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Pentax HD 20-40mm f2.8-4.0 ED Limited Edition – User’s Review


When I changed over from my Pentax K-5 (16mp) to a K-3 (24mp), I felt that my existing lenses were having resolution deficiency issues. The increase in megapixels in the K-3 sensor also decreases the pitch of the pixels. Lenses need to have a higher resolving power in terms of lines/mm.

This issue was discussed extensively in forums and lens review sites. I have to admit that I am now in the process of re-evaluating all the lenses in my possession. I do not want to lug around many lenses during my travels around the world. Every piece of equipment in the camera bag has to be in use to warrant it a place. I was lucky enough to have DSC World lending me the necessary lenses to evaluate before owning it.



I had he opportunity to take the latest Pentax HD 20-40mm f2.8-4.0 ED limited edition for a spin in Nepal. Being a limited edition lens, the mechanically built quality is excellent. It comes with a metal lens caps too. The focusing and zoom rings are smooth. It is a vey small lens and fits well into the camera bag. A tick for its size and built quality.


It is a retro style lens. It reminds me of the style of lens build during the 70’s. The depth of field scale is an added advantage for those who want to use the hyperfocal techniques in landscape and street photography. A tick for its retro design

The lens is weather sealed against adverse environmental conditions. I consider this a crucial feature. I have to give this feature a tick.

The zoom range is somewhat odd, in full frame terms it is a 30-60mm lens. I consider this a standard zoom lens, something on both sides of the standard 50mm equivalent lens. Those who shoot mostly in wide angle view would find the focal lengths lacking. However, for those who shoot mostly in the standard (what the eye sees) view, this is an ideal lens that would give a bit of a reach. No tick for the odd focal lengths.


It is a relatively fast lens with a wide open aperture of f2.8 to f4.0. It is perfect for low light shooting situations. I am now seriously considering fast lenses for my travels instead of zoom reach. One more tick for the fast lens.

This lens is rather pricey. It is retailing for slightly above RM3,000. It would lower its value to performance ratings.



How does it perform in the field?

1. Image Quality – the image quality is very good especially if it is stopped down by a stop. The lens resolve well at the centre and sides.
2. Colour rendition is good to excellent.
3. Lens distortion – It does exhibit slight barrel distortions at the widest end.
4. Chromatic aberration – this is well controlled. However, there are times when there is a need to remove CA via ACR.
5. Flare – the HD coating was supposed to reduce flares and ghosting. It performed well. The HD coating controls the flare and ghosting well.
6. Focusing speed – it focuses reasonably fast though not exceptional.
7. Lens cap – It has a very well made metal lens cap that fits in snuggly. It is much better than the plastic pinch lens caps.


The Pentax 20-40mm lens is a beauty with a retro look and feel. The mechanically built quality is excellent. It is a pretty good all rounder lens for those who want good image quality, lens distortion, chromatic aberration and lens flare control. The main set back is the zoom range. Personally I find this zoom range limiting. I would prefer a wider zoom range. This Pentax HD 20-40mm f2.8-4.0 ED lens is not for everybody. However, for those that need a standard zoom lens, it does not disappoint.



Trekking from Pisang to Manang


Trekking from Chame to Pisang





Trekking from Chame to Pisang

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