A Viewfinder Darkly

Photography tips and tutorials

Computer monitor is an important bit of gear for photography

May 5 2016

by Philip Northeast

Digital camera and computer upgrades are an inevitable part of digital technology.

My newest  computer  struggled when I joined  Adobe’s Creative Cloud photographer’s plan and added the heavyweight Adobe Photoshop. I already used Lightroom and photoshop is useful for serious photo editing rather than the relatively minor adjustments  available in Lightroom.  The windows computer was particularly slow opening Photoshop.

Which of my  computers to replace? The Mac was older and a lower spec than the Windows box and  Macs are generally considered better suited to graphics applications than Windows machines. Then there was the attraction of the Mac’s Thunderbolt ports for faster transfer to and retrieval of photos from  external drives. The Mac also has USB 3 ports to accommodate  more common drives with slower transfer capabilities.

The decision was a new iMac, but which one?  Visiting the local bricks and mortar Apple reseller I to compared an iMac with the 5K retina display, and one with the smaller 4K display.  The same picture on the 5k model looked noticeably clearer and sharper , and that was the decider, the 5K iMac it was. The larger  screen size is also important, on an iPhone or a camera screen a picture may look fine, but viewing it on a larger screen and the defects become apparent.

different size iMacs

different size iMacs

However, the new iMac had an unintended consequence. While cataloguing photos in Lightroom one of the photos seemed to stand out from the others. It is an ordinary subject, a general view of the Hobart waterfront  but it just seemed to have a sharpness that sparkled. Zooming in and it still looked pretty crisp.

The scene of the waterfront that surprised on the large display

The scene of the waterfront that surprised on the large display

One of the great things about digital photography  I was able to check the EXIF data and find the equipment used.  It turned out to be  my Carl Zeiss Planar  50 mm f1.4  prime lens on the Pentax K5. By reputation and testing  in DxOMark, this is a formidable lens.

However,  I had felt slightly underwhelmed by the photos from this lens when looking at them on normal computer monitors. Even on my Dell 2311h Ultrasharp the underlying sharpness was not apparent, the difference did emerge on the 5K retina iMac.

There is a BUT in here. I rechecked the DxoMark test results,  paying particular attention to the sharpness at different aperture settings. Wide open the sharpness  is surprisingly terrible but, stopped down to f5.6  the lens is very sharp right across the whole field of view. Once you go beyond f8  the sharpness starts to deteriorate significantly.

DxOMark sharpness test results for Carl Zeiss 50mm planar lens

DxOMark sharpness test results for Carl Zeiss 50mm planar lens. Top at f2.8 and bottom at f5.6

The DxOMark tests confirmed my subjective observations of the image quality of the Zeiss lens and helped find the aperture setting sweet spot for the lens.  Finding the best aperture is important, not only for this particular lens but for all your lenses.

Of course, this is basic knowledge, but the visual representation on iMac was a nice reminder of the danger of concentrating on the subject at the expense of technical aspects of taking the photograph.

When you spend thousands of dollars on cameras and lenses it does not make sense  to judge and adjust your photographs on a normal low-resolution monitor.  Viewing photographs on a normal monitor is like looking at them through a translucent film. You see all the main shapes and colours, but not the fine details. This makes it difficult to effectively compare and accurately make fine adjustments to photographs.

The final adjustments have always been an essential part of the photographic process. Many computer monitors are designed for word processing, spreadsheets or low-resolution photos more suitable for social media. This is why there are other high-end monitors available apart from the iMacs. There is a   range of professional Eizo monitors available, one example is the CG247  for  $US1,944 from Adorama, as an alternative to the 5K retina display if you work on a Windows machine.


Eizo monitor

Eizo professional grade monitor

This is not an exercise in pixel peeping as the composition is still more important than technical perfection. The aim is minimising any obvious technical shortcomings that may hinder appreciation  of the photographer’s creative vision.


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