HD Pentax-DA 55-300mm f/4.5-6.3 ED PLM WR RE Review

HD Pentax-DA 55-300mm f/4.5-6.3 ED PLM WR RE Handling and Features

The overall appearance and feel are quite similar to the 18-50mm retractable lens that we have already seen. A single easily operated button releases the lens barrel so that the zoom ring can be used. If the camera is switched on whilst the lens is retracted, the shutter release is disabled and a warning message appears on the rear screen. The release of the zoom ring is, like the first lens, quite jerky and stiff in operation, hardly smooth. However, the standard of assembly of the lens, in general, is high, and things do ease up a little once the lens is in use. In contrast, the manual focus ring, which lies closest to the body, is as smooth as silk from the start, operating electronically and also offering QuickShift, where manual focusing can be used to tweak the AF position focused on.

There is little else to see on the lens. The front element is surrounded by the 58mm filter thread and also the bayonet for fixing the provided round lens hood. The hood has a removable slot that allows filters such as a polariser to be rotated without removing the lens hood. The HD coatings reduce flare and the front element is also given an SP (Super Protect) coating to repel grease, dirt and water. The diaphragm has 9 rounded blades to improve bokeh. Weight is 442g or 471g with hood. This is virtually the same as the previous 55-300mm lenses.

Maximum apertures run from f/4.5 to f/6.3, depending on the amount of zoom, with minimum aperture varying from f/22 to f/32. There are 14 elements in 11 groups, including an ED (Extra Low Dispersion) glass. Minimum focus is excellent at 0.95m, which is significantly closer than previous versions. Maximum magnification becomes 0.30x. This is really useful, especially for subjects such as flower studies, where single blooms can be zoomed in on even if at the back of wide borders.

Focusing is via a rear focus system, meaning that the front element does not rotate and the lens remains the same length regardless of the focus position. Zooming does alter the length. A New PLM (Pulse Motor) ensures silent and fast focusing. Obviously the faster the better for a lens that may well be used for wildlife, although the difference seems subjectively to be relatively small at the telephoto end. Weather Resistance is a huge benefit and this gives us considerable freedom to continue shooting in bad weather conditions.

When we come to the mount, we have the standard basic K mount, but with critical modifications that make this version KAF4 and only compatible with the K-70 or later straight out of the box. There is a limited list of other bodies where downloading a firmware update will allow use of the new electromagnetic diaphragm. This applies to the Pentax K-1, K-3 II, K-S2 and K-S1. For the purposes of this review, I updated my almost new K-3 II and there were no problems, apart from locating the firmware on the Ricoh websites, some of which listed it and some not. In the end, the Japanese site was the source.

Handling-wise, the new diaphragm is of no major advantage to stills photography, but I can see that videographers may well appreciate its silent and smooth operation.

There are of course two other 55-300mm lenses, so how does the new optic compare? The original SMC Pentax-DA 55-300mm f/4-5.8 is still an excellent lens, although no longer available new. Its successor, the HD Pentax-DA 55-500mm f/4-5.8 WR adds weather resistance and the new HD coating and is quite possibly the version of choice. The new lens may be slightly more compact when retracted but is little different when in use. The KAF4 mount also limits its usefulness considerably, and I wonder how many people will buy it to find their body is not compatible. However, for those who shoot video, the new silent diaphragm may well be the game changer and this PLM version may well be their natural choice.

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