Pentax 645Z Review

July 30, 2014 | Mark Goldstein | |

Image Quality

All of the sample images in this review were taken using the 51 megapixel Best JPEG setting, which gives an average image size of around 25Mb.

The Pentax 645Z produced photos of outstanding quality. Noise is very well controlled by the Pentax 645Z, first starting to appear at ISO 3200 and becoming more easily detectable at the faster settings of ISO 6400 - 25600 when viewing images at 100% magnification on screen (particularly in the RAW files). The fastest settings of 51200, 102400 and especially 204800 look much better on paper than in reality. Colour saturation is commendably maintained throughout the ISO range.

The 51 megapixel JPEG images were a little soft straight out of the camera at the default sharpening setting and ideally require some further sharpening in an application like Adobe Photoshop, or you can change the in-camera setting. The various Digital Filters quickly produce special effects that would otherwise require you to spend a lot of time in the digital darkroom, while the Custom Images can usefully be tweaked to suit. The D-Range options help make the most out of both the shadows and highlights in a high-contrast scene (and it works for both JPEG and RAW files), while the HDR mode greatly expands the dynamic range of a JPEG by combining three differently exposed images in-camera. The multi exposure mode combines between two and 2,000 different JPEG or RAW images into a single photo.

Noise

There are 12 ISO settings available on the Pentax 645Z. Here are some 100% crops which show the noise levels for each ISO setting, with JPEG on the left and the RAW equivalent on the right:

JPEG

RAW

ISO 100 (100% Crop)

ISO 100 (100% Crop)

iso100.jpg iso100raw.jpg
   

ISO 200 (100% Crop)

ISO 200 (100% Crop)

iso200.jpg iso200raw.jpg
   

ISO 400 (100% Crop)

ISO 400 (100% Crop)

iso400.jpg iso400raw.jpg
   

ISO 800 (100% Crop)

ISO 800 (100% Crop)

iso800.jpg iso800raw.jpg
   

ISO 1600 (100% Crop)

ISO 1600 (100% Crop)

iso1600.jpg iso1600raw.jpg
   

ISO 3200 (100% Crop)

ISO 3200 (100% Crop)

iso3200.jpg iso3200raw.jpg
   

ISO 6400 (100% Crop)

ISO 6400 (100% Crop)

iso6400.jpg iso6400raw.jpg
   

ISO 12800 (100% Crop)

ISO 12800 (100% Crop)

iso12800.jpg iso12800raw.jpg
   

ISO 25600 (100% Crop)

ISO 25600 (100% Crop)

iso25600.jpg iso25600raw.jpg
   

ISO 51200 (100% Crop)

ISO 51200 (100% Crop)

iso51200.jpg iso51200raw.jpg
   

ISO 102400 (100% Crop)

ISO 102400 (100% Crop)

iso102400.jpg iso102400raw.jpg
   

ISO 204800 (100% Crop)

ISO 204800 (100% Crop)

iso204800.jpg iso204800raw.jpg

File Quality

The Pentax 645Z has 3 different JPEG file quality settings available, with Best being the highest quality option, and it also supports RAW (Pentax's PEF format and Adobe DNG). Here are some 100% crops which show the quality of the various options, with the file size shown in brackets.

Best (23.9Mb) (100% Crop)

Better (12Mb) (100% Crop)

quality_best.jpg quality_better.jpg
   

Good (5.85Mb) (100% Crop)

RAW (62.3Mb) (100% Crop)

quality_good.jpg quality_raw.jpg
   

TIF (146Mb) (100% Crop)

 
quality_tif.jpg  

Sharpening

Here are two 100% crops which have been Saved as Web - Quality 50 in Photoshop. The right-hand image has had some sharpening applied in Photoshop. The out-of-the camera images are a little soft at the default sharpening setting and benefit from some further sharpening in a program like Adobe Photoshop. You can also change the in-camera sharpening level to suit your tastes.

Original (100% Crop)

Sharpened (100% Crop)

sharpen1.jpg sharpen1a.jpg
   
sharpen2.jpg sharpen2a.jpg

D-Range

Similar to Nikon's D-lighting, Sony's DRO, and Olympus' Shadow Adjustment Technology, Pentax's D-Range allows you to correct the highlights (On or Off) and/or the shadows (3 different levels) before taking a JPEG or RAW image. Although this option is always at your disposal, remember that it is meant to be used in strong, contrasty lighting at base ISO. Below you can see a comparison between Off and both highlight and shadow correction set to on/full strength; the difference is mainly noticeable in the shadowed areas on the left and right sides of the photo.

Off

On

drange1.jpg drange2.jpg

HDR Capture

The Pentax 645Z's HDR Capture option takes three images with different exposures, and then records a single image that combines the properly exposed parts of each one, expanding its dynamic range. Here is an example which was shot with the five different modes (Off, Auto, 1, 2 and 3). Although the 645Z can microalign images before combining them, allowing hand-held HDR shots to be taken, for best results it's important to always use a tripod to prevent camera shake from blurring the HDR image, and it doesn't work very well for moving subjects.

Off

Auto

hdr_01.jpg hdr_02.jpg
   
HDR1 HDR2
hdr_03.jpg hdr_04.jpg
   
HDR3  
hdr_05.jpg  

Custom Images

Pentax's Custom Images, similar to Nikon's Picture Styles and Canon's Picture Controls, are preset combinations of different sharpness, contrast, saturation and colour tone settings. You can change the saturation, hue, high/low key, contrast and sharpness for each of the seven options”. They are shown below in the following series, which demonstrates the differences.

Bright

Natural

custom_image_01.jpg custom_image_02.jpg
   

Portrait

Landscape

custom_image_03.jpg custom_image_04.jpg
   

Vibrant

Radiant

custom_image_05.jpg custom_image_06.jpg
   

Muted

Bleach Bypass
custom_image_07.jpg custom_image_08.jpg
   

Reversal Film

Monochrome

custom_image_09.jpg custom_image_10.jpg
   

Cross Processing

 
custom_image_11.jpg  

Multi-exposure

The Pentax 645Z has a fantastic multi-exposure mode that allows you to combine between two and 2,000 (!) different JPEG or RAW images into a single photo. Here is an example:

Multi-exposure

multi_exposure.jpg