Hard infinity stops on 200mm Schneider lenses?

I have the majority of lenses for the Kodak Retina Reflex. On the 200mm lens I

have, the split image shows infinity reached at a lens marking of 30 feet. If

I turn the lens to marked infinity, the split has gone past 'aligned'.

 

Several bodies all read the same.

 

Which is correct for these lenses - focused image or marked distance?

 

Thanks for any info,

 

Ian

if you verified the Problem on several bodies you can exclude the misalignment of the mirror/ground glass. Thus I would saythe correct is the focused image, not the marked distance.

I have a CZJ 180/2.8 for the Pentacon6 that has a similar "past infinity" thing. Only difference is that there infinity is at the infinity mark, but you can turn further than infinity.

 

This isn't a fault, it is supposed to make focussing easier.

Thank you for your input. On my lens, the infinity mark does not match with the focus on the screen (of a distant object). Only one way to be sure - I will run some test shots.

Check that the rear elements of your lens were a) not installed backwards as I once did on a Soligor 200m lens or b) not unscrewed slightly as happened on my Nikkor 85mm. Both of these lenses focused past infinity. I assume your gear is OK but just in case.

 

In 1999 or so a similar matter came up on the LUG. If a lens focuses past infinity it could be by design to compensate for thermal expansion of the lens. A warm lens will be longer. Focusing past infinity means making the focal length shorter -- going past the focal length not past infinity in object space. So a warm lens that focuses past infinity is OK. That said I have never experienced this effect.

Miles raises a good point, and this is what came to mind when I read Ian's question. In fact, I once read that current lenses (Canon EF lenses to be specific) are designed with this thermal expansion in mind, so I assumed, perhaps wrongly, that older cameras may have had the same design feature. Even if this is the case though, a lens turned to infinity should be in focus, while still allowing the photographer to turn a bit farther than the infinity mark.

My 4/300 Zeiss Sonnar focuses a bit past infinity. From what I learned about this when it concerned me, the item is designed this way so it'll reach infinity in various weather/temperature conditions.