HD Pentax-DA 55-300mm F4-5.8 ED WR Review

Magnification vs DA* 60-250

As mentioned previously, the DA* 60-250 is the main 'competitor' (or rather, the "is it worth it to get the DA*?" conundrum) of the HD 55-300 WR. In the next series of tests, let's take a look at how the magnification at different distances affects the output of the two lenses. We were originally going to start with the sharpness comparison (now on the next page), however the moon magnification is re-visted as a sharpness test subject, as is the table below identifying the exact pixel magnification differences. Thus, we rearranged the review to accommodate this more logical flow.

Comparison One - Moon Magnification (Max Zoom at Infinity)

For this test, all shots were taken using a tripod and a 12s timer. The camera was oriented up approximately at a 75 degree angle, and all apertures for all lenses across all cameras were set to F8.0. The purpose of this test was to assess the quality of the sharpness and magnification at maximum zoom for each lens at inifinity focus. We chose the moon as the perfect assessment of this because it's a very common subject these lenses would be used to photograph at their maximum zoom.

In the below magnification assessment, we compare not only the 55-300 vs it's DA* big brother, but across Pentax's 16 and 24 megapixel filterless cameras to assess how the resolution of those cameras affect magnification. Click on the below image for a better view.

EDITORIAL NOTE: If you would like to view and examine the above image at 100% crop reproduction (clicking on it is not 100% but a smaller enlargement), then click here. We recommend downloading and saving the 100% crop comparison to your computer rather than viewing from in your internet browser.

As you can see, the HD 55-300 WR (and its unsealed sibling) at 300mm has quite a bit of a magnification edge on the 60-250 at its longest focal length focusing towards infinity. The difference is made even more dramatic once you use the 24 mpx sensor, whose resolution really starts to become a game changer. If you look closely at the two middle moons (K-5 IIs/55-300 and K-3/60-250), they are almost identical in size, with the latter winning by a few hairs. To get more exact than 'a few hairs' we measured across the diameters of each moon at 100% to measure just how large that difference was in pixels, and the percent differences between each:

Just to compare what the Pentax telezooms offer in comparison to a dedicated super telephoto, here is the above image with the Pentax HD DA 560 F5.6 added, also with both the K-5 IIs and K-3 and the same settings as above.

EDITORIAL NOTE: Again, if you would like to view and examine the above image at 100% crop reproduction (clicking on it is not 100% but a smaller enlargement), then click here. We recommend downloading and saving the 100% crop comparison to your computer rather than viewing from in your internet browser.

As you can see, the K-3/55-300 combo is still quite a bit away from the HD DA 560mm when coupled with the 16mpx K-5 IIs. That difference becomes exaggerated when the DA 560 is coupled with the same 24mpx sensor. Between the two lenses actually being compared, however, it is obvious that the DA* requires the K-3's sensor to slightly exceed the HD 55-300's output on the K-5 IIs - a very impressive feat on behalf of the consumer zoom. Note that this is purely in terms of magnification only - we will address the sharpness differences on the next page.

Comparison Two - Middle Distance

For our second comparison, we borrowed a neighbor's stuffed (aka 'prepared') German Goshawk. Yes, it has indeed seen better days, but it's a great subject to assess magnification rather than just a simple test chart or brick wall. Because we wanted to get some distance between the bird of prey and the camera, we went to the hallway and set up a key and fill light on either side of our model. Here's how the photo was shot, with a distance of approximately 8 meters between the camera and Goshawk:

The following settings were in effect for all three shots below:

Clicking on any of the below images will enlarge them:

HD 55-300 300mm	HD 55-300 250mm	DA* 60-250 250mm

Comparison Three - Pseudo Macro (Minimum Focus Distance)

With telephoto lenses, there is a slight tendency to use them as pseudo (Greek for 'false') macro lenses in lieu of dedicated lenses with macro focusing ability. These speciality lenses are capable of 1:2 (50%) or 1:1 (100%) reproduction ratios, the latter of which all of Pentax's current three macro lenses feature. This is especially true near the minimum focus distance because the magnification is at its greatest here and the depth of field at such focal length/magnification ratio combinations is razor thin. As such, we wanted to compare the 'macro' capabilities of these two lenses to see how they compare.

The following comparison was shot of a vase full of flowers, a very common macro or 'still life' subject. The focus for every image was manually set using liveview and Focus Peaking at the far side of the orange flower's central perimeter. See the below image for reference (focus plane = dotted white line; focus point = yellow box):

The following settings were in effect across all lenses on the Pentax K-3, as well as two off-camera strobes in softboxes for all shots:

The D FA 100mm F2.8 Macro WR lens was also added to give a comparison as to what the same scene would look like taken by a dedicated macro lens. All lenses were aligned to approximate the same composition, which proved tricky because the HD 55-300 and the DA* 60-250 were positioned to their minimum focus distances from the flowers, and the D FA 100mm Macro was positioned as best as possible to reflect the same composition as the HD 55-300 WR despite the difference in focal length and focusing distance.

Note that minor post-processing has been applied only in eV compensation solely to balance all the exposures (as close as possible before negatively affecting the image). No adjustments were made to sharpening, tone, contrast, clarity, distortion correction (in camera or post), etc. All were shot RAW (DNG) and then converted to JPEG in Adobe Lightroom 4.4.

Clicking on any image below will enlarge it.

	HD 55-300 0.28x Magnification (1:3.5)	DA* 60-250 0.15x Magnification (1:6.7)	D FA 100mm Macro 0.32x Magnification (1:3.1)	D FA 100mm Macro 1.00x Magnification (1:1)
F2.8	N/A	N/A
F4.0	N/A
F5.8 / F5.6
F8.0
F10
F13
F16
F20
F25

EDITORIAL NOTE: For the third row of images there are two apertures, F5.8 and F5.6. The DA 55-300 has a maximum aperture of F5.8 at 300mm, and the DA* 60-250 and D FA 100mm Macro are capable of the classical f-stop of F5.6. Because of their being so close (one tenth of a stop difference), we've lumped them together as the same aperture for the purposes of the above comparison.

Verdict

By now it's obvious that the DA* 60-250 lags behind the HD 55-300 in magnification, with the latter having a significant advantage across the entire range of focusing distances. Because of the rather daunting discrepency, we can't help but wonder if the lenses are both accurately measured for their reported focal lengths. Is the 55-300 really a 55-400? Or maybe the 60-250 is really a 50-200? We don't have the means to accurately answer that question, however it is certainly a thought worth pondering. Regardless, at the end of the day, users of the HD 55-300 will reap the benefit of significantly higher magnification at all focal lengths and focus distances.

But is that magnification difference all there is to it? Now let's take a look how the sharpness of each compare.