Lens comparison. J8 I10

[fidget]

I am puzzled by the apparent difference in two photos I took whilst trying lenses. The Fed2 was set up on a tripod and frames taken using my collapsable lenses, Ind 10, Ind 22, and Ind 50 at f3.5. I included a shot with a J8 at 3.5 just for interest. I did this on the same roll of film, in the same camera. They were taken in the shade of the house of a fairly naff subject. I was simply looking for major differences. I found some, but not all what I expected. The I50 has a fault as the focus is way off, The I22 is very soft indeed, maybe also a focus problem. The I10 in the photo below gave a good account of itself, when compared to the J8 below, the difference in contrast is very significant.
Both lenses are optically very clean. Straight scan were made in a single group. The density of the negs is very similar. I can expect a difference in exposure, the ambient light was changing a little, but the contrast difference is surprising.
Am I interpreting this correctly?
Dave..
I should add...the J8 shot is the one with the post-it note.

 

[Xmas]

Unfair to have one wide open the other 1.6 stops down. One would expect the J8 (sonnar) to slay the Tessar type, i.e. the F2 should have more contrast? Both at 5.6 would have been fair.

Note Ive had to reassemble J8s, rattle (2nd group lose), fungus, ..., etc.

Noel

 

[fidget]

Thanks, I've not been looking at the sharpness of the pictures, which wouldn't show much on a small scan, just the contrast. would the contrast change on the J8 over the next couple of stops? As for dis-assembling lenses, looks like I've got an Industar 22 and an Industar 50 to attend to. (Maybe it's about time I got a focusing screen and loope on the job).
Dave...

 

[Xmas]

I may be confused I thought the Jupiter would have the greater contrast, If it does not then you may have a Jupiter problem. Wide open lots of the Ru lens will have lots of flare as some were not blackened properly.

The J8s ive seen have been good the J8M bad, e.g. there is a beveled ring of glass at the rear of the 2nd group just forward of the iris, which is not blackened on any of the J8M and is on the J8. This is a marginal problem as the effect is reduces other than wide open by the iris blades.

Noel

 

[Xmas]

Ok another failure.

The contrast on the J8 should only be poor between f2 and F2.6, after thet it should be constant and resonable.

Ther may be a similar problem with the 3.5 between wide open and f4, have a look through the rear with a light source off axis.

Noel

 

[fidget]

Thanks Noel, I think you're right about J8 flare and other problems. Here is a frame of the J8 at f2 from the same series of test pics. Some very strange flare like anomalies, no idea what could cause this as no direct sunlight was falling on the lens when taken. The pic at f3.5 looked ok (if a different contrast from the other lens). Internal bright areas, you say?

 

[Xmas]

Open wide and look through it from rear in dark room with one light source.

There should only be two rings

- one from the rear group some sparkle like a diamond necklace
- one from the centre group more like a search light.

The worst effect when the light source is just outside the normal field of view of the lens. Lots of lens are worse than a j8 or J8m... I quarantined all my J8M until I have time to strip them.

Noel

 

[fidget]

Before I did this little test on a few LTM lenses, I had done a similar test at f2 on 5 Kiev mount lenses, 4x J8, 1x Helios 103. I was looking for close focus errors. I'm not sure if I saw any focus errors which weren't of my making, but all gave a nice exposure with no anomalies of this type. Kiev mount J8s known to be any better for this?

 

[fidget]

Had a look in dark room at light. Didn't see anything that looked odd, just the "searchlight" of the lamp I was looking at. Perhaps a smaller light would be better.

 

[raid]

I just had my Summarit cleaned from inside after getting at f 5.6 and in the shade some very strange looking flare and softness. The repairman told me that there was a milky coating that he then removed. Maybe this is the same problem with your J8.

Raid