DA* 16-50 question.

This thread got me thinking about knowing what to expect from a lens.

I bought the 16-50 just before the prices went stupid last year, and haven't used it a lot since, but when I have, I have to say it has been a bit disappointing. There's something off in the geometry. I know that this is a standard criticism of this lens in some reviews, but I was surprised when I saw how bad it was in the picture below. I appreciate this is the worst case - F2.8 at 16mm. My question is would people expect it to be this bad, or is mine a duffer? Any thoughts appreciated.

[IMG]http://i217.photobucket.com/albums/cc222/Oggy3323/Pincushion.jpg[/IMG]

Nope, that about what you can expect from this lens. Not a duffer.
Simple enough to fix in software or if you have the K7, fix in camera.
Also, compared to some other lenses, that isn't so bad.

Honestly, I'd like to see less for a lens of that price, but then maybe the image quality would probably suffer. It seems with photography that every time you push one thing another has to get pulled.

To be fair, it is not a lens designed for architecture. But, hold it perpendicular to the subject and you probably wont notice the effect quite so much. (If the camera *is*perfectly perpendicular, then something is a bit off.) You can also try standing back a bit and zoom in.

I do not have any experience with this lens but barrel distortion that bad is quite surprising. I know it can be corrected in PP, but all the same that isn't good. I'd be interested in what others have to say as I am contemplating up-grading my kit lens and given what I normally shoot, this would be a major problem for me.

Best wishes, Kris.

This is why it's quite important to know how a lens has been designed and what it's purpose is. For lanscapes this would be very satisfactory, possibly even desireable for some, but for architecture it isn't suitable at all.

Unfortunately manufacturers do not explain the design parameters of their lenses, so we sometimes buy inappropriate lenses for our needs.

The 12-24mm is virtually rectilinear for those who do architecture. It doesn't look as though the 16-50mm is.

In that case I am glad that my last major bout of LBA led me to the 12-24 then, as I would be very unhappy with that degree of barrel distortion. How does it compare to the 16-45 or the 17-70?

Best wishes, Kris.

The 16-45mm is quite reasonable, but has more distortion than the 12-24mm. The 17-70mm I have no experience of.

I have never seen anything like that amount of distortion with my 16-45. (Such a lovely lens, what a shame they discontinued it )

DA*16-50


DA 16-45


DA 17-70


DA 12-24


DA 18-55

So the humble kit lens out performs the 16-50 and the 17-70 in terms of barrel distortion... but as John said, the 12-24 outshines them all. Fascinating.

Thanks Stefan.

K.

I agree with womble.

Thanks for the information Stefan, it looks like the 16-45 lens does not come out to badly either.

Kris Don't forget that the DA*16-50 is a f/2.8 lens so the lens elements are wider/bigger maybe that has something to do with it?

Also the DA12-24 is at the centre of his focal length so you should not really compare the how good the lens is with that data because all the other lenses have almost no barrel distortion over the 24mm.

The data was taken from photozone.de so if you want to see the other focal lengths go ahead.

Just done a quick test with mine outside. 16mm @ f2.8

Wish it would stop raining so I could cut the grass.

[IMG]http://img.photobucket.com/albums/v188/Sockpuppetuk/IMGP3586.jpg[/IMG]

A bit off topic but could someone upload a photo with the lens data (model) in the EXIF, I want to try out a program to remove the distortion but it needs to know the lens.

Stefan - if you are thinking DXO (with a free virus) it does more or less straighten the picture automatically, so either it is very clever, or it knows the characteristics of the lens. I would suspect the latter as it offers downloads for a few Pentax lenses, including this one.

Out of interest I tried the 18-55, which is the only one of the lenses mentioned above that I have and the results are very similar.

Oggy- it's not really a virus but an anti-piracy software that acts almost like one.
I got hold on a version that doesn't have PACE Anti-Piracy.

DxO works by knowing the characteristics of the lens, you need to download the data for you camera and lens. Just did that so only need a photo to try it out on, the distortion of the DA*50-135 is so good as not existing so not a good test subject.