In the time available I investigated specific facilities offered by the Pentax K-5, rather than try to look at all the camera’s capabilities.

Article by John Bebbington FRPS

Background to my Evaluation

My main interest is in Natural History, particularly plants and invertebrates, and I took up photography in the late 1960s so that I could share my passion with others. For me photography has become a passion, but is a servant of my main interest. My images are used to illustrate my and my wife’s Natural History talks, and my photographic presentations. I also lead courses on these topics and am a member of the RPS Associateship and Fellowship Panel in the Natural History category.

My first camera was a Pentax Spotmatic, and I remained loyal to the brand throughout the years when I used film. Most of my photography was done using Kodachrome 25, with Fuji Provia 100 for developing during my photography courses, which meant that use of a tripod for close-ups of flowers and insects was essential, and flash was necessary for any photography of moving insects. To me, as to many other older photographers, getting the image right in the camera was essential, as little could be done if a transparency was not up to standard.

In 2007 I was fortunate to receive a commission which enabled me to purchase not only a DSLR – the Pentax K10D – but also a laptop computer for image processing. The advantages of digital imaging soon became apparent – the range of adjustments available in RAW processing and the options for experimentation and instant calibration of flash equipment were particularly useful, – but I also tried to discipline myself to ‘get it right in the camera’ as often as possible.

The K10D allowed me to shoot reasonably noise-free images at ISO 400, but this was still not ‘fast’ enough for hand-held stalking of butterflies and dragonflies. The arrival of the K-x, with the possibility of shooting at up to ISO 6,400, seemed to offer a solution. Although an entry-level camera, the K-x has allowed me to achieve far more success in this field and produces images which are acceptable for projection at up to ISO 1600, provided that there are not too many areas of uniform tone. However there are still problems in achieving the necessary combination of shutter speed and small aperture which are needed in some cases – increasing the ISO rating to 3200 or 6400 simply produces too much noise.

The Pentax K-5

When Pentax announced the release of the new K-5 the feature which immediately grabbed my attention was the possibility of shooting at very high ISO ratings – up to 51,200! So, would this camera be the answer to my problems?

I had hoped to test the camera on insects in flight and on alpine flowers, but the camera was sent for review in February, when there were almost no insects available. However I was able to evaluate its performance for my requirements pretty thoroughly and I was very impressed.

I downloaded the camera manual from the Pentax website a couple of weeks before the camera arrived and  browsed through it, to help me to decide on my evaluation programme. The Pentax K-5 features which I thought would be most useful were:

• high ISO capability – for insects in flight
• improved autofocus – again for insects in flight
• improved continuous shooting - again for insects in flight
• image stabilisation (‘shake reduction’)
• mirror lock-up
• artificial horizon screen – for landscapes and for wide-angle images of mountain flowers
• weather resistant seals (I have found the K10D usable in quite awful weather conditions!)
• live view and 1080p HD video

ISO Capability


My first tests were photographing frosty Red Dead-nettle flowers in my garden, with the camera mounted on my Sigma 180mm macro lens and my Giottos carbon fibre tripod. At ISO ratings up to 3200 the processed images projected very well and noise levels were very acceptable. At ISO 6400 noise was visible, but did not really detract from the image. From ISO 12,800 upwards noise began to be noticeable and distracting.


A few days of milder weather produced a crop of Jew’s Ear fungus on a dead elm tree and for this I used the 50-200mm Pentax WR zoom lens with a Pentax accessory close-up lens, again with the camera tripod-mounted, to allow a closer approach. The results were similar to those for the Dead-nettle, with ISO ratings up to 3,200 producing very acceptable projection images.

Early one morning I found a cluster of Common Shiny Woodlice under a log – whereas it would have been impossible to obtain a useable image even at ISO 1600 with the K-x, the Pentax K-5 used at ISO 6400 gave me an image which projects well with little visible noise.


Autofocus and Continuous Shooting

Although this is more or less irrelevant for close-up and macro work with flowers and invertebrates it is important for images of  garden birds and flying insects – my eyesight is not what it was and I rely on autofocus in these cases. I found the camera’s autofocus much ‘snappier’ and more reliable than that of the K-x, and the ability to shoot at 7fps for a short burst was also useful.

Image Stabilisation

With shake reduction enabled I was able to shoot handheld at shutter speeds up to 2 stops slower than expected. This would be particularly useful for stalking insects using my 180mm macro lens.

Mirror Lock-up

Although it was possible with both the K10D and the K-x to shoot using mirror lock-up this was always with a set delay for shutter release. With the Pentax K-5 however the mirror can be locked and the shutter fired independently, which allows the photographer to choose the exact moment to capture an image – invaluable for a flower on a windy day for example.

Artificial Horizon Screen

This worked very well for landscape work and meant that it was unnecessary to spend time rotating images when processing. I would find this particularly useful for avoiding perspective distortion in wide-angle flower photography in the mountains, and for avoiding horizon curvature when photographing seashore plants for example. Again, such problems can be corrected during processing, but it is far better to avoid them!

Weather Resistant Seals

Although I would hesitate to take a DSLR out in very wet conditions flowers and insects often provide very attractive images in damp and drizzly weather. I didn’t have the nerve to try the camera out in the rain – it had to go back in perfect condition! However, based on my experience with the K10D, I wouldn’t hesitate to venture out and take photographs in wet weather, using shower caps to protect the camera.

Video Capabilities

I include video clips in my talks, but have previously had to use low-resolution images from a basic point-and-shoot compact, or moderate resolution images from the K-x. The facility to shoot high definition movies is a real bonus for me, although autofocus won’t operate in video mode, which would be a real problem with moving insects.

I tried some video clips of minute white Springtails in my compost bin, and these project very well, with good detail and smoothness.


Conclusions

For my specific interests in close-up and macro photography I have found that the Pentax K-5 offers significant improvements in performance over earlier Pentax DSLRs. The two lenses supplied were of excellent quality but more importantly the camera is compatible with my older flashguns and macro lenses and will work on manual setting with my bellows and with my microscope adaptor.

The most impressive feature for me is the quality of images at high ISO ratings – although I would continue to use the camera on a tripod for close-up and macro work with static subjects, at ISO 100-400, the ability to use ISO 3200 for hand-held insect stalking is a real bonus. The artificial horizon and video capability are also a real improvement over older models, and the separation of mirror lock-up from delayed shutter release is an excellent facility.

All in all I was very impressed by the K-5 and would love to try it out in the summer, when subjects are more readily available! I will certainly be upgrading to this camera in the near future.

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