John Riley reviews the SMC Pentax-DA 70mm f/2.4 Limited lens.
Posted: 29/06/2011 - 12:47
Features
Handling
Performance
Verdict
Specification
The Pentax lens repertoire seems to have its fair share of prime or single focal length lenses, bucking the trend towards the ubiquitous zoom. Many of these Pentax primes are described as Limited, not in the sense of them having a short production life, but rather in the limited number that can be made of these hand assembled, superior optics. The price is relatively high, so the questions are do these lenses indeed have superior finish and construction and are they of a higher optical standard? We shall now attempt to find the answers.
SMC Pentax-DA 70mm f/2.4 Limited: Features
The diminutive SMC Pentax-DA 70mm f/2.4 Limited weighs a very modest 130g, comprises 6 elements in 5 groups and has a 35mm-equivalent focal length of 107mm. This is very close to the traditional film 100/105mm lenses that are extremely popular as general short telephotos and portrait lenses. This 70mm lens, designed for the digital SLRs, is much more compact and machined out of aluminium to a very high standard.
A special extending lens hood, also in high grade aluminium, at first seems to be part of the lens but can be removed and 49mm screw filters can then be fitted. The lens design harks back to the M series days in that distance scales are viewed through a cut out. Depth of Field markings are also provided. The engraving of all the various markings is absolutely superb. The lens cap, again aluminium, is a generously deep push-on design that is lined with black plush velvet. There is no tendency for this to fall off.
There is no aperture ring on this lens, in common with most of the DSLR lens range. As befits a high end lens, a proper bayonet rear cap is provided rather than the push on transit type that comes with the kit lenses.
SMC Pentax-DA 70mm f/2.4 Limited: Handling
We have here a beautiful jewel of a lens, with clearly very superior finish and construction. In terms of handling, it fits cleanly and firmly onto the camera body and is instantly ready for use after the push on cap is removed. The built in extending lens hood is, as mentioned, detachable, but for most purposes can be considered an integral part of the lens.
Focusing is smooth and fast on the K-5 and the added advantage of Quick Shift is available. After AF has locked on, the focusing ring can be adjusted to tweak the final focus position. In this test, this never proved to be necessary but it can be a very useful feature. Manual focus is nicely damped and although a different feel to the classic manual focus lenses it is functionally perfectly satisfactory.
The 70mm focal length is perfect for portraits and during this test I was able to try this out extensively on a couple of photoshoots. This is always a personal choice, but when using film I preffered to use 100mm lenses, so this is as close to the same thing as it gets.
Short telephoto lenses are also very useful for picking out details in general photography and, coupled with such a compact size, this may well be an outstanding lens for general travel.
Those who enjoy fine engineering will also appreciate this lens, but it takes pictures as well and its handling is spot on.
SMC Pentax-DA 70mm f/2.4 Limited: Performance
Looking at the technical charts, it's clear that Pentax have made the decision to heavily correct for chromatic aberrations across most of the field, but allow the corners to drift a little. In the centre, CA is almost banished, as we move out into midfield the control is still excellent. The corners are quite demanding and although CA is visible it is only so in extreme conditions. In practice, CA will not be a problem.
SMC PENTAX-DA 70mm f/2.4 Limited Chromatic Aberration Charts
How to read our CA charts
Chromatic aberration (CA) is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.
Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more.
For this review, the lens was tested on a Pentax K-5 using Imatest.
With such a compact design, I had expected that there would be significant pincushion distortion, but the smaller sensor size does seem to have made lens design easier here. In fact there is indeed pincushion distortion, as with most strong telephoto designs, but it is fairly minimal and in general use not apparent. A better than expected result.
Flare, in common with other Pentax lenses I have tested, is very well controlled and almost impossible to induce. The effective pull out hood helps here as well as the SMC coating.
SMC PENTAX-DA 70mm f/2.4 Limited MTF Charts
How to read our MTF charts
The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges.
The scale on the left side is an indication of actual image resolution and sharpness as LW/PH and is described in detail above. The taller the column, the better the lens performance.
For this review, the lens was tested on a Pentax K-5 using Imatest.
The MTF50 graph looks at the fine resolution and ability to record a very high standard of detail. When MTF measurements started to be used in the 1970s many magazines started off using MTF40 data and quickly reduced that to MTF30 as the figures always looked low. This goes to demonstrate how much more resolution we have for our DSLR lenses. MTF50 is a very high standard and this 70mm lens shows a very good but not exceptional performance in this respect. The resolution is well maintained across the field and there is a very clear peak at f8. This classic rise and fall pattern is the hallmark of a good lens.
The MTF20 graph shows us information about the overall contrast or “bite” of a lens, and the 70mm is a typically Japanese design of the sort that caught the imagination of photographers after they discovered Nikon rangefinders in the 1950s. Rather than high resolution, low contrast lenses such as the German lens makers produced, we had very high contrast lenses with bite that have lower fine resolution. There is no free lunch in lens making. Here Pentax have opted for plenty of bite and at f8 the performance in this respect is superb.
Of course, in the end, these measurements give us clues as to how a lens will perform, but it is the practical result that is most important. The 70mm delivers a very high standard of performance and produces very clean, sharp and contrasty images with a minimum of distortion, flare or CA.
SMC PENTAX-DA 70mm f/2.4 Limited Sample Photos
SMC Pentax-DA 70mm f/2.4 Limited: Verdict
Sometimes when reviewing a lens it's just so hard to actually hand it back after the job is done and this is one of those lenses. It's a superb piece of engineering and has optical qualities that are balanced to just my taste. It is not a macro lens, so very close shots are not possible, but it is ideal for medium range applications and especially portraiture. Highly recommended.
SMC Pentax-DA 70mm f/2.4 Limited Pros
- High quality of construction
- Compact
- High optical quality
- Excellent handling
SMC Pentax-DA 70mm f/2.4 Limited Cons
- Price
Specifications: SMC PENTAX-DA 70mm f/2.4 Limited |
||||
| General | ||||
| Focal Type | Telephoto | |||
| Availability | ||||
| Year announced | 2011 | |||
| Discontinued | Yes | |||
| Dimensions | ||||
| Diameter | 63mm | |||
| Height | 26mm | |||
| Weight | 130g | |||
| Construction | ||||
| Weather-sealed | No | |||
| Groups | 5 | |||
| Elements | 6 | |||
| Lens | ||||
| Maximum magnification | 0.12x | |||
| Internal focusing | No | |||
| 35mm equivalent | 105mm | |||
| Stabilised | No | |||
| Filter Size | 49mm | |||
| Min Aperture | f/22 | |||
| Max Aperture | f/2.4 | |||
| Angle of View | 68° | |||
| Focal Length | 70mm | |||
| Focusing | ||||
| Macro | No | |||
| Box Contents | ||||
| Box Contents | Soft Case, front and rear caps | |||
Members gallery photos using: smc PENTAX-DA 70mm F2.4 Limited
As for the 70mm, I didn't want to give it back, so that speaks pretty well of its qualities!
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290 posts
16 years
London
I can't help thinking that if you'd have had my lens You'd have rated it's optical performance as excellent. Lenses do differ, though!
I got rid of it because a similar focal length macro was more versatile, if not having the extreme optical quality that my DA 70 did. In the end, extreme optical quality is not terribly important unless you are an inveterate pixel peeper and the f2.4 is little faster than the f2.8 macro.
For me, the physical smallness of the lens is neither here nor there since if I'm trying to travel light I use my Panasonic GF2 instead. But if a light short tele for portraits is what you seek then I agree with John's conclusion that there is nothing better than this little gem.
I'll be interested to see you thoughts on the 60-250 zoom. I happily use mine wide open at any focal length without any qualms about the quality and it is the one lens I would regard as essential in my bag on account of it's 4x range and across the frame contrast and crispness.