This international standard was developed in accor-
abbreviationisusedindescribingboththecharacteristicsofan
dance with internationally recognized principles on standard-
image and/or an imaging device such as a scanner.
ization established in the Decision on Principles for the
Federal Agencies Digital Guidelines Initiative Glossary
Development of International Standards, Guides and Recom-
(2)
mendations issued by the World Trade Organization Technical
3.1.4 dynamic range, n—the difference between the bright-
Barriers to Trade (TBT) Committee.
est highlight and darkest value that a sensor can detect and
record in a single image. E2916
2. Referenced Documents
3.1.5 focal length, n—thedistancefromtheopticalcenterof
2.1 ASTM Standards:
a lens to its point of focus at the sensor or image plane when
E1732Terminology Relating to Forensic Science
focused at infinity. E2916
This practice is under the jurisdiction of ASTM Committee E30 on Forensic
Sciences and is the direct responsibility of Subcommittee E30.12 on Digital and
Multimedia Evidence. Available from International Organization for Standardization (ISO), ISO
Current edition approved Sept. 1, 2021. Published October 2021. DOI: 10.1520/ Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
E3235-21. Switzerland, https://www.iso.org.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from Applied Image, Inc., Rochester, NY, https://
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM www.appliedimage.com.
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parentheses refer to a list of references at the end of
the ASTM website. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3235 − 21
3.1.6 lossless compression, n—a data reduction process that minimum scanning resolution for latent print evidence. This
is completely reversible, such that all of the original data can standardappearsprimarilytobehistoricalanddirectedtowards
be retrieved in its original form. E2916 scanners, rather than cameras, though recent studies suggest
that it is suitable for capturing Level 3 detail (8).
3.1.7 lossy compression, n—a data reduction process that is
not completely reversible, and some original data is irretriev-
5.2 While the 1000 ppi resolution standard permits the
ably lost. E2916
capture of level three detail in latent prints, it does not mean
that any image recorded at a lower resolution would necessar-
3.1.8 machine resolution, optical resolution, n—a nominal
ily be of no value for comparison purposes. Such an image
resolution specification for a flatbed scanner based on the
could have captured level two details sufficiently for compari-
actual number of pixels per inch in the sensor array and the
son. However, there are some latent print impressions that are
number of individual steps per inch that the stepper motor can
so degraded or contain such limited quantity of information
move the sensor array. This is to be distinguished from the
that at least 1000 ppi resolution is required to conduct an
maximum resolution specification that is based on resampling.
accurate examination. Some automated fingerprint identifica-
This is also called optical resolution.
tion systems require 1000 ppi for submission purposes. The
I Digital Photo Dictionary (3)
relationship between machine (optical) resolution and achiev-
3.1.9 nominal resolution, n—the number of horizontal and
able resolution (sometimes called resolving power) can vary
vertical pixels an imaging system or sensor is capable of
greatly by manufacturer (8).
capturing. E2916
3.1.10 normal lens, n—a lens designed to approximate the
6. Recommended Photographic Equipment
field of view of the human eye without magnification or
6.1 A digital camera system with the following specifica-
reduction. E2916
tions:
3.1.11 quadripod, n—a generic term for a four-legged cam-
6.1.1 Afull frame, or larger, sensor is suggested because it
era support.
will usually have less image noise as compared to smaller
3.1.12 resizing, n—changingthesizeofanimagebychang-
sensors.
ing the number of pixels per unit of measurement without
6.1.2 Interchangeable Lenses:
adding or subtracting any pixels from the image.
6.1.2.1 Anormalfixedfocallength,orlonger,macrolensis
3.1.13 resampling,n—changingthesizeand/orresolutionof
preferred. Listed below are two common examples of normal
the image by adding or subtracting pixels through interpola-
focal length lenses for different size camera sensors.
tion.
(1)For a full frame sensor, the normal focal lens is 40 mm
Crime Scene Photography, 3rd ed. (4)
to 60 mm.
3.1.14 resolution, n—the act, process, or capability of dis- (2)ForanAPS-C/Hsensor,thenormalfocallensis35mm
to 45 mm.
tinguishing between two separate but adjacent parts or stimuli,
such as elements of detail in an image, or similar colors.
6.1.2.2 Amacro zoom lens set to approximately the normal
Encyclopedia of Photography, 3rd Edition (5)
focal length, or longer, based on the size of the camera sensor
is acceptable.
3.1.15 resolving power, n—see achievable resolution.
6.1.2.3 Optional—Anormal,orlonger,focallengthperspec-
E2916
tive control (PC) macro lens.
3.1.16 tri-linear array, n—thesensorinaflatbedscanner,or
6.1.2.4 Additional Lens Considerations:
digitalscanningback,whichismadeupofthreerowsofpixels
(1)When capturing images for comparative analysis, it is
with a red filter covering one row, a green filter covering the
important to minimize distortion and obtain the correct per-
second row and a blue filter covering the third row.
spective.Ingeneral,normalfocallengthprimelenseshaveless
Federal Agencies Digital Guidelines Initiative Glossary
optical distortion as compared to zoom lenses.
(2)
(2)The photographs of the bottom of a shoe illustrate the
4. Summary of Practice problems of using a wide angle lens as compared to using a
normalfocallengthlensandfillingtheframe.Thephotographs
4.1 Select photographic equipment.
were taken with a 20 mm and 50 mm lens on a DSLR with a
4.2 Create a photographic procedure manual.
full frame sensor (see Figs. 1-4).
6.1.3 Manual and aperture priority exposure modes.
4.3 Verify the resolving power of digital cameras used to
photograph latent print evidence.
6.1.4 Automatic and manual focus.
6.1.5 Remote shutter release port or self-timer.
4.4 Verify the resolving power of scanners used to scan
6.1.5.1 Choice of file format in order of preference
latent print evidence.
6.1.5.2 RAW file format at a maximum bit depth or
5. Significance and Use
RAW+JPEG.
6.1.5.3 Uncompressed or lossless compressed image file
5.1 The procedure described in this document is in accor-
format such as TIFF.
dance with current SWGFAST guidelines (6), as well as
National Institute of Standards and Technology (NIST) stan- 6.1.5.4 If RAW and TIFF are not available, use the highest
dard (7), which specify 1000 pixels per inch (ppi) at 1:1 as the quality JPEG settings.
E3235 − 21
NOTE1—Themostobviousproblemisthedistortionthatcanbeseenin
the straight horizontal part of the ruler that is recorded as being curved.
NOTE 1—On the left and center are enlargements of the photograph
FIG. 1 Photograph of the Bottom of a Shoe (Photographed with a
takenwitha50mmlensoftheheeloftheshoe.Ifyoulookcarefullyyou
20 mm Wide Angle Lens on a Full Frame DSLR)
willseethatthesidesofthecylinders(centerenlargement)arenotvisible
because the camera is far enough from the shoe when filling the frame
with a normal focal length lens to have the flat perspective that is more
accurate for comparison purposes. Compare the center enlargement with
therightenlargementandobservethatwhenthecamerawasmovedcloser
to the shoe to fill the frame with a 20 mm lens that part of the side of the
cylinder is visible.
FIG. 4 Enlargements of the Photograph Taken
6.5 Photographic filters.
6.6 Remote shutter release.
6.7 Sturdycopystand,tripodorotherstudycamerasupport.
6.8 Flat rulers using standard units of measure which are
traceable to a NIST or other national metrological institute
NOTE 1—If you look carefully you will see that the left sides of the
cylinders are visible because the camera is too close to the shoe when
standard (see ISO/IEC 17025 and ISO/IEC 17020, policy for
filling the frame with a wide angle lens.
measurement of uncertainty).
FIG. 2 Enlargement of the Heel of the Shoe
6.9 Level.
6.10 Sparecameramemorycardsandcardstoragecasesfor
empty and used camera cards, unless tethered to a computer.
6.11 Lens cleaner and lens cleaning tissue.
6.12 Photographic log/notes.
6.13 Photo labels/tags
6.14 Computer with appropriate software.
6.15 Camera card reader.
NOTE 1—Notice that with a 50 mm lens the straight edge of the ruler is
straight in the photograph. With a 50 mm lens you will be farther away
6.16 Archival storage device.
from the shoe when filling the frame as compared to a 20 mm wide-angle
6.17 A magnifier.
lens. Since the close-up range of most point and shoot cameras is in the
wide-angle range of their zoom settings, this is one of many reasons why
6.18 For camera resolution testing, an opaque or a
a point and shoot camera should not be used for this type of photography.
transparent, or both, resolution test target with resolution bars
FIG. 3 Photograph of the Bottom of a Shoe (Photographed with a
within the range of 9.8 to 13 cycles per millimetre (c/mm),
50 mm Normal Focal Length Lens on a Full Frame DSLR)
which is also, called line pairs per millimetre (lp/mm). Reso-
6.2 Point and shoot and cell phone cameras are not recom- lution targets are calibrated by an accredited calibration pro-
mended for taking photographs intended for comparative vider traceable to NIST or equivalent metrology institute.
analysis purposes for several reasons, some of which include,
6.19 A flatbed scanner either from the FBI Certified Bio-
but are not limited to:
metric Products List (9)or with the following specifications:
6.2.1 The lenses are usually not as well corrected for
6.19.1 A preferred machine resolution of 2400 ppi 1200
distortion.
minimum.
6.2.2 The macro range is usually in the wide-angle zoom
6.19.2 A reflected document size of at least 8.5×11 in.
range.
6.19.3 A minimum Dmax rating of 4.0.
6.3 Spare batteries for any camera using removable batter- 6.19.4 Atransmitted light (transparency) adapter of at least
ies. 4×5 in. 8×10 in. is preferred.
6.4 Appropriate light sources (for example, floodlights, 6.20 Fortheflatbedscannerhigherresolutiontargetsshould
flashlights, LASER, alternate light sources (ALS), or a com- be needed to determine at what point increasing the nominal
bination thereof). resolution setting only increases the file size, without any
E3235 − 21
increase in achievable resolution. Targets with resolution bars
upto100lp/mmshouldbeadequateforthistask.Thesehigher
resolution targets should require the use of a low power
microscope to visually verify the line pairs. Resolution targets
shall be certified traceable to NIST or equivalent metrology
institute.
7. Recommended Protocol for Verifying the Resolving
Power of Digital Cameras Used to Photograph Latent
FIG. 6 Many Persons Mistake Filling the Short Dimension of the
Print Evidence
Viewfinder with the Long Dimension of the Latent Print and Ruler
7.1 As with scanners, camera systems also rarely achieve
nominal resolution in practice. One recent study showed that
high-resolution black-and-white TMAX film with a nominal
resolution of 34.56 megapixels using a stabilized professional
camera under studio conditions was able to achieve a pixel-
equivalent resolution of 13.75 megapixels (10).
7.2 There is a dearth of peer reviewed literature comparing
opticalandachievedresolution,buttheachievedresolutioncan
beapproximated.Jain (11)hasdemonstratedthatsamplingata
nominal1000ppicanprovidelevelthreedetails.Zhang,etal.,
FIG. 7 Filling the Long Dimension of the Viewfinder with the
(12)hassimilarresults.ByapplicationoftheNyquisttheorem,
Long Dimension of the Latent Print and Ruler
a 1000 ppi nominal resolution can theoretically achieve a
maximum resolution of 500 line pairs. In practice, as noted
Nikon, you should have to also determine the smaller pixel
elsewhere, Nyquist sampling is inadequate; and three to four
dimensions that the camera should default to whenever a lens
samples are required instead of two, resulting in resolution
designed for a smaller sensor (DX lens) is attached to the
between 250 to 330 line pairs per inch, or 9.8 to 13 cycles per
camera. For a Nikon D810 using a DX lens, this would be
millimetre.
4800×3200pixels.Thisadditionalresolvingpowertestingalso
7.3 Camera Resolution Testing:
applies only if the camera is to be set to a lower resolution
7.3.1 This step defines the largest area that can be photo-
setting.
graphed and still meet the 1000 ppi resolution standard at an
7.3.2.2 To determine the largest area that can be photo-
achievableresolutionthatisadequatetorecord3rdleveldetails
graphed at a nominal resolution of 1000 ppi, divide each pixel
inalatentprint.Iftheareacoveredbythelatentprintevidence
dimension of the digital camera’s sensor by 1000 ppi. Using
and a ruler is smaller than the determined value, the photo-
the full sensor in a Nikon D810, this would equal 7.36×4.912
graph should be taken filling the frame with the latent print
in. This makes the maximum field of view approximately
evidence and ruler (see Figs. 5-7).
7.35×4.9in.Ifyouareusingametricscale,multiplyinchesby
7.3.2 Determine the maximum field of view in which a
25.4 to convert inches to millimetres (approximately 187
minimum nominal resolution of 1000 ppi should be achieved
mm×124 mm, see Fig. 8).
foreachcameraandlenscombinationtobeusedtophotograph
7.3.2.3 Not all camera optical viewfinders cover 100 % of
latent print evidence.
the capture area. Take a test image of a template drawn on a
7.3.2.1 Determine the effective pixel dimensions of the
sheet of graph paper lined in tenths of an inch to determine
camera’ssensorasstatedbythemanufacturer.Thiscanusually
coverage of the optical viewfinder. If the camera has a live
be found in an image size setting in the camera menu. For this
view capability, compare the optical viewfinder field of view
exampleaDSLRcamerausingafullframelens(FXor35mm
with both the live view field of view and the captured image.
film camera lens) and the full sensor this would be 7360×4912
7.3.2.4 Makeatemplateonprecisiongraphpapertooutline
pixels. However with some full frame sensor cameras such as
the maximum area that can be photographed at the 1000 ppi
nominal resolution standard (see Fig. 9).
7.3.2.5 Place the template on a flat surface.
7.3.2.6 Mount the camera on a tripod or copy stand above
the flat surface on which the template rests. Ensure the camera
focal plane is parallel with the template.
7.3.2.7 If using a fixed focal length lens, proceed to step
7.3.2.8. If using a zoom lens, proceed to step 7.3.2.9.
7.3.2.8 While looking through the viewfinder, adjust the
height of the camera to fill the frame with the template, while
keepingtheimageinsharpfocuswiththecamerasettomanual
FIG. 5 This Is Not Filling the Frame. Nikon is a trademark of Nikon Corporation in Tokyo, Japan.
E3235 − 21
NOTE 1—The diagram on the left shows the pixel dimensions of the full frame sensor of a DSLR camera that was used as an example. The diagram
on the right shows the approximate area that represents a nominal resolution of 1000 ppi with the camera set to an image size of 4912×7360 pixels.
FIG. 8 Converting Inches to Millimetres
NOTE 1—The graph paper was photographed with the black lines at the edge of the optical viewfinder. The area approximately 0.05 in. outside of the
opticalviewfinderwasincludedintheimagebutnotvisibleintheviewfinder.However,thisareawasvisibleinliveview.Fortheresolvingpowersamples
used in this document, the resolution test target was photographed at this magnification. Using precision graph paper also makes it easier to determine
ifthelenshasexcessivebarrelorpincushiondistortionandifthedistor
...