[Foma2]

I took some shots of a ISO 12233 chart using a few days ago.
Three lenses were used :
- Pentax SMCP-DA* 16-50mm f/2.8 ED SDM
- Sigma 10-20 mm F4-5.6 DC EX HSM
- Pentax DA 18-55mm f/3.5-5.6
Camera : Pentax K-5ii.
I have just done pixel peeping checks Pentax DA 18-55mm 3.5-5.6 vs Pentax 16-50mm 2.8 for photos taken at 18mm with F8.
I did not see any significant improvement from neither CA nor MTF perspective.
I compared both centre and corner areas.
It is a kind of shoking results to me as 16-50 cost me almost ten times more than 18-55 and I understand advantages of 16-50 lens (2.8 constant aperture, WR, wider) but my expectation was that it should be better optically as well.

Am I wrong ? Or do I do something not quite right ?

[stevebrot]

Am I wrong ? Or do I do something not quite right ?

You forgot to read the fine print on the instructions that came with the DA* 16-50..."Do not compare directly to any less expensive lenses. Doing so may cause disappointment and buyer remorse."

I am just kidding of course.


Steve

[filoxophy]

I would expect (hope?) for there to be a difference, but at f/8 I'm not shocked that there isn't.

[pacerr]

The difference isn't necessarily the very best that any given individual lens can achieve but how far it can push the outer edges of the performance envelope before it becomes unusable.

On any given Sunday the worst team in the league might win one but if ya wanna win bets on every game all season . . .

[vonBaloney]

Compare them at 18/3.5 and 50/5.6. Also note (again) that you can shoot the more expensive one at f2.8 in both cases...

[Driline]

I have both lenses. Chart or no chart, in a real world situation the DA*16-50 blows away the kit lens at any focal length or aperture.

[Nicolas06]

@f/8 most modern lenses are really sharp in the center.

Lenses difference cannot be seen on charts, because well most photographers goal is not to take gorgous photos of charts to begin with.

Looking at 100% crop is easy and you can see all the defects of your photos. But this is not how normal peoples would you at your photo on a screen or on print anyway. That's not that important in the end except if you plan to print 30x40" with people looking at all the details from a short viewing distance.

The nice things of many high end optics are the better micro contrast, the better color rendition, the better ability to separate your subject from background, performance at wide appertures, resistance to flare in focus/out of focus transitions... All the kind of things that make your photos pop.

In ideal conditions and for easy subjects, the basic lenses will already give good results, sometime even great. The high end optics is able to take great shoot in more shooting conditions. Assuming in all case the the photographer is good, anyway. That's by far the most important aspect for the final outcome.

[robjmitchell]

The 16-50 2.8 is not a lens known for its sharpness. The colours, out of focus rendering and most importantly contrast are what makes the lens shine. The kit lens may be ok for sharpness but the photos it produces are rather dull in comparison. You obviously have a darker viewfinder and can't manipulated depth of field in the kit lens.

[Foma2]

Thanks for your comments. Now I see where I went wrong.
Nicolas06, robjmitchell you just reminded me that a very basic $100 p&s camera can actually get very good pictures comparable to the ones taken with >$1500 lenses. There is only one condition - the should be ideal (the sene should be well lit, F stop in the sweet spot, no flar,glare, no need for good bokeh, etc).

Thanks again. I was just a bit disappointed last night looking into test photos.

[robjmitchell]

I suspect the 16-50/2.8 was designed more with wedding/portraiture in mind rather than landscape photography. In this respect it excels. There are plenty of people who would prefer the lens to be razor sharp although the extra mm on the wide end makes that pretty hard to design.

[Rondec]

I think the big differences will be at wider apertures. Folks that plan to shoot at f8 all of the time could really go with cheaper options. On the other hand, I have found my 16-50 to be decent at f2.8 and quite sharp at f4.

This is a shot at 18mm and f2.8 taken recently...