HD vs. SMC Pentax Limited Primes
Aberrations and Flare
On this page, we'll take a look at the difference that the HD coating makes when it comes to ghosting, flare, and contrast.
Contrast and Flare
The HD coating improves contrast in backlit situations where flare is present or is a risk. Compare these two images taken with the 70mm lenses shooting next to the sun. Both photos were taken at 1/1000s, F5.6, and ISO 100 in manual mode. JPEGs straight from the camera are shown below.
Click on any thumbnail on this page to enlarge and browse.
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| HD Pentax-DA 70mm Limited | smc Pentax-DA 70mm Limited |
It is evident that the HD lens has better contrast and much less flare. There is a good level of flare across most of the frame from the SMC lens.
Ghosting
Shooting straight into the sun is not advisable, but doing so will typically show you the worst-case scenario as far as ghosting goes. The photos below were taken using the same manual settings as the previous two examples.
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| HD Pentax-DA 70mm Limited | smc Pentax-DA 70mm Limited |
There is no significant difference between the results from the two lenses in this situation, except that the SMC lens produces a more rigid starburst effect.
Ghosting and Flare at Night
We subjected the lenses to a tough test, shooting directly into a street light at night.
HD Version | smc Version | |
15mmF5.6 |  |  |
21mmF5.6 |  |  |
35mmF4 |  |  |
35mmF8 |  |  |
40mmF5.6 |  |  |
70mmF4 |  |  |
The performance of the 15 mm lenses, HD as well as smc, is amazing. Flare and ghosting is exceptionally well controlled. For the other lenses the HD versions control flare and ghosting significantly better than their smc counterparts. The HD 35 mm lens stands out together with the two 15 mm lenses.
In the flare that is present on the 15mm photo, also notice how it's hexagonal on the SMC 15mm but circular on the HD 15mm.
Star Burst
The smc Pentax-DA 15 mm lens has been a favorite amongst our users for night photography due to its wide range and beautiful star bursts. We have to report, unfortunately, that the rounded aperture blades of the HD version spoil the results. The starburst from the HD lens is effectivaly blurred by the rounded blades and therefore not as well-defined as the star burst from the smc version. The only remedy would be to stop down to F11 or F16 which of course means a much longer exposure time and diffraction.
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| HD 15mm Limited at F5.6 | SMC 15mm Limited at F5.6 |
On the other hand, those who prefer a smoother rendering of strong light sources might prefer the HD variants of the other 4 lenses. The sword cuts both ways, unfortunately: it's hard to classify either lens series as "better" than the other.
Fringing
Fringing (also known as chromatic aberrations) is not prevalent on the Limited lenses, be that the SMC versions or the HD versions, even in areas containing brightly-lit edges. We tried hard to provoke fringing and only got coma rather than chromatic aberrations in the shots below.
The Scene
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| HD Pentax-DA 70mm Limited | smc Pentax-DA 70mm Limited |
There is no visible difference between the performance of the HD and the SMC variants.
Verdict
The HD coating controls flare and ghosting better than the SMC coating. HD coating also enhances contrast. The difference between HD and SMC is somewhat lens dependent and practically non-exisitng for the 15 mm lens.
Not related to the coating but to the shape of the aperture blades is the star burst aberration. The smc lenses are preferable for star bursts since their aperture blades are not rounded, but this comes at the expense of more flare. The exception is the smc 15mm which controls flare as well as the HD counterpart while rendering a much nicer star burst effect.
