DSLR – Pentax Body

Along with the K-7 DSLR, Pentax has launched the smc PENTAX-DA 18-55mm F3.5-5.6AL WR and smc PENTAX-DA 50-200mm F4-5.6ED WR weather-resistant lenses. Treated with Super-Protect (SP) coating for dust resistance and designed with environmental sealing, both the lenses complement the latest Pentax weather-resistant DSLRs. Priced at $199.95 USD for the DA 18-55mm and $249.95 USD for the DA 50-200mm, the lenses will start shipping in July 2009.

Press release:

May 19, 2009: HOYA CORPORATION PENTAX Imaging Systems Division is pleased to announce the launch of two compact, lightweight zoom lenses: the smc PENTAXDA18-55mmF3.5-5.6AL WR, and the smc PENTAX DA50-200mmF4-5.6ED WR. Featuring a newly designed, simplified weather-resistant construction, these zoom lenses offer excellent reliability in various outdoor applications — especially in rain, fog and mist.

Common features
Simplified weather-resistant construction
The new zoom lenses feature a simplified weather-resistant construction designed to minimize the intrusion of water and moisture into the lens barrel. With these lenses mounted on PENTAX weather resistant digital SLR camera bodies, the user is assured of improved durability and reliability during shooting in rain, fog or mist and at locations subject to a spray or splash of water.

SP coating to block dust and dirt
The front surface of these lenses is treated with PENTAX-original SP (Super Protect) coating, which applies a special fluorine compound to the lens surface through a vapor deposition process. This SP coating not only effectively repels dust, water and grease, but it also makes it easy to wipe off fingerprints and cosmetics.

Digital-SLR-exclusive optical design
PENTAX has optimized the characteristics of these lenses — including lens coating, curvature and positioning of optical elements — to reproduce the finest possible digital images. As a result, they are practically free of flare and ghost images, and bring out the best in the PENTAX digital SLR camera bodies they are coupled with.

Their image circle is also perfectly proportioned to the size of the image sensor used in PENTAX digital SLR cameras, helping to reduce the camera’s overall size and weight and guarantee outstanding cost performance.

Quick-Shift Focus system for instant AF/MF switching
After the subject is captured in focus by the camera’s AF system, the unique Quick-Shift Focus system lets the photographer instantly switch to manual-focus operation for final pinpoint focus adjustment.

Other features

• Durable, dependable metallic lens mount
• Lens hood with a PL (polarizing filter) window included as a standard accessory

Overview of the smc PENTAX-DA18-55 F3.5-5.6AL WR lens
This standard zoom lens covers focal lengths from 27.5mm wide angle to 84.5mm moderate telephoto (in the 35mm format). Incorporating a high-performance aspherical (AL) optical element and a super-low dispersion glass optical element in its optics, it assures outstanding image resolution and remarkable brightness, even at the edges, while effectively compensating various aberrations.

Overview of the smc PENTAX-DA50-200 F4-5.6ED WR lens
This telephoto zoom lens covers focal lengths from 76.5mm moderate telephoto to 307mm super telephoto (in the 35mm format). Incorporating an extra-low dispersion (ED) glass optical element in its optics, it assures excellent description of the subject in various telephoto applications, including portraiture, sports/action and landscape, while effectively compensating chromatic aberration over the entire zoom range.

 

smc PENTAX-DA 18-55mm and smc PENTAX-DA 50-200mm specifications

 

The smc DA 15mm F4 ED AL Limited is Pentax’s latest lens, which was shown in prototype form at Photokina 2008 and formally introduced in March 2009. It’s a rare beast indeed: a wide angle fixed focal length (‘prime’) lens that is purpose-designed for APS-C format digital SLRs. The 15mm focal length gives an angle of view equivalent to a 22.5mm lens on the 35mm format; in essence, this lens is the modern equivalent of old favourites such as the 24mm F2.8 or the 21mm F3.5. The ‘Limited’ tag denotes premium construction, with the lens barrel made entirely from high-grade aluminium, which comes as a refreshing change from the engineering plastics used almost universally by other manufacturers.

As a fixed focal length lens, the 15mm is much smaller and lighter than zooms with a similar angle of view, and requires rather simpler optics as well. The formula uses 8 elements in 6 groups, including one hybrid aspherical element and one extra-low dispersion (ED) glass element, which combine to minimize distortion and chromatic aberrations. Other key attractions of the design are the ‘quick shift’ focus system, which allows manual adjustment even when the camera is set to autofocus mode, and a clever built-in sliding petal-shaped hood.

In a market dominated by identikit zooms, it’s certainly refreshing to see Pentax offering a genuine alternative, and catering to users who value the advantages of prime lenses over the undoubted flexibility of zooms. However the rapid advance in computer-aided lens design, coupled with manufacturing technologies such as glass-moulding for the inexpensive mass-production of aspheric elements, means that the once-yawning gulf in image quality between primes and zooms has narrowed considerably over the past decade. So the question is, does the 15mm F4 still have enough on offer to make any practical sense?

Headline features

• 15mm wideangle focal length, F4 maximum aperture
• ‘Quick Shift’ system allows manual adjustment of focus in AF mode
• Built-in sliding petal-shaped lens hood
• High quality aluminium construction

The 15mm F4 is a member of Pentax’s family of ‘Limited’ primes, which are unique amongst mainstream autofocus lenses in having a barrel sculpted entirely from high grade aluminium. Build quality is, in a word, superb, with fine engineering in every detail, complemented by markings which are engraved into the barrel as opposed to simply painted on. With its jewel-like construction, this is a lens which will certainly appeal to traditionalist photographers brought up on good old-fashioned manual focus SLRs and their all-metal primes.

The most unusual feature of the design is the built-in petal type hood, which retracts by sliding back into the lens body. While sliding hoods aren’t anything new, they are generally seen on larger lenses (normally telephotos) and tend to be simple cylinders in shape; managing to squeeze one into a body this small is an impressive feat of design and engineering.

	The lens mount is Pentax’s standard KAF type, using a mixture of electronic and mechanical connections to interface with the camera.  To mount the lens, align the red dot with that on the camera body, and twist clockwise. The black metal lever controls the aperture, and autofocus is driven from the camera body using a screw coupler; three and a half turns are required to travel from infinity to closest focus.
	The filter thread is 49mm and does not rotate on autofocus, which is good for filter users. In this view that unique petal-shaped sliding lens hood is shown fully retracted. However it still protrudes past the filter thread, which may make use of square filter systems (such as Cokin or Lee) rather problematic. Unscrewing polarizers can also be quite difficult, as there’s limited space to grip them.
	Here’s that very clever lens hood fully extended. It has slight ridges at the front that act as grips, making it easy to slide in and out. The movement is smooth, adding to the overall impression of precision engineering, and the inside is lined with black felt to minimize the reflection of stray light into the lens.
	The lens can be used with normal thickness (as opposed to slim) polarizers without vignetting, making for a far more economical solution than the slimline 77mm filters required with most wideangle zooms. As can be seen here, though, you have no chance of adjusting the filter with the lens hood extended. Get used to retracting the hood, rotating the filter, then extending the hood again.
	The focus ring has a 5mm wide grip, machined directly into the aluminium. It rotates 80 degrees anticlockwise from infinity to 0.18m, with a super-smooth action. Pentax’s ‘quick shift’ manual focus system allows you to tweak focus manually even which the camera is set to AF.
	Pentax has provided a proper distance and depth of field scale, with the markings engraved into the lens barrel rather than simply painted on. This (in principle at least) allows you to use hyperfocal or zone focus techniques very simply, great for street or landscape photography, for example.

The Pentax 15mm F4 performs quite competently in our studio tests. However like the Sigma 10-20mm F4-5.6 we tested recently, it shows distinct curvature of field, which causes problems with our (flat-field) chart tests at the shooting distance used (approx 2m). As with the Sigma, we have chosen to present data that is technically slightly rear-focused, and therefore gives a better impressions of the edge and corner sharpness at the expense of the centre (this data is also most representative of the results obtained when using the camera’s autofocus). Our test sample was also slightly decentered, giving marginally softer results on the right side of frame.

Compared to the Sigma 10-20mm F4-5.6 EX DC HSM (at 14mm), the 15mm F4 comes out on top; it’s a hair sharper, and has lower distortion and falloff. Unfortunately it doesn’t come out so well against the excellent Tokina AT-X PRO SD 12-24mm F4 (IF) DX, which we’d expect to perform near-identically to Pentax’s own smc DA 12-24mm F4 ED AL (IF) – in this case the zoom is sharper, and has lower falloff and equally low distortion, although it does show more chromatic aberration.

Chromatic aberration

Lateral chromatic aberration is visible in many real-world situations, taking the form of red/cyan fringing which is most visible on high contrast edges towards the corners of the frame. The samples below show how this appears in real-life, and how effectively it can be removed in post-processing. In this case, we’ve used Adobe Camera RAW v4.6, with a value of -20 applied to the ‘Fix red/cyan fringe’ slider in the ‘Lens Corrections’ tab. This has essentially eliminated the red component of the CA, leaving just moderate (and visually less disturbing) blue/yellow fringing in the extreme corners of the frame.

• Compact and lightweight
• High quality aluminium construction
• Quick shift manual focus system
• Built-in sliding hood (but see below)
• Good flare resistance
• Almost no distortion
• Small 49mm thread, doesn’t require slim filters

• Rather soft at F4 – F5.6
• Hood design causes problems with filter use (particularly square systems)

Overall conclusion

The Pentax smc DA 15mm F4 ED AL Limited is a unique lens in the current market, a small, lightweight wideangle prime for APS-C cameras. And let’s make it clear from the outset that Pentax should be applauded for producing such a lens, to provide a genuine alternative to the wideangle zooms which are the only option in other manufacturers’ lineups. This is indeed typical of the company’s attitude towards primes in general; it makes arguably the best APS-C optimized set currently on the market, which counts as something of a selling point for the K system as a whole.

The 15mm is not a bad performer, either. Chromatic aberration is reasonably under control (and easy to correct if necessary), falloff is low at just 1.3 stops wide open, and rectilinear distortion is essentially absent. Also important in real-world shooting is the fact that the lens is very resistant to flare when shooting into the light, an especially desirable characteristic for a wideangle optic. Unfortunately though it’s rather soft wide open, and even when stopped down is never breathtakingly sharp in the fashion we’d hope for from a premium prime. This is a little disappointing, especially considering the price and relatively slow maximum aperture; but then again you rarely have to shoot a lens this wide at F4 anyway (especially with the in-body stabilization in all current and recent Pentax DSLRs).

One positive aspect not to be overlooked though is Pentax’s signature ‘Limited’ build quality, which is excellent. The machined aluminium barrel, engraved markings and smooth focus ring may have no effect on the final image, but they certainly make the lens a more desirable object in its own right, and one which is a pleasure to use. The sliding lens hood, of course, will have a genuinely positive impact on image quality, and the fact that it’s built-in makes it much more likely to be used as a matter of course. Thankfully the metal construction doesn’t result in excess weight, and the lens is eminently portable, making it ideal if you don’t want to deal with the bulk of a wideangle zoom.

There are some issues with filter usage, which is something of a double-edged sword. On the plus side, polarizer fans can use standard 49mm filters, rather than the 77mm slimline types required by most wideangle zooms. This can easily amount to $100 difference in price, which is not to be overlooked. However filters can have something of a tendency to bind in place on the lens (presumably due to its aluminium thread), at which point removing them can become a frustrating battle, as the retracting hood impedes your grip. If you do use a polarizer you’ll also find yourself spending a lot of time sliding the hood to and fro, to gain access to the filter and adjust its angle. The other problem is that the hood protrudes past the thread when fully retracted, which will cause problems with square filter systems and therefore neutral density gradients – the other most useful type when shooting with wideangle lenses.

The real problem for the 15mm F4, though, lies in the competition, and specifically Pentax’s own 12-24mm F4 zoom. This has much in common optically with the Tokina AT-X PRO SD 12-24mm F4 (IF) ED, which we tested recently and found to be a superior performer in almost all regards. It’s simply much sharper than the 15mm F4, especially wide open, and exhibits lower falloff and equally low distortion (although it does suffer more from chromatic aberration). It’s not often a zoom lens can outgun a prime in terms of image quality, but that certainly seems to be the case here, and by a surprising margin too. At current prices at least you also pay relatively little extra for all the flexibility of the zoom (but do bear in mind the 12-24mm is a well-established product, and the 15mm brand new, so its price is likely to fall over time).

So overall we have a lens which is difficult to categorize. Its very uniqueness makes it desirable – if you want something a bit wider than the 18-55mm kit lens, but without the bulk of a wideangle zoom, it’s your only choice. Like all of Pentax’s Limited series primes, it’s also a finely crafted piece of kit which is a delight to use – a somewhat frivolous reason to choose one, perhaps, although still perfectly valid in its own way. Shot carefully stopped-down to its sweet spot, it also delivers very good but not outstanding image quality. So if your priorities lie in keeping your kit small, light and discreet, it’s a great option, but for most users we can’t help but feel that a wideangle zoom still makes more sense. Ultimately when compared to the alternatives, the 15mm F4 falls just short of offering enough of the expected advantages of a prime (smaller, faster, sharper, and cheaper) to earn our highest recommendation.

Recommended

The full review can be found at www.DPReview.com.

Please, support me and buy from my affiliates.
Kamil Wawrzyszko

The power of PENTAX!!!

PMA 2009: Pentax has announced the availability of the DA 15mm F4 ED AL Limited ultra wide-angle lens. Incorporating most of the DA* series lens features, it offers a 23mm (35mm equiv.) angle of view and includes a Hybrid Aspherical lens and an Extra-Low-Dispersion glass optical element to minimize distortion and chromatic aberration. With a light aluminium body and a compact design, this lens will start shipping in April 2009 for $649.95 USD.

Press Release:

PENTAX announces a new ultra-wide angle lens, the smc PENTAX-DA15mm F4ED AL Limited

PENTAX U.K. is pleased to announce the launch of the smc PENTAX-DA15mm F4 ED AL Limited, designed for exclusive use with Pentax digital SLR cameras.  This is the newest lens to join the acclaimed Pentax Limited series family. Maintaining the highest standards, the Limited series is renowned for unbeatable construction and unsurpassed image quality. This new Limited series lens will continue that tradition while providing users with a new ultra-wide perspective.

Main features of the smc PENTAX-DA15mmF4ED AL Limited

Ultra-wide-angle perspective
When mounted on a PENTAX digital SLR camera body, this new lens offers the equivalent to a 23mm angle of view in the 35mm format. This lets the photographer create unique, eye-catching images with visual effects only possible from an ultra-wide-angle lens, such as enhanced perspective and an emphasized depth of field. It is the ideal lens for sweeping landscapes, magnificent architecture and confined interiors.

Limited Lens-series quality for incredible images and an appealing compact design.
The PENTAX Limited Lens series combines extensive testing with the incredible knowledge of our engineers to provide every user with a lens designed for the ultimate in image reproduction.  True to form, this new lens not only ensures excellent image quality, but also produces sharp, clear images with outstanding contrast, even at the maximum aperture. This is because its optical design has been optimised for digital photography.  In addition, the lens barrel, hood, and cap are all made of high-grade aluminium, providing reliable construction in an attractive lens.

High-performance optics
This lens incorporates a hybrid aspherical (AL) lens and an optical element of extra-low-dispersion (ED) glass to ensure high-quality image reproduction with minimal aberrations, including lateral chromatic aberration. Additionally, for an ultra-wide-angle lens, the smc PENTAX-DA15mmF4ED AL Limited has excellent control over image distortion.

Compact, lightweight design
Thanks to its newly developed optics, this lens is designed to be extremely compact and lightweight despite its ultra-wide-angle perspective. Since it has no dome-shaped protrusion at the front end, the photographer can mount commercial 49mm-diameter filters, including circular polarizing filters popular in landscape photography.

Other features

• Flower-shaped lens hood, with extendible design for easy carrying
• Minimum focusing distance of 18 centimetres (or 0.59 feet) for close-up photography
• PENTAX-developed Quick-Shift Focus System for instant switching to manual-focus operation after the subject is captured in focus by the AF system
• PENTAX-original Super Protect (SP) coating applied to the front surface of the lens, making it easy to wipe off fingerprints, cosmetics and other stains

Price
RRP £569.99

smc PENTAX DA 15mm F4 ED AL Limited lens specifications

This Pentax lens is perfect for portrait photographer. But read on to see what experts say:

The Pentax smc FA 50mm F1.4 is something of an anomaly in the company’s current lens lineup, as the last of their film-era primes featuring plastic construction and an aperture ring. This actually reflects the fact that Pentax are probably the leading proponents of modern-design fixed-focal length lenses, with their range of compact ‘pancake’ lenses and ‘Limited’ series high quality primes being the envy of users of other systems. Indeed we can probably presume that the 50mm F1.4 will itself be superseded by the recently-announced Pentax-DA* 55mm F1.4 SDM lens, but in the meantime it stands as the most obvious option for users seeking a fast prime for low light and portrait work.

The 50mm F1.4 features a traditional design of 7 elements in 6 groups, with all of the lens surfaces spherical in profile. In this regard it’s very similar to the Canon EF 50mm F1.4 USM and Nikon AF-Nikkor 50mm F1.4D which we’ve reviewed recently, and therefore looks somewhat dated when compared to the all-new, aspheric-element Sigma 50mm F1.4 EX DG HSM. The ‘smc’ designation indicates treatment with Pentax’s ‘super multi coating’ for the minimization of flare, and the ‘FA’ designation indicates that, unlike the newer ‘DA’ digitally optimized lenses, its image circle covers the 35mm full-frame format.

With Pentax concentrating their attentions on the APS-C format, the function of this lens has subtly changed from the days of 35mm film, and the 1.5x crop factor means it now acts more like a classic short ‘portrait’ telephoto, instead of the general purpose ‘standard’ lens it was designed to be. The question to be asked is therefore whether it’s well suited to this role, especially given the high resolution demands of the smaller sensor. Read on to find out.

Headline features

• 50mm focal length
• Fast F1.4 maximum aperture

Pentax smc FA 50mm F1.4 specifications:

* Supplied accessories may differ in each country or area

Highly Recommended

You can  read full review at http://www.dpreview.com/lensreviews/pentax_50_1p4_p15/ .

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All that you need to know before you buy a lens:

Before you make a decision about buying a lens (and to understand how photos are affected by various settings), you need to understand the basics. If you don’t understand something, just keep reading as it will become clearer towards the end.

Types of lenses:

• – Prime lenses – fixed focal length (no zoom – just one angle of view). Why? Because you get very high quality for a relatively low price. Achieving the same quality with a zoom lens is a big challenge, so the price goes up.
• – Zoom lenses – pretty obvious (variable focal length, but lower quality)

Zoom lenses can be classified as with:

• Fixed maximum aperture (or f/ number) – the same amount of light falls in across the whole zoom range.
• Variable maximum aperture – amount of light falling in decreases with zooming in (getting close to the object, so faster shutter speed is required to avoid motion blur)

Wide - A wide angle lens is a lens which has a shorter focal length than that of a ‘standard’ lens, allowing a much wider area to be brought into frame. To obtain a wider view, the centre lens has to be closer to the sensor (or film if you are using a film camera) of your camera, which means the lens must be shorter in overall length. A lens with a lower focal length (in millimetres) is always wider angle than a lens with a higher focal length. For example, an 18mm focal length is wider angle than a 55mm focal length. Wide angle lenses for digital cameras typically range from about 8mm to 35mm.

Standard - A standard lens is one which is in between wide angle and telephoto. Standard lenses for digital cameras typically range from about 35mm to 80mm.

Telephoto - A telephoto lens allows you to zoom in on far away subjects. The telephoto range is the widest range of focal lengths, ranging from under a hundred to over a thousand millimeters. These lenses are also the longest and bulkiest of all lenses, and it is not uncommon for a telephoto lens to weigh a pound or more. Telephoto lenses for digital cameras typically range from 80mm to 1200mm or more.

Fisheye - A fisheye lens is an extremely wide angle lens which captures at least a 180 degree field of view, and takes distorted pictures which bulge outwards in the middle, similar to a fish eye. Fisheye lenses were originally developed for use in meteorology and astronomy, but became popular with photographers for the unique images that they produce.

Macro - A macro lens is a lens of any focal length (but typically standard or short telephoto) which allows an extremely close minimum focusing distance to the subject. True macro lenses also feature a 1:1 (life size) reproduction ratio. Macro lenses are used for extreme close-up photography.

Parameters:

Focal length – is the distance between the sensor (or film in film cameras) and the lens (the nearest piece of glass to the sensor) or how far you zoom in or zoom out, that’s why zoom is given in mm as it reflects the focal length, which is measured in mm.

Focal length at Wikipedia

Aperture / f-number: Size of the opening inside of your lens that regulates the amount of light falling in, and also, as a side effect, it regulates the depth of filed (area of sharpness in the picture). The higher the f-number, the smaller the aperture (like that makes our life easier, but f-number is a mathematical value of focal length divided by aperture diameter in mm). Aperture can be set both in the camera and on the lens (although many lenses do not have that option), but the change happens in the lens only.

Aperture at Wikipedia

Depth of field – the length (distance) which will be in focus in the photo. It depends on the aperture and the size of sensor. Compact cameras have very small sensors, so the effect is difficult to observe.

At f/32, the background is distracting.     At f/5.6, the flowers are isolated from the background.

Depth of field at Wikipedia

Sharpness—or the lack of it—is immediately noticeable when you look at a photograph. If you are making a portrait, you want only the person to be sharply focused, but not a distracting background. In a landscape, on the other hand, often you will want everything sharp from close-up rock to far away mountain. Once you understand how to control depth of field, you will feel much more confident when you want to make sure something is—or isn’t— sharp.To control depth of field, you have three factors to work with.

• Aperture size. The smaller the aperture, the greater the depth of field. The larger the aperture, the shallower the depth of field.
• Camera-to-subject distance. As you move father from the subject you are focused on, you increase depth of field. As you move closer, you decrease it.
• Lens focal length. Using a wide-angle lens or zooming out increases depth of field. Using a long lens or zooming in decreases it.

Each of these three factors affects depth of field by itself, but even more so in combination. You can get the shallowest depth of field with a lens zoomed in on a nearby subject using a large aperture. You get the greatest depth of field when you are far from a subject, with the lens zoomed to a wide angle, and using a small aperture.

Stop – this usually refers to one step between one f-number and another (just another way of describing aperture changes). Each stop up increases light intake by 100%, and each stop down decreases light intake by 50%. If in automatic mode, the camera will compensate this by slowing down or speeding up the shutter speed. Cameras and lenses can usually operate in steps of 1/2 or 1/3 stops.

Resolution – similarly like the camera, a lens has resolution, but it’s more difficult to measure and it changes between the centre of the lens and its edges. Kit lens might have resolution of around 10M pixels or less, while good lenses will have up to 50M pixels (don’t quote me on that as I’m not an expert). You won’t find any info on lens resolution on the box as it’s not that important and subject to debate.

Other factors related to the lens, although not regulated by the lens:

Shutter speed – how long the sensor is exposed to light while the photo is taken. The shorter the time, the less blur in the photo, but less light falls in, so you need to have more light on the object photographed. If the photo is still dark and you cannot slower the shutter speed, you can decrease the f/number and/or increase ISO. This is set in the camera and does not affect the lens directly, but your camera might decide to change aperture of the lens to reflect the shutter speed changes (depending on the camera mode currently in use).

35mm equivalent – this matters only when coupled with a camera. It’s a standard that tells you how big or small angle of view is. You can compare it to different currencies; to know the value of something in another currency, you need to know what the exchange rate is, but in if everybody used, for example, only Euro, you would not have to calculate. So in photography we use the equivalent, so we do not have to calculate it ourselves.

E.g. with some cameras 18mm lens will give you the same angle as 28mm with other cameras, that’s why we use the equivalent, so 35mm equivalent of 28mm is always the same on each camera, although real distance will be different (I know, the more I explain, the less you understand). 35 mm is the size of a standard film exposure; hence this has become the baseline for other sizes. Digital SLR’s usually have smaller sensors (with factor of 1.5 or 1.6 – so called APS-C size), but there are some full frame (35mm) DSLR’s – they are usually more expensive and for professional use. All Pentax DSLR bodies are APS-C, so 18mm will always be equivalent of 28mm on 35mm (18×1.5=28). Check Wikipedia article if you need more explanation: 35mm equivalent

Please, let me know in the comment if you need more explanation or if you need answers to some other issues.

Regards

Kamil