focus test : three jupiters 8 on leica m4

[nzeeman]

here is small focus test i made with my three jupiters 8
focus is on three X. distance is 1m. these are crops from photo - i cut off part which doesnt contain any info for easier watching. book is "confederacy of dunces" from john kennedy toole - i recommend it to everyone...

jupiter from 50s

jupiter from 60s

jupiter from 80s

i think that all three held up pretty well 50s was perfect, and results are pretty similar to my earlier check. target is always inside dof so i think any shift is there due to my focusing error.
sorry for scans but they are best i can find in belgrade. 🙁

 

[nzeeman]

here is how it looks in full size without crop
jupiter 8 from 50s

jupiter 8 from 60s

jupiter 8 from 80s

 

[andrealed]

Wide Open?

 

[myoptic3]

Useful test. The first lens would seem to be the keeper. Thanks for reminding me about that book. I read it a long time ago and would like to reread it again.

 

[nzeeman]

oh yes i forgot - all photos are wide open.

yes first one is keeper in fact all three are because in real life you cant see those slight differences. as you see from text in book that shift is ony few lines up or down - so its just few cm.
i said i made another test some time ago and i noticed another thing also - those earlier jupiter 8 have more vignetting than new one. also corners seem sharper at new one. so i think that they made some slight changes in design during time. i think reid asked in some thread if changes were made.

 

[Spyderman]

When you look at the original uncropped pictures, you can see that in the first two the XXX is about in the middle of DOF, but in the last one, the XXX is in the front part of the DOF - means that the actual plane of focus is slightly behind the XXX. But since all are within DOF, I'd say just ignore it and use them.

 

[nzeeman]

it is interesting that last one usually focus best, but i must have made slight mistake in test.

 

[brachal]

i said i made another test some time ago and i noticed another thing also - those earlier jupiter 8 have more vignetting than new one. also corners seem sharper at new one. so i think that they made some slight changes in design during time. i think reid asked in some thread if changes were made.

I remember a Brian Sweeny post where he tried matching the front element of a late J-8 with an old J-8 that had scratches on its front element. It wouldn't fit, which seems to be pretty clear evidence that the lens formula was modified at least once over the years.

Unrelated, but I live only a few blocks away from Toole's last home here in New Orleans. It has a modest plaque on the fence. Confederacy is not just a great New Orleans book; it is a great book.

 

[nzeeman]

Unrelated, but I live only a few blocks away from Toole's last home here in New Orleans. It has a modest plaque on the fence. Confederacy is not just a great New Orleans book; it is a great book.

it would be nice if you take some photo of that plaque. i would be very interested to see it... his early novel neon bible is also interesting - too bad his life was so short...

 

[brachal]

it would be nice if you take some photo of that plaque. i would be very interested to see it... his early novel neon bible is also interesting - too bad his life was so short...

Nzeeman,

Happy to do so; it's just a short walk away. I've been very busy lately (still haven't been able to setup that I-61 vs 2.8 Elmar test I promised), but I ought to be able to get you some pictures in a day or two.

 

[nzeeman]

thanks a lot! and no need to hurry.

 

[raid]

I am waiting for Brian to come back and inform me what has happened with the Sonnar pre-war 5cm/2 and the J-8 "merger project". I may get back a lens that has a J-8 rear optical element and a Sonnar front element. The J8 is a great lens after all, so a Frankenstein version of it cannot be bad.

 

[nzeeman]

i wonder if they changed design of lens - maybe they put one element less like in that jupiter 17 which they made for cutting down expenses. maybe they decided to make it cheaper but not to change name...

 

[januaryman]

I am waiting for Brian to come back and inform me what has happened with the Sonnar pre-war 5cm/2 and the J-8 "merger project". I may get back a lens that has a J-8 rear optical element and a Sonnar front element. The J8 is a great lens after all, so a Frankenstein version of it cannot be bad.

Let's stop a moment and remember the aftermath of Frankenstein's experiment and the havoc the resulting monster created! Be careful!!! 😉

 

[brachal]

Nzeeman,

Sorry this took so long. Here is a picture of the house and a picture of the plaque. Proudly taken with a digital point 'n shoot. Nice house in the University neighborhood.

 

[sanmich]

focusing accurately an RF at close distance can be tricky.
There are variations between different instances of focusing the same lens.
before drawing any conclusion about a specific lens, I would repeat the experiment several times and average the results.

 

[brachal]

focusing accurately an RF at close distance can be tricky.
There are variations between different instances of the same lens.
before drawing any conclusion about a specific lens, I would repeat the experiment several times and average the results.

Good advice. I got out on the front porch today to do a comparison of my I-61LD and 2.8 Elmar ... it's harder than I thought. Hopefully things will turn out. I'd also say that camera choice is important. I found my IIIf to be much easier focus with confidence at 1.2 meters than my Fed-3. That 1.5x focusing window is pretty neat.

 

[sanmich]

Also, be aware that although perfectly in spec, different camera can focus a bit differently. Not enough to through a good lens out of focus, but enough to add a substantial errror to your measurements.
So, I would add, run a few tests for each lens on at least two or three cameras.