Pentax cant focus to infinity with helios 44-2

nikki

Veteran
Sep 12, 2011
103
Dublin ,Ireland
I bought a helios 44-2 lens at a car boot sale for €20 and got an adapter on ebay for my pentax k20d.Its a beautiful lans , very sharp but unless im doing close ups I cannot focus to infinity.Is it the adapter and if so where would I get a better one ?
Has anyone ever tried one of these? Any help would be greatly appreciated:)
 

chromatin64

Veteran
Apr 26, 2011
104
A Leekist in York, UK
Just a thought - is it focusing past infinity? In other words, is infinity focus reached before the lens reaches its focusing limit?

I think there are often problems with adapted lenses because of minor differences in flange distance/lens register.
 

arachide

Regular
Feb 15, 2012
18
Nikki, I originally bought a cheap M42 to K-mount adapter on eBay. I wound up buying a Pentax one instead because when I threaded an M42 lens onto my k-x, the lens would wind up being upside down, which made focusing a pain. I don't remember there being an issue with focusing to infinity but I can try it out on my ME Super (a friend is borrowing my k-x at the moment).
 

grebeman

Old Codgers Group
Nikki,
Is the adapter in two parts? Almost certainly the lens needs to be moved away from the sensor by a very small amount, it's probably only three or four thousanths of an inch, about three or four thicknesses of aluminium cooking foil. I'm more familiar with adapters for screw mounted lenses where the lens screws into an inner ring which is held by very small screws in an outer ring that has the camera bayonet on it. It is possible to disassemble this type and shim the inner ring with the cooking foil cut like a large washer to move it the required distance forwards. It would require the use of very small watchmakers screwdrivers. I have used this very successfully with Voigtlander LTM lens adapters.

Barrie
 

nikki

Veteran
Sep 12, 2011
103
Dublin ,Ireland
Thanks everyone for your replies,firstly it is focusing past infinity - ithink (its focusing up to infinity but i need to focus somemore)-thats why i think it could be an adapter problem, it doesnt screw in upside down and there is a gap between the lens and sensor. I was on the internet and saw pics of helios with screws so you can put in foil but my lans does not have any screws !!!
I will be able to use this lens for close ups and macro but it was so sharp I thought I would use it as a 50mm but wont work for that !:frown:
 

arachide

Regular
Feb 15, 2012
18
Nikki, there should be a metal spring that locks the adapter into place. Some of the adapters come with a device that will depress the spring, enabling you to remove the twist the adapter off. Otherwise you can use the tip of a pen to press the spring in. In this photo it is right next to the orange dot on the lens mount.
 
Jan 31, 2011
164
Newcastle, Australia
Sue
Nikki I have the same issue with my K-5 + adapter + MC-Rokkor 50mm. I love the lens, I can use it for almost anything, but infinity focus is a dud. I can focus up to about 30 ft but anything past that is just useless. I've just been using it for pseudo-macro and closeups and will probably sell it on once I decide to get a proper 50mm lens. I havent much cash so I'm going to get a HorusBennu. Korean, its the only one they make, and it has really interesting bokeh. Only $56AU.

Then again I might try a different adapter, as well.
 

Luckypenguin

Hall of Famer
Dec 24, 2010
123
Brisbane, Australia
Nic
A lens/adapter combination that focuses past infinity is fine, since it is still capable of focusing at infinity if you wind the focus ring back a touch. If it never reaches infinity, THEN you have a problem. In that case your adapter is acting as a pseudo extension tube.
 

grebeman

Old Codgers Group
Nikki,

This is a quote from the Wikipedi "Pentax K mount" page:-

"M42

Pentax supplies adapters to fit M42 screw-mount lenses, as do several third-party manufacturers. The M42 screw-mount system was used by Pentax prior to the introduction of the K mount. Pentax designed the K-mount wide enough to allow an adapter to fit between the M42 thread and the K bayonet. They also kept the same flange focal distance (also called registration distance or register) as the M42 screw mount, so that M42 lenses focus correctly using the correct adapter (such as Pentax original[2] or Bower). There are however other third-party adapters that add to the flange focal distance so that one loses the ability to focus to infinity. The loss of infinity-focus may not be significant in macro or close-up photography.

There is great debate in the Pentax community over the applicability and safety of adapters other than those supplied by Pentax. Many users of third-party infinity-focus adapters, such as Bowers, report difficulty in removing the adapters from camera bodies. Such adapters may require modification before they may be safely used. Official Pentax adapters, and flanged non-infinity-focus adapters, do not provoke such problems."

Barrie
 

nikki

Veteran
Sep 12, 2011
103
Dublin ,Ireland
Thanks for all the replies , I might see if I can get the actual pentax to m42 adapter, although they are hard to come by.It makes more sense to use the adapter made by pentax and who knows I might get some more m42 lenses.I have used cheaper adapters for micro four thirds and have never had a problem but maybe the DSLR is different.
Thanks again
Nikki
 

nikki

Veteran
Sep 12, 2011
103
Dublin ,Ireland
Thanks I have ordered a pentax one from the states - I will see if its works better .I have not put the cheap one back on since I had so much trouble getting it off ( I had to use a pliers !):)
 

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