Spyderman
Well-known
1.) have you checked RF calibration of Bessa body?
2.) If you don't mind another film test - do it this way:
- get beer cans or whiskey bottles and arrange them on a table like this:
_____o
____o
___O camera here -> X
__o
_o
and focus on the big "O" bottle. This way you will know if it's just a soft image, or the plane of focus is somewhere in front or behind "O"
Try this at various distances like 1m, 2m, 3m, 5m. This might reveal the mystery...
PS: Focussing on newspaper parallel to the film plane shows nothing. Just a slight focussing error and it comes out soft.
2.) If you don't mind another film test - do it this way:
- get beer cans or whiskey bottles and arrange them on a table like this:
_____o
____o
___O camera here -> X
__o
_o
and focus on the big "O" bottle. This way you will know if it's just a soft image, or the plane of focus is somewhere in front or behind "O"
Try this at various distances like 1m, 2m, 3m, 5m. This might reveal the mystery...
PS: Focussing on newspaper parallel to the film plane shows nothing. Just a slight focussing error and it comes out soft.
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mrtoml
Mancunian
Thanks for your reply. I will try the test you mentioned tomorrow. I agree that it would help.Spyderman said:1.) have you checked RF calibration of Bessa body?
2.) If you don't mind another film test - do it this way:
- get beer cans or whiskey bottles and arrange them on a table like this:
_____o
____o
___O camera here -> X
__o
_o
and focus on the big "O" bottle. This way you will know if it's just a soft image, or the plane of focus is somewhere in front or behind "O"
Try this at various distances like 1m, 2m, 3m, 5m. This might reveal the mystery...
I don't agree with this. At f5.6 you would have to be way off with your focus to miss a newspaper pinned to a wall using a tripod and a cable release. The depth of field at 3m is 2.5m-3.75m in focus. Even at f4 the dof is 2.63-3.49m. Or are RFs really that difficult to focus
This test is also useful for checking things like lens distortion, vignetting and edge softness. I use it to test my slr lenses all the time.
Best
Mark
Spyderman
Well-known
You're right. Sorry for my previous statement.
But if you want to check focussing, it is better wide open - so that the focussing error really shows. I don't see a point in testing focussing with stopped down lens. You won't be able to tell where the plane of focus is...
mrtoml
Mancunian
Spyderman said:
Point taken. I'll try your test and let you know how it goes.
mrtoml
Mancunian
Jupiter lens test versus Nokton
Jupiter lens test versus Nokton
I got hold of a 50mm Nokton today so in my lens test I could compare my suspect J-8 with the Nokton.
The J-8 seems to be focussing quite a few inches behind where it's supposed to while the Nokton seems more or less OK within a certain margin of error - it might be focussing a little in front (a couple of inches which could be my error).
Below are 2 cropped scans both at f2 using Spyderman's beer bottle test. I focussed on the label of the bottle with the film canister cap on top of it. In both cases the distance was around 1.4m. I used a tripod and cable release and didn't move the camera in between shots.
The Nokton scan looks like the correct bottle is in focus although the bottle in front also seems in focus, while the J-8 is softer overall and seems to be focussing on the 2nd bottle behind which is much worse. The J-8 scans are still out at higher f stops whereas the Nokton just improves.
So can I conclude that the J-8 is out? Assuming that I focussed reasonably correctly that is. I can live with the Nokton as it is, but at some point I guess I should get the Bessa body checked out. Does anyone know who can do this in the UK?
Jupiter lens test versus Nokton
I got hold of a 50mm Nokton today so in my lens test I could compare my suspect J-8 with the Nokton.
The J-8 seems to be focussing quite a few inches behind where it's supposed to while the Nokton seems more or less OK within a certain margin of error - it might be focussing a little in front (a couple of inches which could be my error).
Below are 2 cropped scans both at f2 using Spyderman's beer bottle test. I focussed on the label of the bottle with the film canister cap on top of it. In both cases the distance was around 1.4m. I used a tripod and cable release and didn't move the camera in between shots.
The Nokton scan looks like the correct bottle is in focus although the bottle in front also seems in focus, while the J-8 is softer overall and seems to be focussing on the 2nd bottle behind which is much worse. The J-8 scans are still out at higher f stops whereas the Nokton just improves.
So can I conclude that the J-8 is out? Assuming that I focussed reasonably correctly that is
. I can live with the Nokton as it is, but at some point I guess I should get the Bessa body checked out. Does anyone know who can do this in the UK?Attachments
Spyderman
Well-known
The reason might be the difference in standard focal length of Leica lenses and FSU LTM lenses. Read here Dante Stella's article: http://www.dantestella.com/technical/compat.html
I add a citation from the page:
So what you are facing is the same problem everybody is facing when using FSU lens on a Leica standard LTM body.
If you're courageous you can recalibrate your Bessa (in this thread http://www.rangefinderforum.com/forums/showthread.php?t=26119 ), but then you would have to use only FSU tele lenses. There would be no problem with Leica or CV wideangles, because those have larger DOF and the error won't be visible at all.
The simplest solution is: don't use the lens close up and wide open. Just stop it down a little when you photograph from small distance and you won't see the error.
I add a citation from the page:
So what you are facing is the same problem everybody is facing when using FSU lens on a Leica standard LTM body.
If you're courageous you can recalibrate your Bessa (in this thread http://www.rangefinderforum.com/forums/showthread.php?t=26119 ), but then you would have to use only FSU tele lenses. There would be no problem with Leica or CV wideangles, because those have larger DOF and the error won't be visible at all.
The simplest solution is: don't use the lens close up and wide open. Just stop it down a little when you photograph from small distance and you won't see the error.
mrtoml
Mancunian
Spyderman said:
Thanks. I will try the lens again when the weather is brighter so I can stop it down. The weather here is so dull at the moment that it is no good. I thought this lens would be OK because I asked the seller about this issue before I bought the kit and he said he had no problems with it. But maybe he stopped it down!
I now have the Nokton 50 and a used 35 Skopar classic on the way so I will be well set up. It would be good to keep the J-8 and get used to using it as it is a nice light compact lens that I can carry easily. The Nokton is much bigger. In fact the Nokton Bessa combination seems almost as big as my K1000 + 50mm lens SLR, but not as heavy. I have seen nice shots with the J-8 so I know what it should be capable of.
Hopefully now I can start to take some pictures! Thanks to everyone for helping.
Spyderman
Well-known
I guess you have read my story. I adjusted Bessa, so now I use J-9 and J-8 and they both focus spot on. My latest acquisition CV 35/2.5 is fine thanks to the larger DOF of the focal length.
I'm sure you will be happy with the CV lenses and you'll love the tiny Skopar (after using Nokton ).
I just wanted to add that you don't always have to stop down the J-8, maybe you could just intentionally focus a bit closer than your subject to compensate for the error - but only when shooting at close distances - the infinity seems allright according to the 2-camera-facing-lenses test.
EDIT: To see what the J-8 is capable of - see Raid's test of 15 50mm lenses. That's an interesting reading... and I think apart from lower contrast the J-8 stopped down 2-stops performs exceptionally well even against Leitzs, Canons and Nikkors.
I'm sure you will be happy with the CV lenses and you'll love the tiny Skopar (after using Nokton
).I just wanted to add that you don't always have to stop down the J-8, maybe you could just intentionally focus a bit closer than your subject to compensate for the error - but only when shooting at close distances - the infinity seems allright according to the 2-camera-facing-lenses test.
EDIT: To see what the J-8 is capable of - see Raid's test of 15 50mm lenses. That's an interesting reading... and I think apart from lower contrast the J-8 stopped down 2-stops performs exceptionally well even against Leitzs, Canons and Nikkors.
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