First offcial test of Pentax 16-50/2.8

Started Sep 15, 2007 | Discussions thread
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Broda Contributing Member • Posts: 638
First offcial test of Pentax 16-50/2.8

Guys I think I will be the first one here to announce test report regarding new Pentax glass it is 16-50/2.8. It was done by polish guys who kind of work in the same way that our host Phil does. It would be kind of polish version of this website. They have tested many lenses in the past but not till recently they have started doing it for pentax so far they analyzed 40/2.8 and FA50/1.4, the second one being by far sharper than the first one with some very spectacular results especially at f/4. Although overall it seemed that 40/2.8 would be a better option for DSRL because of new coating… at least that is what they suggest anyway now they have this magnificent piece of glass and since pentax finally ship it out there were many different opinions about this lens especially here on this forum. Ok lets get to it … there will be a link on the bottom if somebody is interested in finding out more details or looking at some charts.

Anyway let’s start with the construction of this lens. On their website it would be point # 3 (point #1 is general introduction of the lens but that we all know point #2 would give you specifications and pictures of the lens itself). In point # 3 they stated that it is large pieces of glass very nicely build. They liked focusing ring because of its size, comfort to grip, and pleasure to use.
Point # 4

It is a resolution chart the top one is for center resolution while the bottom one shows you edge resolution. Guys who do the testing claim that resolution of 30 lpmm is an average one while good fixed lens should easily go beyond 40 lpmm just like pentax FA50/1.4 did in their tests. Pentax 16-50 according to their tests has much better resolution to start with better than the Tokina version. At F/2.8 center resolution is above 30 lpmmm at focal lengths of 16 and 30mm while 50mm is around 26 lpmm. It gets better from there this lens sweet spot for center resolution is reached at F/5.6 when at 30 and 50 mm focal lengths it gets beyond 40 lpmm while at 16mm it is right below it at about 39 lpmm. Actually center resolution is way above that average 30 lpmm from F/4 to F/16 at all focal lengths.

Edge resolution is a different story. Wide open at f/2.8 it does reach 20 lpmm at 16mm while at 30 and 50mm this lens comes short. Obviously these are very disappointing results. For example at 16mm edge resolution never goes beyond 30 lpmm it comes just short of it at F/8. It does better job at 50mm when edge resolution goes beyond 30 lpmm from F/5.6 to F/16. The best results for edge resolution were found for 30mm when edge resolution gets over 30 lpmm from f/4 to f/16 while at f/5.6 reaches about 39 lpmm, combine that with center resolution and it is one great sweet spot that can easily compete with fixed lenses. At focal length of 30mm that lens can compete with fixed lenses with both center and edge resolution at 50mm it gets worse and at 16mm it is way below any expectations I would say especially for that kind of money.
Point # 5

Chromatic Aberration - they discuss CA and they mentioned that tokina lens really struggled especially at 16 mm they hoped that pentax would be better because of extra ED element … unfortunately it ends with hopes because CA at 16mm is terrible they have a sample picture showing corner of a picture that they took and you can clearly see that CA problem is very serious they actually stated that tokina version had actually better results regarding CA even though has one less ED element. You can see more on the website.
Point # 6

Distortion – at 16mm it is - 4.1% at 30mm it gets down to 0.1% and at 50mm it gets up to 0.71%. Pretty good results except at 16mm.
Point # 7

I don’t really know what exact word is for it. It analyzes how sun beams bend when they pass though pieces of glass in particular lens. If they create a small circle that would be considered perfect scenario you can see from their results it is pretty bad. Left side shows this result for center and right side for the edge.
Point # 8

Lens Vignetting – at 16mm at f/2.8 it is terrible 46% (- 1.8EV). If it gets below 10% it becomes unseen for human eye. At 16mm it actually never get below that 10% it is best result is at f/16 and that would be 19%.

At 30mm at f/2.8 it reaches 21% (- 0.7EV) stepping down to f/5.6 get this lens below 10%

At 50mm at f/2.8 it reaches 28% ( -0.97EV) at f/4 gets down to 13% while at f/5.6 gets below 10%
Point # 9

Reflections – it really talks about coating that is being applied on lenses. I am not sure what specific word is used to describe it… I cant explain this one myself you have to go and see results on your own even those guys were amazed since they really admired pentax coating on previous lenses they tested (FA50 and DA40) while stating it could be actually the best one out there. Unfortunately this lens does not deliver
Point # 10

AF – worked nicely but they got different results so if you are out there working with your K10 listen you need to upgrade your firmware to version 1.3 you will see huge difference it gets quieter, smoother, and faster. According to their founding’s it took about 0.5 s to go from 0.3m to infinity. It took a bit more time for this lens to go back from infinity to 0.3m. AF was pretty accurate in the studio environment it had a tendency to miss target about 6% of the time. This result is almost outstanding. From all the reviews I read in the past I don’t remember seeing better one.

Overall it is disappoint lens. They liked the way it was build, it offers nice range and sealing but results unfortunately are not matching the price tag for this lens. Below is the link. Have a good one.*_16-50_mm_F2.8_AL_ED_IF_SDM_Wstę ;p.html

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