screwmount lens focusing issues

*hwblanks* · 01-19-2008, 12:39 PM

I have what I consider a strange problem with my Kaligar 35/2.8. When I focus to infinity and take a picture at a distance, I can never get the focus sharp--no matter how I set ISO and f-stops, all my pics come out fuzzy. If I focus on something closer up, then I can get a reasonably sharp picture. Both pics I've included were taken at 400ISO. The house pic was taken at f4 and the flower pic was taken at either f2.8 or 4.

Any ideas as to what could be going on?

Thanks,
Heather

BTW, I have a 135/3.5 Super Tak that sharpens just fine.

blende8 · 01-19-2008, 12:54 PM

Just a guess:
Perhaps infinity is not really infinity on your lens and you actually set the focus "past infinity"?
This will give you a photo without a field of sharpness.
You can test this by applying small focussing steps around infinity.

ricosuave · 01-19-2008, 01:07 PM

i'd imagine it's your m42 adapter not allowing you focus at infinity.
what kind of adapter is it?

*hwblanks* · 01-19-2008, 01:17 PM

I tried that and no matter what I do, it won't focus correctly. In order for it to focus, I would have to turn it way past infinity, which is impossible.

I'm about ready to chunk this lens.

Heather

*hwblanks* · 01-19-2008, 01:18 PM

Originally Posted by ricosuave

i'd imagine it's your m42 adapter not allowing you focus at infinity.
what kind of adapter is it?

I don't know, as my 135 Super Tak focuses just fine. My adapter is a no-name adapter that I bought off of Fleabay. Do you think getting the genuine Pentax adapter would help?

Thanks!

Heather

blende8 · 01-19-2008, 01:19 PM

Originally Posted by ricosuave

i'd imagine it's your m42 adapter not allowing you focus at infinity.
what kind of adapter is it?

Of course! Now that you say it.

This is the most probable solution.
If it is one of those Chinese ones that protrude out of the bajonett, you cannot focus at infinity anymore.

MNCurt-K10D · 01-19-2008, 01:51 PM

It is almost certainly your adapter - as noted by others, the flange prevents the lens from ever 'pulling in' far enough to focus at infinity. As to why your 135mm works OK, I'd hazard a guess that it actually can focus 'beyond infinity' a little bit.

My first M42 adapter was a non-Pentax unit that did not have the collar found on eBay... it worked OK, but was not all that easy to install and remove from the camera body - you needed to use a supplied metal 'key' to get it out, and even then you had to do it just right. So I went off and bought a genuine Pentax adapter from Henry's in Canada, right at the most disadvantageous exchange rate! Now I believe you can get them directly from the Pentax Webstore (PentaxWebstore Mount Adapter B (35mm Screwmount to Bayonet))... It works great, fits perfectly, goes on and off easily - making using M42 lenses (I have a number of Takumars that I've collected to go with my 1968 Spotmatic!) a true pleasure.

Curt

*hwblanks* · 01-19-2008, 02:14 PM

Thanks for all the help! Problem solved!

I will see about getting the genuine Pentax adapter. The only problem is that the Pentax Webstore is out of them.

I've seen a couple on Fleabay, but they want $42 & change + shipping, which is significantly more than the $30.95 + shipping the Pentax Webstore charges. I requested to be notified once they get more in. I hope i won't have to wait too long.

Heather

FotoPete · 01-19-2008, 02:29 PM

Well depends on the adapter too. You can by the proper adapters from chinese ebayers. You just need to know which ones to look for.

Pentax specifically designed the KMount with the M42 Mount in mind and so both types of lenses have the same flange (lens mount to film) distance. That adapter you bought extends the length of the lens but like 1mm and enough to make your camera 'farsighted'.

A genuine Pentax and a third party M42-Kmount adapter.

3rd party adapter on the camera. Notice how the adapter sits 'flush' with the K Mount Plate?

Just remember the design when you are looking for adapters and don't buy the fat doughnut types that are like yours. You don't need the genuine pentax adapter. Alot of other places sell generic ones like B&H. You can also find the proper M42-K adapters around on ebay like some Russian stores have them, Roxsen (HK based) etc.

*hwblanks* · 01-19-2008, 02:34 PM

Pete,

I see that...your pics really help. A previous poster mentioned that the 3rd party adapters are hard to get off, so I'm better off getting the genuine Pentax adapter. What has been your experience?

Thanks!
Heather

MNCurt-K10D · 01-19-2008, 03:30 PM

Heather --

I checked my non-Pentax adapter - it is a 'Bower', available at Adorama for $15 plus shipping. I looks just like the non-Pentax adapter in Pete's post, right down to the 'key' used to install/remove it. Let me clarify my comments on the ease of use, Bower versus Pentax... not wanting to mess up my new K10D, I first tried the Bower adapter on my KM and ZX-5n bodies. The KM's mount si sort of plasticky, and the adapter did not easily turn and lock. It was better on the ZX-5n's metal lens mount. In both cases, removal was the tricky part - the 'key' has to be inserted correctly to release the spring latch which locks the adapter to the mount. Then you have to turn the adapter a few degrees (to clear the latch) and then back the 'key' out about half way before you can turn it the rest of the way to the removeal position. Once you get the hang of it, it is easy, but with the Pentax unit, you unset the latch with a fingernail or tip of a ball-point pen, turn it a little and then it easily rotates the rest of the way with fingertip pressure... all in all, it just 'feels' better, in my opinion. Worth 2X the cost (or more) and the wait? That is an individual decision!

Curt

rormeister · 01-19-2008, 03:51 PM

Heather,

Try Kenmore Camera. They sell the Pentax units for $19.95. Be sure to insist the words Pentax or Asahi Pentax are 'Engraved' not painted on the surface.

Good luck!

Mike Cash · 01-19-2008, 07:14 PM

I use a "Roxsen" adapter, purchased from eBay, and it works just fine and can be removed with my fingernail.

krypticide · 09-30-2008, 07:52 PM

Just got an SMC 135mm f/3.5, with the genuine Pentax adapter. Works great, and I was so surprised to see that other modes besides M works! Looks like my K10D just meters through whatever aperture I manually set, and adjusts shutter speed or ISO depending on what I'm manually setting. Awesome!

troyz · 09-30-2008, 08:07 PM

Originally Posted by rormeister

Heather,

Try Kenmore Camera. They sell the Pentax units for $19.95. Be sure to insist the words Pentax or Asahi Pentax are 'Engraved' not painted on the surface.

Good luck!

No need to insist -- just order. I purchased mine there (retail) and it's the real thing. I think it's more than $19.95 though.