Index of Technical Articles and Blogs

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The links that follow are to the technical photographic articles on the site of Rob's Photography New Zealand. You can see the blogs index  here

Determining print sizes for prints from digital cameras

Advantages and disadvantages of cropping images instead of using lenses with longer focal lengths. This article also gives some examples of the calculation of focal length and it discusses the controversy surrounding the definition of the term "photographic reach".

Relationships between crop factor, field of view, photographic reach, image size, pixel density, and pixel size

Amazing image quality of images captured using the Sony Zeiss FE 55mm F/1.8 lens on the full frame 42.4mp Sony A7RII: This page includes a selection of images that demonstrate the excellent image quality and amazing detail that can be captured using this lens. To give you an appreciation of how these images will appear when greatly enlarged, crops of just small areas of the images are included, or the full-sized image is published. A similar page that shows the excellent clarity of selected Sony A99 and A900 images can be seen  here.

Do you need to upgrade your digital camera?

Full frame cameras vs APS-C cameras:  Analysis of the crop factor and "telephoto advantage" of an APS-C camera

Appendix 1  of the  above article  shows the image size and pixel density calculations based on  area  measurements.

Appendix 2  of the  above article  includes the following sections:

Calculation of pixel pitch

Calculation of the area of one pixel

Pixel level vs image level in digital photography (also refers to the Studio Test Scene  published by Digital Photography Review)

Case study: High ISO low light images of the Sony A77 compared with those of the Sony A55

Downscaling and upscaling images for comparative purposes: can apples be compared with oranges?

Appendix 3  of the  above article  provides a very valuable summary of the approximate mathematical relationships between image size, pixel density, and pixel size (for both linear and area relationships). The information in Appendix 3 can be used as a template for calculating the pixel density and pixel size of any camera with a 3:2 aspect ratio.

Practical examples of the application of the "pixel density advantage" template:

A 36mp full frame camera (such as the Sony Alpha 7R or the Nikon D800) compared with a 24mp APS-C camera (such as the Sony A77 or the Nikon D3200)

A 36mp full frame camera (such as the Sony Alpha 7R or the Nikon D800) compared with a 16mp full frame camera (such as the Nikon D4)


A 36mp full frame camera (such as the Sony Alpha 7R or the Nikon D800) compared with a 22 mp full frame camera (such as the Canon 5D Mark III)


A 24mp FF camera (such as the Sony A99 or the Sony A7) compared with a 24mp APS-C camera (such as the Sony A77II or the Nikon D3200)


Canon EOS 7D Mark II compared with the Canon EOS 5D Mark III


Nikon D800 compared with the Nikon D3200  


Sony A7S (ILCE-7S) compared with the Sony A77II / A77 / A65


Sony A77II (ILCA-77M2) / A77 / A65 compared with the 36mp Sony A7R (ILCE-7R)


Sony SLT-A77 / A77II / A65 compared with the Sony A99 / Sony A7 / Sony A7II


Sony A6300 (ILCE-6300) compared with the 42.4mp Sony A7R II (ILCE-7R M2)


Index  of  Blogs

In keeping with the conventional blog tradition, the blogs on this site are presented in date order and include, for example, random thoughts and projects, and references to discussions on photographic forums that I have found to be very interesting. These blogs are quite informal and thus differ from the style of my more comprehensive articles that are listed above.

Triptych photography

Rare visit of a Leopard Seal to Eastbourne Beach, Wellington Harbour

Could this vintage Sony memory stick be worth a lot of money?

Canon Wonder Camera Concept: Displayed at World Expo 2010, Shanghai, China

Is Photography an Art or a Science?

Sony A99 high ISO bird images in very low light

Sony A7RII: Rare 4K video of kiwi bird mating ritual

Sony A7RII with the Sony Zeiss 55mm F/1.8 lens compared with the Sony A99 with the Carl Zeiss 24mm-70mm F/2.8 lens