Question about Pentax-DA 50-200mm F4-F5.6 ED

Hi everybody,

I'm new to the world of SLRs and am not too familiar with lens testing methodologies (other than to put it on and take pictures). I just wanted to confirm a few characteristics of the lens I've noticed to check that I don't have a faulty copy (I'm probably just being paranoid, but I don't know any better yet .

Three things I've noticed:

1) Vignetting at wide open apertures which goes away after closing it down 1 or 2 stops.

2) Occasional difficulties with obtaining focus lock on distant objects compared to my other lens, the Sigma 17-70, at similar focal lengths (e.g. a leafy tree in the distance).

3) Occasionally (which is the strange part) the focus ring doesn't feel smooth while turning (a light but distinct roughness).

If anybody can confirm these characteristics or even add a few more that you think I should know about, I would greatly appreciate it.

Also, this is my first post and I'd just like to say that I've enjoyed reading and viewing all your posts and pictures. They helped greatly in my decision to get the K10D.

chefzilla said:

1) Vignetting at wide open apertures which goes away after closing
it down 1 or 2 stops.

Click to expand...

Can't say I have noticed this but haven't really looked

chefzilla said:

2) Occasional difficulties with obtaining focus lock on distant
objects compared to my other lens, the Sigma 17-70, at similar
focal lengths (e.g. a leafy tree in the distance).

Click to expand...

Have both but again I haven't noticed

chefzilla said:

3) Occasionally (which is the strange part) the focus ring doesn't
feel smooth while turning (a light but distinct roughness).

Click to expand...

Mine seems not bad just a touch of grating - not concerned though
Check here to see what photozone say re vignetting
http://www.photozone.de/8Reviews/index.html
--
Regards Dean - Capturing Creation

chefzilla said:

1) Vignetting at wide open apertures which goes away after closing
it down 1 or 2 stops.

Click to expand...

Yes i found it quite visible... i like using the lens at F8.0 for sharpness, low or no CA and low vignetting

chefzilla said:

2) Occasional difficulties with obtaining focus lock on distant
objects compared to my other lens, the Sigma 17-70, at similar
focal lengths (e.g. a leafy tree in the distance).

Click to expand...

I have notice this but its so rare that i am not worrying about it... it could just be my technique or somthing i hadn't thought of

chefzilla said:

3) Occasionally (which is the strange part) the focus ring doesn't
feel smooth while turning (a light but distinct roughness).

Click to expand...

My focus ring is more scratchy then my zoom ring but both are a bit scratchy... i'm not worries... pay $200ca for a lens and expect it to work like a $200ca lens... however it perfoms most excellently considering its price.

chefzilla said:

If anybody can confirm these characteristics or even add a few more
that you think I should know about, I would greatly appreciate it.

Click to expand...

confirmed?

chefzilla said:

Also, this is my first post and I'd just like to say that I've
enjoyed reading and viewing all your posts and pictures. They
helped greatly in my decision to get the K10D.

Click to expand...

Welcome to the forum!
--
Mike from Canada

'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote '



http://www.airliners.net/search/photo.search?sort_order=views%20DESC&first_this_page=0&page_limit=61&&emailsearch=mighty_mike88%40hotmail.com&thumbnails=

Thank you both for your replies. I'm much more confident that my lens is fine now. I agree with you Mike (and of course the many others that have made the claim), considering the price, this lens performs very well.

I'd like to post some pictures to support this, but I need to figure out a good way of hosting them first. Not sure how long my internet provider would be happy with me if I used there site...

I must have the only good copy of the DA 50-200, samples below...

chefzilla said:

Hi everybody,

I'm new to the world of SLRs and am not too familiar with lens
testing methodologies (other than to put it on and take pictures).
I just wanted to confirm a few characteristics of the lens I've
noticed to check that I don't have a faulty copy (I'm probably just
being paranoid, but I don't know any better yet .

Three things I've noticed:
1) Vignetting at wide open apertures which goes away after closing
it down 1 or 2 stops.

Click to expand...

If so, I have not noticed

chefzilla said:

2) Occasional difficulties with obtaining focus lock on distant
objects compared to my other lens, the Sigma 17-70, at similar
focal lengths (e.g. a leafy tree in the distance).

Click to expand...

No problem there either

chefzilla said:

3) Occasionally (which is the strange part) the focus ring doesn't
feel smooth while turning (a light but distinct roughness).

Click to expand...

The focus ring has minimum tension to it but not rough, even when I over-ride the AF. The focus and zoom feel much better then my Sigma 24-135/2.8

chefzilla said:

If anybody can confirm these characteristics or even add a few more
that you think I should know about, I would greatly appreciate it.

Also, this is my first post and I'd just like to say that I've

Click to expand...

Welcome aboard

chefzilla said:

enjoyed reading and viewing all your posts and pictures. They
helped greatly in my decision to get the K10D.

Click to expand...

This pic at 200mm wide open, cropped and PP for web



Actual pic with no PP, no cropping, from DS and only resized for web



I just took the next pics a few minutes ago with the K10 and on-board flash in a dimmly lit room and subject was 12' from me. No PP, as shot, P mode, jpg. AF was quick and dead on



100% crop, not resized and no PP



Any questions

--



My Pentax *ist DS galleries http://www.pbase.com/wjwncpro/wjwncpro (GMT-5)

Thanks for the reply and the illustrative pictures. I'd just like to note that I've only really noticed the vignetting on lighter colored backgrounds. Otherwise it is difficult to notice as you said.

As a follow up to my original post, here are some test shots I took with the lens and uploaded onto Picasa:
http://picasaweb.google.com/mkwaner/LensTestSmcPentaxDA50200mmF4F56ED

Teddy bear shots were done at 4 different focal lengths:
50 mm @ F/4, F/5.6, F/8, F/11
105 mm @ F4.5, F/5.6, F/8, F/11
150 mm @ F/5.6, F/8, F/11
200 mm @ F/5.6, F/8, F/11

The shot with the tree in it is an example of what I had difficulty obtaining focus lock on.

Hope these are helpful.