[tr13]

Here is some data on this old gem:

May be you know about this thread Manual Focus Gem Discovered: Pentax SLR Talk Forum: Digital Photography Review

But this thread have few misleading data.

1) Buy only original 28-200mm as in picture below. Tokina is absolutely different lens with different optical formula (look at crop from Vivitar box, Tokina have fewer elements).
2) Lens could come either in PK/A or PK A/R mounts. In former you must remoive Ricoh pin. On both you must use file to remove excessive lever protection.
3) Closed down, lens is PP friend. Good wide open, but as on many old lenses have some abberations. Contrast is lower due to many glass surfaces and not top-notch coatings. Abberations are almost absent if close down (see below).
4) Corners are controlled quite well. Only my old 80-200mm zoom is able to archive such corner sharpness at 200mm. Below is brick wall at 200mm, right-top corner, 100% crop, only +1 sharpness in camera.

Attached Images

       

[pbo]

I don't really have anything to say about the vivitar lens you've got there, but I've got something about aperture flange - it's held in place with 3 tiny screws. Just take them out, and flange will go out - it's not like your aperture lever is gonna be in danger or something... Unless, in some specific lens, those three screws held something related to aperture mechanism - then it's better to leave it in there.

[tr13]

I don't really have anything to say about the vivitar lens you've got there, but I've got something about aperture flange - it's held in place with 3 tiny screws. Just take them out, and flange will go out - it's not like your aperture lever is gonna be in danger or something... Unless, in some specific lens, those three screws held something related to aperture mechanism - then it's better to leave it in there.

I don't agree here. First, it is held by two screws only :-) And if you remove it, circular thing that help to center rear elements also must be removed.
It took me 4 minutes to make it just right using file.

[pbo]

I don't agree here. First, it is held by two screws only :-) And if you remove it, circular thing that help to center rear elements also must be removed.
It took me 4 minutes to make it just right using file.

Whatev, I don't have a file to begin with I did try nudging the rear elements - and they don't move anyways...

[tr13]

One thing I forgot to add.
As lens is one touch type, its focusing is worse then good old two touch zooms.
Not so well damped and usable range is quite short (in macro it is better).
My lens also focuses slightly pass infinity.

[dragonfly]

I picked up a nice copy of this lens this weekend. I removed the mount to release the r-pin, but when I put the mount back on the A pin doesn't stick out. Also, the aperture release button doesn't lock the aperture ring anymore. I should probably open it up again and look at the inside. It looked like there was a little bump on the inside of the aperture ring that is supposed to engage the A pin. Do I have to do anything special when I put it back together?

I haven't managed to find a decent tool for modifying the flange.

[Lloydy]

I love mine, it gets a lot of use as a walkaround lens even though it weighs a ton.

I paid £5 for it, and chopped the Ricoh shroud down with a junior hacksaw and file and ditched the pin. Once the coupling was off ( 4 screws ) it was easy.