M8 Jupiter 3 problems

[eleskin]

I just received my Jupiter 3 lens and I have noticed the lens is blurry at all apertures and focus ranges when I tried it with my M8. I stopped the lens all the way down in bright sunlight and no sharpness or detail!! This lens is Contax mount (for Kiev rangefinder) and I used the Contax to M adapter. I also have a mint Helios 103 50mm f1.8 that is tack sharp and is in focus with my Contax to M adapter. My feeling is the copy of the J3 I received has a lens element out of position somewhere. Just to see, I unscrewed both the front and rear retaining rings that hold all the glass in place. It seems the mount is cast and the lenses just drop into this thing and are locked in with the rings. The front element is one peice and the internal and rear are groups cemented together.

So my question is what should I adjust to get a reasonably sharp focus? Maybe I need to swap another set of lens elements?

 

[Mr_Flibble]

Does the dot line up with the f-stops properly? It could be the front lens-unit isn't screwed in completely.

Mr Sweeney could probably tell you more.

 

[rwchisholm]

Email moderator Brian Sweeney. He can help you

 

[Sonnar Brian]

The J-3 is a 1-3-3 formula lens, so your has all of the pieces. I have seen a rear module inserted backwards on a Zeiss Opton 50/2, but not on a J-3. Post a picture of the front and back of the lens if you can.

Does the Distance scale on the adapter agree with the rangefinder?

I have seen some lenses with a rear module that interferes with the RF cam follower of the camera. I am going to suggest that you reassemble the lens and use the distamce scale of the Adapter for focus. Use a test target with receding lines:

My fence has been used to test MANY J-3's, J-8's, and Sonnars.

 

[bizarrius]

The J-3 is a 1-3-3 formula lens, so your has all of the pieces. I have seen a rear module inserted backwards on a Zeiss Opton 50/2, but not on a J-3. Post a picture of the front and back of the lens if you can.

Does the Distance scale on the adapter agree with the rangefinder?

I have seen some lenses with a rear module that interferes with the RF cam follower of the camera. I am going to suggest that you reassemble the lens and use the distamce scale of the Adapter for focus. Use a test target with receding lines:

My fence has been used to test MANY J-3's, J-8's, and Sonnars.

i want that lens!!! please? help? what should i buy? that is the best bokeh i have ever seen in my life.

 

[Sonnar Brian]

The lens in the shim test is a J-8 that I put together from some parts lenses. Transferred the glass from a J-8 that looked like it was used as a projection lens (No Aperture) into another Fixture, and into yet a different late black focus mount. Shimmed it for the Leica, and sold it here on RFF for $65...

 

[bizarrius]

now i have to track down the buyer and make im an offer ? :/

 

[Sonnar Brian]

Off the original Topic I know... BUT: Most J-8's, even the late, Black ones- are quite good. KMZ manufactured them. The quality of the later LTM J-8's is usually quite good, and they are very easy to Shim for Leica.

 

[Sonnar Brian]

Back on Topic: on the J-3. Make sure the triplets are pressed firmly into place, even all the way around. When putting the front element in- tap on the side to help center it as you tighten the retaining ring. I put mine in an ultrasonic cleaner, and let it "vibrate" as I tighten it. Does it work? "seems to help" center the elements. Edge to edge sharpness using the fence slats is good.

 

[Sonnar Brian]

Here is a J-3 on the M9 for a "fence Test", wide-open.

 

[mcaplin]

Brian - do you have any advice as to what to look for when buying a J3? You must have seen a few of them by now. Or is it just a lottery?
Thanks

 

[Mr_Flibble]

The early once are generally considered to have better quality control as I recall.

 

[Sonnar Brian]

The chrome ones are better. I've seen a few lemons that seem to be production start-up problems. The KMZ lenses from late 1951 to 1956 have been good, but I had an early 1950 KMZ J-3 that had design problems. The 1953 through 1956 KMZ lneses (Trapezoid insignia) that I have used have been the best. I have never used a 1952 lens: suspect they are good as well. I reworked one that 1951 that had mismatched optics, transplanted the front element on front triplet into a new fixture with a new rear triplet.

The Gomz (triplet insignia)/Zomz (eyeball) that i have used from 1958 up to the 70s have been good. 1956- some issues, 1957- not as good as the later ones. So, i suspect production start up issues on some lenses. The worst for me have been the Black Valdai J-3's. I bought four optics modules and parted them all out to reuse the front elements on older lenses.